2 * Wmall compatible decoder
3 * Copyright (c) 2007 Baptiste Coudurier, Benjamin Larsson, Ulion
4 * Copyright (c) 2008 - 2011 Sascha Sommer, Benjamin Larsson
5 * Copyright (c) 2011 Andreas Ă–man
7 * This file is part of FFmpeg.
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
26 * @brief wmall decoder implementation
27 * Wmall is an MDCT based codec comparable to wma standard or AAC.
28 * The decoding therefore consists of the following steps:
29 * - bitstream decoding
30 * - reconstruction of per-channel data
31 * - rescaling and inverse quantization
33 * - windowing and overlapp-add
35 * The compressed wmall bitstream is split into individual packets.
36 * Every such packet contains one or more wma frames.
37 * The compressed frames may have a variable length and frames may
38 * cross packet boundaries.
39 * Common to all wmall frames is the number of samples that are stored in
41 * The number of samples and a few other decode flags are stored
42 * as extradata that has to be passed to the decoder.
44 * The wmall frames themselves are again split into a variable number of
45 * subframes. Every subframe contains the data for 2^N time domain samples
46 * where N varies between 7 and 12.
48 * Example wmall bitstream (in samples):
50 * || packet 0 || packet 1 || packet 2 packets
51 * ---------------------------------------------------
52 * || frame 0 || frame 1 || frame 2 || frames
53 * ---------------------------------------------------
54 * || | | || | | | || || subframes of channel 0
55 * ---------------------------------------------------
56 * || | | || | | | || || subframes of channel 1
57 * ---------------------------------------------------
59 * The frame layouts for the individual channels of a wma frame does not need
62 * However, if the offsets and lengths of several subframes of a frame are the
63 * same, the subframes of the channels can be grouped.
64 * Every group may then use special coding techniques like M/S stereo coding
65 * to improve the compression ratio. These channel transformations do not
66 * need to be applied to a whole subframe. Instead, they can also work on
67 * individual scale factor bands (see below).
68 * The coefficients that carry the audio signal in the frequency domain
69 * are transmitted as huffman-coded vectors with 4, 2 and 1 elements.
70 * In addition to that, the encoder can switch to a runlevel coding scheme
71 * by transmitting subframe_length / 128 zero coefficients.
73 * Before the audio signal can be converted to the time domain, the
74 * coefficients have to be rescaled and inverse quantized.
75 * A subframe is therefore split into several scale factor bands that get
76 * scaled individually.
77 * Scale factors are submitted for every frame but they might be shared
78 * between the subframes of a channel. Scale factors are initially DPCM-coded.
79 * Once scale factors are shared, the differences are transmitted as runlevel
81 * Every subframe length and offset combination in the frame layout shares a
82 * common quantization factor that can be adjusted for every channel by a
84 * After the inverse quantization, the coefficients get processed by an IMDCT.
85 * The resulting values are then windowed with a sine window and the first half
86 * of the values are added to the second half of the output from the previous
87 * subframe in order to reconstruct the output samples.
97 /** current decoder limitations */
98 #define WMALL_MAX_CHANNELS 8 ///< max number of handled channels
99 #define MAX_SUBFRAMES 32 ///< max number of subframes per channel
100 #define MAX_BANDS 29 ///< max number of scale factor bands
101 #define MAX_FRAMESIZE 32768 ///< maximum compressed frame size
103 #define WMALL_BLOCK_MIN_BITS 6 ///< log2 of min block size
104 #define WMALL_BLOCK_MAX_BITS 12 ///< log2 of max block size
105 #define WMALL_BLOCK_MAX_SIZE (1 << WMALL_BLOCK_MAX_BITS) ///< maximum block size
106 #define WMALL_BLOCK_SIZES (WMALL_BLOCK_MAX_BITS - WMALL_BLOCK_MIN_BITS + 1) ///< possible block sizes
110 #define SCALEVLCBITS 8
111 #define VEC4MAXDEPTH ((HUFF_VEC4_MAXBITS+VLCBITS-1)/VLCBITS)
112 #define VEC2MAXDEPTH ((HUFF_VEC2_MAXBITS+VLCBITS-1)/VLCBITS)
113 #define VEC1MAXDEPTH ((HUFF_VEC1_MAXBITS+VLCBITS-1)/VLCBITS)
114 #define SCALEMAXDEPTH ((HUFF_SCALE_MAXBITS+SCALEVLCBITS-1)/SCALEVLCBITS)
115 #define SCALERLMAXDEPTH ((HUFF_SCALE_RL_MAXBITS+VLCBITS-1)/VLCBITS)
117 static float sin64[33]; ///< sinus table for decorrelation
120 * @brief frame specific decoder context for a single channel
123 int16_t prev_block_len; ///< length of the previous block
124 uint8_t transmit_coefs;
125 uint8_t num_subframes;
126 uint16_t subframe_len[MAX_SUBFRAMES]; ///< subframe length in samples
127 uint16_t subframe_offset[MAX_SUBFRAMES]; ///< subframe positions in the current frame
128 uint8_t cur_subframe; ///< current subframe number
129 uint16_t decoded_samples; ///< number of already processed samples
130 uint8_t grouped; ///< channel is part of a group
131 int quant_step; ///< quantization step for the current subframe
132 int8_t reuse_sf; ///< share scale factors between subframes
133 int8_t scale_factor_step; ///< scaling step for the current subframe
134 int max_scale_factor; ///< maximum scale factor for the current subframe
135 int saved_scale_factors[2][MAX_BANDS]; ///< resampled and (previously) transmitted scale factor values
136 int8_t scale_factor_idx; ///< index for the transmitted scale factor values (used for resampling)
137 int* scale_factors; ///< pointer to the scale factor values used for decoding
138 uint8_t table_idx; ///< index in sf_offsets for the scale factor reference block
139 float* coeffs; ///< pointer to the subframe decode buffer
140 uint16_t num_vec_coeffs; ///< number of vector coded coefficients
141 DECLARE_ALIGNED(16, float, out)[WMALL_BLOCK_MAX_SIZE + WMALL_BLOCK_MAX_SIZE / 2]; ///< output buffer
142 int transient_counter; ///< number of transient samples from the beginning of transient zone
146 * @brief channel group for channel transformations
149 uint8_t num_channels; ///< number of channels in the group
150 int8_t transform; ///< transform on / off
151 int8_t transform_band[MAX_BANDS]; ///< controls if the transform is enabled for a certain band
152 float decorrelation_matrix[WMALL_MAX_CHANNELS*WMALL_MAX_CHANNELS];
153 float* channel_data[WMALL_MAX_CHANNELS]; ///< transformation coefficients
157 * @brief main decoder context
159 typedef struct WmallDecodeCtx {
160 /* generic decoder variables */
161 AVCodecContext* avctx; ///< codec context for av_log
162 DSPContext dsp; ///< accelerated DSP functions
163 uint8_t frame_data[MAX_FRAMESIZE +
164 FF_INPUT_BUFFER_PADDING_SIZE];///< compressed frame data
165 PutBitContext pb; ///< context for filling the frame_data buffer
166 FFTContext mdct_ctx[WMALL_BLOCK_SIZES]; ///< MDCT context per block size
167 DECLARE_ALIGNED(16, float, tmp)[WMALL_BLOCK_MAX_SIZE]; ///< IMDCT output buffer
168 float* windows[WMALL_BLOCK_SIZES]; ///< windows for the different block sizes
170 /* frame size dependent frame information (set during initialization) */
171 uint32_t decode_flags; ///< used compression features
172 uint8_t len_prefix; ///< frame is prefixed with its length
173 uint8_t dynamic_range_compression; ///< frame contains DRC data
174 uint8_t bits_per_sample; ///< integer audio sample size for the unscaled IMDCT output (used to scale to [-1.0, 1.0])
175 uint16_t samples_per_frame; ///< number of samples to output
176 uint16_t log2_frame_size;
177 int8_t num_channels; ///< number of channels in the stream (same as AVCodecContext.num_channels)
178 int8_t lfe_channel; ///< lfe channel index
179 uint8_t max_num_subframes;
180 uint8_t subframe_len_bits; ///< number of bits used for the subframe length
181 uint8_t max_subframe_len_bit; ///< flag indicating that the subframe is of maximum size when the first subframe length bit is 1
182 uint16_t min_samples_per_subframe;
183 int8_t num_sfb[WMALL_BLOCK_SIZES]; ///< scale factor bands per block size
184 int16_t sfb_offsets[WMALL_BLOCK_SIZES][MAX_BANDS]; ///< scale factor band offsets (multiples of 4)
185 int8_t sf_offsets[WMALL_BLOCK_SIZES][WMALL_BLOCK_SIZES][MAX_BANDS]; ///< scale factor resample matrix
186 int16_t subwoofer_cutoffs[WMALL_BLOCK_SIZES]; ///< subwoofer cutoff values
188 /* packet decode state */
189 GetBitContext pgb; ///< bitstream reader context for the packet
190 int next_packet_start; ///< start offset of the next wma packet in the demuxer packet
191 uint8_t packet_offset; ///< frame offset in the packet
192 uint8_t packet_sequence_number; ///< current packet number
193 int num_saved_bits; ///< saved number of bits
194 int frame_offset; ///< frame offset in the bit reservoir
195 int subframe_offset; ///< subframe offset in the bit reservoir
196 uint8_t packet_loss; ///< set in case of bitstream error
197 uint8_t packet_done; ///< set when a packet is fully decoded
199 /* frame decode state */
200 uint32_t frame_num; ///< current frame number (not used for decoding)
201 GetBitContext gb; ///< bitstream reader context
202 int buf_bit_size; ///< buffer size in bits
203 float* samples; ///< current samplebuffer pointer
204 float* samples_end; ///< maximum samplebuffer pointer
205 uint8_t drc_gain; ///< gain for the DRC tool
206 int8_t skip_frame; ///< skip output step
207 int8_t parsed_all_subframes; ///< all subframes decoded?
209 /* subframe/block decode state */
210 int16_t subframe_len; ///< current subframe length
211 int8_t channels_for_cur_subframe; ///< number of channels that contain the subframe
212 int8_t channel_indexes_for_cur_subframe[WMALL_MAX_CHANNELS];
213 int8_t num_bands; ///< number of scale factor bands
214 int8_t transmit_num_vec_coeffs; ///< number of vector coded coefficients is part of the bitstream
215 int16_t* cur_sfb_offsets; ///< sfb offsets for the current block
216 uint8_t table_idx; ///< index for the num_sfb, sfb_offsets, sf_offsets and subwoofer_cutoffs tables
217 int8_t esc_len; ///< length of escaped coefficients
219 uint8_t num_chgroups; ///< number of channel groups
220 WmallChannelGrp chgroup[WMALL_MAX_CHANNELS]; ///< channel group information
222 WmallChannelCtx channel[WMALL_MAX_CHANNELS]; ///< per channel data
226 uint8_t do_arith_coding;
227 uint8_t do_ac_filter;
228 uint8_t do_inter_ch_decorr;
232 int8_t acfilter_order;
233 int8_t acfilter_scaling;
234 int acfilter_coeffs[16];
237 int8_t mclms_scaling;
238 int16_t mclms_coeffs[128];
239 int16_t mclms_coeffs_cur[4];
240 int16_t mclms_prevvalues[64]; // FIXME: should be 32-bit / 16-bit depending on bit-depth
241 int16_t mclms_updates[64];
253 int16_t lms_prevvalues[512]; // FIXME: see above
254 int16_t lms_updates[512]; // and here too
256 } cdlms[2][9]; /* XXX: Here, 2 is the max. no. of channels allowed,
257 9 is the maximum no. of filters per channel.
258 Question is, why 2 if WMALL_MAX_CHANNELS == 8 */
265 int is_channel_coded[2]; // XXX: same question as above applies here too (and below)
269 int transient_pos[2];
274 int channel_residues[2][2048];
277 int lpc_coefs[2][40];
282 int channel_coeffs[2][2048]; // FIXME: should be 32-bit / 16-bit depending on bit-depth
288 #define dprintf(pctx, ...) av_log(pctx, AV_LOG_DEBUG, __VA_ARGS__)
291 static int num_logged_tiles = 0;
292 static int num_logged_subframes = 0;
293 static int num_lms_update_call = 0;
296 *@brief helper function to print the most important members of the context
299 static void av_cold dump_context(WmallDecodeCtx *s)
301 #define PRINT(a, b) av_log(s->avctx, AV_LOG_DEBUG, " %s = %d\n", a, b);
302 #define PRINT_HEX(a, b) av_log(s->avctx, AV_LOG_DEBUG, " %s = %x\n", a, b);
304 PRINT("ed sample bit depth", s->bits_per_sample);
305 PRINT_HEX("ed decode flags", s->decode_flags);
306 PRINT("samples per frame", s->samples_per_frame);
307 PRINT("log2 frame size", s->log2_frame_size);
308 PRINT("max num subframes", s->max_num_subframes);
309 PRINT("len prefix", s->len_prefix);
310 PRINT("num channels", s->num_channels);
313 static void dump_int_buffer(uint8_t *buffer, int size, int length, int delimiter)
317 for (i=0 ; i<length ; i++) {
319 av_log(0, 0, "\n[%d] ", i);
320 av_log(0, 0, "%d, ", *(int16_t *)(buffer + i * size));
327 *@brief Uninitialize the decoder and free all resources.
328 *@param avctx codec context
329 *@return 0 on success, < 0 otherwise
331 static av_cold int decode_end(AVCodecContext *avctx)
333 WmallDecodeCtx *s = avctx->priv_data;
336 for (i = 0; i < WMALL_BLOCK_SIZES; i++)
337 ff_mdct_end(&s->mdct_ctx[i]);
343 *@brief Initialize the decoder.
344 *@param avctx codec context
345 *@return 0 on success, -1 otherwise
347 static av_cold int decode_init(AVCodecContext *avctx)
349 WmallDecodeCtx *s = avctx->priv_data;
350 uint8_t *edata_ptr = avctx->extradata;
351 unsigned int channel_mask;
353 int log2_max_num_subframes;
354 int num_possible_block_sizes;
357 dsputil_init(&s->dsp, avctx);
358 init_put_bits(&s->pb, s->frame_data, MAX_FRAMESIZE);
360 avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
362 if (avctx->extradata_size >= 18) {
363 s->decode_flags = AV_RL16(edata_ptr+14);
364 channel_mask = AV_RL32(edata_ptr+2);
365 s->bits_per_sample = AV_RL16(edata_ptr);
366 /** dump the extradata */
367 for (i = 0; i < avctx->extradata_size; i++)
368 dprintf(avctx, "[%x] ", avctx->extradata[i]);
369 dprintf(avctx, "\n");
372 av_log_ask_for_sample(avctx, "Unknown extradata size\n");
373 return AVERROR_INVALIDDATA;
377 s->log2_frame_size = av_log2(avctx->block_align) + 4;
380 s->skip_frame = 1; /* skip first frame */
382 s->len_prefix = (s->decode_flags & 0x40);
385 s->samples_per_frame = 1 << ff_wma_get_frame_len_bits(avctx->sample_rate,
388 /** init previous block len */
389 for (i = 0; i < avctx->channels; i++)
390 s->channel[i].prev_block_len = s->samples_per_frame;
393 log2_max_num_subframes = ((s->decode_flags & 0x38) >> 3);
394 s->max_num_subframes = 1 << log2_max_num_subframes;
395 s->max_subframe_len_bit = 0;
396 s->subframe_len_bits = av_log2(log2_max_num_subframes) + 1;
398 num_possible_block_sizes = log2_max_num_subframes + 1;
399 s->min_samples_per_subframe = s->samples_per_frame / s->max_num_subframes;
400 s->dynamic_range_compression = (s->decode_flags & 0x80);
402 s->bV3RTM = s->decode_flags & 0x100;
404 if (s->max_num_subframes > MAX_SUBFRAMES) {
405 av_log(avctx, AV_LOG_ERROR, "invalid number of subframes %i\n",
406 s->max_num_subframes);
407 return AVERROR_INVALIDDATA;
410 s->num_channels = avctx->channels;
412 /** extract lfe channel position */
415 if (channel_mask & 8) {
417 for (mask = 1; mask < 16; mask <<= 1) {
418 if (channel_mask & mask)
423 if (s->num_channels < 0) {
424 av_log(avctx, AV_LOG_ERROR, "invalid number of channels %d\n", s->num_channels);
425 return AVERROR_INVALIDDATA;
426 } else if (s->num_channels > WMALL_MAX_CHANNELS) {
427 av_log_ask_for_sample(avctx, "unsupported number of channels\n");
428 return AVERROR_PATCHWELCOME;
431 avctx->channel_layout = channel_mask;
436 *@brief Decode the subframe length.
438 *@param offset sample offset in the frame
439 *@return decoded subframe length on success, < 0 in case of an error
441 static int decode_subframe_length(WmallDecodeCtx *s, int offset)
444 int subframe_len, len;
446 /** no need to read from the bitstream when only one length is possible */
447 if (offset == s->samples_per_frame - s->min_samples_per_subframe)
448 return s->min_samples_per_subframe;
450 len = av_log2(s->max_num_subframes - 1) + 1;
451 frame_len_ratio = get_bits(&s->gb, len);
453 subframe_len = s->min_samples_per_subframe * (frame_len_ratio + 1);
455 /** sanity check the length */
456 if (subframe_len < s->min_samples_per_subframe ||
457 subframe_len > s->samples_per_frame) {
458 av_log(s->avctx, AV_LOG_ERROR, "broken frame: subframe_len %i\n",
460 return AVERROR_INVALIDDATA;
466 *@brief Decode how the data in the frame is split into subframes.
467 * Every WMA frame contains the encoded data for a fixed number of
468 * samples per channel. The data for every channel might be split
469 * into several subframes. This function will reconstruct the list of
470 * subframes for every channel.
472 * If the subframes are not evenly split, the algorithm estimates the
473 * channels with the lowest number of total samples.
474 * Afterwards, for each of these channels a bit is read from the
475 * bitstream that indicates if the channel contains a subframe with the
476 * next subframe size that is going to be read from the bitstream or not.
477 * If a channel contains such a subframe, the subframe size gets added to
478 * the channel's subframe list.
479 * The algorithm repeats these steps until the frame is properly divided
480 * between the individual channels.
483 *@return 0 on success, < 0 in case of an error
485 static int decode_tilehdr(WmallDecodeCtx *s)
487 uint16_t num_samples[WMALL_MAX_CHANNELS]; /**< sum of samples for all currently known subframes of a channel */
488 uint8_t contains_subframe[WMALL_MAX_CHANNELS]; /**< flag indicating if a channel contains the current subframe */
489 int channels_for_cur_subframe = s->num_channels; /**< number of channels that contain the current subframe */
490 int fixed_channel_layout = 0; /**< flag indicating that all channels use the same subfra2me offsets and sizes */
491 int min_channel_len = 0; /**< smallest sum of samples (channels with this length will be processed first) */
494 /* Should never consume more than 3073 bits (256 iterations for the
495 * while loop when always the minimum amount of 128 samples is substracted
496 * from missing samples in the 8 channel case).
497 * 1 + BLOCK_MAX_SIZE * MAX_CHANNELS / BLOCK_MIN_SIZE * (MAX_CHANNELS + 4)
500 /** reset tiling information */
501 for (c = 0; c < s->num_channels; c++)
502 s->channel[c].num_subframes = 0;
504 memset(num_samples, 0, sizeof(num_samples));
506 if (s->max_num_subframes == 1 || get_bits1(&s->gb))
507 fixed_channel_layout = 1;
509 /** loop until the frame data is split between the subframes */
513 /** check which channels contain the subframe */
514 for (c = 0; c < s->num_channels; c++) {
515 if (num_samples[c] == min_channel_len) {
516 if (fixed_channel_layout || channels_for_cur_subframe == 1 ||
517 (min_channel_len == s->samples_per_frame - s->min_samples_per_subframe)) {
518 contains_subframe[c] = 1;
521 contains_subframe[c] = get_bits1(&s->gb);
524 contains_subframe[c] = 0;
527 /** get subframe length, subframe_len == 0 is not allowed */
528 if ((subframe_len = decode_subframe_length(s, min_channel_len)) <= 0)
529 return AVERROR_INVALIDDATA;
530 /** add subframes to the individual channels and find new min_channel_len */
531 min_channel_len += subframe_len;
532 for (c = 0; c < s->num_channels; c++) {
533 WmallChannelCtx* chan = &s->channel[c];
535 if (contains_subframe[c]) {
536 if (chan->num_subframes >= MAX_SUBFRAMES) {
537 av_log(s->avctx, AV_LOG_ERROR,
538 "broken frame: num subframes > 31\n");
539 return AVERROR_INVALIDDATA;
541 chan->subframe_len[chan->num_subframes] = subframe_len;
542 num_samples[c] += subframe_len;
543 ++chan->num_subframes;
544 if (num_samples[c] > s->samples_per_frame) {
545 av_log(s->avctx, AV_LOG_ERROR, "broken frame: "
546 "channel len(%d) > samples_per_frame(%d)\n",
547 num_samples[c], s->samples_per_frame);
548 return AVERROR_INVALIDDATA;
550 } else if (num_samples[c] <= min_channel_len) {
551 if (num_samples[c] < min_channel_len) {
552 channels_for_cur_subframe = 0;
553 min_channel_len = num_samples[c];
555 ++channels_for_cur_subframe;
558 } while (min_channel_len < s->samples_per_frame);
560 for (c = 0; c < s->num_channels; c++) {
563 for (i = 0; i < s->channel[c].num_subframes; i++) {
564 s->channel[c].subframe_offset[i] = offset;
565 offset += s->channel[c].subframe_len[i];
573 static int my_log2(unsigned int i)
575 unsigned int iLog2 = 0;
576 while ((i >> iLog2) > 1)
585 static void decode_ac_filter(WmallDecodeCtx *s)
588 s->acfilter_order = get_bits(&s->gb, 4) + 1;
589 s->acfilter_scaling = get_bits(&s->gb, 4);
591 for(i = 0; i < s->acfilter_order; i++) {
592 s->acfilter_coeffs[i] = get_bits(&s->gb, s->acfilter_scaling) + 1;
600 static void decode_mclms(WmallDecodeCtx *s)
602 s->mclms_order = (get_bits(&s->gb, 4) + 1) * 2;
603 s->mclms_scaling = get_bits(&s->gb, 4);
604 if(get_bits1(&s->gb)) {
608 int cbits = av_log2(s->mclms_scaling + 1);
609 assert(cbits == my_log2(s->mclms_scaling + 1));
610 if(1 << cbits < s->mclms_scaling + 1)
613 send_coef_bits = (cbits ? get_bits(&s->gb, cbits) : 0) + 2;
615 for(i = 0; i < s->mclms_order * s->num_channels * s->num_channels; i++) {
616 s->mclms_coeffs[i] = get_bits(&s->gb, send_coef_bits);
619 for(i = 0; i < s->num_channels; i++) {
621 for(c = 0; c < i; c++) {
622 s->mclms_coeffs_cur[i * s->num_channels + c] = get_bits(&s->gb, send_coef_bits);
632 static void decode_cdlms(WmallDecodeCtx *s)
635 int cdlms_send_coef = get_bits1(&s->gb);
637 for(c = 0; c < s->num_channels; c++) {
638 s->cdlms_ttl[c] = get_bits(&s->gb, 3) + 1;
639 for(i = 0; i < s->cdlms_ttl[c]; i++) {
640 s->cdlms[c][i].order = (get_bits(&s->gb, 7) + 1) * 8;
643 for(i = 0; i < s->cdlms_ttl[c]; i++) {
644 s->cdlms[c][i].scaling = get_bits(&s->gb, 4);
647 if(cdlms_send_coef) {
648 for(i = 0; i < s->cdlms_ttl[c]; i++) {
649 int cbits, shift_l, shift_r, j;
650 cbits = av_log2(s->cdlms[c][i].order);
651 if(1 << cbits < s->cdlms[c][i].order)
653 s->cdlms[c][i].coefsend = get_bits(&s->gb, cbits) + 1;
655 cbits = av_log2(s->cdlms[c][i].scaling + 1);
656 if(1 << cbits < s->cdlms[c][i].scaling + 1)
659 s->cdlms[c][i].bitsend = get_bits(&s->gb, cbits) + 2;
660 shift_l = 32 - s->cdlms[c][i].bitsend;
661 shift_r = 32 - 2 - s->cdlms[c][i].scaling;
662 for(j = 0; j < s->cdlms[c][i].coefsend; j++) {
663 s->cdlms[c][i].coefs[j] =
664 (get_bits(&s->gb, s->cdlms[c][i].bitsend) << shift_l) >> shift_r;
674 static int decode_channel_residues(WmallDecodeCtx *s, int ch, int tile_size)
677 unsigned int ave_mean;
678 s->transient[ch] = get_bits1(&s->gb);
679 if(s->transient[ch]) {
680 s->transient_pos[ch] = get_bits(&s->gb, av_log2(tile_size));
681 if (s->transient_pos[ch])
682 s->transient[ch] = 0;
683 s->channel[ch].transient_counter =
684 FFMAX(s->channel[ch].transient_counter, s->samples_per_frame / 2);
685 } else if (s->channel[ch].transient_counter)
686 s->transient[ch] = 1;
688 if(s->seekable_tile) {
689 ave_mean = get_bits(&s->gb, s->bits_per_sample);
690 s->ave_sum[ch] = ave_mean << (s->movave_scaling + 1);
691 // s->ave_sum[ch] *= 2;
694 if(s->seekable_tile) {
695 if(s->do_inter_ch_decorr)
696 s->channel_residues[ch][0] = get_sbits(&s->gb, s->bits_per_sample + 1);
698 s->channel_residues[ch][0] = get_sbits(&s->gb, s->bits_per_sample);
701 //av_log(0, 0, "%8d: ", num_logged_tiles++);
702 for(; i < tile_size; i++) {
703 int quo = 0, rem, rem_bits, residue;
704 while(get_bits1(&s->gb))
707 quo += get_bits_long(&s->gb, get_bits(&s->gb, 5) + 1);
709 ave_mean = (s->ave_sum[ch] + (1 << s->movave_scaling)) >> (s->movave_scaling + 1);
710 rem_bits = av_ceil_log2(ave_mean);
711 rem = rem_bits ? get_bits(&s->gb, rem_bits) : 0;
712 residue = (quo << rem_bits) + rem;
714 s->ave_sum[ch] = residue + s->ave_sum[ch] - (s->ave_sum[ch] >> s->movave_scaling);
717 residue = -(residue >> 1) - 1;
719 residue = residue >> 1;
720 s->channel_residues[ch][i] = residue;
722 dump_int_buffer(s->channel_residues[ch], 4, tile_size, 16);
733 decode_lpc(WmallDecodeCtx *s)
736 s->lpc_order = get_bits(&s->gb, 5) + 1;
737 s->lpc_scaling = get_bits(&s->gb, 4);
738 s->lpc_intbits = get_bits(&s->gb, 3) + 1;
739 cbits = s->lpc_scaling + s->lpc_intbits;
740 for(ch = 0; ch < s->num_channels; ch++) {
741 for(i = 0; i < s->lpc_order; i++) {
742 s->lpc_coefs[ch][i] = get_sbits(&s->gb, cbits);
748 static void clear_codec_buffers(WmallDecodeCtx *s)
752 memset(s->acfilter_coeffs, 0, 16 * sizeof(int));
753 memset(s->lpc_coefs , 0, 40 * 2 * sizeof(int));
755 memset(s->mclms_coeffs , 0, 128 * sizeof(int16_t));
756 memset(s->mclms_coeffs_cur, 0, 4 * sizeof(int16_t));
757 memset(s->mclms_prevvalues, 0, 64 * sizeof(int));
758 memset(s->mclms_updates , 0, 64 * sizeof(int16_t));
760 for (ich = 0; ich < s->num_channels; ich++) {
761 for (ilms = 0; ilms < s->cdlms_ttl[ich]; ilms++) {
762 memset(s->cdlms[ich][ilms].coefs , 0, 256 * sizeof(int16_t));
763 memset(s->cdlms[ich][ilms].lms_prevvalues, 0, 512 * sizeof(int16_t));
764 memset(s->cdlms[ich][ilms].lms_updates , 0, 512 * sizeof(int16_t));
771 *@brief Resets filter parameters and transient area at new seekable tile
773 static void reset_codec(WmallDecodeCtx *s)
776 s->mclms_recent = s->mclms_order * s->num_channels;
777 for (ich = 0; ich < s->num_channels; ich++) {
778 for (ilms = 0; ilms < s->cdlms_ttl[ich]; ilms++)
779 s->cdlms[ich][ilms].recent = s->cdlms[ich][ilms].order;
780 /* first sample of a seekable subframe is considered as the starting of
781 a transient area which is samples_per_frame samples long */
782 s->channel[ich].transient_counter = s->samples_per_frame;
783 s->transient[ich] = 1;
784 s->transient_pos[ich] = 0;
790 static void mclms_update(WmallDecodeCtx *s, int icoef, int *pred)
794 int order = s->mclms_order;
795 int num_channels = s->num_channels;
796 int range = 1 << (s->bits_per_sample - 1);
797 int bps = s->bits_per_sample > 16 ? 4 : 2; // bytes per sample
799 for (ich = 0; ich < num_channels; ich++) {
800 pred_error = s->channel_residues[ich][icoef] - pred[ich];
801 if (pred_error > 0) {
802 for (i = 0; i < order * num_channels; i++)
803 s->mclms_coeffs[i + ich * order * num_channels] +=
804 s->mclms_updates[s->mclms_recent + i];
805 for (j = 0; j < ich; j++) {
806 if (s->channel_residues[j][icoef] > 0)
807 s->mclms_coeffs_cur[ich * num_channels + j] += 1;
808 else if (s->channel_residues[j][icoef] < 0)
809 s->mclms_coeffs_cur[ich * num_channels + j] -= 1;
811 } else if (pred_error < 0) {
812 for (i = 0; i < order * num_channels; i++)
813 s->mclms_coeffs[i + ich * order * num_channels] -=
814 s->mclms_updates[s->mclms_recent + i];
815 for (j = 0; j < ich; j++) {
816 if (s->channel_residues[j][icoef] > 0)
817 s->mclms_coeffs_cur[ich * num_channels + j] -= 1;
818 else if (s->channel_residues[j][icoef] < 0)
819 s->mclms_coeffs_cur[ich * num_channels + j] += 1;
824 for (ich = num_channels - 1; ich >= 0; ich--) {
826 s->mclms_prevvalues[s->mclms_recent] = s->channel_residues[ich][icoef];
827 if (s->channel_residues[ich][icoef] > range - 1)
828 s->mclms_prevvalues[s->mclms_recent] = range - 1;
829 else if (s->channel_residues[ich][icoef] < -range)
830 s->mclms_prevvalues[s->mclms_recent] = -range;
832 s->mclms_updates[s->mclms_recent] = 0;
833 if (s->channel_residues[ich][icoef] > 0)
834 s->mclms_updates[s->mclms_recent] = 1;
835 else if (s->channel_residues[ich][icoef] < 0)
836 s->mclms_updates[s->mclms_recent] = -1;
839 if (s->mclms_recent == 0) {
840 memcpy(&s->mclms_prevvalues[order * num_channels],
842 bps * order * num_channels);
843 memcpy(&s->mclms_updates[order * num_channels],
845 bps * order * num_channels);
846 s->mclms_recent = num_channels * order;
850 static void mclms_predict(WmallDecodeCtx *s, int icoef, int *pred)
853 int order = s->mclms_order;
854 int num_channels = s->num_channels;
856 for (ich = 0; ich < num_channels; ich++) {
857 if (!s->is_channel_coded[ich])
860 for (i = 0; i < order * num_channels; i++)
861 pred[ich] += s->mclms_prevvalues[i + s->mclms_recent] *
862 s->mclms_coeffs[i + order * num_channels * ich];
863 for (i = 0; i < ich; i++)
864 pred[ich] += s->channel_residues[i][icoef] *
865 s->mclms_coeffs_cur[i + num_channels * ich];
866 pred[ich] += 1 << s->mclms_scaling - 1;
867 pred[ich] >>= s->mclms_scaling;
868 s->channel_residues[ich][icoef] += pred[ich];
872 static void revert_mclms(WmallDecodeCtx *s, int tile_size)
874 int icoef, pred[s->num_channels];
875 for (icoef = 0; icoef < tile_size; icoef++) {
876 mclms_predict(s, icoef, pred);
877 mclms_update(s, icoef, pred);
881 static int lms_predict(WmallDecodeCtx *s, int ich, int ilms)
885 int recent = s->cdlms[ich][ilms].recent;
887 for (icoef = 0; icoef < s->cdlms[ich][ilms].order; icoef++)
888 pred += s->cdlms[ich][ilms].coefs[icoef] *
889 s->cdlms[ich][ilms].lms_prevvalues[icoef + recent];
891 //pred += (1 << (s->cdlms[ich][ilms].scaling - 1));
892 /* XXX: Table 29 has:
893 iPred >= cdlms[iCh][ilms].scaling;
894 seems to me like a missing > */
895 //pred >>= s->cdlms[ich][ilms].scaling;
899 static void lms_update(WmallDecodeCtx *s, int ich, int ilms, int input, int residue)
902 int recent = s->cdlms[ich][ilms].recent;
903 int range = 1 << s->bits_per_sample - 1;
904 int bps = s->bits_per_sample > 16 ? 4 : 2; // bytes per sample
907 for (icoef = 0; icoef < s->cdlms[ich][ilms].order; icoef++)
908 s->cdlms[ich][ilms].coefs[icoef] -=
909 s->cdlms[ich][ilms].lms_updates[icoef + recent];
910 } else if (residue > 0) {
911 for (icoef = 0; icoef < s->cdlms[ich][ilms].order; icoef++)
912 s->cdlms[ich][ilms].coefs[icoef] +=
913 s->cdlms[ich][ilms].lms_updates[icoef + recent]; /* spec mistakenly
914 dropped the recent */
920 /* XXX: This memcpy()s will probably fail if a fixed 32-bit buffer is used.
921 follow kshishkov's suggestion of using a union. */
922 memcpy(&s->cdlms[ich][ilms].lms_prevvalues[s->cdlms[ich][ilms].order],
923 s->cdlms[ich][ilms].lms_prevvalues,
924 bps * s->cdlms[ich][ilms].order);
925 memcpy(&s->cdlms[ich][ilms].lms_updates[s->cdlms[ich][ilms].order],
926 s->cdlms[ich][ilms].lms_updates,
927 bps * s->cdlms[ich][ilms].order);
928 recent = s->cdlms[ich][ilms].order - 1;
931 s->cdlms[ich][ilms].lms_prevvalues[recent] = av_clip(input, -range, range - 1);
933 s->cdlms[ich][ilms].lms_updates[recent] = 0;
935 s->cdlms[ich][ilms].lms_updates[recent] = -s->update_speed[ich];
937 s->cdlms[ich][ilms].lms_updates[recent] = s->update_speed[ich];
940 cdlms[iCh][ilms].updates[iRecent + cdlms[iCh][ilms].order >> 4] >>= 2;
941 lms_updates[iCh][ilms][iRecent + cdlms[iCh][ilms].order >> 3] >>= 1;
943 Questions is - are cdlms[iCh][ilms].updates[] and lms_updates[][][] two
944 seperate buffers? Here I've assumed that the two are same which makes
947 s->cdlms[ich][ilms].lms_updates[recent + (s->cdlms[ich][ilms].order >> 4)] >>= 2;
948 s->cdlms[ich][ilms].lms_updates[recent + (s->cdlms[ich][ilms].order >> 3)] >>= 1;
949 s->cdlms[ich][ilms].recent = recent;
952 static void use_high_update_speed(WmallDecodeCtx *s, int ich)
954 int ilms, recent, icoef;
955 for (ilms = s->cdlms_ttl[ich] - 1; ilms >= 0; ilms--) {
956 recent = s->cdlms[ich][ilms].recent;
957 if (s->update_speed[ich] == 16)
960 for (icoef = 0; icoef < s->cdlms[ich][ilms].order; icoef++)
961 s->cdlms[ich][ilms].lms_updates[icoef + recent] *= 2;
963 for (icoef = 0; icoef < s->cdlms[ich][ilms].order; icoef++)
964 s->cdlms[ich][ilms].lms_updates[icoef] *= 2;
967 s->update_speed[ich] = 16;
970 static void use_normal_update_speed(WmallDecodeCtx *s, int ich)
972 int ilms, recent, icoef;
973 for (ilms = s->cdlms_ttl[ich] - 1; ilms >= 0; ilms--) {
974 recent = s->cdlms[ich][ilms].recent;
975 if (s->update_speed[ich] == 8)
978 for (icoef = 0; icoef < s->cdlms[ich][ilms].order; icoef++)
979 s->cdlms[ich][ilms].lms_updates[icoef + recent] /= 2;
981 for (icoef = 0; icoef < s->cdlms[ich][ilms].order; icoef++)
982 s->cdlms[ich][ilms].lms_updates[icoef] /= 2;
985 s->update_speed[ich] = 8;
988 static void revert_cdlms(WmallDecodeCtx *s, int ch, int coef_begin, int coef_end)
995 num_lms = s->cdlms_ttl[ch];
996 for (ilms = num_lms - 1; ilms >= 0; ilms--) {
997 //s->cdlms[ch][ilms].recent = s->cdlms[ch][ilms].order;
998 for (icoef = coef_begin; icoef < coef_end; icoef++) {
999 pred = 1 << (s->cdlms[ch][ilms].scaling - 1);
1000 residue = s->channel_residues[ch][icoef];
1001 pred += lms_predict(s, ch, ilms);
1002 input = residue + (pred >> s->cdlms[ch][ilms].scaling);
1003 lms_update(s, ch, ilms, input, residue);
1004 s->channel_residues[ch][icoef] = input;
1012 *@brief Decode a single subframe (block).
1013 *@param s codec context
1014 *@return 0 on success, < 0 when decoding failed
1016 static int decode_subframe(WmallDecodeCtx *s)
1018 int offset = s->samples_per_frame;
1019 int subframe_len = s->samples_per_frame;
1021 int total_samples = s->samples_per_frame * s->num_channels;
1025 s->subframe_offset = get_bits_count(&s->gb);
1027 /** reset channel context and find the next block offset and size
1028 == the next block of the channel with the smallest number of
1031 for (i = 0; i < s->num_channels; i++) {
1032 s->channel[i].grouped = 0;
1033 if (offset > s->channel[i].decoded_samples) {
1034 offset = s->channel[i].decoded_samples;
1036 s->channel[i].subframe_len[s->channel[i].cur_subframe];
1040 /** get a list of all channels that contain the estimated block */
1041 s->channels_for_cur_subframe = 0;
1042 for (i = 0; i < s->num_channels; i++) {
1043 const int cur_subframe = s->channel[i].cur_subframe;
1044 /** substract already processed samples */
1045 total_samples -= s->channel[i].decoded_samples;
1047 /** and count if there are multiple subframes that match our profile */
1048 if (offset == s->channel[i].decoded_samples &&
1049 subframe_len == s->channel[i].subframe_len[cur_subframe]) {
1050 total_samples -= s->channel[i].subframe_len[cur_subframe];
1051 s->channel[i].decoded_samples +=
1052 s->channel[i].subframe_len[cur_subframe];
1053 s->channel_indexes_for_cur_subframe[s->channels_for_cur_subframe] = i;
1054 ++s->channels_for_cur_subframe;
1058 /** check if the frame will be complete after processing the
1061 s->parsed_all_subframes = 1;
1064 s->seekable_tile = get_bits1(&s->gb);
1065 if(s->seekable_tile) {
1066 clear_codec_buffers(s);
1068 s->do_arith_coding = get_bits1(&s->gb);
1069 if(s->do_arith_coding) {
1070 dprintf(s->avctx, "do_arith_coding == 1");
1073 s->do_ac_filter = get_bits1(&s->gb);
1074 s->do_inter_ch_decorr = get_bits1(&s->gb);
1075 s->do_mclms = get_bits1(&s->gb);
1078 decode_ac_filter(s);
1084 s->movave_scaling = get_bits(&s->gb, 3);
1085 s->quant_stepsize = get_bits(&s->gb, 8) + 1;
1090 rawpcm_tile = get_bits1(&s->gb);
1092 for(i = 0; i < s->num_channels; i++) {
1093 s->is_channel_coded[i] = 1;
1098 for(i = 0; i < s->num_channels; i++) {
1099 s->is_channel_coded[i] = get_bits1(&s->gb);
1104 s->do_lpc = get_bits1(&s->gb);
1114 if(get_bits1(&s->gb)) {
1115 padding_zeroes = get_bits(&s->gb, 5);
1122 int bits = s->bits_per_sample - padding_zeroes;
1124 dprintf(s->avctx, "RAWPCM %d bits per sample. total %d bits, remain=%d\n", bits,
1125 bits * s->num_channels * subframe_len, get_bits_count(&s->gb));
1126 for(i = 0; i < s->num_channels; i++) {
1127 for(j = 0; j < subframe_len; j++) {
1128 s->channel_coeffs[i][j] = get_sbits(&s->gb, bits);
1129 // dprintf(s->avctx, "PCM[%d][%d] = 0x%04x\n", i, j, s->channel_coeffs[i][j]);
1133 for(i = 0; i < s->num_channels; i++)
1134 if(s->is_channel_coded[i]) {
1135 decode_channel_residues(s, i, subframe_len);
1136 if (s->seekable_tile)
1137 use_high_update_speed(s, i);
1139 use_normal_update_speed(s, i);
1140 revert_cdlms(s, i, 0, subframe_len);
1144 /** handled one subframe */
1146 for (i = 0; i < s->channels_for_cur_subframe; i++) {
1147 int c = s->channel_indexes_for_cur_subframe[i];
1148 if (s->channel[c].cur_subframe >= s->channel[c].num_subframes) {
1149 av_log(s->avctx, AV_LOG_ERROR, "broken subframe\n");
1150 return AVERROR_INVALIDDATA;
1152 ++s->channel[c].cur_subframe;
1154 num_logged_subframes++;
1159 *@brief Decode one WMA frame.
1160 *@param s codec context
1161 *@return 0 if the trailer bit indicates that this is the last frame,
1162 * 1 if there are additional frames
1164 static int decode_frame(WmallDecodeCtx *s)
1166 GetBitContext* gb = &s->gb;
1167 int more_frames = 0;
1171 /** check for potential output buffer overflow */
1172 if (s->num_channels * s->samples_per_frame > s->samples_end - s->samples) {
1173 /** return an error if no frame could be decoded at all */
1174 av_log(s->avctx, AV_LOG_ERROR,
1175 "not enough space for the output samples\n");
1180 /** get frame length */
1182 len = get_bits(gb, s->log2_frame_size);
1184 /** decode tile information */
1185 if (decode_tilehdr(s)) {
1190 /** read drc info */
1191 if (s->dynamic_range_compression) {
1192 s->drc_gain = get_bits(gb, 8);
1195 /** no idea what these are for, might be the number of samples
1196 that need to be skipped at the beginning or end of a stream */
1197 if (get_bits1(gb)) {
1200 /** usually true for the first frame */
1201 if (get_bits1(gb)) {
1202 skip = get_bits(gb, av_log2(s->samples_per_frame * 2));
1203 dprintf(s->avctx, "start skip: %i\n", skip);
1206 /** sometimes true for the last frame */
1207 if (get_bits1(gb)) {
1208 skip = get_bits(gb, av_log2(s->samples_per_frame * 2));
1209 dprintf(s->avctx, "end skip: %i\n", skip);
1214 /** reset subframe states */
1215 s->parsed_all_subframes = 0;
1216 for (i = 0; i < s->num_channels; i++) {
1217 s->channel[i].decoded_samples = 0;
1218 s->channel[i].cur_subframe = 0;
1219 s->channel[i].reuse_sf = 0;
1222 /** decode all subframes */
1223 while (!s->parsed_all_subframes) {
1224 if (decode_subframe(s) < 0) {
1230 dprintf(s->avctx, "Frame done\n");
1232 if (s->skip_frame) {
1235 s->samples += s->num_channels * s->samples_per_frame;
1237 if (s->len_prefix) {
1238 if (len != (get_bits_count(gb) - s->frame_offset) + 2) {
1239 /** FIXME: not sure if this is always an error */
1240 av_log(s->avctx, AV_LOG_ERROR,
1241 "frame[%i] would have to skip %i bits\n", s->frame_num,
1242 len - (get_bits_count(gb) - s->frame_offset) - 1);
1247 /** skip the rest of the frame data */
1248 skip_bits_long(gb, len - (get_bits_count(gb) - s->frame_offset) - 1);
1251 while (get_bits_count(gb) < s->num_saved_bits && get_bits1(gb) == 0) {
1252 dprintf(s->avctx, "skip1\n");
1257 /** decode trailer bit */
1258 more_frames = get_bits1(gb);
1264 *@brief Calculate remaining input buffer length.
1265 *@param s codec context
1266 *@param gb bitstream reader context
1267 *@return remaining size in bits
1269 static int remaining_bits(WmallDecodeCtx *s, GetBitContext *gb)
1271 return s->buf_bit_size - get_bits_count(gb);
1275 *@brief Fill the bit reservoir with a (partial) frame.
1276 *@param s codec context
1277 *@param gb bitstream reader context
1278 *@param len length of the partial frame
1279 *@param append decides wether to reset the buffer or not
1281 static void save_bits(WmallDecodeCtx *s, GetBitContext* gb, int len,
1286 /** when the frame data does not need to be concatenated, the input buffer
1287 is resetted and additional bits from the previous frame are copyed
1288 and skipped later so that a fast byte copy is possible */
1291 s->frame_offset = get_bits_count(gb) & 7;
1292 s->num_saved_bits = s->frame_offset;
1293 init_put_bits(&s->pb, s->frame_data, MAX_FRAMESIZE);
1296 buflen = (s->num_saved_bits + len + 8) >> 3;
1298 if (len <= 0 || buflen > MAX_FRAMESIZE) {
1299 av_log_ask_for_sample(s->avctx, "input buffer too small\n");
1304 s->num_saved_bits += len;
1306 avpriv_copy_bits(&s->pb, gb->buffer + (get_bits_count(gb) >> 3),
1309 int align = 8 - (get_bits_count(gb) & 7);
1310 align = FFMIN(align, len);
1311 put_bits(&s->pb, align, get_bits(gb, align));
1313 avpriv_copy_bits(&s->pb, gb->buffer + (get_bits_count(gb) >> 3), len);
1315 skip_bits_long(gb, len);
1318 PutBitContext tmp = s->pb;
1319 flush_put_bits(&tmp);
1322 init_get_bits(&s->gb, s->frame_data, s->num_saved_bits);
1323 skip_bits(&s->gb, s->frame_offset);
1327 *@brief Decode a single WMA packet.
1328 *@param avctx codec context
1329 *@param data the output buffer
1330 *@param data_size number of bytes that were written to the output buffer
1331 *@param avpkt input packet
1332 *@return number of bytes that were read from the input buffer
1334 static int decode_packet(AVCodecContext *avctx,
1335 void *data, int *data_size, AVPacket* avpkt)
1337 WmallDecodeCtx *s = avctx->priv_data;
1338 GetBitContext* gb = &s->pgb;
1339 const uint8_t* buf = avpkt->data;
1340 int buf_size = avpkt->size;
1341 int num_bits_prev_frame;
1342 int packet_sequence_number;
1345 s->samples_end = (float*)((int8_t*)data + *data_size);
1348 if (s->packet_done || s->packet_loss) {
1351 /** sanity check for the buffer length */
1352 if (buf_size < avctx->block_align)
1355 s->next_packet_start = buf_size - avctx->block_align;
1356 buf_size = avctx->block_align;
1357 s->buf_bit_size = buf_size << 3;
1359 /** parse packet header */
1360 init_get_bits(gb, buf, s->buf_bit_size);
1361 packet_sequence_number = get_bits(gb, 4);
1362 int seekable_frame_in_packet = get_bits1(gb);
1363 int spliced_packet = get_bits1(gb);
1365 /** get number of bits that need to be added to the previous frame */
1366 num_bits_prev_frame = get_bits(gb, s->log2_frame_size);
1368 /** check for packet loss */
1369 if (!s->packet_loss &&
1370 ((s->packet_sequence_number + 1) & 0xF) != packet_sequence_number) {
1372 av_log(avctx, AV_LOG_ERROR, "Packet loss detected! seq %x vs %x\n",
1373 s->packet_sequence_number, packet_sequence_number);
1375 s->packet_sequence_number = packet_sequence_number;
1377 if (num_bits_prev_frame > 0) {
1378 int remaining_packet_bits = s->buf_bit_size - get_bits_count(gb);
1379 if (num_bits_prev_frame >= remaining_packet_bits) {
1380 num_bits_prev_frame = remaining_packet_bits;
1384 /** append the previous frame data to the remaining data from the
1385 previous packet to create a full frame */
1386 save_bits(s, gb, num_bits_prev_frame, 1);
1388 /** decode the cross packet frame if it is valid */
1389 if (!s->packet_loss)
1391 } else if (s->num_saved_bits - s->frame_offset) {
1392 dprintf(avctx, "ignoring %x previously saved bits\n",
1393 s->num_saved_bits - s->frame_offset);
1396 if (s->packet_loss) {
1397 /** reset number of saved bits so that the decoder
1398 does not start to decode incomplete frames in the
1399 s->len_prefix == 0 case */
1400 s->num_saved_bits = 0;
1407 s->buf_bit_size = (avpkt->size - s->next_packet_start) << 3;
1408 init_get_bits(gb, avpkt->data, s->buf_bit_size);
1409 skip_bits(gb, s->packet_offset);
1411 if (s->len_prefix && remaining_bits(s, gb) > s->log2_frame_size &&
1412 (frame_size = show_bits(gb, s->log2_frame_size)) &&
1413 frame_size <= remaining_bits(s, gb)) {
1414 save_bits(s, gb, frame_size, 0);
1415 s->packet_done = !decode_frame(s);
1416 } else if (!s->len_prefix
1417 && s->num_saved_bits > get_bits_count(&s->gb)) {
1418 /** when the frames do not have a length prefix, we don't know
1419 the compressed length of the individual frames
1420 however, we know what part of a new packet belongs to the
1422 therefore we save the incoming packet first, then we append
1423 the "previous frame" data from the next packet so that
1424 we get a buffer that only contains full frames */
1425 s->packet_done = !decode_frame(s);
1431 if (s->packet_done && !s->packet_loss &&
1432 remaining_bits(s, gb) > 0) {
1433 /** save the rest of the data so that it can be decoded
1434 with the next packet */
1435 save_bits(s, gb, remaining_bits(s, gb), 0);
1438 *data_size = 0; // (int8_t *)s->samples - (int8_t *)data;
1439 s->packet_offset = get_bits_count(gb) & 7;
1441 return (s->packet_loss) ? AVERROR_INVALIDDATA : get_bits_count(gb) >> 3;
1445 *@brief Clear decoder buffers (for seeking).
1446 *@param avctx codec context
1448 static void flush(AVCodecContext *avctx)
1450 WmallDecodeCtx *s = avctx->priv_data;
1452 /** reset output buffer as a part of it is used during the windowing of a
1454 for (i = 0; i < s->num_channels; i++)
1455 memset(s->channel[i].out, 0, s->samples_per_frame *
1456 sizeof(*s->channel[i].out));
1462 *@brief wmall decoder
1464 AVCodec ff_wmalossless_decoder = {
1467 CODEC_ID_WMALOSSLESS,
1468 sizeof(WmallDecodeCtx),
1473 .capabilities = CODEC_CAP_SUBFRAMES,
1475 .long_name = NULL_IF_CONFIG_SMALL("Windows Media Audio 9 Lossless"),