wmall: Working bitstream parser

libavcodec/Makefile

@@ -408,6 +408,7 @@ OBJS-$(CONFIG_VP6_DECODER)             += vp6.o vp56.o vp56data.o vp56dsp.o \
 OBJS-$(CONFIG_VP8_DECODER)             += vp8.o vp8dsp.o vp56rac.o
 OBJS-$(CONFIG_VQA_DECODER)             += vqavideo.o
 OBJS-$(CONFIG_WAVPACK_DECODER)         += wavpack.o
+OBJS-$(CONFIG_WMALOSSLESS_DECODER)     += wmalosslessdec.o wma.o
 OBJS-$(CONFIG_WMAPRO_DECODER)          += wmaprodec.o wma.o
 OBJS-$(CONFIG_WMAV1_DECODER)           += wmadec.o wma.o aactab.o
 OBJS-$(CONFIG_WMAV1_ENCODER)           += wmaenc.o wma.o aactab.o

libavcodec/allcodecs.c

@@ -284,6 +284,7 @@ void avcodec_register_all(void)
     REGISTER_DECODER (VMDAUDIO, vmdaudio);
     REGISTER_ENCDEC  (VORBIS, vorbis);
     REGISTER_DECODER (WAVPACK, wavpack);
+    REGISTER_DECODER (WMALOSSLESS, wmalossless);
     REGISTER_DECODER (WMAPRO, wmapro);
     REGISTER_ENCDEC  (WMAV1, wmav1);
     REGISTER_ENCDEC  (WMAV2, wmav2);

libavcodec/wmalosslessdec.c

+/*
+ * Wmall compatible decoder
+ * Copyright (c) 2007 Baptiste Coudurier, Benjamin Larsson, Ulion
+ * Copyright (c) 2008 - 2011 Sascha Sommer, Benjamin Larsson
+ * Copyright (c) 2011 Andreas Öman
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * @brief wmall decoder implementation
+ * Wmall is an MDCT based codec comparable to wma standard or AAC.
+ * The decoding therefore consists of the following steps:
+ * - bitstream decoding
+ * - reconstruction of per-channel data
+ * - rescaling and inverse quantization
+ * - IMDCT
+ * - windowing and overlapp-add
+ *
+ * The compressed wmall bitstream is split into individual packets.
+ * Every such packet contains one or more wma frames.
+ * The compressed frames may have a variable length and frames may
+ * cross packet boundaries.
+ * Common to all wmall frames is the number of samples that are stored in
+ * a frame.
+ * The number of samples and a few other decode flags are stored
+ * as extradata that has to be passed to the decoder.
+ *
+ * The wmall frames themselves are again split into a variable number of
+ * subframes. Every subframe contains the data for 2^N time domain samples
+ * where N varies between 7 and 12.
+ *
+ * Example wmall bitstream (in samples):
+ *
+ * ||   packet 0           || packet 1 || packet 2      packets
+ * ---------------------------------------------------
+ * || frame 0      || frame 1       || frame 2    ||    frames
+ * ---------------------------------------------------
+ * ||   |      |   ||   |   |   |   ||            ||    subframes of channel 0
+ * ---------------------------------------------------
+ * ||      |   |   ||   |   |   |   ||            ||    subframes of channel 1
+ * ---------------------------------------------------
+ *
+ * The frame layouts for the individual channels of a wma frame does not need
+ * to be the same.
+ *
+ * However, if the offsets and lengths of several subframes of a frame are the
+ * same, the subframes of the channels can be grouped.
+ * Every group may then use special coding techniques like M/S stereo coding
+ * to improve the compression ratio. These channel transformations do not
+ * need to be applied to a whole subframe. Instead, they can also work on
+ * individual scale factor bands (see below).
+ * The coefficients that carry the audio signal in the frequency domain
+ * are transmitted as huffman-coded vectors with 4, 2 and 1 elements.
+ * In addition to that, the encoder can switch to a runlevel coding scheme
+ * by transmitting subframe_length / 128 zero coefficients.
+ *
+ * Before the audio signal can be converted to the time domain, the
+ * coefficients have to be rescaled and inverse quantized.
+ * A subframe is therefore split into several scale factor bands that get
+ * scaled individually.
+ * Scale factors are submitted for every frame but they might be shared
+ * between the subframes of a channel. Scale factors are initially DPCM-coded.
+ * Once scale factors are shared, the differences are transmitted as runlevel
+ * codes.
+ * Every subframe length and offset combination in the frame layout shares a
+ * common quantization factor that can be adjusted for every channel by a
+ * modifier.
+ * After the inverse quantization, the coefficients get processed by an IMDCT.
+ * The resulting values are then windowed with a sine window and the first half
+ * of the values are added to the second half of the output from the previous
+ * subframe in order to reconstruct the output samples.
+ */
+
+#include "avcodec.h"
+#include "internal.h"
+#include "get_bits.h"
+#include "put_bits.h"
+#include "dsputil.h"
+#include "wma.h"
+
+/** current decoder limitations */
+#define WMALL_MAX_CHANNELS    8                             ///< max number of handled channels
+#define MAX_SUBFRAMES  32                                    ///< max number of subframes per channel
+#define MAX_BANDS      29                                    ///< max number of scale factor bands
+#define MAX_FRAMESIZE  32768                                 ///< maximum compressed frame size
+
+#define WMALL_BLOCK_MIN_BITS  6                                           ///< log2 of min block size
+#define WMALL_BLOCK_MAX_BITS 12                                           ///< log2 of max block size
+#define WMALL_BLOCK_MAX_SIZE (1 << WMALL_BLOCK_MAX_BITS)                 ///< maximum block size
+#define WMALL_BLOCK_SIZES    (WMALL_BLOCK_MAX_BITS - WMALL_BLOCK_MIN_BITS + 1) ///< possible block sizes
+
+
+#define VLCBITS            9
+#define SCALEVLCBITS       8
+#define VEC4MAXDEPTH    ((HUFF_VEC4_MAXBITS+VLCBITS-1)/VLCBITS)
+#define VEC2MAXDEPTH    ((HUFF_VEC2_MAXBITS+VLCBITS-1)/VLCBITS)
+#define VEC1MAXDEPTH    ((HUFF_VEC1_MAXBITS+VLCBITS-1)/VLCBITS)
+#define SCALEMAXDEPTH   ((HUFF_SCALE_MAXBITS+SCALEVLCBITS-1)/SCALEVLCBITS)
+#define SCALERLMAXDEPTH ((HUFF_SCALE_RL_MAXBITS+VLCBITS-1)/VLCBITS)
+
+static float            sin64[33];        ///< sinus table for decorrelation
+
+/**
+ * @brief frame specific decoder context for a single channel
+ */
+typedef struct {
+    int16_t  prev_block_len;                          ///< length of the previous block
+    uint8_t  transmit_coefs;
+    uint8_t  num_subframes;
+    uint16_t subframe_len[MAX_SUBFRAMES];             ///< subframe length in samples
+    uint16_t subframe_offset[MAX_SUBFRAMES];          ///< subframe positions in the current frame
+    uint8_t  cur_subframe;                            ///< current subframe number
+    uint16_t decoded_samples;                         ///< number of already processed samples
+    uint8_t  grouped;                                 ///< channel is part of a group
+    int      quant_step;                              ///< quantization step for the current subframe
+    int8_t   reuse_sf;                                ///< share scale factors between subframes
+    int8_t   scale_factor_step;                       ///< scaling step for the current subframe
+    int      max_scale_factor;                        ///< maximum scale factor for the current subframe
+    int      saved_scale_factors[2][MAX_BANDS];       ///< resampled and (previously) transmitted scale factor values
+    int8_t   scale_factor_idx;                        ///< index for the transmitted scale factor values (used for resampling)
+    int*     scale_factors;                           ///< pointer to the scale factor values used for decoding
+    uint8_t  table_idx;                               ///< index in sf_offsets for the scale factor reference block
+    float*   coeffs;                                  ///< pointer to the subframe decode buffer
+    uint16_t num_vec_coeffs;                          ///< number of vector coded coefficients
+    DECLARE_ALIGNED(16, float, out)[WMALL_BLOCK_MAX_SIZE + WMALL_BLOCK_MAX_SIZE / 2]; ///< output buffer
+} WmallChannelCtx;
+
+/**
+ * @brief channel group for channel transformations
+ */
+typedef struct {
+    uint8_t num_channels;                                     ///< number of channels in the group
+    int8_t  transform;                                        ///< transform on / off
+    int8_t  transform_band[MAX_BANDS];                        ///< controls if the transform is enabled for a certain band
+    float   decorrelation_matrix[WMALL_MAX_CHANNELS*WMALL_MAX_CHANNELS];
+    float*  channel_data[WMALL_MAX_CHANNELS];                ///< transformation coefficients
+} WmallChannelGrp;
+
+/**
+ * @brief main decoder context
+ */
+typedef struct WmallDecodeCtx {
+    /* generic decoder variables */
+    AVCodecContext*  avctx;                         ///< codec context for av_log
+    DSPContext       dsp;                           ///< accelerated DSP functions
+    uint8_t          frame_data[MAX_FRAMESIZE +
+                      FF_INPUT_BUFFER_PADDING_SIZE];///< compressed frame data
+    PutBitContext    pb;                            ///< context for filling the frame_data buffer
+    FFTContext       mdct_ctx[WMALL_BLOCK_SIZES];  ///< MDCT context per block size
+    DECLARE_ALIGNED(16, float, tmp)[WMALL_BLOCK_MAX_SIZE]; ///< IMDCT output buffer
+    float*           windows[WMALL_BLOCK_SIZES];   ///< windows for the different block sizes
+
+    /* frame size dependent frame information (set during initialization) */
+    uint32_t         decode_flags;                  ///< used compression features
+    uint8_t          len_prefix;                    ///< frame is prefixed with its length
+    uint8_t          dynamic_range_compression;     ///< frame contains DRC data
+    uint8_t          bits_per_sample;               ///< integer audio sample size for the unscaled IMDCT output (used to scale to [-1.0, 1.0])
+    uint16_t         samples_per_frame;             ///< number of samples to output
+    uint16_t         log2_frame_size;
+    int8_t           num_channels;                  ///< number of channels in the stream (same as AVCodecContext.num_channels)
+    int8_t           lfe_channel;                   ///< lfe channel index
+    uint8_t          max_num_subframes;
+    uint8_t          subframe_len_bits;             ///< number of bits used for the subframe length
+    uint8_t          max_subframe_len_bit;          ///< flag indicating that the subframe is of maximum size when the first subframe length bit is 1
+    uint16_t         min_samples_per_subframe;
+    int8_t           num_sfb[WMALL_BLOCK_SIZES];   ///< scale factor bands per block size
+    int16_t          sfb_offsets[WMALL_BLOCK_SIZES][MAX_BANDS];                    ///< scale factor band offsets (multiples of 4)
+    int8_t           sf_offsets[WMALL_BLOCK_SIZES][WMALL_BLOCK_SIZES][MAX_BANDS]; ///< scale factor resample matrix
+    int16_t          subwoofer_cutoffs[WMALL_BLOCK_SIZES]; ///< subwoofer cutoff values
+
+    /* packet decode state */
+    GetBitContext    pgb;                           ///< 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
+    int              num_saved_bits;                ///< saved number of bits
+    int              frame_offset;                  ///< frame offset in the bit reservoir
+    int              subframe_offset;               ///< subframe offset in the bit reservoir
+    uint8_t          packet_loss;                   ///< set in case of bitstream error
+    uint8_t          packet_done;                   ///< set when a packet is fully decoded
+
+    /* frame decode state */
+    uint32_t         frame_num;                     ///< current frame number (not used for decoding)
+    GetBitContext    gb;                            ///< bitstream reader context
+    int              buf_bit_size;                  ///< buffer size in bits
+    float*           samples;                       ///< current samplebuffer pointer
+    float*           samples_end;                   ///< maximum samplebuffer pointer
+    uint8_t          drc_gain;                      ///< gain for the DRC tool
+    int8_t           skip_frame;                    ///< skip output step
+    int8_t           parsed_all_subframes;          ///< all subframes decoded?
+
+    /* subframe/block decode state */
+    int16_t          subframe_len;                  ///< current subframe length
+    int8_t           channels_for_cur_subframe;     ///< number of channels that contain the subframe
+    int8_t           channel_indexes_for_cur_subframe[WMALL_MAX_CHANNELS];
+    int8_t           num_bands;                     ///< number of scale factor bands
+    int8_t           transmit_num_vec_coeffs;       ///< number of vector coded coefficients is part of the bitstream
+    int16_t*         cur_sfb_offsets;               ///< sfb offsets for the current block
+    uint8_t          table_idx;                     ///< index for the num_sfb, sfb_offsets, sf_offsets and subwoofer_cutoffs tables
+    int8_t           esc_len;                       ///< length of escaped coefficients
+
+    uint8_t          num_chgroups;                  ///< number of channel groups
+    WmallChannelGrp chgroup[WMALL_MAX_CHANNELS];  ///< channel group information
+
+    WmallChannelCtx channel[WMALL_MAX_CHANNELS];  ///< per channel data
+
+    // WMA lossless
+    
+    uint8_t do_arith_coding;
+    uint8_t do_ac_filter;
+    uint8_t do_inter_ch_decorr;
+    uint8_t do_mclms;
+    uint8_t do_lpc;
+
+    int8_t acfilter_order;
+    int8_t acfilter_scaling;
+    int acfilter_coeffs[16];
+
+    int8_t mclms_order;
+    int8_t mclms_scaling;
+    int16_t mclms_coeffs[128];
+    int16_t mclms_coeffs_cur[4];
+
+    int movave_scaling;
+    int quant_stepsize;
+
+    struct {
+	int order;
+	int scaling;
+	int coefsend;
+	int bitsend;
+	int16_t coefs[256];
+    } cdlms[2][9];
+
+
+    int cdlms_ttl[2];
+
+    int bV3RTM;
+
+    int is_channel_coded[2];
+
+    int transient[2];
+    int transient_pos[2];
+    int seekable_tile;
+
+    int ave_sum[2];
+
+    int channel_residues[2][2048];
+
+
+    int lpc_coefs[2][40];
+    int lpc_order;
+    int lpc_scaling;
+    int lpc_intbits;
+
+    int channel_coeffs[2][2048];
+
+} WmallDecodeCtx;
+
+
+#undef dprintf
+#define dprintf(pctx, ...) av_log(pctx, AV_LOG_DEBUG, __VA_ARGS__)
+
+
+/**
+ *@brief helper function to print the most important members of the context
+ *@param s context
+ */
+static void av_cold dump_context(WmallDecodeCtx *s)
+{
+#define PRINT(a, b)     av_log(s->avctx, AV_LOG_DEBUG, " %s = %d\n", a, b);
+#define PRINT_HEX(a, b) av_log(s->avctx, AV_LOG_DEBUG, " %s = %x\n", a, b);
+
+    PRINT("ed sample bit depth", s->bits_per_sample);
+    PRINT_HEX("ed decode flags", s->decode_flags);
+    PRINT("samples per frame",   s->samples_per_frame);
+    PRINT("log2 frame size",     s->log2_frame_size);
+    PRINT("max num subframes",   s->max_num_subframes);
+    PRINT("len prefix",          s->len_prefix);
+    PRINT("num channels",        s->num_channels);
+}
+
+/**
+ *@brief Uninitialize the decoder and free all resources.
+ *@param avctx codec context
+ *@return 0 on success, < 0 otherwise
+ */
+static av_cold int decode_end(AVCodecContext *avctx)
+{
+    WmallDecodeCtx *s = avctx->priv_data;
+    int i;
+
+    for (i = 0; i < WMALL_BLOCK_SIZES; i++)
+        ff_mdct_end(&s->mdct_ctx[i]);
+
+    return 0;
+}
+
+/**
+ *@brief Initialize the decoder.
+ *@param avctx codec context
+ *@return 0 on success, -1 otherwise
+ */
+static av_cold int decode_init(AVCodecContext *avctx)
+{
+    WmallDecodeCtx *s = avctx->priv_data;
+    uint8_t *edata_ptr = avctx->extradata;
+    unsigned int channel_mask;
+    int i;
+    int log2_max_num_subframes;
+    int num_possible_block_sizes;
+
+    s->avctx = avctx;
+    dsputil_init(&s->dsp, avctx);
+    init_put_bits(&s->pb, s->frame_data, MAX_FRAMESIZE);
+
+    avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
+
+    if (avctx->extradata_size >= 18) {
+        s->decode_flags    = AV_RL16(edata_ptr+14);
+        channel_mask       = AV_RL32(edata_ptr+2);
+        s->bits_per_sample = AV_RL16(edata_ptr);
+        /** dump the extradata */
+        for (i = 0; i < avctx->extradata_size; i++)
+            dprintf(avctx, "[%x] ", avctx->extradata[i]);
+        dprintf(avctx, "\n");
+
+    } else {
+        av_log_ask_for_sample(avctx, "Unknown extradata size\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    /** generic init */
+    s->log2_frame_size = av_log2(avctx->block_align) + 4;
+
+    /** frame info */
+    s->skip_frame  = 1; /* skip first frame */
+    s->packet_loss = 1;
+    s->len_prefix  = (s->decode_flags & 0x40);
+
+    /** get frame len */
+    s->samples_per_frame = 1 << ff_wma_get_frame_len_bits(avctx->sample_rate,
+                                                          3, s->decode_flags);
+
+    /** init previous block len */
+    for (i = 0; i < avctx->channels; i++)
+        s->channel[i].prev_block_len = s->samples_per_frame;
+
+    /** subframe info */
+    log2_max_num_subframes       = ((s->decode_flags & 0x38) >> 3);
+    s->max_num_subframes         = 1 << log2_max_num_subframes;
+    s->max_subframe_len_bit = 0;
+    s->subframe_len_bits = av_log2(log2_max_num_subframes) + 1;
+
+    num_possible_block_sizes     = log2_max_num_subframes + 1;
+    s->min_samples_per_subframe  = s->samples_per_frame / s->max_num_subframes;
+    s->dynamic_range_compression = (s->decode_flags & 0x80);
+
+    s->bV3RTM = s->decode_flags & 0x100;
+
+    if (s->max_num_subframes > MAX_SUBFRAMES) {
+        av_log(avctx, AV_LOG_ERROR, "invalid number of subframes %i\n",
+               s->max_num_subframes);
+        return AVERROR_INVALIDDATA;
+    }
+
+    s->num_channels = avctx->channels;
+
+    /** extract lfe channel position */
+    s->lfe_channel = -1;
+
+    if (channel_mask & 8) {
+        unsigned int mask;
+        for (mask = 1; mask < 16; mask <<= 1) {
+            if (channel_mask & mask)
+                ++s->lfe_channel;
+        }
+    }
+
+    if (s->num_channels < 0) {
+        av_log(avctx, AV_LOG_ERROR, "invalid number of channels %d\n", s->num_channels);
+        return AVERROR_INVALIDDATA;
+    } else if (s->num_channels > WMALL_MAX_CHANNELS) {
+        av_log_ask_for_sample(avctx, "unsupported number of channels\n");
+        return AVERROR_PATCHWELCOME;
+    }
+
+    avctx->channel_layout = channel_mask;
+    return 0;
+}
+
+/**
+ *@brief Decode the subframe length.
+ *@param s context
+ *@param offset sample offset in the frame
+ *@return decoded subframe length on success, < 0 in case of an error
+ */
+static int decode_subframe_length(WmallDecodeCtx *s, int offset)
+{
+    int frame_len_ratio;
+    int subframe_len, len;
+
+    /** no need to read from the bitstream when only one length is possible */
+    if (offset == s->samples_per_frame - s->min_samples_per_subframe)
+        return s->min_samples_per_subframe;
+
+    len = av_log2(s->max_num_subframes - 1) + 1;
+    frame_len_ratio = get_bits(&s->gb, len);
+
+    subframe_len = s->min_samples_per_subframe * (frame_len_ratio + 1);
+
+    /** sanity check the length */
+    if (subframe_len < s->min_samples_per_subframe ||
+        subframe_len > s->samples_per_frame) {
+        av_log(s->avctx, AV_LOG_ERROR, "broken frame: subframe_len %i\n",
+               subframe_len);
+        return AVERROR_INVALIDDATA;
+    }
+    return subframe_len;
+}
+
+/**
+ *@brief Decode how the data in the frame is split into subframes.
+ *       Every WMA frame contains the encoded data for a fixed number of
+ *       samples per channel. The data for every channel might be split
+ *       into several subframes. This function will reconstruct the list of
+ *       subframes for every channel.
+ *
+ *       If the subframes are not evenly split, the algorithm estimates the
+ *       channels with the lowest number of total samples.
+ *       Afterwards, for each of these channels a bit is read from the
+ *       bitstream that indicates if the channel contains a subframe with the
+ *       next subframe size that is going to be read from the bitstream or not.
+ *       If a channel contains such a subframe, the subframe size gets added to
+ *       the channel's subframe list.
+ *       The algorithm repeats these steps until the frame is properly divided
+ *       between the individual channels.
+ *
+ *@param s context
+ *@return 0 on success, < 0 in case of an error
+ */
+static int decode_tilehdr(WmallDecodeCtx *s)
+{
+    uint16_t num_samples[WMALL_MAX_CHANNELS];        /**< sum of samples for all currently known subframes of a channel */
+    uint8_t  contains_subframe[WMALL_MAX_CHANNELS];  /**< flag indicating if a channel contains the current subframe */
+    int channels_for_cur_subframe = s->num_channels;  /**< number of channels that contain the current subframe */
+    int fixed_channel_layout = 0;                     /**< flag indicating that all channels use the same subfra2me offsets and sizes */
+    int min_channel_len = 0;                          /**< smallest sum of samples (channels with this length will be processed first) */
+    int c;
+
+    /* Should never consume more than 3073 bits (256 iterations for the
+     * while loop when always the minimum amount of 128 samples is substracted
+     * from missing samples in the 8 channel case).
+     * 1 + BLOCK_MAX_SIZE * MAX_CHANNELS / BLOCK_MIN_SIZE * (MAX_CHANNELS  + 4)
+     */
+
+    /** reset tiling information */
+    for (c = 0; c < s->num_channels; c++)
+        s->channel[c].num_subframes = 0;
+
+    memset(num_samples, 0, sizeof(num_samples));
+
+    if (s->max_num_subframes == 1 || get_bits1(&s->gb))
+        fixed_channel_layout = 1;
+
+    /** loop until the frame data is split between the subframes */
+    do {
+        int subframe_len;
+
+        /** check which channels contain the subframe */
+        for (c = 0; c < s->num_channels; c++) {
+            if (num_samples[c] == min_channel_len) {
+                if (fixed_channel_layout || channels_for_cur_subframe == 1 ||
+		    (min_channel_len == s->samples_per_frame - s->min_samples_per_subframe)) {
+                    contains_subframe[c] = 1;
+		}		    
+                else {
+                    contains_subframe[c] = get_bits1(&s->gb);
+		}
+            } else
+                contains_subframe[c] = 0;
+        }
+
+        /** get subframe length, subframe_len == 0 is not allowed */
+        if ((subframe_len = decode_subframe_length(s, min_channel_len)) <= 0)
+            return AVERROR_INVALIDDATA;
+        /** add subframes to the individual channels and find new min_channel_len */
+        min_channel_len += subframe_len;
+        for (c = 0; c < s->num_channels; c++) {
+            WmallChannelCtx* chan = &s->channel[c];
+
+            if (contains_subframe[c]) {
+                if (chan->num_subframes >= MAX_SUBFRAMES) {
+                    av_log(s->avctx, AV_LOG_ERROR,
+                           "broken frame: num subframes > 31\n");
+                    return AVERROR_INVALIDDATA;
+                }
+                chan->subframe_len[chan->num_subframes] = subframe_len;
+                num_samples[c] += subframe_len;
+                ++chan->num_subframes;
+                if (num_samples[c] > s->samples_per_frame) {
+                    av_log(s->avctx, AV_LOG_ERROR, "broken frame: "
+                           "channel len(%d) > samples_per_frame(%d)\n",
+			   num_samples[c], s->samples_per_frame);
+                    return AVERROR_INVALIDDATA;
+                }
+            } else if (num_samples[c] <= min_channel_len) {
+                if (num_samples[c] < min_channel_len) {
+                    channels_for_cur_subframe = 0;
+                    min_channel_len = num_samples[c];
+                }
+                ++channels_for_cur_subframe;
+            }
+        }
+    } while (min_channel_len < s->samples_per_frame);
+
+    for (c = 0; c < s->num_channels; c++) {
+        int i;
+        int offset = 0;
+        for (i = 0; i < s->channel[c].num_subframes; i++) {
+            s->channel[c].subframe_offset[i] = offset;
+            offset += s->channel[c].subframe_len[i];
+        }
+    }
+
+    return 0;
+}
+
+
+static int my_log2(unsigned int i)
+{
+    unsigned int iLog2 = 0;
+    while ((i >> iLog2) > 1)
+	iLog2++;
+    return iLog2;
+}
+
+
+/**
+ *
+ */
+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);
+
+    for(i = 0; i < s->acfilter_order; i++) {
+	s->acfilter_coeffs[i] = get_bits(&s->gb, 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)) {
+	// mclms_send_coef
+	int i;
+	int send_coef_bits;
+	int cbits = av_log2(s->mclms_scaling + 1);
+	assert(cbits == my_log2(s->mclms_scaling + 1));
+	if(1 << cbits < s->mclms_scaling + 1)
+	    cbits++;
+
+	send_coef_bits = (cbits ? get_bits(&s->gb, cbits) : 0) + 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);
+	}	    
+
+	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);
+	    }
+	}
+    }
+}
+
+
+/**
+ *
+ */
+static void decode_cdlms(WmallDecodeCtx *s)
+{
+    int c, i;
+    int cdlms_send_coef = get_bits1(&s->gb);
+
+    for(c = 0; c < s->num_channels; c++) {
+	s->cdlms_ttl[c] = get_bits(&s->gb, 3) + 1;
+	for(i = 0; i < s->cdlms_ttl[c]; i++) {
+	    s->cdlms[c][i].order = (get_bits(&s->gb, 7) + 1) * 8;
+	}
+
+	for(i = 0; i < s->cdlms_ttl[c]; i++) {
+	    s->cdlms[c][i].scaling = get_bits(&s->gb, 4);
+	}
+
+	if(cdlms_send_coef) {
+	    for(i = 0; i < s->cdlms_ttl[c]; i++) {
+		int cbits, shift_l, shift_r, j;
+		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;
+
+		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_bits(&s->gb, cbits) + 2;
+		shift_l = 32 - s->cdlms[c][i].bitsend;
+		shift_r = 32 - 2 - s->cdlms[c][i].scaling;
+		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;
+		}
+	    }
+	}
+    }
+}
+
+/**
+ *
+ */
+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);
+    if(s->transient[ch])
+	s->transient_pos[ch] = get_bits(&s->gb, av_log2(tile_size));
+    
+    if(s->seekable_tile) {
+	ave_mean = get_bits(&s->gb, s->bits_per_sample);
+	s->ave_sum[ch] = ave_mean << (s->movave_scaling + 1);
+//	s->ave_sum[ch] *= 2;
+    }
+
+    if(s->seekable_tile) {
+	if(s->do_inter_ch_decorr)
+	    s->channel_residues[ch][0] = get_sbits(&s->gb, s->bits_per_sample + 1);
+	else
+	    s->channel_residues[ch][0] = get_sbits(&s->gb, s->bits_per_sample);
+	i++;
+    }
+    for(; i < tile_size; i++) {
+	int quo = 0, rem, rem_bits, residue;
+	while(get_bits1(&s->gb))
+	    quo++;
+	if(quo >= 32)
+	    quo += get_bits_long(&s->gb, get_bits(&s->gb, 5) + 1);
+
+       	ave_mean = (s->ave_sum[ch] + (1 << s->movave_scaling)) >> (s->movave_scaling + 1);
+	rem_bits = av_ceil_log2(ave_mean);
+	rem = rem_bits ? get_bits(&s->gb, rem_bits) : 0;
+	residue = (quo << rem_bits) + rem;
+
+	s->ave_sum[ch] = residue + s->ave_sum[ch] - (s->ave_sum[ch] >> s->movave_scaling);
+
+	if(residue & 1)
+	    residue = -(residue >> 1) - 1;
+	else
+	    residue = residue >> 1;
+	s->channel_residues[ch][i] = residue;
+
+//	dprintf(s->avctx, "%5d: %5d %10d %12d %12d %5d %-16d %04x\n",i, quo, ave_mean, s->ave_sum[ch], rem, rem_bits, s->channel_residues[ch][i], show_bits(&s->gb, 16));
+    }
+
+    return 0;
+
+}
+
+
+/**
+ *
+ */
+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;
+    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);
+	}
+    }
+}
+
+
+
+/**
+ *@brief Decode a single subframe (block).
+ *@param s codec context
+ *@return 0 on success, < 0 when decoding failed
+ */
+static int decode_subframe(WmallDecodeCtx *s)
+{
+    int offset = s->samples_per_frame;
+    int subframe_len = s->samples_per_frame;
+    int i;
+    int total_samples   = s->samples_per_frame * s->num_channels;
+    int rawpcm_tile;
+    int padding_zeroes;
+
+    s->subframe_offset = get_bits_count(&s->gb);
+
+    /** reset channel context and find the next block offset and size
+        == the next block of the channel with the smallest number of
+        decoded samples
+    */
+    for (i = 0; i < s->num_channels; i++) {
+        s->channel[i].grouped = 0;
+        if (offset > s->channel[i].decoded_samples) {
+            offset = s->channel[i].decoded_samples;
+            subframe_len =
+                s->channel[i].subframe_len[s->channel[i].cur_subframe];
+        }
+    }
+
+    /** get a list of all channels that contain the estimated block */
+    s->channels_for_cur_subframe = 0;
+    for (i = 0; i < s->num_channels; i++) {
+        const int cur_subframe = s->channel[i].cur_subframe;
+        /** substract already processed samples */
+        total_samples -= s->channel[i].decoded_samples;
+
+        /** and count if there are multiple subframes that match our profile */
+        if (offset == s->channel[i].decoded_samples &&
+            subframe_len == s->channel[i].subframe_len[cur_subframe]) {
+            total_samples -= s->channel[i].subframe_len[cur_subframe];
+            s->channel[i].decoded_samples +=
+                s->channel[i].subframe_len[cur_subframe];
+            s->channel_indexes_for_cur_subframe[s->channels_for_cur_subframe] = i;
+            ++s->channels_for_cur_subframe;
+        }
+    }
+
+    /** check if the frame will be complete after processing the
+        estimated block */
+    if (!total_samples)
+        s->parsed_all_subframes = 1;
+
+
+    s->seekable_tile = get_bits1(&s->gb);
+    if(s->seekable_tile) {
+	s->do_arith_coding    = get_bits1(&s->gb);
+	if(s->do_arith_coding) {
+	    dprintf(s->avctx, "do_arith_coding == 1");
+	    abort();
+	}
+	s->do_ac_filter       = get_bits1(&s->gb);
+	s->do_inter_ch_decorr = get_bits1(&s->gb);
+	s->do_mclms           = get_bits1(&s->gb);
+	
+	if(s->do_ac_filter)
+	    decode_ac_filter(s);
+
+	if(s->do_mclms)
+	    decode_mclms(s);
+
+	decode_cdlms(s);
+	s->movave_scaling = get_bits(&s->gb, 3);
+	s->quant_stepsize = get_bits(&s->gb, 8) + 1;
+    }
+
+    rawpcm_tile = get_bits1(&s->gb);
+
+    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);
+	}
+
+	if(s->bV3RTM) {
+	    // LPC
+	    s->do_lpc = get_bits1(&s->gb);
+	    if(s->do_lpc) {
+		decode_lpc(s);
+	    }
+	} else {
+	    s->do_lpc = 0;
+	}
+    }
+
+
+    if(get_bits1(&s->gb)) {
+	padding_zeroes = get_bits(&s->gb, 5);
+    } else {
+	padding_zeroes = 0;
+    }
+
+    if(rawpcm_tile) {
+	
+	int bits = s->bits_per_sample - padding_zeroes;
+	int j;
+	dprintf(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));
+	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);
+//		dprintf(s->avctx, "PCM[%d][%d] = 0x%04x\n", i, j, s->channel_coeffs[i][j]);
+	    }
+	}
+    } else {
+	for(i = 0; i < s->num_channels; i++)
+	    if(s->is_channel_coded[i])
+		decode_channel_residues(s, i, subframe_len);
+    }
+
+    /** handled one subframe */
+
+    for (i = 0; i < s->channels_for_cur_subframe; i++) {
+        int c = s->channel_indexes_for_cur_subframe[i];
+        if (s->channel[c].cur_subframe >= s->channel[c].num_subframes) {
+            av_log(s->avctx, AV_LOG_ERROR, "broken subframe\n");
+            return AVERROR_INVALIDDATA;
+        }
+        ++s->channel[c].cur_subframe;
+    }
+    return 0;
+}
+
+/**
+ *@brief Decode one WMA frame.
+ *@param s codec context
+ *@return 0 if the trailer bit indicates that this is the last frame,
+ *        1 if there are additional frames
+ */
+static int decode_frame(WmallDecodeCtx *s)
+{
+    GetBitContext* gb = &s->gb;
+    int more_frames = 0;
+    int len = 0;
+    int i;
+
+    /** check for potential output buffer overflow */
+    if (s->num_channels * s->samples_per_frame > s->samples_end - s->samples) {
+        /** return an error if no frame could be decoded at all */
+        av_log(s->avctx, AV_LOG_ERROR,
+               "not enough space for the output samples\n");
+        s->packet_loss = 1;
+        return 0;
+    }
+
+    /** get frame length */
+    if (s->len_prefix)
+        len = get_bits(gb, s->log2_frame_size);
+
+    /** decode tile information */
+    if (decode_tilehdr(s)) {
+        s->packet_loss = 1;
+        return 0;
+    }
+
+    /** read drc info */
+    if (s->dynamic_range_compression) {
+        s->drc_gain = get_bits(gb, 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)) {
+        int skip;
+
+        /** usually true for the first frame */
+        if (get_bits1(gb)) {
+            skip = get_bits(gb, av_log2(s->samples_per_frame * 2));
+            dprintf(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));
+            dprintf(s->avctx, "end skip: %i\n", skip);
+        }
+
+    }
+
+    /** reset subframe states */
+    s->parsed_all_subframes = 0;
+    for (i = 0; i < s->num_channels; i++) {
+        s->channel[i].decoded_samples = 0;
+        s->channel[i].cur_subframe    = 0;
+        s->channel[i].reuse_sf        = 0;
+    }
+
+    /** decode all subframes */
+    while (!s->parsed_all_subframes) {
+        if (decode_subframe(s) < 0) {
+            s->packet_loss = 1;
+            return 0;
+        }
+    }
+
+    dprintf(s->avctx, "Frame done\n");
+
+    if (s->skip_frame) {
+        s->skip_frame = 0;
+    } else
+        s->samples += s->num_channels * s->samples_per_frame;
+
+    if (s->len_prefix) {
+        if (len != (get_bits_count(gb) - s->frame_offset) + 2) {
+            /** FIXME: not sure if this is always an error */
+            av_log(s->avctx, AV_LOG_ERROR,
+                   "frame[%i] would have to skip %i bits\n", s->frame_num,
+                   len - (get_bits_count(gb) - 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);
+    } else {
+/*
+        while (get_bits_count(gb) < s->num_saved_bits && get_bits1(gb) == 0) {
+	    dprintf(s->avctx, "skip1\n");
+        }
+*/
+    }
+
+    /** decode trailer bit */
+    more_frames = get_bits1(gb);
+    ++s->frame_num;
+    return more_frames;
+}
+
+/**
+ *@brief Calculate remaining input buffer length.
+ *@param s codec context
+ *@param gb bitstream reader context
+ *@return remaining size in bits
+ */
+static int remaining_bits(WmallDecodeCtx *s, GetBitContext *gb)
+{
+    return s->buf_bit_size - get_bits_count(gb);
+}
+
+/**
+ *@brief Fill the bit reservoir with a (partial) frame.
+ *@param s codec context
+ *@param gb bitstream reader context
+ *@param len length of the partial frame
+ *@param append decides wether to reset the buffer or not
+ */
+static void save_bits(WmallDecodeCtx *s, GetBitContext* gb, int len,
+                      int append)
+{
+    int buflen;
+
+    /** when the frame data does not need to be concatenated, the input buffer
+        is resetted and additional bits from the previous frame are copyed
+        and skipped later so that a fast byte copy is possible */
+
+    if (!append) {
+        s->frame_offset = get_bits_count(gb) & 7;
+        s->num_saved_bits = s->frame_offset;
+        init_put_bits(&s->pb, s->frame_data, MAX_FRAMESIZE);
+    }
+
+    buflen = (s->num_saved_bits + len + 8) >> 3;
+
+    if (len <= 0 || buflen > MAX_FRAMESIZE) {
+        av_log_ask_for_sample(s->avctx, "input buffer too small\n");
+        s->packet_loss = 1;
+        return;
+    }
+
+    s->num_saved_bits += len;
+    if (!append) {
+        ff_copy_bits(&s->pb, gb->buffer + (get_bits_count(gb) >> 3),
+                     s->num_saved_bits);
+    } else {
+        int align = 8 - (get_bits_count(gb) & 7);
+        align = FFMIN(align, len);
+        put_bits(&s->pb, align, get_bits(gb, align));
+        len -= align;
+        ff_copy_bits(&s->pb, gb->buffer + (get_bits_count(gb) >> 3), len);
+    }
+    skip_bits_long(gb, 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);
+}
+
+/**
+ *@brief Decode a single WMA packet.
+ *@param avctx codec context
+ *@param data the output buffer
+ *@param data_size number of bytes that were written to the output buffer
+ *@param avpkt input packet
+ *@return number of bytes that were read from the input buffer
+ */
+static int decode_packet(AVCodecContext *avctx,
+                         void *data, int *data_size, AVPacket* avpkt)
+{
+    WmallDecodeCtx *s = avctx->priv_data;
+    GetBitContext* gb  = &s->pgb;
+    const uint8_t* buf = avpkt->data;
+    int buf_size       = avpkt->size;
+    int num_bits_prev_frame;
+    int packet_sequence_number;
+
+    s->samples       = data;
+    s->samples_end   = (float*)((int8_t*)data + *data_size);
+    *data_size = 0;
+
+    if (s->packet_done || s->packet_loss) {
+        s->packet_done = 0;
+
+        /** sanity check for the buffer length */
+        if (buf_size < avctx->block_align)
+            return 0;
+
+        s->next_packet_start = buf_size - avctx->block_align;
+        buf_size = avctx->block_align;
+        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);
+	int seekable_frame_in_packet = get_bits1(gb);
+	int spliced_packet = get_bits1(gb);
+
+        /** get number of bits that need to be added to the previous frame */
+        num_bits_prev_frame = get_bits(gb, s->log2_frame_size);
+
+        /** check for packet loss */
+        if (!s->packet_loss &&
+            ((s->packet_sequence_number + 1) & 0xF) != packet_sequence_number) {
+            s->packet_loss = 1;
+            av_log(avctx, AV_LOG_ERROR, "Packet loss detected! seq %x vs %x\n",
+                   s->packet_sequence_number, packet_sequence_number);
+        }
+        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);
+            if (num_bits_prev_frame >= remaining_packet_bits) {
+                num_bits_prev_frame = remaining_packet_bits;
+                s->packet_done = 1;
+            }
+
+            /** 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);
+
+            /** decode the cross packet frame if it is valid */
+            if (!s->packet_loss)
+		decode_frame(s);
+        } else if (s->num_saved_bits - s->frame_offset) {
+            dprintf(avctx, "ignoring %x previously saved bits\n",
+                    s->num_saved_bits - s->frame_offset);
+        }
+
+        if (s->packet_loss) {
+            /** reset number of saved bits so that the decoder
+                does not start to decode incomplete frames in the
+                s->len_prefix == 0 case */
+            s->num_saved_bits = 0;
+            s->packet_loss = 0;
+        }
+
+    } 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);
+            s->packet_done = !decode_frame(s);
+        } else if (!s->len_prefix
+                   && s->num_saved_bits > get_bits_count(&s->gb)) {
+            /** 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 save the incoming packet first, then we append
+                the "previous frame" data from the next packet so that
+                we get a buffer that only contains full frames */
+            s->packet_done = !decode_frame(s);
+        } else {
+            s->packet_done = 1;
+	}
+    }
+
+    if (s->packet_done && !s->packet_loss &&
+        remaining_bits(s, gb) > 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);
+    }
+
+    *data_size = 0; // (int8_t *)s->samples - (int8_t *)data;
+    s->packet_offset = get_bits_count(gb) & 7;
+
+    return (s->packet_loss) ? AVERROR_INVALIDDATA : get_bits_count(gb) >> 3;
+}
+
+/**
+ *@brief Clear decoder buffers (for seeking).
+ *@param avctx codec context
+ */
+static void flush(AVCodecContext *avctx)
+{
+    WmallDecodeCtx *s = avctx->priv_data;
+    int i;
+    /** reset output buffer as a part of it is used during the windowing of a
+        new frame */
+    for (i = 0; i < s->num_channels; i++)
+        memset(s->channel[i].out, 0, s->samples_per_frame *
+               sizeof(*s->channel[i].out));
+    s->packet_loss = 1;
+}
+
+
+/**
+ *@brief wmall decoder
+ */
+AVCodec wmalossless_decoder = {
+    "wmalossless",
+    AVMEDIA_TYPE_AUDIO,
+    CODEC_ID_WMALOSSLESS,
+    sizeof(WmallDecodeCtx),
+    decode_init,
+    NULL,
+    decode_end,
+    decode_packet,
+    .capabilities = CODEC_CAP_SUBFRAMES,
+    .flush= flush,
+    .long_name = NULL_IF_CONFIG_SMALL("Windows Media Audio 9 Lossless"),
+};