wma: Convert to the new bitstream reader

libavcodec/wma.c

@@ -22,6 +22,7 @@
 #include "libavutil/attributes.h"
 
 #include "avcodec.h"
+#include "bitstream.h"
 #include "internal.h"
 #include "sinewin.h"
 #include "wma.h"
@@ -382,30 +383,30 @@ int ff_wma_end(AVCodecContext *avctx)
 
 /**
  * Decode an uncompressed coefficient.
- * @param gb GetBitContext
+ * @param bc BitstreamContext
  * @return the decoded coefficient
  */
-unsigned int ff_wma_get_large_val(GetBitContext *gb)
+unsigned int ff_wma_get_large_val(BitstreamContext *bc)
 {
     /** consumes up to 34 bits */
     int n_bits = 8;
     /** decode length */
-    if (get_bits1(gb)) {
+    if (bitstream_read_bit(bc)) {
         n_bits += 8;
-        if (get_bits1(gb)) {
+        if (bitstream_read_bit(bc)) {
             n_bits += 8;
-            if (get_bits1(gb))
+            if (bitstream_read_bit(bc))
                 n_bits += 7;
         }
     }
-    return get_bits_long(gb, n_bits);
+    return bitstream_read(bc, n_bits);
 }
 
 /**
  * Decode run level compressed coefficients.
  * @param avctx codec context
- * @param gb bitstream reader context
- * @param vlc vlc table for get_vlc2
+ * @param bc bitstream reader context
+ * @param vlc VLC table for bitstream_read_vlc
  * @param level_table level codes
  * @param run_table run codes
  * @param version 0 for wma1,2 1 for wmapro
@@ -417,7 +418,7 @@ unsigned int ff_wma_get_large_val(GetBitContext *gb)
  * @param coef_nb_bits number of bits for escaped level codes
  * @return 0 on success, -1 otherwise
  */
-int ff_wma_run_level_decode(AVCodecContext *avctx, GetBitContext *gb,
+int ff_wma_run_level_decode(AVCodecContext *avctx, BitstreamContext *bc,
                             VLC *vlc, const float *level_table,
                             const uint16_t *run_table, int version,
                             WMACoef *ptr, int offset, int num_coefs,
@@ -429,11 +430,11 @@ int ff_wma_run_level_decode(AVCodecContext *avctx, GetBitContext *gb,
     uint32_t *iptr = (uint32_t *) ptr;
     const unsigned int coef_mask = block_len - 1;
     for (; offset < num_coefs; offset++) {
-        code = get_vlc2(gb, vlc->table, VLCBITS, VLCMAX);
+        code = bitstream_read_vlc(bc, vlc->table, VLCBITS, VLCMAX);
         if (code > 1) {
             /** normal code */
             offset                  += run_table[code];
-            sign                     = get_bits1(gb) - 1;
+            sign                     = bitstream_read_bit(bc) - 1;
             iptr[offset & coef_mask] = ilvl[code] ^ sign << 31;
         } else if (code == 1) {
             /** EOB */
@@ -441,26 +442,26 @@ int ff_wma_run_level_decode(AVCodecContext *avctx, GetBitContext *gb,
         } else {
             /** escape */
             if (!version) {
-                level = get_bits(gb, coef_nb_bits);
+                level = bitstream_read(bc, coef_nb_bits);
                 /** NOTE: this is rather suboptimal. reading
                  *  block_len_bits would be better */
-                offset += get_bits(gb, frame_len_bits);
+                offset += bitstream_read(bc, frame_len_bits);
             } else {
-                level = ff_wma_get_large_val(gb);
+                level = ff_wma_get_large_val(bc);
                 /** escape decode */
-                if (get_bits1(gb)) {
-                    if (get_bits1(gb)) {
-                        if (get_bits1(gb)) {
+                if (bitstream_read_bit(bc)) {
+                    if (bitstream_read_bit(bc)) {
+                        if (bitstream_read_bit(bc)) {
                             av_log(avctx, AV_LOG_ERROR,
                                    "broken escape sequence\n");
                             return -1;
                         } else
-                            offset += get_bits(gb, frame_len_bits) + 4;
+                            offset += bitstream_read(bc, frame_len_bits) + 4;
                     } else
-                        offset += get_bits(gb, 2) + 1;
+                        offset += bitstream_read(bc, 2) + 1;
                 }
             }
-            sign                    = get_bits1(gb) - 1;
+            sign                    = bitstream_read_bit(bc) - 1;
             ptr[offset & coef_mask] = (level ^ sign) - sign;
         }
     }

libavcodec/wma.h

@@ -25,8 +25,8 @@
 #include "libavutil/float_dsp.h"
 
 #include "avcodec.h"
+#include "bitstream.h"
 #include "fft.h"
-#include "get_bits.h"
 #include "put_bits.h"
 
 /* size of blocks */
@@ -66,7 +66,7 @@ typedef struct CoefVLCTable {
 
 typedef struct WMACodecContext {
     AVCodecContext *avctx;
-    GetBitContext gb;
+    BitstreamContext bc;
     PutBitContext pb;
     int version;                            ///< 1 = 0x160 (WMAV1), 2 = 0x161 (WMAV2)
     int use_bit_reservoir;
@@ -147,8 +147,8 @@ extern const uint8_t  ff_aac_scalefactor_bits[121];
 int ff_wma_init(AVCodecContext *avctx, int flags2);
 int ff_wma_total_gain_to_bits(int total_gain);
 int ff_wma_end(AVCodecContext *avctx);
-unsigned int ff_wma_get_large_val(GetBitContext *gb);
-int ff_wma_run_level_decode(AVCodecContext *avctx, GetBitContext *gb,
+unsigned int ff_wma_get_large_val(BitstreamContext *bc);
+int ff_wma_run_level_decode(AVCodecContext *avctx, BitstreamContext *bc,
                             VLC *vlc, const float *level_table,
                             const uint16_t *run_table, int version,
                             WMACoef *ptr, int offset, int num_coefs,

libavcodec/wmadec.c

@@ -36,6 +36,7 @@
 #include "libavutil/attributes.h"
 
 #include "avcodec.h"
+#include "bitstream.h"
 #include "internal.h"
 #include "wma.h"
 
@@ -209,9 +210,9 @@ static void decode_exp_lsp(WMACodecContext *s, int ch)
 
     for (i = 0; i < NB_LSP_COEFS; i++) {
         if (i == 0 || i >= 8)
-            val = get_bits(&s->gb, 3);
+            val = bitstream_read(&s->bc, 3);
         else
-            val = get_bits(&s->gb, 4);
+            val = bitstream_read(&s->bc, 4);
         lsp_coefs[i] = ff_wma_lsp_codebook[i][val];
     }
 
@@ -318,7 +319,7 @@ static int decode_exp_vlc(WMACodecContext *s, int ch)
     q_end     = q + s->block_len;
     max_scale = 0;
     if (s->version == 1) {
-        last_exp  = get_bits(&s->gb, 5) + 10;
+        last_exp  = bitstream_read(&s->bc, 5) + 10;
         v         = ptab[last_exp];
         iv        = iptab[last_exp];
         max_scale = v;
@@ -333,7 +334,7 @@ static int decode_exp_vlc(WMACodecContext *s, int ch)
         last_exp = 36;
 
     while (q < q_end) {
-        code = get_vlc2(&s->gb, s->exp_vlc.table, EXPVLCBITS, EXPMAX);
+        code = bitstream_read_vlc(&s->bc, s->exp_vlc.table, EXPVLCBITS, EXPMAX);
         if (code < 0) {
             av_log(s->avctx, AV_LOG_ERROR, "Exponent vlc invalid\n");
             return -1;
@@ -436,7 +437,7 @@ static int wma_decode_block(WMACodecContext *s)
 
         if (s->reset_block_lengths) {
             s->reset_block_lengths = 0;
-            v                      = get_bits(&s->gb, n);
+            v                      = bitstream_read(&s->bc, n);
             if (v >= s->nb_block_sizes) {
                 av_log(s->avctx, AV_LOG_ERROR,
                        "prev_block_len_bits %d out of range\n",
@@ -444,7 +445,7 @@ static int wma_decode_block(WMACodecContext *s)
                 return -1;
             }
             s->prev_block_len_bits = s->frame_len_bits - v;
-            v                      = get_bits(&s->gb, n);
+            v                      = bitstream_read(&s->bc, n);
             if (v >= s->nb_block_sizes) {
                 av_log(s->avctx, AV_LOG_ERROR,
                        "block_len_bits %d out of range\n",
@@ -457,7 +458,7 @@ static int wma_decode_block(WMACodecContext *s)
             s->prev_block_len_bits = s->block_len_bits;
             s->block_len_bits      = s->next_block_len_bits;
         }
-        v = get_bits(&s->gb, n);
+        v = bitstream_read(&s->bc, n);
         if (v >= s->nb_block_sizes) {
             av_log(s->avctx, AV_LOG_ERROR,
                    "next_block_len_bits %d out of range\n",
@@ -480,10 +481,10 @@ static int wma_decode_block(WMACodecContext *s)
     }
 
     if (s->avctx->channels == 2)
-        s->ms_stereo = get_bits1(&s->gb);
+        s->ms_stereo = bitstream_read_bit(&s->bc);
     v = 0;
     for (ch = 0; ch < s->avctx->channels; ch++) {
-        a                    = get_bits1(&s->gb);
+        a                    = bitstream_read_bit(&s->bc);
         s->channel_coded[ch] = a;
         v                   |= a;
     }
@@ -499,7 +500,7 @@ static int wma_decode_block(WMACodecContext *s)
      * coef escape coding */
     total_gain = 1;
     for (;;) {
-        a           = get_bits(&s->gb, 7);
+        a           = bitstream_read(&s->bc, 7);
         total_gain += a;
         if (a != 127)
             break;
@@ -519,7 +520,7 @@ static int wma_decode_block(WMACodecContext *s)
                 int i, n, a;
                 n = s->exponent_high_sizes[bsize];
                 for (i = 0; i < n; i++) {
-                    a                         = get_bits1(&s->gb);
+                    a                         = bitstream_read_bit(&s->bc);
                     s->high_band_coded[ch][i] = a;
                     /* if noise coding, the coefficients are not transmitted */
                     if (a)
@@ -536,9 +537,10 @@ static int wma_decode_block(WMACodecContext *s)
                 for (i = 0; i < n; i++) {
                     if (s->high_band_coded[ch][i]) {
                         if (val == (int) 0x80000000) {
-                            val = get_bits(&s->gb, 7) - 19;
+                            val = bitstream_read(&s->bc, 7) - 19;
                         } else {
-                            code = get_vlc2(&s->gb, s->hgain_vlc.table,
+                            code = bitstream_read_vlc(&s->bc,
+                                                      s->hgain_vlc.table,
                                                       HGAINVLCBITS, HGAINMAX);
                             if (code < 0) {
                                 av_log(s->avctx, AV_LOG_ERROR,
@@ -555,7 +557,7 @@ static int wma_decode_block(WMACodecContext *s)
     }
 
     /* exponents can be reused in short blocks. */
-    if ((s->block_len_bits == s->frame_len_bits) || get_bits1(&s->gb)) {
+    if ((s->block_len_bits == s->frame_len_bits) || bitstream_read_bit(&s->bc)) {
         for (ch = 0; ch < s->avctx->channels; ch++) {
             if (s->channel_coded[ch]) {
                 if (s->use_exp_vlc) {
@@ -579,13 +581,13 @@ static int wma_decode_block(WMACodecContext *s)
              * there is potentially less energy there */
             tindex = (ch == 1 && s->ms_stereo);
             memset(ptr, 0, s->block_len * sizeof(WMACoef));
-            ff_wma_run_level_decode(s->avctx, &s->gb, &s->coef_vlc[tindex],
+            ff_wma_run_level_decode(s->avctx, &s->bc, &s->coef_vlc[tindex],
                                     s->level_table[tindex], s->run_table[tindex],
                                     0, ptr, 0, nb_coefs[ch],
                                     s->block_len, s->frame_len_bits, coef_nb_bits);
         }
         if (s->version == 1 && s->avctx->channels >= 2)
-            align_get_bits(&s->gb);
+            bitstream_align(&s->bc);
     }
 
     /* normalize */
@@ -810,12 +812,12 @@ static int wma_decode_superframe(AVCodecContext *avctx, void *data,
     }
     buf_size = avctx->block_align;
 
-    init_get_bits(&s->gb, buf, buf_size * 8);
+    bitstream_init8(&s->bc, buf, buf_size);
 
     if (s->use_bit_reservoir) {
         /* read super frame header */
-        skip_bits(&s->gb, 4); /* super frame index */
-        nb_frames = get_bits(&s->gb, 4) - (s->last_superframe_len <= 0);
+        bitstream_skip(&s->bc, 4); /* super frame index */
+        nb_frames = bitstream_read(&s->bc, 4) - (s->last_superframe_len <= 0);
     } else
         nb_frames = 1;
 
@@ -829,11 +831,11 @@ static int wma_decode_superframe(AVCodecContext *avctx, void *data,
     samples_offset = 0;
 
     if (s->use_bit_reservoir) {
-        bit_offset = get_bits(&s->gb, s->byte_offset_bits + 3);
-        if (bit_offset > get_bits_left(&s->gb)) {
+        bit_offset = bitstream_read(&s->bc, s->byte_offset_bits + 3);
+        if (bit_offset > bitstream_bits_left(&s->bc)) {
             av_log(avctx, AV_LOG_ERROR,
                    "Invalid last frame bit offset %d > buf size %d (%d)\n",
-                   bit_offset, get_bits_left(&s->gb), buf_size);
+                   bit_offset, bitstream_bits_left(&s->bc), buf_size);
             goto fail;
         }
 
@@ -845,19 +847,19 @@ static int wma_decode_superframe(AVCodecContext *avctx, void *data,
             q   = s->last_superframe + s->last_superframe_len;
             len = bit_offset;
             while (len > 7) {
-                *q++ = (get_bits) (&s->gb, 8);
+                *q++ = bitstream_read(&s->bc, 8);
                 len -= 8;
             }
             if (len > 0)
-                *q++ = (get_bits) (&s->gb, len) << (8 - len);
+                *q++ = bitstream_read(&s->bc, len) << (8 - len);
             memset(q, 0, AV_INPUT_BUFFER_PADDING_SIZE);
 
             /* XXX: bit_offset bits into last frame */
-            init_get_bits(&s->gb, s->last_superframe,
+            bitstream_init(&s->bc, s->last_superframe,
                            s->last_superframe_len * 8 + bit_offset);
             /* skip unused bits */
             if (s->last_bitoffset > 0)
-                skip_bits(&s->gb, s->last_bitoffset);
+                bitstream_skip(&s->bc, s->last_bitoffset);
             /* this frame is stored in the last superframe and in the
              * current one */
             if (wma_decode_frame(s, samples, samples_offset) < 0)
@@ -870,10 +872,10 @@ static int wma_decode_superframe(AVCodecContext *avctx, void *data,
         pos = bit_offset + 4 + 4 + s->byte_offset_bits + 3;
         if (pos >= MAX_CODED_SUPERFRAME_SIZE * 8 || pos > buf_size * 8)
             return AVERROR_INVALIDDATA;
-        init_get_bits(&s->gb, buf + (pos >> 3), (buf_size - (pos >> 3)) * 8);
+        bitstream_init8(&s->bc, buf + (pos >> 3), buf_size - (pos >> 3));
         len = pos & 7;
         if (len > 0)
-            skip_bits(&s->gb, len);
+            bitstream_skip(&s->bc, len);
 
         s->reset_block_lengths = 1;
         for (i = 0; i < nb_frames; i++) {
@@ -883,7 +885,7 @@ static int wma_decode_superframe(AVCodecContext *avctx, void *data,
         }
 
         /* we copy the end of the frame in the last frame buffer */
-        pos               = get_bits_count(&s->gb) +
+        pos               = bitstream_tell(&s->bc) +
                             ((bit_offset + 4 + 4 + s->byte_offset_bits + 3) & ~7);
         s->last_bitoffset = pos & 7;
         pos             >>= 3;

libavcodec/wmalosslessdec.c

@@ -28,8 +28,8 @@
 #include "libavutil/avassert.h"
 
 #include "avcodec.h"
+#include "bitstream.h"
 #include "internal.h"
-#include "get_bits.h"
 #include "put_bits.h"
 #include "wma.h"
 #include "wma_common.h"
@@ -87,7 +87,7 @@ typedef struct WmallDecodeCtx {
     uint16_t        min_samples_per_subframe;
 
     /* packet decode state */
-    GetBitContext   pgb;                            ///< bitstream reader context for the packet
+    BitstreamContext pbc;                           ///< bitstream reader context for the packet
     int             next_packet_start;              ///< start offset of the next WMA packet in the demuxer packet
     uint8_t         packet_offset;                  ///< offset to the frame in the packet
     uint8_t         packet_sequence_number;         ///< current packet number
@@ -99,7 +99,7 @@ typedef struct WmallDecodeCtx {
 
     /* frame decode state */
     uint32_t        frame_num;                      ///< current frame number (not used for decoding)
-    GetBitContext   gb;                             ///< bitstream reader context
+    BitstreamContext bc;                            ///< bitstream reader context
     int             buf_bit_size;                   ///< buffer size in bits
     int16_t         *samples_16[WMALL_MAX_CHANNELS]; ///< current sample buffer pointer (16-bit)
     int32_t         *samples_32[WMALL_MAX_CHANNELS]; ///< current sample buffer pointer (24-bit)
@@ -286,7 +286,7 @@ static int decode_subframe_length(WmallDecodeCtx *s, int offset)
         return s->min_samples_per_subframe;
 
     len             = av_log2(s->max_num_subframes - 1) + 1;
-    frame_len_ratio = get_bits(&s->gb, len);
+    frame_len_ratio = bitstream_read(&s->bc, len);
     subframe_len    = s->min_samples_per_subframe * (frame_len_ratio + 1);
 
     /* sanity check the length */
@@ -332,7 +332,7 @@ static int decode_tilehdr(WmallDecodeCtx *s)
     for (c = 0; c < s->num_channels; c++)
         s->channel[c].num_subframes = 0;
 
-    tile_aligned = get_bits1(&s->gb);
+    tile_aligned = bitstream_read_bit(&s->bc);
     if (s->max_num_subframes == 1 || tile_aligned)
         fixed_channel_layout = 1;
 
@@ -347,7 +347,7 @@ static int decode_tilehdr(WmallDecodeCtx *s)
                    (min_channel_len == s->samples_per_frame - s->min_samples_per_subframe)) {
                     contains_subframe[c] = in_use = 1;
                 } else {
-                    if (get_bits1(&s->gb))
+                    if (bitstream_read_bit(&s->bc))
                         contains_subframe[c] = in_use = 1;
                 }
             } else
@@ -407,32 +407,32 @@ static int decode_tilehdr(WmallDecodeCtx *s)
 static void decode_ac_filter(WmallDecodeCtx *s)
 {
     int i;
-    s->acfilter_order   = get_bits(&s->gb, 4) + 1;
-    s->acfilter_scaling = get_bits(&s->gb, 4);
+    s->acfilter_order   = bitstream_read(&s->bc, 4) + 1;
+    s->acfilter_scaling = bitstream_read(&s->bc, 4);
 
     for (i = 0; i < s->acfilter_order; i++)
-        s->acfilter_coeffs[i] = get_bitsz(&s->gb, s->acfilter_scaling) + 1;
+        s->acfilter_coeffs[i] = bitstream_read(&s->bc, s->acfilter_scaling) + 1;
 }
 
 static void decode_mclms(WmallDecodeCtx *s)
 {
-    s->mclms_order   = (get_bits(&s->gb, 4) + 1) * 2;
-    s->mclms_scaling = get_bits(&s->gb, 4);
-    if (get_bits1(&s->gb)) {
+    s->mclms_order   = (bitstream_read(&s->bc, 4) + 1) * 2;
+    s->mclms_scaling =  bitstream_read(&s->bc, 4);
+    if (bitstream_read_bit(&s->bc)) {
         int i, send_coef_bits;
         int cbits = av_log2(s->mclms_scaling + 1);
         if (1 << cbits < s->mclms_scaling + 1)
             cbits++;
 
-        send_coef_bits = get_bitsz(&s->gb, cbits) + 2;
+        send_coef_bits = bitstream_read(&s->bc, cbits) + 2;
 
         for (i = 0; i < s->mclms_order * s->num_channels * s->num_channels; i++)
-            s->mclms_coeffs[i] = get_bits(&s->gb, send_coef_bits);
+            s->mclms_coeffs[i] = bitstream_read(&s->bc, send_coef_bits);
 
         for (i = 0; i < s->num_channels; i++) {
             int c;
             for (c = 0; c < i; c++)
-                s->mclms_coeffs_cur[i * s->num_channels + c] = get_bits(&s->gb, send_coef_bits);
+                s->mclms_coeffs_cur[i * s->num_channels + c] = bitstream_read(&s->bc, send_coef_bits);
         }
     }
 }
@@ -440,12 +440,12 @@ static void decode_mclms(WmallDecodeCtx *s)
 static int decode_cdlms(WmallDecodeCtx *s)
 {
     int c, i;
-    int cdlms_send_coef = get_bits1(&s->gb);
+    int cdlms_send_coef = bitstream_read_bit(&s->bc);
 
     for (c = 0; c < s->num_channels; c++) {
-        s->cdlms_ttl[c] = get_bits(&s->gb, 3) + 1;
+        s->cdlms_ttl[c] = bitstream_read(&s->bc, 3) + 1;
         for (i = 0; i < s->cdlms_ttl[c]; i++) {
-            s->cdlms[c][i].order = (get_bits(&s->gb, 7) + 1) * 8;
+            s->cdlms[c][i].order = (bitstream_read(&s->bc, 7) + 1) * 8;
             if (s->cdlms[c][i].order > MAX_ORDER) {
                 av_log(s->avctx, AV_LOG_ERROR,
                        "Order[%d][%d] %d > max (%d), not supported\n",
@@ -456,7 +456,7 @@ static int decode_cdlms(WmallDecodeCtx *s)
         }
 
         for (i = 0; i < s->cdlms_ttl[c]; i++)
-            s->cdlms[c][i].scaling = get_bits(&s->gb, 4);
+            s->cdlms[c][i].scaling = bitstream_read(&s->bc, 4);
 
         if (cdlms_send_coef) {
             for (i = 0; i < s->cdlms_ttl[c]; i++) {
@@ -464,18 +464,18 @@ static int decode_cdlms(WmallDecodeCtx *s)
                 cbits = av_log2(s->cdlms[c][i].order);
                 if ((1 << cbits) < s->cdlms[c][i].order)
                     cbits++;
-                s->cdlms[c][i].coefsend = get_bits(&s->gb, cbits) + 1;
+                s->cdlms[c][i].coefsend = bitstream_read(&s->bc, cbits) + 1;
 
                 cbits = av_log2(s->cdlms[c][i].scaling + 1);
                 if ((1 << cbits) < s->cdlms[c][i].scaling + 1)
                     cbits++;
 
-                s->cdlms[c][i].bitsend = get_bitsz(&s->gb, cbits) + 2;
+                s->cdlms[c][i].bitsend = bitstream_read(&s->bc, cbits) + 2;
                 shift_l = 32 - s->cdlms[c][i].bitsend;
                 shift_r = 32 - s->cdlms[c][i].scaling - 2;
                 for (j = 0; j < s->cdlms[c][i].coefsend; j++)
                     s->cdlms[c][i].coefs[j] =
-                        (get_bits(&s->gb, s->cdlms[c][i].bitsend) << shift_l) >> shift_r;
+                        (bitstream_read(&s->bc, s->cdlms[c][i].bitsend) << shift_l) >> shift_r;
             }
         }
     }
@@ -487,9 +487,9 @@ static int decode_channel_residues(WmallDecodeCtx *s, int ch, int tile_size)
 {
     int i = 0;
     unsigned int ave_mean;
-    s->transient[ch] = get_bits1(&s->gb);
+    s->transient[ch] = bitstream_read_bit(&s->bc);
     if (s->transient[ch]) {
-        s->transient_pos[ch] = get_bits(&s->gb, av_log2(tile_size));
+        s->transient_pos[ch] = bitstream_read(&s->bc, av_log2(tile_size));
         if (s->transient_pos[ch])
             s->transient[ch] = 0;
         s->channel[ch].transient_counter =
@@ -498,33 +498,33 @@ static int decode_channel_residues(WmallDecodeCtx *s, int ch, int tile_size)
         s->transient[ch] = 1;
 
     if (s->seekable_tile) {
-        ave_mean = get_bits(&s->gb, s->bits_per_sample);
+        ave_mean = bitstream_read(&s->bc, s->bits_per_sample);
         s->ave_sum[ch] = ave_mean << (s->movave_scaling + 1);
     }
 
     if (s->seekable_tile) {
         if (s->do_inter_ch_decorr)
-            s->channel_residues[ch][0] = get_sbits(&s->gb, s->bits_per_sample + 1);
+            s->channel_residues[ch][0] = bitstream_read_signed(&s->bc, s->bits_per_sample + 1);
         else
-            s->channel_residues[ch][0] = get_sbits(&s->gb, s->bits_per_sample);
+            s->channel_residues[ch][0] = bitstream_read_signed(&s->bc, s->bits_per_sample);
         i++;
     }
     for (; i < tile_size; i++) {
         int quo = 0, rem, rem_bits, residue;
-        while(get_bits1(&s->gb)) {
+        while (bitstream_read_bit(&s->bc)) {
             quo++;
-            if (get_bits_left(&s->gb) <= 0)
+            if (bitstream_bits_left(&s->bc) <= 0)
                 return -1;
         }
         if (quo >= 32)
-            quo += get_bits_long(&s->gb, get_bits(&s->gb, 5) + 1);
+            quo += bitstream_read(&s->bc, bitstream_read(&s->bc, 5) + 1);
 
         ave_mean = (s->ave_sum[ch] + (1 << s->movave_scaling)) >> (s->movave_scaling + 1);
         if (ave_mean <= 1)
             residue = quo;
         else {
             rem_bits = av_ceil_log2(ave_mean);
-            rem      = rem_bits ? get_bits_long(&s->gb, rem_bits) : 0;
+            rem      = rem_bits ? bitstream_read(&s->bc, rem_bits) : 0;
             residue  = (quo << rem_bits) + rem;
         }
 
@@ -545,13 +545,13 @@ static int decode_channel_residues(WmallDecodeCtx *s, int ch, int tile_size)
 static void decode_lpc(WmallDecodeCtx *s)
 {
     int ch, i, cbits;
-    s->lpc_order   = get_bits(&s->gb, 5) + 1;
-    s->lpc_scaling = get_bits(&s->gb, 4);
-    s->lpc_intbits = get_bits(&s->gb, 3) + 1;
+    s->lpc_order   = bitstream_read(&s->bc, 5) + 1;
+    s->lpc_scaling = bitstream_read(&s->bc, 4);
+    s->lpc_intbits = bitstream_read(&s->bc, 3) + 1;
     cbits = s->lpc_scaling + s->lpc_intbits;
     for (ch = 0; ch < s->num_channels; ch++)
         for (i = 0; i < s->lpc_order; i++)
-            s->lpc_coefs[ch][i] = get_sbits(&s->gb, cbits);
+            s->lpc_coefs[ch][i] = bitstream_read_signed(&s->bc, cbits);
 }
 
 static void clear_codec_buffers(WmallDecodeCtx *s)
@@ -846,7 +846,7 @@ static int decode_subframe(WmallDecodeCtx *s)
     int total_samples = s->samples_per_frame * s->num_channels;
     int i, j, rawpcm_tile, padding_zeroes, res;
 
-    s->subframe_offset = get_bits_count(&s->gb);
+    s->subframe_offset = bitstream_tell(&s->bc);
 
     /* reset channel context and find the next block offset and size
         == the next block of the channel with the smallest number of
@@ -883,18 +883,18 @@ static int decode_subframe(WmallDecodeCtx *s)
         s->parsed_all_subframes = 1;
 
 
-    s->seekable_tile = get_bits1(&s->gb);
+    s->seekable_tile = bitstream_read_bit(&s->bc);
     if (s->seekable_tile) {
         clear_codec_buffers(s);
 
-        s->do_arith_coding    = get_bits1(&s->gb);
+        s->do_arith_coding    = bitstream_read_bit(&s->bc);
         if (s->do_arith_coding) {
             avpriv_request_sample(s->avctx, "Arithmetic coding");
             return AVERROR_PATCHWELCOME;
         }
-        s->do_ac_filter       = get_bits1(&s->gb);
-        s->do_inter_ch_decorr = get_bits1(&s->gb);
-        s->do_mclms           = get_bits1(&s->gb);
+        s->do_ac_filter       = bitstream_read_bit(&s->bc);
+        s->do_inter_ch_decorr = bitstream_read_bit(&s->bc);
+        s->do_mclms           = bitstream_read_bit(&s->bc);
 
         if (s->do_ac_filter)
             decode_ac_filter(s);
@@ -904,8 +904,8 @@ static int decode_subframe(WmallDecodeCtx *s)
 
         if ((res = decode_cdlms(s)) < 0)
             return res;
-        s->movave_scaling = get_bits(&s->gb, 3);
-        s->quant_stepsize = get_bits(&s->gb, 8) + 1;
+        s->movave_scaling = bitstream_read(&s->bc, 3);
+        s->quant_stepsize = bitstream_read(&s->bc, 8) + 1;
 
         reset_codec(s);
     } else if (!s->cdlms[0][0].order) {
@@ -915,18 +915,18 @@ static int decode_subframe(WmallDecodeCtx *s)
         return -1;
     }
 
-    rawpcm_tile = get_bits1(&s->gb);
+    rawpcm_tile = bitstream_read_bit(&s->bc);
 
     for (i = 0; i < s->num_channels; i++)
         s->is_channel_coded[i] = 1;
 
     if (!rawpcm_tile) {
         for (i = 0; i < s->num_channels; i++)
-            s->is_channel_coded[i] = get_bits1(&s->gb);
+            s->is_channel_coded[i] = bitstream_read_bit(&s->bc);
 
         if (s->bV3RTM) {
             // LPC
-            s->do_lpc = get_bits1(&s->gb);
+            s->do_lpc = bitstream_read_bit(&s->bc);
             if (s->do_lpc) {
                 decode_lpc(s);
                 avpriv_request_sample(s->avctx, "Expect wrong output since "
@@ -937,8 +937,8 @@ static int decode_subframe(WmallDecodeCtx *s)
     }
 
 
-    if (get_bits1(&s->gb))
-        padding_zeroes = get_bits(&s->gb, 5);
+    if (bitstream_read_bit(&s->bc))
+        padding_zeroes = bitstream_read(&s->bc, 5);
     else
         padding_zeroes = 0;
 
@@ -951,10 +951,10 @@ static int decode_subframe(WmallDecodeCtx *s)
         }
         ff_dlog(s->avctx, "RAWPCM %d bits per sample. "
                 "total %d bits, remain=%d\n", bits,
-                bits * s->num_channels * subframe_len, get_bits_count(&s->gb));
+                bits * s->num_channels * subframe_len, bitstream_tell(&s->bc));
         for (i = 0; i < s->num_channels; i++)
             for (j = 0; j < subframe_len; j++)
-                s->channel_coeffs[i][j] = get_sbits(&s->gb, bits);
+                s->channel_coeffs[i][j] = bitstream_read_signed(&s->bc, bits);
     } else {
         for (i = 0; i < s->num_channels; i++)
             if (s->is_channel_coded[i]) {
@@ -1015,7 +1015,7 @@ static int decode_subframe(WmallDecodeCtx *s)
  */
 static int decode_frame(WmallDecodeCtx *s)
 {
-    GetBitContext* gb = &s->gb;
+    BitstreamContext *bc = &s->bc;
     int more_frames = 0, len = 0, i, ret;
 
     s->frame->nb_samples = s->samples_per_frame;
@@ -1033,7 +1033,7 @@ static int decode_frame(WmallDecodeCtx *s)
 
     /* get frame length */
     if (s->len_prefix)
-        len = get_bits(gb, s->log2_frame_size);
+        len = bitstream_read(bc, s->log2_frame_size);
 
     /* decode tile information */
     if (decode_tilehdr(s)) {
@@ -1043,22 +1043,22 @@ static int decode_frame(WmallDecodeCtx *s)
 
     /* read drc info */
     if (s->dynamic_range_compression)
-        s->drc_gain = get_bits(gb, 8);
+        s->drc_gain = bitstream_read(bc, 8);
 
     /* no idea what these are for, might be the number of samples
        that need to be skipped at the beginning or end of a stream */
-    if (get_bits1(gb)) {
+    if (bitstream_read_bit(bc)) {
         int av_unused skip;
 
         /* usually true for the first frame */
-        if (get_bits1(gb)) {
-            skip = get_bits(gb, av_log2(s->samples_per_frame * 2));
+        if (bitstream_read_bit(bc)) {
+            skip = bitstream_read(bc, av_log2(s->samples_per_frame * 2));
             ff_dlog(s->avctx, "start skip: %i\n", skip);
         }
 
         /* sometimes true for the last frame */
-        if (get_bits1(gb)) {
-            skip = get_bits(gb, av_log2(s->samples_per_frame * 2));
+        if (bitstream_read_bit(bc)) {
+            skip = bitstream_read(bc, av_log2(s->samples_per_frame * 2));
             ff_dlog(s->avctx, "end skip: %i\n", skip);
         }
 
@@ -1085,22 +1085,22 @@ static int decode_frame(WmallDecodeCtx *s)
         s->skip_frame = 0;
 
     if (s->len_prefix) {
-        if (len != (get_bits_count(gb) - s->frame_offset) + 2) {
+        if (len != (bitstream_tell(bc) - s->frame_offset) + 2) {
             /* FIXME: not sure if this is always an error */
             av_log(s->avctx, AV_LOG_ERROR,
                    "frame[%"PRIu32"] would have to skip %i bits\n",
                    s->frame_num,
-                   len - (get_bits_count(gb) - s->frame_offset) - 1);
+                   len - (bitstream_tell(bc) - s->frame_offset) - 1);
             s->packet_loss = 1;
             return 0;
         }
 
         /* skip the rest of the frame data */
-        skip_bits_long(gb, len - (get_bits_count(gb) - s->frame_offset) - 1);
+        bitstream_skip(bc, len - (bitstream_tell(bc) - s->frame_offset) - 1);
     }
 
     /* decode trailer bit */
-    more_frames = get_bits1(gb);
+    more_frames = bitstream_read_bit(bc);
     ++s->frame_num;
     return more_frames;
 }
@@ -1108,22 +1108,22 @@ static int decode_frame(WmallDecodeCtx *s)
 /**
  * @brief Calculate remaining input buffer length.
  * @param s  codec context
- * @param gb bitstream reader context
+ * @param bc bitstream reader context
  * @return remaining size in bits
  */
-static int remaining_bits(WmallDecodeCtx *s, GetBitContext *gb)
+static int remaining_bits(WmallDecodeCtx *s, BitstreamContext *bc)
 {
-    return s->buf_bit_size - get_bits_count(gb);
+    return s->buf_bit_size - bitstream_tell(bc);
 }
 
 /**
  * @brief Fill the bit reservoir with a (partial) frame.
  * @param s      codec context
- * @param gb     bitstream reader context
+ * @param bc     bitstream reader context
  * @param len    length of the partial frame
  * @param append decides whether to reset the buffer or not
  */
-static void save_bits(WmallDecodeCtx *s, GetBitContext* gb, int len,
+static void save_bits(WmallDecodeCtx *s, BitstreamContext *bc, int len,
                       int append)
 {
     int buflen;
@@ -1134,7 +1134,7 @@ static void save_bits(WmallDecodeCtx *s, GetBitContext* gb, int len,
         and skipped later so that a fast byte copy is possible */
 
     if (!append) {
-        s->frame_offset   = get_bits_count(gb) & 7;
+        s->frame_offset   = bitstream_tell(bc) & 7;
         s->num_saved_bits = s->frame_offset;
         init_put_bits(&s->pb, s->frame_data, MAX_FRAMESIZE);
     }
@@ -1149,29 +1149,29 @@ static void save_bits(WmallDecodeCtx *s, GetBitContext* gb, int len,
 
     s->num_saved_bits += len;
     if (!append) {
-        avpriv_copy_bits(&s->pb, gb->buffer + (get_bits_count(gb) >> 3),
+        avpriv_copy_bits(&s->pb, bc->buffer + (bitstream_tell(bc) >> 3),
                          s->num_saved_bits);
     } else {
-        int align = 8 - (get_bits_count(gb) & 7);
+        int align = 8 - (bitstream_tell(bc) & 7);
         align = FFMIN(align, len);
-        put_bits(&s->pb, align, get_bits(gb, align));
+        put_bits(&s->pb, align, bitstream_read(bc, align));
         len -= align;
-        avpriv_copy_bits(&s->pb, gb->buffer + (get_bits_count(gb) >> 3), len);
+        avpriv_copy_bits(&s->pb, bc->buffer + (bitstream_tell(bc) >> 3), len);
     }
-    skip_bits_long(gb, len);
+    bitstream_skip(bc, len);
 
     tmp = s->pb;
     flush_put_bits(&tmp);
 
-    init_get_bits(&s->gb, s->frame_data, s->num_saved_bits);
-    skip_bits(&s->gb, s->frame_offset);
+    bitstream_init(&s->bc, s->frame_data, s->num_saved_bits);
+    bitstream_skip(&s->bc, s->frame_offset);
 }
 
 static int decode_packet(AVCodecContext *avctx, void *data, int *got_frame_ptr,
                          AVPacket* avpkt)
 {
     WmallDecodeCtx *s = avctx->priv_data;
-    GetBitContext* gb  = &s->pgb;
+    BitstreamContext *bc = &s->pbc;
     const uint8_t* buf = avpkt->data;
     int buf_size       = avpkt->size;
     int num_bits_prev_frame, packet_sequence_number, spliced_packet;
@@ -1190,15 +1190,15 @@ static int decode_packet(AVCodecContext *avctx, void *data, int *got_frame_ptr,
         s->buf_bit_size      = buf_size << 3;
 
         /* parse packet header */
-        init_get_bits(gb, buf, s->buf_bit_size);
-        packet_sequence_number = get_bits(gb, 4);
-        skip_bits(gb, 1);   // Skip seekable_frame_in_packet, currently unused
-        spliced_packet = get_bits1(gb);
+        bitstream_init(bc, buf, s->buf_bit_size);
+        packet_sequence_number = bitstream_read(bc, 4);
+        bitstream_skip(bc, 1); // Skip seekable_frame_in_packet, currently ununused
+        spliced_packet = bitstream_read_bit(bc);
         if (spliced_packet)
             avpriv_request_sample(avctx, "Bitstream splicing");
 
         /* get number of bits that need to be added to the previous frame */
-        num_bits_prev_frame = get_bits(gb, s->log2_frame_size);
+        num_bits_prev_frame = bitstream_read(bc, s->log2_frame_size);
 
         /* check for packet loss */
         if (!s->packet_loss &&
@@ -1211,7 +1211,7 @@ static int decode_packet(AVCodecContext *avctx, void *data, int *got_frame_ptr,
         s->packet_sequence_number = packet_sequence_number;
 
         if (num_bits_prev_frame > 0) {
-            int remaining_packet_bits = s->buf_bit_size - get_bits_count(gb);
+            int remaining_packet_bits = s->buf_bit_size - bitstream_tell(bc);
             if (num_bits_prev_frame >= remaining_packet_bits) {
                 num_bits_prev_frame = remaining_packet_bits;
                 s->packet_done = 1;
@@ -1219,7 +1219,7 @@ static int decode_packet(AVCodecContext *avctx, void *data, int *got_frame_ptr,
 
             /* Append the previous frame data to the remaining data from the
              * previous packet to create a full frame. */
-            save_bits(s, gb, num_bits_prev_frame, 1);
+            save_bits(s, bc, num_bits_prev_frame, 1);
 
             /* decode the cross packet frame if it is valid */
             if (num_bits_prev_frame < remaining_packet_bits && !s->packet_loss)
@@ -1241,16 +1241,16 @@ static int decode_packet(AVCodecContext *avctx, void *data, int *got_frame_ptr,
         int frame_size;
 
         s->buf_bit_size = (avpkt->size - s->next_packet_start) << 3;
-        init_get_bits(gb, avpkt->data, s->buf_bit_size);
-        skip_bits(gb, s->packet_offset);
+        bitstream_init(bc, avpkt->data, s->buf_bit_size);
+        bitstream_skip(bc, s->packet_offset);
 
-        if (s->len_prefix && remaining_bits(s, gb) > s->log2_frame_size &&
-            (frame_size = show_bits(gb, s->log2_frame_size)) &&
-            frame_size <= remaining_bits(s, gb)) {
-            save_bits(s, gb, frame_size, 0);
+        if (s->len_prefix && remaining_bits(s, bc) > s->log2_frame_size &&
+            (frame_size = bitstream_peek(bc, s->log2_frame_size)) &&
+            frame_size <= remaining_bits(s, bc)) {
+            save_bits(s, bc, frame_size, 0);
             s->packet_done = !decode_frame(s);
         } else if (!s->len_prefix
-                   && s->num_saved_bits > get_bits_count(&s->gb)) {
+                   && s->num_saved_bits > bitstream_tell(&s->bc)) {
             /* when the frames do not have a length prefix, we don't know the
              * compressed length of the individual frames however, we know what
              * part of a new packet belongs to the previous frame therefore we
@@ -1264,18 +1264,18 @@ static int decode_packet(AVCodecContext *avctx, void *data, int *got_frame_ptr,
     }
 
     if (s->packet_done && !s->packet_loss &&
-        remaining_bits(s, gb) > 0) {
+        remaining_bits(s, bc) > 0) {
         /* save the rest of the data so that it can be decoded
          * with the next packet */
-        save_bits(s, gb, remaining_bits(s, gb), 0);
+        save_bits(s, bc, remaining_bits(s, bc), 0);
     }
 
     *got_frame_ptr   = s->frame->nb_samples > 0;
     av_frame_move_ref(data, s->frame);
 
-    s->packet_offset = get_bits_count(gb) & 7;
+    s->packet_offset = bitstream_tell(bc) & 7;
 
-    return (s->packet_loss) ? AVERROR_INVALIDDATA : get_bits_count(gb) >> 3;
+    return (s->packet_loss) ? AVERROR_INVALIDDATA : bitstream_tell(bc) >> 3;
 }
 
 static void flush(AVCodecContext *avctx)

libavcodec/wmaprodec.c

@@ -91,9 +91,10 @@
 #include "libavutil/float_dsp.h"
 #include "libavutil/intfloat.h"
 #include "libavutil/intreadwrite.h"
+
 #include "avcodec.h"
+#include "bitstream.h"
 #include "internal.h"
-#include "get_bits.h"
 #include "put_bits.h"
 #include "wmaprodata.h"
 #include "sinewin.h"
@@ -197,7 +198,7 @@ typedef struct WMAProDecodeCtx {
     int16_t          subwoofer_cutoffs[WMAPRO_BLOCK_SIZES]; ///< subwoofer cutoff values
 
     /* packet decode state */
-    GetBitContext    pgb;                           ///< bitstream reader context for the packet
+    BitstreamContext pbc;                           ///< bitstream reader context for the packet
     int              next_packet_start;             ///< start offset of the next wma packet in the demuxer packet
     uint8_t          packet_offset;                 ///< frame offset in the packet
     uint8_t          packet_sequence_number;        ///< current packet number
@@ -209,7 +210,7 @@ typedef struct WMAProDecodeCtx {
 
     /* frame decode state */
     uint32_t         frame_num;                     ///< current frame number (not used for decoding)
-    GetBitContext    gb;                            ///< bitstream reader context
+    BitstreamContext bc;                            ///< bitstream reader context
     int              buf_bit_size;                  ///< buffer size in bits
     uint8_t          drc_gain;                      ///< gain for the DRC tool
     int8_t           skip_frame;                    ///< skip output step
@@ -495,10 +496,11 @@ static int decode_subframe_length(WMAProDecodeCtx *s, int offset)
 
     /** 1 bit indicates if the subframe is of maximum length */
     if (s->max_subframe_len_bit) {
-        if (get_bits1(&s->gb))
-            frame_len_shift = 1 + get_bits(&s->gb, s->subframe_len_bits-1);
+        if (bitstream_read_bit(&s->bc))
+            frame_len_shift = 1 + bitstream_read(&s->bc,
+                                                 s->subframe_len_bits - 1);
     } else
-        frame_len_shift = get_bits(&s->gb, s->subframe_len_bits);
+        frame_len_shift = bitstream_read(&s->bc, s->subframe_len_bits);
 
     subframe_len = s->samples_per_frame >> frame_len_shift;
 
@@ -551,7 +553,7 @@ static int decode_tilehdr(WMAProDecodeCtx *s)
     for (c = 0; c < s->avctx->channels; c++)
         s->channel[c].num_subframes = 0;
 
-    if (s->max_num_subframes == 1 || get_bits1(&s->gb))
+    if (s->max_num_subframes == 1 || bitstream_read_bit(&s->bc))
         fixed_channel_layout = 1;
 
     /** loop until the frame data is split between the subframes */
@@ -565,7 +567,7 @@ static int decode_tilehdr(WMAProDecodeCtx *s)
                    (min_channel_len == s->samples_per_frame - s->min_samples_per_subframe))
                     contains_subframe[c] = 1;
                 else
-                    contains_subframe[c] = get_bits1(&s->gb);
+                    contains_subframe[c] = bitstream_read_bit(&s->bc);
             } else
                 contains_subframe[c] = 0;
         }
@@ -633,11 +635,11 @@ static void decode_decorrelation_matrix(WMAProDecodeCtx *s,
            s->avctx->channels * sizeof(*chgroup->decorrelation_matrix));
 
     for (i = 0; i < chgroup->num_channels * (chgroup->num_channels - 1) >> 1; i++)
-        rotation_offset[i] = get_bits(&s->gb, 6);
+        rotation_offset[i] = bitstream_read(&s->bc, 6);
 
     for (i = 0; i < chgroup->num_channels; i++)
         chgroup->decorrelation_matrix[chgroup->num_channels * i + i] =
-            get_bits1(&s->gb) ? 1.0 : -1.0;
+            bitstream_read_bit(&s->bc) ? 1.0 : -1.0;
 
     for (i = 1; i < chgroup->num_channels; i++) {
         int x;
@@ -686,7 +688,7 @@ static int decode_channel_transform(WMAProDecodeCtx* s)
     if (s->avctx->channels > 1) {
         int remaining_channels = s->channels_for_cur_subframe;
 
-        if (get_bits1(&s->gb)) {
+        if (bitstream_read_bit(&s->bc)) {
             avpriv_request_sample(s->avctx,
                                   "Channel transform bit");
             return AVERROR_PATCHWELCOME;
@@ -704,7 +706,7 @@ static int decode_channel_transform(WMAProDecodeCtx* s)
                 for (i = 0; i < s->channels_for_cur_subframe; i++) {
                     int channel_idx = s->channel_indexes_for_cur_subframe[i];
                     if (!s->channel[channel_idx].grouped
-                        && get_bits1(&s->gb)) {
+                        && bitstream_read_bit(&s->bc)) {
                         ++chgroup->num_channels;
                         s->channel[channel_idx].grouped = 1;
                         *channel_data++ = s->channel[channel_idx].coeffs;
@@ -722,8 +724,8 @@ static int decode_channel_transform(WMAProDecodeCtx* s)
 
             /** decode transform type */
             if (chgroup->num_channels == 2) {
-                if (get_bits1(&s->gb)) {
-                    if (get_bits1(&s->gb)) {
+                if (bitstream_read_bit(&s->bc)) {
+                    if (bitstream_read_bit(&s->bc)) {
                         avpriv_request_sample(s->avctx,
                                               "Unknown channel transform type");
                         return AVERROR_PATCHWELCOME;
@@ -744,9 +746,9 @@ static int decode_channel_transform(WMAProDecodeCtx* s)
                     }
                 }
             } else if (chgroup->num_channels > 2) {
-                if (get_bits1(&s->gb)) {
+                if (bitstream_read_bit(&s->bc)) {
                     chgroup->transform = 1;
-                    if (get_bits1(&s->gb)) {
+                    if (bitstream_read_bit(&s->bc)) {
                         decode_decorrelation_matrix(s, chgroup);
                     } else {
                         /** FIXME: more than 6 coupled channels not supported */
@@ -765,11 +767,11 @@ static int decode_channel_transform(WMAProDecodeCtx* s)
 
             /** decode transform on / off */
             if (chgroup->transform) {
-                if (!get_bits1(&s->gb)) {
+                if (!bitstream_read_bit(&s->bc)) {
                     int i;
                     /** transform can be enabled for individual bands */
                     for (i = 0; i < s->num_bands; i++) {
-                        chgroup->transform_band[i] = get_bits1(&s->gb);
+                        chgroup->transform_band[i] = bitstream_read_bit(&s->bc);
                     }
                 } else {
                     memset(chgroup->transform_band, 1, s->num_bands);
@@ -809,7 +811,7 @@ static int decode_coeffs(WMAProDecodeCtx *s, int c)
 
     ff_dlog(s->avctx, "decode coefficients for channel %i\n", c);
 
-    vlctable = get_bits1(&s->gb);
+    vlctable = bitstream_read_bit(&s->bc);
     vlc = &coef_vlc[vlctable];
 
     if (vlctable) {
@@ -828,19 +830,19 @@ static int decode_coeffs(WMAProDecodeCtx *s, int c)
         int i;
         unsigned int idx;
 
-        idx = get_vlc2(&s->gb, vec4_vlc.table, VLCBITS, VEC4MAXDEPTH);
+        idx = bitstream_read_vlc(&s->bc, vec4_vlc.table, VLCBITS, VEC4MAXDEPTH);
 
         if (idx == HUFF_VEC4_SIZE - 1) {
             for (i = 0; i < 4; i += 2) {
-                idx = get_vlc2(&s->gb, vec2_vlc.table, VLCBITS, VEC2MAXDEPTH);
+                idx = bitstream_read_vlc(&s->bc, vec2_vlc.table, VLCBITS, VEC2MAXDEPTH);
                 if (idx == HUFF_VEC2_SIZE - 1) {
                     uint32_t v0, v1;
-                    v0 = get_vlc2(&s->gb, vec1_vlc.table, VLCBITS, VEC1MAXDEPTH);
+                    v0 = bitstream_read_vlc(&s->bc, vec1_vlc.table, VLCBITS, VEC1MAXDEPTH);
                     if (v0 == HUFF_VEC1_SIZE - 1)
-                        v0 += ff_wma_get_large_val(&s->gb);
-                    v1 = get_vlc2(&s->gb, vec1_vlc.table, VLCBITS, VEC1MAXDEPTH);
+                        v0 += ff_wma_get_large_val(&s->bc);
+                    v1 = bitstream_read_vlc(&s->bc, vec1_vlc.table, VLCBITS, VEC1MAXDEPTH);
                     if (v1 == HUFF_VEC1_SIZE - 1)
-                        v1 += ff_wma_get_large_val(&s->gb);
+                        v1 += ff_wma_get_large_val(&s->bc);
                     vals[i  ] = av_float2int(v0);
                     vals[i+1] = av_float2int(v1);
                 } else {
@@ -858,7 +860,7 @@ static int decode_coeffs(WMAProDecodeCtx *s, int c)
         /** decode sign */
         for (i = 0; i < 4; i++) {
             if (vals[i]) {
-                uint32_t sign = get_bits1(&s->gb) - 1;
+                uint32_t sign = bitstream_read_bit(&s->bc) - 1;
                 AV_WN32A(&ci->coeffs[cur_coeff], vals[i] ^ sign << 31);
                 num_zeros = 0;
             } else {
@@ -875,7 +877,7 @@ static int decode_coeffs(WMAProDecodeCtx *s, int c)
     if (cur_coeff < s->subframe_len) {
         memset(&ci->coeffs[cur_coeff], 0,
                sizeof(*ci->coeffs) * (s->subframe_len - cur_coeff));
-        if (ff_wma_run_level_decode(s->avctx, &s->gb, vlc,
+        if (ff_wma_run_level_decode(s->avctx, &s->bc, vlc,
                                     level, run, 1, ci->coeffs,
                                     cur_coeff, s->subframe_len,
                                     s->subframe_len, s->esc_len, 0))
@@ -918,15 +920,14 @@ static int decode_scale_factors(WMAProDecodeCtx* s)
                     s->channel[c].saved_scale_factors[s->channel[c].scale_factor_idx][*sf_offsets++];
         }
 
-        if (!s->channel[c].cur_subframe || get_bits1(&s->gb)) {
-
+        if (!s->channel[c].cur_subframe || bitstream_read_bit(&s->bc)) {
             if (!s->channel[c].reuse_sf) {
                 int val;
                 /** decode DPCM coded scale factors */
-                s->channel[c].scale_factor_step = get_bits(&s->gb, 2) + 1;
+                s->channel[c].scale_factor_step = bitstream_read(&s->bc, 2) + 1;
                 val = 45 / s->channel[c].scale_factor_step;
                 for (sf = s->channel[c].scale_factors; sf < sf_end; sf++) {
-                    val += get_vlc2(&s->gb, sf_vlc.table, SCALEVLCBITS, SCALEMAXDEPTH) - 60;
+                    val += bitstream_read_vlc(&s->bc, sf_vlc.table, SCALEVLCBITS, SCALEMAXDEPTH) - 60;
                     *sf = val;
                 }
             } else {
@@ -938,10 +939,10 @@ static int decode_scale_factors(WMAProDecodeCtx* s)
                     int val;
                     int sign;
 
-                    idx = get_vlc2(&s->gb, sf_rl_vlc.table, VLCBITS, SCALERLMAXDEPTH);
+                    idx = bitstream_read_vlc(&s->bc, sf_rl_vlc.table, VLCBITS, SCALERLMAXDEPTH);
 
                     if (!idx) {
-                        uint32_t code = get_bits(&s->gb, 14);
+                        uint32_t code = bitstream_read(&s->bc, 14);
                         val  =  code >> 6;
                         sign = (code & 1) - 1;
                         skip = (code & 0x3f) >> 1;
@@ -950,7 +951,7 @@ static int decode_scale_factors(WMAProDecodeCtx* s)
                     } else {
                         skip = scale_rl_run[idx];
                         val  = scale_rl_level[idx];
-                        sign = get_bits1(&s->gb)-1;
+                        sign = bitstream_read_bit(&s->bc)-1;
                     }
 
                     i += skip;
@@ -1077,7 +1078,7 @@ static int decode_subframe(WMAProDecodeCtx *s)
     int transmit_coeffs = 0;
     int cur_subwoofer_cutoff;
 
-    s->subframe_offset = get_bits_count(&s->gb);
+    s->subframe_offset = bitstream_tell(&s->bc);
 
     /** reset channel context and find the next block offset and size
         == the next block of the channel with the smallest number of
@@ -1141,25 +1142,25 @@ static int decode_subframe(WMAProDecodeCtx *s)
     s->esc_len = av_log2(s->subframe_len - 1) + 1;
 
     /** skip extended header if any */
-    if (get_bits1(&s->gb)) {
+    if (bitstream_read_bit(&s->bc)) {
         int num_fill_bits;
-        if (!(num_fill_bits = get_bits(&s->gb, 2))) {
-            int len = get_bits(&s->gb, 4);
-            num_fill_bits = get_bitsz(&s->gb, len) + 1;
+        if (!(num_fill_bits = bitstream_read(&s->bc, 2))) {
+            int len       = bitstream_read(&s->bc, 4);
+            num_fill_bits = bitstream_read(&s->bc, len) + 1;
         }
 
         if (num_fill_bits >= 0) {
-            if (get_bits_count(&s->gb) + num_fill_bits > s->num_saved_bits) {
+            if (bitstream_tell(&s->bc) + num_fill_bits > s->num_saved_bits) {
                 av_log(s->avctx, AV_LOG_ERROR, "invalid number of fill bits\n");
                 return AVERROR_INVALIDDATA;
             }
 
-            skip_bits_long(&s->gb, num_fill_bits);
+            bitstream_skip(&s->bc, num_fill_bits);
         }
     }
 
     /** no idea for what the following bit is used */
-    if (get_bits1(&s->gb)) {
+    if (bitstream_read_bit(&s->bc)) {
         avpriv_request_sample(s->avctx, "Reserved bit");
         return AVERROR_PATCHWELCOME;
     }
@@ -1171,7 +1172,7 @@ static int decode_subframe(WMAProDecodeCtx *s)
 
     for (i = 0; i < s->channels_for_cur_subframe; i++) {
         int c = s->channel_indexes_for_cur_subframe[i];
-        if ((s->channel[c].transmit_coefs = get_bits1(&s->gb)))
+        if ((s->channel[c].transmit_coefs = bitstream_read_bit(&s->bc)))
             transmit_coeffs = 1;
     }
 
@@ -1180,11 +1181,11 @@ static int decode_subframe(WMAProDecodeCtx *s)
         int quant_step = 90 * s->bits_per_sample >> 4;
 
         /** decode number of vector coded coefficients */
-        if ((s->transmit_num_vec_coeffs = get_bits1(&s->gb))) {
+        if ((s->transmit_num_vec_coeffs = bitstream_read_bit(&s->bc))) {
             int num_bits = av_log2((s->subframe_len + 3)/4) + 1;
             for (i = 0; i < s->channels_for_cur_subframe; i++) {
                 int c = s->channel_indexes_for_cur_subframe[i];
-                int num_vec_coeffs = get_bits(&s->gb, num_bits) << 2;
+                int num_vec_coeffs = bitstream_read(&s->bc, num_bits) << 2;
                 if (num_vec_coeffs + offset > FF_ARRAY_ELEMS(s->channel[c].out)) {
                     av_log(s->avctx, AV_LOG_ERROR, "num_vec_coeffs %d is too large\n", num_vec_coeffs);
                     return AVERROR_INVALIDDATA;
@@ -1198,13 +1199,13 @@ static int decode_subframe(WMAProDecodeCtx *s)
             }
         }
         /** decode quantization step */
-        step = get_sbits(&s->gb, 6);
+        step = bitstream_read_signed(&s->bc, 6);
         quant_step += step;
         if (step == -32 || step == 31) {
             const int sign = (step == 31) - 1;
             int quant = 0;
-            while (get_bits_count(&s->gb) + 5 < s->num_saved_bits &&
-                   (step = get_bits(&s->gb, 5)) == 31) {
+            while (bitstream_tell(&s->bc) + 5 < s->num_saved_bits &&
+                   (step = bitstream_read(&s->bc, 5)) == 31) {
                 quant += 31;
             }
             quant_step += ((quant + step) ^ sign) - sign;
@@ -1218,13 +1219,13 @@ static int decode_subframe(WMAProDecodeCtx *s)
         if (s->channels_for_cur_subframe == 1) {
             s->channel[s->channel_indexes_for_cur_subframe[0]].quant_step = quant_step;
         } else {
-            int modifier_len = get_bits(&s->gb, 3);
+            int modifier_len = bitstream_read(&s->bc, 3);
             for (i = 0; i < s->channels_for_cur_subframe; i++) {
                 int c = s->channel_indexes_for_cur_subframe[i];
                 s->channel[c].quant_step = quant_step;
-                if (get_bits1(&s->gb)) {
+                if (bitstream_read_bit(&s->bc)) {
                     if (modifier_len) {
-                        s->channel[c].quant_step += get_bits(&s->gb, modifier_len) + 1;
+                        s->channel[c].quant_step += bitstream_read(&s->bc, modifier_len) + 1;
                     } else
                         ++s->channel[c].quant_step;
                 }
@@ -1237,13 +1238,13 @@ static int decode_subframe(WMAProDecodeCtx *s)
     }
 
     ff_dlog(s->avctx, "BITSTREAM: subframe header length was %i\n",
-            get_bits_count(&s->gb) - s->subframe_offset);
+            bitstream_tell(&s->bc) - s->subframe_offset);
 
     /** parse coefficients */
     for (i = 0; i < s->channels_for_cur_subframe; i++) {
         int c = s->channel_indexes_for_cur_subframe[i];
         if (s->channel[c].transmit_coefs &&
-            get_bits_count(&s->gb) < s->num_saved_bits) {
+            bitstream_tell(&s->bc) < s->num_saved_bits) {
             decode_coeffs(s, c);
         } else
             memset(s->channel[c].coeffs, 0,
@@ -1251,7 +1252,7 @@ static int decode_subframe(WMAProDecodeCtx *s)
     }
 
     ff_dlog(s->avctx, "BITSTREAM: subframe length was %i\n",
-            get_bits_count(&s->gb) - s->subframe_offset);
+            bitstream_tell(&s->bc) - s->subframe_offset);
 
     if (transmit_coeffs) {
         FFTContext *mdct = &s->mdct_ctx[av_log2(subframe_len) - WMAPRO_BLOCK_MIN_BITS];
@@ -1309,14 +1310,14 @@ static int decode_subframe(WMAProDecodeCtx *s)
 static int decode_frame(WMAProDecodeCtx *s, AVFrame *frame, int *got_frame_ptr)
 {
     AVCodecContext *avctx = s->avctx;
-    GetBitContext* gb = &s->gb;
+    BitstreamContext *bc = &s->bc;
     int more_frames = 0;
     int len = 0;
     int i, ret;
 
     /** get frame length */
     if (s->len_prefix)
-        len = get_bits(gb, s->log2_frame_size);
+        len = bitstream_read(bc, s->log2_frame_size);
 
     ff_dlog(s->avctx, "decoding frame with length %x\n", len);
 
@@ -1327,40 +1328,40 @@ static int decode_frame(WMAProDecodeCtx *s, AVFrame *frame, int *got_frame_ptr)
     }
 
     /** read postproc transform */
-    if (s->avctx->channels > 1 && get_bits1(gb)) {
-        if (get_bits1(gb)) {
+    if (s->avctx->channels > 1 && bitstream_read_bit(bc)) {
+        if (bitstream_read_bit(bc)) {
             for (i = 0; i < avctx->channels * avctx->channels; i++)
-                skip_bits(gb, 4);
+                bitstream_skip(bc, 4);
         }
     }
 
     /** read drc info */
     if (s->dynamic_range_compression) {
-        s->drc_gain = get_bits(gb, 8);
+        s->drc_gain = bitstream_read(bc, 8);
         ff_dlog(s->avctx, "drc_gain %i\n", s->drc_gain);
     }
 
     /** no idea what these are for, might be the number of samples
         that need to be skipped at the beginning or end of a stream */
-    if (get_bits1(gb)) {
+    if (bitstream_read_bit(bc)) {
         int av_unused skip;
 
         /** usually true for the first frame */
-        if (get_bits1(gb)) {
-            skip = get_bits(gb, av_log2(s->samples_per_frame * 2));
+        if (bitstream_read_bit(bc)) {
+            skip = bitstream_read(bc, av_log2(s->samples_per_frame * 2));
             ff_dlog(s->avctx, "start skip: %i\n", skip);
         }
 
         /** sometimes true for the last frame */
-        if (get_bits1(gb)) {
-            skip = get_bits(gb, av_log2(s->samples_per_frame * 2));
+        if (bitstream_read_bit(bc)) {
+            skip = bitstream_read(bc, av_log2(s->samples_per_frame * 2));
             ff_dlog(s->avctx, "end skip: %i\n", skip);
         }
 
     }
 
     ff_dlog(s->avctx, "BITSTREAM: frame header length was %i\n",
-            get_bits_count(gb) - s->frame_offset);
+            bitstream_tell(bc) - s->frame_offset);
 
     /** reset subframe states */
     s->parsed_all_subframes = 0;
@@ -1407,25 +1408,25 @@ static int decode_frame(WMAProDecodeCtx *s, AVFrame *frame, int *got_frame_ptr)
     }
 
     if (s->len_prefix) {
-        if (len != (get_bits_count(gb) - s->frame_offset) + 2) {
+        if (len != (bitstream_tell(bc) - s->frame_offset) + 2) {
             /** FIXME: not sure if this is always an error */
             av_log(s->avctx, AV_LOG_ERROR,
                    "frame[%"PRIu32"] would have to skip %i bits\n",
                    s->frame_num,
-                   len - (get_bits_count(gb) - s->frame_offset) - 1);
+                   len - (bitstream_tell(bc) - s->frame_offset) - 1);
             s->packet_loss = 1;
             return 0;
         }
 
         /** skip the rest of the frame data */
-        skip_bits_long(gb, len - (get_bits_count(gb) - s->frame_offset) - 1);
+        bitstream_skip(bc, len - (bitstream_tell(bc) - s->frame_offset) - 1);
     } else {
-        while (get_bits_count(gb) < s->num_saved_bits && get_bits1(gb) == 0) {
+        while (bitstream_tell(bc) < s->num_saved_bits && bitstream_read_bit(bc) == 0) {
         }
     }
 
     /** decode trailer bit */
-    more_frames = get_bits1(gb);
+    more_frames = bitstream_read_bit(bc);
 
     ++s->frame_num;
     return more_frames;
@@ -1434,22 +1435,22 @@ static int decode_frame(WMAProDecodeCtx *s, AVFrame *frame, int *got_frame_ptr)
 /**
  *@brief Calculate remaining input buffer length.
  *@param s codec context
- *@param gb bitstream reader context
+ *@param bc bitstream reader context
  *@return remaining size in bits
  */
-static int remaining_bits(WMAProDecodeCtx *s, GetBitContext *gb)
+static int remaining_bits(WMAProDecodeCtx *s, BitstreamContext *bc)
 {
-    return s->buf_bit_size - get_bits_count(gb);
+    return s->buf_bit_size - bitstream_tell(bc);
 }
 
 /**
  *@brief Fill the bit reservoir with a (partial) frame.
  *@param s codec context
- *@param gb bitstream reader context
+ *@param bc bitstream reader context
  *@param len length of the partial frame
  *@param append decides whether to reset the buffer or not
  */
-static void save_bits(WMAProDecodeCtx *s, GetBitContext* gb, int len,
+static void save_bits(WMAProDecodeCtx *s, BitstreamContext *bc, int len,
                       int append)
 {
     int buflen;
@@ -1459,7 +1460,7 @@ static void save_bits(WMAProDecodeCtx *s, GetBitContext* gb, int len,
         and skipped later so that a fast byte copy is possible */
 
     if (!append) {
-        s->frame_offset = get_bits_count(gb) & 7;
+        s->frame_offset = bitstream_tell(bc) & 7;
         s->num_saved_bits = s->frame_offset;
         init_put_bits(&s->pb, s->frame_data, MAX_FRAMESIZE);
     }
@@ -1482,24 +1483,24 @@ static void save_bits(WMAProDecodeCtx *s, GetBitContext* gb, int len,
 
     s->num_saved_bits += len;
     if (!append) {
-        avpriv_copy_bits(&s->pb, gb->buffer + (get_bits_count(gb) >> 3),
+        avpriv_copy_bits(&s->pb, bc->buffer + (bitstream_tell(bc) >> 3),
                          s->num_saved_bits);
     } else {
-        int align = 8 - (get_bits_count(gb) & 7);
+        int align = 8 - (bitstream_tell(bc) & 7);
         align = FFMIN(align, len);
-        put_bits(&s->pb, align, get_bits(gb, align));
+        put_bits(&s->pb, align, bitstream_read(bc, align));
         len -= align;
-        avpriv_copy_bits(&s->pb, gb->buffer + (get_bits_count(gb) >> 3), len);
+        avpriv_copy_bits(&s->pb, bc->buffer + (bitstream_tell(bc) >> 3), len);
     }
-    skip_bits_long(gb, len);
+    bitstream_skip(bc, len);
 
     {
         PutBitContext tmp = s->pb;
         flush_put_bits(&tmp);
     }
 
-    init_get_bits(&s->gb, s->frame_data, s->num_saved_bits);
-    skip_bits(&s->gb, s->frame_offset);
+    bitstream_init(&s->bc, s->frame_data, s->num_saved_bits);
+    bitstream_skip(&s->bc, s->frame_offset);
 }
 
 /**
@@ -1513,7 +1514,7 @@ static int decode_packet(AVCodecContext *avctx, void *data,
                          int *got_frame_ptr, AVPacket* avpkt)
 {
     WMAProDecodeCtx *s = avctx->priv_data;
-    GetBitContext* gb  = &s->pgb;
+    BitstreamContext *bc = &s->pbc;
     const uint8_t* buf = avpkt->data;
     int buf_size       = avpkt->size;
     int num_bits_prev_frame;
@@ -1536,12 +1537,12 @@ static int decode_packet(AVCodecContext *avctx, void *data,
         s->buf_bit_size = buf_size << 3;
 
         /** parse packet header */
-        init_get_bits(gb, buf, s->buf_bit_size);
-        packet_sequence_number = get_bits(gb, 4);
-        skip_bits(gb, 2);
+        bitstream_init(bc, buf, s->buf_bit_size);
+        packet_sequence_number = bitstream_read(bc, 4);
+        bitstream_skip(bc, 2);
 
         /** get number of bits that need to be added to the previous frame */
-        num_bits_prev_frame = get_bits(gb, s->log2_frame_size);
+        num_bits_prev_frame = bitstream_read(bc, s->log2_frame_size);
         ff_dlog(avctx, "packet[%d]: nbpf %x\n", avctx->frame_number,
                 num_bits_prev_frame);
 
@@ -1556,7 +1557,7 @@ static int decode_packet(AVCodecContext *avctx, void *data,
         s->packet_sequence_number = packet_sequence_number;
 
         if (num_bits_prev_frame > 0) {
-            int remaining_packet_bits = s->buf_bit_size - get_bits_count(gb);
+            int remaining_packet_bits = s->buf_bit_size - bitstream_tell(bc);
             if (num_bits_prev_frame >= remaining_packet_bits) {
                 num_bits_prev_frame = remaining_packet_bits;
                 s->packet_done = 1;
@@ -1564,7 +1565,7 @@ static int decode_packet(AVCodecContext *avctx, void *data,
 
             /** append the previous frame data to the remaining data from the
                 previous packet to create a full frame */
-            save_bits(s, gb, num_bits_prev_frame, 1);
+            save_bits(s, bc, num_bits_prev_frame, 1);
             ff_dlog(avctx, "accumulated %x bits of frame data\n",
                     s->num_saved_bits - s->frame_offset);
 
@@ -1587,15 +1588,15 @@ static int decode_packet(AVCodecContext *avctx, void *data,
     } else {
         int frame_size;
         s->buf_bit_size = (avpkt->size - s->next_packet_start) << 3;
-        init_get_bits(gb, avpkt->data, s->buf_bit_size);
-        skip_bits(gb, s->packet_offset);
-        if (s->len_prefix && remaining_bits(s, gb) > s->log2_frame_size &&
-            (frame_size = show_bits(gb, s->log2_frame_size)) &&
-            frame_size <= remaining_bits(s, gb)) {
-            save_bits(s, gb, frame_size, 0);
+        bitstream_init(bc, avpkt->data, s->buf_bit_size);
+        bitstream_skip(bc, s->packet_offset);
+        if (s->len_prefix && remaining_bits(s, bc) > s->log2_frame_size &&
+            (frame_size = bitstream_peek(bc, s->log2_frame_size)) &&
+            frame_size <= remaining_bits(s, bc)) {
+            save_bits(s, bc, frame_size, 0);
             s->packet_done = !decode_frame(s, data, got_frame_ptr);
         } else if (!s->len_prefix
-                   && s->num_saved_bits > get_bits_count(&s->gb)) {
+                   && s->num_saved_bits > bitstream_tell(&s->bc)) {
             /** when the frames do not have a length prefix, we don't know
                 the compressed length of the individual frames
                 however, we know what part of a new packet belongs to the
@@ -1609,17 +1610,17 @@ static int decode_packet(AVCodecContext *avctx, void *data,
     }
 
     if (s->packet_done && !s->packet_loss &&
-        remaining_bits(s, gb) > 0) {
+        remaining_bits(s, bc) > 0) {
         /** save the rest of the data so that it can be decoded
             with the next packet */
-        save_bits(s, gb, remaining_bits(s, gb), 0);
+        save_bits(s, bc, remaining_bits(s, bc), 0);
     }
 
-    s->packet_offset = get_bits_count(gb) & 7;
+    s->packet_offset = bitstream_tell(bc) & 7;
     if (s->packet_loss)
         return AVERROR_INVALIDDATA;
 
-    return get_bits_count(gb) >> 3;
+    return bitstream_tell(bc) >> 3;
 }
 
 /**

libavcodec/wmavoice.c

@@ -25,16 +25,15 @@
  * @author Ronald S. Bultje <rsbultje@gmail.com>
  */
 
-#define UNCHECKED_BITSTREAM_READER 1
-
 #include <math.h>
 
 #include "libavutil/channel_layout.h"
 #include "libavutil/float_dsp.h"
 #include "libavutil/mem.h"
+
 #include "avcodec.h"
+#include "bitstream.h"
 #include "internal.h"
-#include "get_bits.h"
 #include "put_bits.h"
 #include "wmavoice_data.h"
 #include "celp_filters.h"
@@ -136,7 +135,7 @@ typedef struct WMAVoiceContext {
      * @name Global values specified in the stream header / extradata or used all over.
      * @{
      */
-    GetBitContext gb;             ///< packet bitreader. During decoder init,
+    BitstreamContext bc;          ///< packet bitreader. During decoder init,
                                   ///< it contains the extradata from the
                                   ///< demuxer. During decoding, it contains
                                   ///< packet data.
@@ -296,20 +295,20 @@ typedef struct WMAVoiceContext {
 
 /**
  * Set up the variable bit mode (VBM) tree from container extradata.
- * @param gb bit I/O context.
- *           The bit context (s->gb) should be loaded with byte 23-46 of the
+ * @param bc bit I/O context.
+ *           The bit context (s->bc) should be loaded with byte 23-46 of the
  *           container extradata (i.e. the ones containing the VBM tree).
  * @param vbm_tree pointer to array to which the decoded VBM tree will be
  *                 written.
  * @return 0 on success, <0 on error.
  */
-static av_cold int decode_vbmtree(GetBitContext *gb, int8_t vbm_tree[25])
+static av_cold int decode_vbmtree(BitstreamContext *bc, int8_t vbm_tree[25])
 {
     int cntr[8] = { 0 }, n, res;
 
     memset(vbm_tree, 0xff, sizeof(vbm_tree[0]) * 25);
     for (n = 0; n < 17; n++) {
-        res = get_bits(gb, 3);
+        res = bitstream_read(bc, 3);
         if (cntr[res] > 3) // should be >= 3 + (res == 7))
             return -1;
         vbm_tree[res * 3 + cntr[res]++] = n;
@@ -401,8 +400,8 @@ static av_cold int wmavoice_decode_init(AVCodecContext *ctx)
     for (n = 0; n < s->lsps; n++)
         s->prev_lsps[n] = M_PI * (n + 1.0) / (s->lsps + 1.0);
 
-    init_get_bits(&s->gb, ctx->extradata + 22, (ctx->extradata_size - 22) << 3);
-    if (decode_vbmtree(&s->gb, s->vbm_tree) < 0) {
+    bitstream_init8(&s->bc, ctx->extradata + 22, ctx->extradata_size - 22);
+    if (decode_vbmtree(&s->bc, s->vbm_tree) < 0) {
         av_log(ctx, AV_LOG_ERROR, "Invalid VBM tree; broken extradata?\n");
         return AVERROR_INVALIDDATA;
     }
@@ -857,7 +856,7 @@ static void dequant_lsps(double *lsps, int num,
 /**
  * Parse 10 independently-coded LSPs.
  */
-static void dequant_lsp10i(GetBitContext *gb, double *lsps)
+static void dequant_lsp10i(BitstreamContext *bc, double *lsps)
 {
     static const uint16_t vec_sizes[4] = { 256, 64, 32, 32 };
     static const double mul_lsf[4] = {
@@ -870,10 +869,10 @@ static void dequant_lsp10i(GetBitContext *gb, double *lsps)
     };
     uint16_t v[4];
 
-    v[0] = get_bits(gb, 8);
-    v[1] = get_bits(gb, 6);
-    v[2] = get_bits(gb, 5);
-    v[3] = get_bits(gb, 5);
+    v[0] = bitstream_read(bc, 8);
+    v[1] = bitstream_read(bc, 6);
+    v[2] = bitstream_read(bc, 5);
+    v[3] = bitstream_read(bc, 5);
 
     dequant_lsps(lsps, 10, v, vec_sizes, 4, wmavoice_dq_lsp10i,
                  mul_lsf, base_lsf);
@@ -883,7 +882,7 @@ static void dequant_lsp10i(GetBitContext *gb, double *lsps)
  * Parse 10 independently-coded LSPs, and then derive the tables to
  * generate LSPs for the other frames from them (residual coding).
  */
-static void dequant_lsp10r(GetBitContext *gb,
+static void dequant_lsp10r(BitstreamContext *bc,
                            double *i_lsps, const double *old,
                            double *a1, double *a2, int q_mode)
 {
@@ -899,12 +898,12 @@ static void dequant_lsp10r(GetBitContext *gb,
     uint16_t interpol, v[3];
     int n;
 
-    dequant_lsp10i(gb, i_lsps);
+    dequant_lsp10i(bc, i_lsps);
 
-    interpol = get_bits(gb, 5);
-    v[0]     = get_bits(gb, 7);
-    v[1]     = get_bits(gb, 6);
-    v[2]     = get_bits(gb, 6);
+    interpol = bitstream_read(bc, 5);
+    v[0]     = bitstream_read(bc, 7);
+    v[1]     = bitstream_read(bc, 6);
+    v[2]     = bitstream_read(bc, 6);
 
     for (n = 0; n < 10; n++) {
         double delta = old[n] - i_lsps[n];
@@ -919,7 +918,7 @@ static void dequant_lsp10r(GetBitContext *gb,
 /**
  * Parse 16 independently-coded LSPs.
  */
-static void dequant_lsp16i(GetBitContext *gb, double *lsps)
+static void dequant_lsp16i(BitstreamContext *bc, double *lsps)
 {
     static const uint16_t vec_sizes[5] = { 256, 64, 128, 64, 128 };
     static const double mul_lsf[5] = {
@@ -934,11 +933,11 @@ static void dequant_lsp16i(GetBitContext *gb, double *lsps)
     };
     uint16_t v[5];
 
-    v[0] = get_bits(gb, 8);
-    v[1] = get_bits(gb, 6);
-    v[2] = get_bits(gb, 7);
-    v[3] = get_bits(gb, 6);
-    v[4] = get_bits(gb, 7);
+    v[0] = bitstream_read(bc, 8);
+    v[1] = bitstream_read(bc, 6);
+    v[2] = bitstream_read(bc, 7);
+    v[3] = bitstream_read(bc, 6);
+    v[4] = bitstream_read(bc, 7);
 
     dequant_lsps( lsps,     5,  v,     vec_sizes,    2,
                  wmavoice_dq_lsp16i1,  mul_lsf,     base_lsf);
@@ -952,7 +951,7 @@ static void dequant_lsp16i(GetBitContext *gb, double *lsps)
  * Parse 16 independently-coded LSPs, and then derive the tables to
  * generate LSPs for the other frames from them (residual coding).
  */
-static void dequant_lsp16r(GetBitContext *gb,
+static void dequant_lsp16r(BitstreamContext *bc,
                            double *i_lsps, const double *old,
                            double *a1, double *a2, int q_mode)
 {
@@ -968,12 +967,12 @@ static void dequant_lsp16r(GetBitContext *gb,
     uint16_t interpol, v[3];
     int n;
 
-    dequant_lsp16i(gb, i_lsps);
+    dequant_lsp16i(bc, i_lsps);
 
-    interpol = get_bits(gb, 5);
-    v[0]     = get_bits(gb, 7);
-    v[1]     = get_bits(gb, 7);
-    v[2]     = get_bits(gb, 7);
+    interpol = bitstream_read(bc, 5);
+    v[0]     = bitstream_read(bc, 7);
+    v[1]     = bitstream_read(bc, 7);
+    v[2]     = bitstream_read(bc, 7);
 
     for (n = 0; n < 16; n++) {
         double delta = old[n] - i_lsps[n];
@@ -999,10 +998,10 @@ static void dequant_lsp16r(GetBitContext *gb,
  * Parse the offset of the first pitch-adaptive window pulses, and
  * the distribution of pulses between the two blocks in this frame.
  * @param s WMA Voice decoding context private data
- * @param gb bit I/O context
+ * @param bc bit I/O context
  * @param pitch pitch for each block in this frame
  */
-static void aw_parse_coords(WMAVoiceContext *s, GetBitContext *gb,
+static void aw_parse_coords(WMAVoiceContext *s, BitstreamContext *bc,
                             const int *pitch)
 {
     static const int16_t start_offset[94] = {
@@ -1019,9 +1018,9 @@ static void aw_parse_coords(WMAVoiceContext *s, GetBitContext *gb,
 
     /* position of pulse */
     s->aw_idx_is_ext = 0;
-    if ((bits = get_bits(gb, 6)) >= 54) {
+    if ((bits = bitstream_read(bc, 6)) >= 54) {
         s->aw_idx_is_ext = 1;
-        bits += (bits - 54) * 3 + get_bits(gb, 2);
+        bits += (bits - 54) * 3 + bitstream_read(bc, 2);
     }
 
     /* for a repeated pulse at pulse_off with a pitch_lag of pitch[], count
@@ -1049,12 +1048,12 @@ static void aw_parse_coords(WMAVoiceContext *s, GetBitContext *gb,
 /**
  * Apply second set of pitch-adaptive window pulses.
  * @param s WMA Voice decoding context private data
- * @param gb bit I/O context
+ * @param bc bit I/O context
  * @param block_idx block index in frame [0, 1]
  * @param fcb structure containing fixed codebook vector info
  * @return -1 on error, 0 otherwise
  */
-static int aw_pulse_set2(WMAVoiceContext *s, GetBitContext *gb,
+static int aw_pulse_set2(WMAVoiceContext *s, BitstreamContext *bc,
                          int block_idx, AMRFixed *fcb)
 {
     uint16_t use_mask_mem[9]; // only 5 are used, rest is padding
@@ -1108,7 +1107,7 @@ static int aw_pulse_set2(WMAVoiceContext *s, GetBitContext *gb,
         }
 
     /* find the 'aidx'th offset that is not excluded */
-    aidx = get_bits(gb, s->aw_n_pulses[0] > 0 ? 5 - 2 * block_idx : 4);
+    aidx = bitstream_read(bc, s->aw_n_pulses[0] > 0 ? 5 - 2 * block_idx : 4);
     for (n = 0; n <= aidx; pulse_start++) {
         for (idx = pulse_start; idx < 0; idx += fcb->pitch_lag) ;
         if (idx >= MAX_FRAMESIZE / 2) { // find from zero
@@ -1128,7 +1127,7 @@ static int aw_pulse_set2(WMAVoiceContext *s, GetBitContext *gb,
     }
 
     fcb->x[fcb->n] = start_off;
-    fcb->y[fcb->n] = get_bits1(gb) ? -1.0 : 1.0;
+    fcb->y[fcb->n] = bitstream_read_bit(bc) ? -1.0 : 1.0;
     fcb->n++;
 
     /* set offset for next block, relative to start of that block */
@@ -1140,14 +1139,14 @@ static int aw_pulse_set2(WMAVoiceContext *s, GetBitContext *gb,
 /**
  * Apply first set of pitch-adaptive window pulses.
  * @param s WMA Voice decoding context private data
- * @param gb bit I/O context
+ * @param bc bit I/O context
  * @param block_idx block index in frame [0, 1]
  * @param fcb storage location for fixed codebook pulse info
  */
-static void aw_pulse_set1(WMAVoiceContext *s, GetBitContext *gb,
+static void aw_pulse_set1(WMAVoiceContext *s, BitstreamContext *bc,
                           int block_idx, AMRFixed *fcb)
 {
-    int val = get_bits(gb, 12 - 2 * (s->aw_idx_is_ext && !block_idx));
+    int val = bitstream_read(bc, 12 - 2 * (s->aw_idx_is_ext && !block_idx));
     float v;
 
     if (s->aw_n_pulses[block_idx] > 0) {
@@ -1241,7 +1240,7 @@ static int pRNG(int frame_cntr, int block_num, int block_size)
  * Parse hardcoded signal for a single block.
  * @note see #synth_block().
  */
-static void synth_block_hardcoded(WMAVoiceContext *s, GetBitContext *gb,
+static void synth_block_hardcoded(WMAVoiceContext *s, BitstreamContext *bc,
                                  int block_idx, int size,
                                  const struct frame_type_desc *frame_desc,
                                  float *excitation)
@@ -1256,8 +1255,8 @@ static void synth_block_hardcoded(WMAVoiceContext *s, GetBitContext *gb,
         r_idx = pRNG(s->frame_cntr, block_idx, size);
         gain  = s->silence_gain;
     } else /* FCB_TYPE_HARDCODED */ {
-        r_idx = get_bits(gb, 8);
-        gain  = wmavoice_gain_universal[get_bits(gb, 6)];
+        r_idx = bitstream_read(bc, 8);
+        gain  = wmavoice_gain_universal[bitstream_read(bc, 6)];
     }
 
     /* Clear gain prediction parameters */
@@ -1272,7 +1271,7 @@ static void synth_block_hardcoded(WMAVoiceContext *s, GetBitContext *gb,
  * Parse FCB/ACB signal for a single block.
  * @note see #synth_block().
  */
-static void synth_block_fcb_acb(WMAVoiceContext *s, GetBitContext *gb,
+static void synth_block_fcb_acb(WMAVoiceContext *s, BitstreamContext *bc,
                                 int block_idx, int size,
                                 int block_pitch_sh2,
                                 const struct frame_type_desc *frame_desc,
@@ -1296,8 +1295,8 @@ static void synth_block_fcb_acb(WMAVoiceContext *s, GetBitContext *gb,
     /* For the other frame types, this is where we apply the innovation
      * (fixed) codebook pulses of the speech signal. */
     if (frame_desc->fcb_type == FCB_TYPE_AW_PULSES) {
-        aw_pulse_set1(s, gb, block_idx, &fcb);
-        if (aw_pulse_set2(s, gb, block_idx, &fcb)) {
+        aw_pulse_set1(s, bc, block_idx, &fcb);
+        if (aw_pulse_set2(s, bc, block_idx, &fcb)) {
             /* Conceal the block with silence and return.
              * Skip the correct amount of bits to read the next
              * block from the correct offset. */
@@ -1306,7 +1305,7 @@ static void synth_block_fcb_acb(WMAVoiceContext *s, GetBitContext *gb,
             for (n = 0; n < size; n++)
                 excitation[n] =
                     wmavoice_std_codebook[r_idx + n] * s->silence_gain;
-            skip_bits(gb, 7 + 1);
+            bitstream_skip(bc, 7 + 1);
             return;
         }
     } else /* FCB_TYPE_EXC_PULSES */ {
@@ -1319,12 +1318,12 @@ static void synth_block_fcb_acb(WMAVoiceContext *s, GetBitContext *gb,
             float sign;
             int pos1, pos2;
 
-            sign           = get_bits1(gb) ? 1.0 : -1.0;
-            pos1           = get_bits(gb, offset_nbits);
+            sign           = bitstream_read_bit(bc) ? 1.0 : -1.0;
+            pos1           = bitstream_read(bc, offset_nbits);
             fcb.x[fcb.n]   = n + 5 * pos1;
             fcb.y[fcb.n++] = sign;
             if (n < frame_desc->dbl_pulses) {
-                pos2           = get_bits(gb, offset_nbits);
+                pos2           = bitstream_read(bc, offset_nbits);
                 fcb.x[fcb.n]   = n + 5 * pos2;
                 fcb.y[fcb.n++] = (pos1 < pos2) ? -sign : sign;
             }
@@ -1334,7 +1333,7 @@ static void synth_block_fcb_acb(WMAVoiceContext *s, GetBitContext *gb,
 
     /* Calculate gain for adaptive & fixed codebook signal.
      * see ff_amr_set_fixed_gain(). */
-    idx = get_bits(gb, 7);
+    idx = bitstream_read(bc, 7);
     fcb_gain = expf(avpriv_scalarproduct_float_c(s->gain_pred_err,
                                                  gain_coeff, 6) -
                     5.2409161640 + wmavoice_gain_codebook_fcb[idx]);
@@ -1396,7 +1395,7 @@ static void synth_block_fcb_acb(WMAVoiceContext *s, GetBitContext *gb,
  * @note we assume enough bits are available, caller should check.
  *
  * @param s WMA Voice decoding context private data
- * @param gb bit I/O context
+ * @param bc bit I/O context
  * @param block_idx index of the to-be-read block
  * @param size amount of samples to be read in this block
  * @param block_pitch_sh2 pitch for this block << 2
@@ -1407,7 +1406,7 @@ static void synth_block_fcb_acb(WMAVoiceContext *s, GetBitContext *gb,
  * @param synth target memory for the speech synthesis filter output
  * @return 0 on success, <0 on error.
  */
-static void synth_block(WMAVoiceContext *s, GetBitContext *gb,
+static void synth_block(WMAVoiceContext *s, BitstreamContext *bc,
                         int block_idx, int size,
                         int block_pitch_sh2,
                         const double *lsps, const double *prev_lsps,
@@ -1420,9 +1419,9 @@ static void synth_block(WMAVoiceContext *s, GetBitContext *gb,
     int n;
 
     if (frame_desc->acb_type == ACB_TYPE_NONE)
-        synth_block_hardcoded(s, gb, block_idx, size, frame_desc, excitation);
+        synth_block_hardcoded(s, bc, block_idx, size, frame_desc, excitation);
     else
-        synth_block_fcb_acb(s, gb, block_idx, size, block_pitch_sh2,
+        synth_block_fcb_acb(s, bc, block_idx, size, block_pitch_sh2,
                             frame_desc, excitation);
 
     /* convert interpolated LSPs to LPCs */
@@ -1440,7 +1439,7 @@ static void synth_block(WMAVoiceContext *s, GetBitContext *gb,
  * @note we assume enough bits are available, caller should check.
  *
  * @param ctx WMA Voice decoder context
- * @param gb bit I/O context (s->gb or one for cross-packet superframes)
+ * @param bc bit I/O context (s->bc or one for cross-packet superframes)
  * @param frame_idx Frame number within superframe [0-2]
  * @param samples pointer to output sample buffer, has space for at least 160
  *                samples
@@ -1450,8 +1449,8 @@ static void synth_block(WMAVoiceContext *s, GetBitContext *gb,
  * @param synth target buffer for synthesized speech data
  * @return 0 on success, <0 on error.
  */
-static int synth_frame(AVCodecContext *ctx, GetBitContext *gb, int frame_idx,
-                       float *samples,
+static int synth_frame(AVCodecContext *ctx, BitstreamContext *bc,
+                       int frame_idx, float *samples,
                        const double *lsps, const double *prev_lsps,
                        float *excitation, float *synth)
 {
@@ -1460,7 +1459,7 @@ static int synth_frame(AVCodecContext *ctx, GetBitContext *gb, int frame_idx,
     int pitch[MAX_BLOCKS], last_block_pitch;
 
     /* Parse frame type ("frame header"), see frame_descs */
-    int bd_idx = s->vbm_tree[get_vlc2(gb, frame_type_vlc.table, 6, 3)], block_nsamples;
+    int bd_idx = s->vbm_tree[bitstream_read_vlc(bc, frame_type_vlc.table, 6, 3)], block_nsamples;
 
     if (bd_idx < 0) {
         av_log(ctx, AV_LOG_ERROR,
@@ -1478,7 +1477,7 @@ static int synth_frame(AVCodecContext *ctx, GetBitContext *gb, int frame_idx,
          * incrementing/decrementing prev_frame_pitch to cur_pitch_val. */
         n_blocks_x2      = frame_descs[bd_idx].n_blocks << 1;
         log_n_blocks_x2  = frame_descs[bd_idx].log_n_blocks + 1;
-        cur_pitch_val    = s->min_pitch_val + get_bits(gb, s->pitch_nbits);
+        cur_pitch_val    = s->min_pitch_val + bitstream_read(bc, s->pitch_nbits);
         cur_pitch_val    = FFMIN(cur_pitch_val, s->max_pitch_val - 1);
         if (s->last_acb_type == ACB_TYPE_NONE ||
             20 * abs(cur_pitch_val - s->last_pitch_val) >
@@ -1502,10 +1501,10 @@ static int synth_frame(AVCodecContext *ctx, GetBitContext *gb, int frame_idx,
     /* Global gain (if silence) and pitch-adaptive window coordinates */
     switch (frame_descs[bd_idx].fcb_type) {
     case FCB_TYPE_SILENCE:
-        s->silence_gain = wmavoice_gain_silence[get_bits(gb, 8)];
+        s->silence_gain = wmavoice_gain_silence[bitstream_read(bc, 8)];
         break;
     case FCB_TYPE_AW_PULSES:
-        aw_parse_coords(s, gb, pitch);
+        aw_parse_coords(s, bc, pitch);
         break;
     }
 
@@ -1526,10 +1525,10 @@ static int synth_frame(AVCodecContext *ctx, GetBitContext *gb, int frame_idx,
                 t3 =  s->block_conv_table[3] - s->block_conv_table[2] + 1;
 
             if (n == 0) {
-                block_pitch = get_bits(gb, s->block_pitch_nbits);
+                block_pitch = bitstream_read(bc, s->block_pitch_nbits);
             } else
                 block_pitch = last_block_pitch - s->block_delta_pitch_hrange +
-                                 get_bits(gb, s->block_delta_pitch_nbits);
+                              bitstream_read(bc, s->block_delta_pitch_nbits);
             /* Convert last_ so that any next delta is within _range */
             last_block_pitch = av_clip(block_pitch,
                                        s->block_delta_pitch_hrange,
@@ -1567,7 +1566,7 @@ static int synth_frame(AVCodecContext *ctx, GetBitContext *gb, int frame_idx,
             break;
         }
 
-        synth_block(s, gb, n, block_nsamples, bl_pitch_sh2,
+        synth_block(s, bc, n, block_nsamples, bl_pitch_sh2,
                     lsps, prev_lsps, &frame_descs[bd_idx],
                     &excitation[n * block_nsamples],
                     &synth[n * block_nsamples]);
@@ -1658,32 +1657,32 @@ static void stabilize_lsps(double *lsps, int num)
 /**
  * Test if there's enough bits to read 1 superframe.
  *
- * @param orig_gb bit I/O context used for reading. This function
+ * @param orig_bc bit I/O context used for reading. This function
  *                does not modify the state of the bitreader; it
  *                only uses it to copy the current stream position
  * @param s WMA Voice decoding context private data
  * @return < 0 on error, 1 on not enough bits or 0 if OK.
  */
-static int check_bits_for_superframe(GetBitContext *orig_gb,
+static int check_bits_for_superframe(BitstreamContext *orig_bc,
                                      WMAVoiceContext *s)
 {
-    GetBitContext s_gb, *gb = &s_gb;
+    BitstreamContext s_bc, *bc = &s_bc;
     int n, need_bits, bd_idx;
     const struct frame_type_desc *frame_desc;
 
     /* initialize a copy */
-    *gb = *orig_gb;
+    *bc = *orig_bc;
 
     /* superframe header */
-    if (get_bits_left(gb) < 14)
+    if (bitstream_bits_left(bc) < 14)
         return 1;
-    if (!get_bits1(gb))
+    if (!bitstream_read_bit(bc))
         return AVERROR(ENOSYS);           // WMAPro-in-WMAVoice superframe
-    if (get_bits1(gb)) skip_bits(gb, 12); // number of  samples in superframe
+    if (bitstream_read_bit(bc)) bitstream_skip(bc, 12); // number of  samples in superframe
     if (s->has_residual_lsps) {           // residual LSPs (for all frames)
-        if (get_bits_left(gb) < s->sframe_lsp_bitsize)
+        if (bitstream_bits_left(bc) < s->sframe_lsp_bitsize)
             return 1;
-        skip_bits_long(gb, s->sframe_lsp_bitsize);
+        bitstream_skip(bc, s->sframe_lsp_bitsize);
     }
 
     /* frames */
@@ -1691,24 +1690,25 @@ static int check_bits_for_superframe(GetBitContext *orig_gb,
         int aw_idx_is_ext = 0;
 
         if (!s->has_residual_lsps) {     // independent LSPs (per-frame)
-           if (get_bits_left(gb) < s->frame_lsp_bitsize) return 1;
-           skip_bits_long(gb, s->frame_lsp_bitsize);
+           if (bitstream_bits_left(bc) < s->frame_lsp_bitsize)
+               return 1;
+           bitstream_skip(bc, s->frame_lsp_bitsize);
         }
-        bd_idx = s->vbm_tree[get_vlc2(gb, frame_type_vlc.table, 6, 3)];
+        bd_idx = s->vbm_tree[bitstream_read_vlc(bc, frame_type_vlc.table, 6, 3)];
         if (bd_idx < 0)
             return AVERROR_INVALIDDATA; // invalid frame type VLC code
         frame_desc = &frame_descs[bd_idx];
         if (frame_desc->acb_type == ACB_TYPE_ASYMMETRIC) {
-            if (get_bits_left(gb) < s->pitch_nbits)
+            if (bitstream_bits_left(bc) < s->pitch_nbits)
                 return 1;
-            skip_bits_long(gb, s->pitch_nbits);
+            bitstream_skip(bc, s->pitch_nbits);
         }
         if (frame_desc->fcb_type == FCB_TYPE_SILENCE) {
-            skip_bits(gb, 8);
+            bitstream_skip(bc, 8);
         } else if (frame_desc->fcb_type == FCB_TYPE_AW_PULSES) {
-            int tmp = get_bits(gb, 6);
+            int tmp = bitstream_read(bc, 6);
             if (tmp >= 0x36) {
-                skip_bits(gb, 2);
+                bitstream_skip(bc, 2);
                 aw_idx_is_ext = 1;
             }
         }
@@ -1722,9 +1722,9 @@ static int check_bits_for_superframe(GetBitContext *orig_gb,
         } else
             need_bits = 0;
         need_bits += frame_desc->frame_size;
-        if (get_bits_left(gb) < need_bits)
+        if (bitstream_bits_left(bc) < need_bits)
             return 1;
-        skip_bits_long(gb, need_bits);
+        bitstream_skip(bc, need_bits);
     }
 
     return 0;
@@ -1733,7 +1733,7 @@ static int check_bits_for_superframe(GetBitContext *orig_gb,
 /**
  * Synthesize output samples for a single superframe. If we have any data
  * cached in s->sframe_cache, that will be used instead of whatever is loaded
- * in s->gb.
+ * in s->bc.
  *
  * WMA Voice superframes contain 3 frames, each containing 160 audio samples,
  * to give a total of 480 samples per frame. See #synth_frame() for frame
@@ -1751,7 +1751,7 @@ static int synth_superframe(AVCodecContext *ctx, AVFrame *frame,
                             int *got_frame_ptr)
 {
     WMAVoiceContext *s = ctx->priv_data;
-    GetBitContext *gb = &s->gb, s_gb;
+    BitstreamContext *bc = &s->bc, s_bc;
     int n, res, n_samples = 480;
     double lsps[MAX_FRAMES][MAX_LSPS];
     const double *mean_lsf = s->lsps == 16 ?
@@ -1766,12 +1766,12 @@ static int synth_superframe(AVCodecContext *ctx, AVFrame *frame,
            s->history_nsamples * sizeof(*excitation));
 
     if (s->sframe_cache_size > 0) {
-        gb = &s_gb;
-        init_get_bits(gb, s->sframe_cache, s->sframe_cache_size);
+        bc = &s_bc;
+        bitstream_init(bc, s->sframe_cache, s->sframe_cache_size);
         s->sframe_cache_size = 0;
     }
 
-    if ((res = check_bits_for_superframe(gb, s)) == 1) {
+    if ((res = check_bits_for_superframe(bc, s)) == 1) {
         *got_frame_ptr = 0;
         return 1;
     } else if (res < 0)
@@ -1781,14 +1781,14 @@ static int synth_superframe(AVCodecContext *ctx, AVFrame *frame,
      * speech samples (the actual codec) and WMAVoice music samples, which
      * are really WMAPro-in-WMAVoice-superframes. I've never seen those in
      * the wild yet. */
-    if (!get_bits1(gb)) {
+    if (!bitstream_read_bit(bc)) {
         avpriv_request_sample(ctx, "WMAPro-in-WMAVoice");
         return AVERROR_PATCHWELCOME;
     }
 
     /* (optional) nr. of samples in superframe; always <= 480 and >= 0 */
-    if (get_bits1(gb)) {
-        if ((n_samples = get_bits(gb, 12)) > 480) {
+    if (bitstream_read_bit(bc)) {
+        if ((n_samples = bitstream_read(bc, 12)) > 480) {
             av_log(ctx, AV_LOG_ERROR,
                    "Superframe encodes >480 samples (%d), not allowed\n",
                    n_samples);
@@ -1803,9 +1803,9 @@ static int synth_superframe(AVCodecContext *ctx, AVFrame *frame,
             prev_lsps[n] = s->prev_lsps[n] - mean_lsf[n];
 
         if (s->lsps == 10) {
-            dequant_lsp10r(gb, lsps[2], prev_lsps, a1, a2, s->lsp_q_mode);
+            dequant_lsp10r(bc, lsps[2], prev_lsps, a1, a2, s->lsp_q_mode);
         } else /* s->lsps == 16 */
-            dequant_lsp16r(gb, lsps[2], prev_lsps, a1, a2, s->lsp_q_mode);
+            dequant_lsp16r(bc, lsps[2], prev_lsps, a1, a2, s->lsp_q_mode);
 
         for (n = 0; n < s->lsps; n++) {
             lsps[0][n]  = mean_lsf[n] + (a1[n]           - a2[n * 2]);
@@ -1831,16 +1831,16 @@ static int synth_superframe(AVCodecContext *ctx, AVFrame *frame,
             int m;
 
             if (s->lsps == 10) {
-                dequant_lsp10i(gb, lsps[n]);
+                dequant_lsp10i(bc, lsps[n]);
             } else /* s->lsps == 16 */
-                dequant_lsp16i(gb, lsps[n]);
+                dequant_lsp16i(bc, lsps[n]);
 
             for (m = 0; m < s->lsps; m++)
                 lsps[n][m] += mean_lsf[m];
             stabilize_lsps(lsps[n], s->lsps);
         }
 
-        if ((res = synth_frame(ctx, gb, n,
+        if ((res = synth_frame(ctx, bc, n,
                                &samples[n * MAX_FRAMESIZE],
                                lsps[n], n == 0 ? s->prev_lsps : lsps[n - 1],
                                &excitation[s->history_nsamples + n * MAX_FRAMESIZE],
@@ -1853,9 +1853,9 @@ static int synth_superframe(AVCodecContext *ctx, AVFrame *frame,
     /* Statistics? FIXME - we don't check for length, a slight overrun
      * will be caught by internal buffer padding, and anything else
      * will be skipped, not read. */
-    if (get_bits1(gb)) {
-        res = get_bits(gb, 4);
-        skip_bits(gb, 10 * (res + 1));
+    if (bitstream_read_bit(bc)) {
+        res = bitstream_read(bc, 4);
+        bitstream_skip(bc, 10 * (res + 1));
     }
 
     *got_frame_ptr = 1;
@@ -1883,31 +1883,31 @@ static int synth_superframe(AVCodecContext *ctx, AVFrame *frame,
  */
 static int parse_packet_header(WMAVoiceContext *s)
 {
-    GetBitContext *gb = &s->gb;
+    BitstreamContext *bc = &s->bc;
     unsigned int res;
 
-    if (get_bits_left(gb) < 11)
+    if (bitstream_bits_left(bc) < 11)
         return 1;
-    skip_bits(gb, 4);          // packet sequence number
-    s->has_residual_lsps = get_bits1(gb);
+    bitstream_skip(bc, 4);      // packet sequence number
+    s->has_residual_lsps = bitstream_read_bit(bc);
     do {
-        res = get_bits(gb, 6); // number of superframes per packet
+        res = bitstream_read(bc, 6); // number of superframes per packet
                                      // (minus first one if there is spillover)
-        if (get_bits_left(gb) < 6 * (res == 0x3F) + s->spillover_bitsize)
+        if (bitstream_bits_left(bc) < 6 * (res == 0x3F) + s->spillover_bitsize)
             return 1;
     } while (res == 0x3F);
-    s->spillover_nbits   = get_bits(gb, s->spillover_bitsize);
+    s->spillover_nbits = bitstream_read(bc, s->spillover_bitsize);
 
     return 0;
 }
 
 /**
- * Copy (unaligned) bits from gb/data/size to pb.
+ * Copy (unaligned) bits from bc/data/size to pb.
  *
  * @param pb target buffer to copy bits into
  * @param data source buffer to copy bits from
  * @param size size of the source data, in bytes
- * @param gb bit I/O context specifying the current position in the source.
+ * @param bc bit I/O context specifying the current position in the source.
  *           data. This function might use this to align the bit position to
  *           a whole-byte boundary before calling #avpriv_copy_bits() on aligned
  *           source data
@@ -1918,18 +1918,18 @@ static int parse_packet_header(WMAVoiceContext *s)
  */
 static void copy_bits(PutBitContext *pb,
                       const uint8_t *data, int size,
-                      GetBitContext *gb, int nbits)
+                      BitstreamContext *bc, int nbits)
 {
     int rmn_bytes, rmn_bits;
 
-    rmn_bits = rmn_bytes = get_bits_left(gb);
+    rmn_bits = rmn_bytes = bitstream_bits_left(bc);
     if (rmn_bits < nbits)
         return;
     if (nbits > pb->size_in_bits - put_bits_count(pb))
         return;
     rmn_bits &= 7; rmn_bytes >>= 3;
     if ((rmn_bits = FFMIN(rmn_bits, nbits)) > 0)
-        put_bits(pb, rmn_bits, get_bits(gb, rmn_bits));
+        put_bits(pb, rmn_bits, bitstream_read(bc, rmn_bits));
     avpriv_copy_bits(pb, data + size - rmn_bytes,
                  FFMIN(nbits - rmn_bits, rmn_bytes << 3));
 }
@@ -1949,7 +1949,7 @@ static int wmavoice_decode_packet(AVCodecContext *ctx, void *data,
                                   int *got_frame_ptr, AVPacket *avpkt)
 {
     WMAVoiceContext *s = ctx->priv_data;
-    GetBitContext *gb = &s->gb;
+    BitstreamContext *bc = &s->bc;
     int size, res, pos;
 
     /* Packets are sometimes a multiple of ctx->block_align, with a packet
@@ -1962,7 +1962,7 @@ static int wmavoice_decode_packet(AVCodecContext *ctx, void *data,
         *got_frame_ptr = 0;
         return 0;
     }
-    init_get_bits(&s->gb, avpkt->data, size << 3);
+    bitstream_init8(&s->bc, avpkt->data, size);
 
     /* size == ctx->block_align is used to indicate whether we are dealing with
      * a new packet or a packet of which we already read the packet header
@@ -1976,8 +1976,8 @@ static int wmavoice_decode_packet(AVCodecContext *ctx, void *data,
          * continuing to parse new superframes in the current packet. */
         if (s->spillover_nbits > 0) {
             if (s->sframe_cache_size > 0) {
-                int cnt = get_bits_count(gb);
-                copy_bits(&s->pb, avpkt->data, size, gb, s->spillover_nbits);
+                int cnt = bitstream_tell(bc);
+                copy_bits(&s->pb, avpkt->data, size, bc, s->spillover_nbits);
                 flush_put_bits(&s->pb);
                 s->sframe_cache_size += s->spillover_nbits;
                 if ((res = synth_superframe(ctx, data, got_frame_ptr)) == 0 &&
@@ -1986,33 +1986,33 @@ static int wmavoice_decode_packet(AVCodecContext *ctx, void *data,
                     s->skip_bits_next = cnt & 7;
                     return cnt >> 3;
                 } else
-                    skip_bits_long (gb, s->spillover_nbits - cnt +
-                                    get_bits_count(gb)); // resync
+                    bitstream_skip (bc, s->spillover_nbits - cnt +
+                                    bitstream_tell(bc)); // resync
             } else
-                skip_bits_long(gb, s->spillover_nbits);  // resync
+                bitstream_skip(bc, s->spillover_nbits);  // resync
         }
     } else if (s->skip_bits_next)
-        skip_bits(gb, s->skip_bits_next);
+        bitstream_skip(bc, s->skip_bits_next);
 
     /* Try parsing superframes in current packet */
     s->sframe_cache_size = 0;
     s->skip_bits_next = 0;
-    pos = get_bits_left(gb);
+    pos = bitstream_bits_left(bc);
     if ((res = synth_superframe(ctx, data, got_frame_ptr)) < 0) {
         return res;
     } else if (*got_frame_ptr) {
-        int cnt = get_bits_count(gb);
+        int cnt = bitstream_tell(bc);
         s->skip_bits_next = cnt & 7;
         return cnt >> 3;
     } else if ((s->sframe_cache_size = pos) > 0) {
         /* rewind bit reader to start of last (incomplete) superframe... */
-        init_get_bits(gb, avpkt->data, size << 3);
-        skip_bits_long(gb, (size << 3) - pos);
-        assert(get_bits_left(gb) == pos);
+        bitstream_init8(bc, avpkt->data, size);
+        bitstream_skip(bc, (size << 3) - pos);
+        assert(bitstream_bits_left(bc) == pos);
 
         /* ...and cache it for spillover in next packet */
         init_put_bits(&s->pb, s->sframe_cache, SFRAME_CACHE_MAXSIZE);
-        copy_bits(&s->pb, avpkt->data, size, gb, s->sframe_cache_size);
+        copy_bits(&s->pb, avpkt->data, size, bc, s->sframe_cache_size);
         // FIXME bad - just copy bytes as whole and add use the
         // skip_bits_next field
     }