metasound: add last missing modes (8kHz @ 6kbps per channel)

Signed-off-by: Anton Khirnov <anton@khirnov.net>

Changelog

@@ -32,7 +32,7 @@ version 10:
   the -noaccurate_seek option.
 - avconv -t option can now be used for inputs, to limit the duration of
   data read from an input file
-- incomplete Voxware MetaSound decoder
+- Voxware MetaSound decoder
 - WebP decoder
 - Error Resilient AAC syntax (ER AAC LC) decoding
 - Low Delay AAC (ER AAC LD) decoding

doc/general.texi

@@ -827,7 +827,6 @@ following image formats are supported:
 @item Vorbis                 @tab  E  @tab  X
     @tab A native but very primitive encoder exists.
 @item Voxware MetaSound      @tab     @tab  X
-    @tab imperfect and incomplete support
 @item WavPack                @tab  E  @tab  X
     @tab supported through external library libwavpack
 @item Westwood Audio (SND1)  @tab     @tab  X

libavcodec/metasound.c

@@ -187,7 +187,7 @@ static int metasound_read_bitstream(AVCodecContext *avctx, TwinVQContext *tctx,
 
         sub = mtab->fmode[bits->ftype].sub;
 
-        if (bits->ftype != TWINVQ_FT_SHORT)
+        if (bits->ftype != TWINVQ_FT_SHORT && !tctx->is_6kbps)
             get_bits(&gb, 2);
 
         read_cb_data(tctx, &gb, bits->main_coeffs, bits->ftype);
@@ -307,6 +307,12 @@ static av_cold int metasound_decode_init(AVCodecContext *avctx)
     ibps = avctx->bit_rate / (1000 * avctx->channels);
 
     switch ((avctx->channels << 16) + (isampf << 8) + ibps) {
+    case (1 << 16) + ( 8 << 8) +  6:
+        tctx->mtab = &ff_metasound_mode0806;
+        break;
+    case (2 << 16) + ( 8 << 8) +  6:
+        tctx->mtab = &ff_metasound_mode0806s;
+        break;
     case (1 << 16) + ( 8 << 8) +  8:
         tctx->mtab = &ff_metasound_mode0808;
         break;
@@ -362,6 +368,7 @@ static av_cold int metasound_decode_init(AVCodecContext *avctx)
     tctx->decode_ppc     = decode_ppc;
     tctx->frame_size     = avctx->bit_rate * tctx->mtab->size
                                            / avctx->sample_rate;
+    tctx->is_6kbps       = ibps == 6;
 
     return ff_twinvq_decode_init(avctx);
 }

libavcodec/metasound_data.c

@@ -15190,6 +15190,24 @@ static const uint16_t bark_tab_s44_128[] = {
     1, 2, 1, 2, 3, 4, 6, 10, 23, 76
 };
 
+const TwinVQModeTab ff_metasound_mode0806 = {
+    {
+        {  8, bark_tab_s8_64,  10, fcb8s, 1, 5, cb0806ss0, cb0806ss1, 27 },
+        {  2, bark_tab_m8_256, 20, fcb8m, 2, 5, cb0806sm0, cb0806sm1, 22 },
+        {  1, bark_tab_l8_512, 30, fcb8l, 3, 6, cb0806sl0, cb0806sl1, 24 }
+    },
+    512, 12, lsp8, 1, 5, 3, 3, shape8, 8, 28, 20, 6, 200
+};
+
+const TwinVQModeTab ff_metasound_mode0806s = {
+    {
+        {  8, bark_tab_s8s_64,  10, fcb8ss, 1, 5, cb0806ss0, cb0806ss1, 27 },
+        {  2, bark_tab_m8s_256, 20, fcb8sm, 2, 5, cb0806sm0, cb0806sm1, 22 },
+        {  1, bark_tab_l8s_512, 30, fcb8sl, 3, 6, cb0806sl0, cb0806sl1, 24 }
+    },
+    512, 12, lsp8s, 1, 5, 3, 3, shape8s, 8, 28, 20, 6, 200
+};
+
 const TwinVQModeTab ff_metasound_mode0808 = {
     {
         { 8, bark_tab_s8_64,  10, fcb8s, 1, 5, cb0808s0, cb0808s1, 18 },

libavcodec/twinvq.c

@@ -706,7 +706,7 @@ static av_cold void init_bitstream_params(TwinVQContext *tctx)
             TWINVQ_WINDOW_TYPE_BITS +
             mtab->fmode[i].sub * (bse_bits[i] + n_ch * TWINVQ_SUB_GAIN_BITS);
 
-    if (tctx->codec == TWINVQ_CODEC_METASOUND) {
+    if (tctx->codec == TWINVQ_CODEC_METASOUND && !tctx->is_6kbps) {
         bsize_no_main_cb[1] += 2;
         bsize_no_main_cb[2] += 2;
     }

libavcodec/twinvq.h

@@ -141,6 +141,8 @@ typedef struct TwinVQContext {
 
     const TwinVQModeTab *mtab;
 
+    int is_6kbps;
+
     // history
     float lsp_hist[2][20];           ///< LSP coefficients of the last frame
     float bark_hist[3][2][40];       ///< BSE coefficients of last frame

libavcodec/twinvqdec.c

@@ -402,6 +402,7 @@ static av_cold int twinvq_decode_init(AVCodecContext *avctx)
     tctx->decode_ppc     = decode_ppc;
     tctx->frame_size     = avctx->bit_rate * tctx->mtab->size
                                            / avctx->sample_rate + 8;
+    tctx->is_6kbps       = 0;
     if (avctx->block_align && avctx->block_align * 8 / tctx->frame_size > 1) {
         av_log(avctx, AV_LOG_ERROR,
                "VQF TwinVQ should have only one frame per packet\n");