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* Copyright (c) 2005 Jeff Muizelaar
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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* @author Jeff Muizelaar
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#include "bitstream.h"
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#define MAX_CHANNELS 8
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#define MAX_BLOCKSIZE 65535
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#define OUT_BUFFER_SIZE 16384
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#define WAVE_FORMAT_PCM 0x0001
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#define DEFAULT_BLOCK_SIZE 256
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#define BITSHIFTSIZE 2
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#define V2LPCQOFFSET (1 << LPCQUANT)
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#define FN_BLOCKSIZE 5
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#define VERBATIM_CKSIZE_SIZE 5
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#define VERBATIM_BYTE_SIZE 8
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#define CANONICAL_HEADER_SIZE 44
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typedef struct ShortenContext {
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AVCodecContext *avctx;
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int min_framesize, max_framesize;
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int32_t *decoded[MAX_CHANNELS];
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int32_t *offset[MAX_CHANNELS];
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int allocated_bitstream_size;
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uint8_t header[OUT_BUFFER_SIZE];
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static int shorten_decode_init(AVCodecContext * avctx)
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ShortenContext *s = avctx->priv_data;
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static void allocate_buffers(ShortenContext *s)
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for (chan=0; chan<s->channels; chan++) {
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s->offset[chan] = av_realloc(s->offset[chan], sizeof(int32_t)*FFMAX(1, s->nmean));
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s->decoded[chan] = av_realloc(s->decoded[chan], sizeof(int32_t)*(s->blocksize + s->nwrap));
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for (i=0; i<s->nwrap; i++)
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s->decoded[chan][i] = 0;
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s->decoded[chan] += s->nwrap;
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static inline unsigned int get_uint(ShortenContext *s, int k)
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k = get_ur_golomb_shorten(&s->gb, ULONGSIZE);
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return get_ur_golomb_shorten(&s->gb, k);
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static void fix_bitshift(ShortenContext *s, int32_t *buffer)
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if (s->bitshift != 0)
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for (i = 0; i < s->blocksize; i++)
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buffer[s->nwrap + i] <<= s->bitshift;
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static void init_offset(ShortenContext *s)
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int nblock = FFMAX(1, s->nmean);
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/* initialise offset */
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switch (s->internal_ftype)
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av_log(s->avctx, AV_LOG_ERROR, "unknown audio type");
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for (chan = 0; chan < s->channels; chan++)
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for (i = 0; i < nblock; i++)
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s->offset[chan][i] = mean;
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static int inline get_le32(GetBitContext *gb)
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return bswap_32(get_bits_long(gb, 32));
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static short inline get_le16(GetBitContext *gb)
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return bswap_16(get_bits_long(gb, 16));
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static int decode_wave_header(AVCodecContext *avctx, uint8_t *header, int header_size)
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init_get_bits(&hb, header, header_size*8);
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if (get_le32(&hb) != MKTAG('R','I','F','F')) {
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av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
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chunk_size = get_le32(&hb);
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if (get_le32(&hb) != MKTAG('W','A','V','E')) {
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av_log(avctx, AV_LOG_ERROR, "missing WAVE tag\n");
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while (get_le32(&hb) != MKTAG('f','m','t',' ')) {
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skip_bits(&hb, 8*len);
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av_log(avctx, AV_LOG_ERROR, "fmt chunk was too short\n");
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wave_format = get_le16(&hb);
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switch (wave_format) {
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case WAVE_FORMAT_PCM:
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av_log(avctx, AV_LOG_ERROR, "unsupported wave format\n");
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avctx->channels = get_le16(&hb);
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avctx->sample_rate = get_le32(&hb);
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avctx->bit_rate = get_le32(&hb) * 8;
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avctx->block_align = get_le16(&hb);
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avctx->bits_per_sample = get_le16(&hb);
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if (avctx->bits_per_sample != 16) {
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av_log(avctx, AV_LOG_ERROR, "unsupported number of bits per sample\n");
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av_log(avctx, AV_LOG_INFO, "%d header bytes unparsed\n", len);
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static int16_t * interleave_buffer(int16_t *samples, int nchan, int blocksize, int32_t **buffer) {
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for (i=0; i<blocksize; i++)
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for (chan=0; chan < nchan; chan++)
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*samples++ = FFMIN(buffer[chan][i], 32768);
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static void decode_subframe_lpc(ShortenContext *s, int channel, int residual_size, int pred_order)
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int coeffs[pred_order];
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for (i=0; i<pred_order; i++)
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coeffs[i] = get_sr_golomb_shorten(&s->gb, LPCQUANT);
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for (i=0; i < s->blocksize; i++) {
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for (j=0; j<pred_order; j++)
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sum += coeffs[j] * s->decoded[channel][i-j-1];
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s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + (sum >> LPCQUANT);
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static int shorten_decode_frame(AVCodecContext *avctx,
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void *data, int *data_size,
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uint8_t *buf, int buf_size)
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ShortenContext *s = avctx->priv_data;
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int i, input_buf_size = 0;
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int16_t *samples = data;
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if(s->max_framesize == 0){
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s->max_framesize= 1024; // should hopefully be enough for the first header
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s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
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if(1 && s->max_framesize){//FIXME truncated
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buf_size= FFMIN(buf_size, s->max_framesize - s->bitstream_size);
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input_buf_size= buf_size;
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if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
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// printf("memmove\n");
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memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
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s->bitstream_index=0;
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memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
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buf= &s->bitstream[s->bitstream_index];
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buf_size += s->bitstream_size;
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s->bitstream_size= buf_size;
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if(buf_size < s->max_framesize){
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//dprintf("wanna more data ... %d\n", buf_size);
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return input_buf_size;
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init_get_bits(&s->gb, buf, buf_size*8);
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get_bits(&s->gb, s->bitindex);
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/* shorten signature */
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if (get_bits_long(&s->gb, 32) != bswap_32(ff_get_fourcc("ajkg"))) {
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av_log(s->avctx, AV_LOG_ERROR, "missing shorten magic 'ajkg'\n");
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s->blocksize = DEFAULT_BLOCK_SIZE;
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s->version = get_bits(&s->gb, 8);
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s->internal_ftype = get_uint(s, TYPESIZE);
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s->channels = get_uint(s, CHANSIZE);
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if (s->channels > MAX_CHANNELS) {
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av_log(s->avctx, AV_LOG_ERROR, "too many channels: %d\n", s->channels);
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/* get blocksize if version > 0 */
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if (s->version > 0) {
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s->blocksize = get_uint(s, av_log2(DEFAULT_BLOCK_SIZE));
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maxnlpc = get_uint(s, LPCQSIZE);
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s->nmean = get_uint(s, 0);
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skip_bytes = get_uint(s, NSKIPSIZE);
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for (i=0; i<skip_bytes; i++) {
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skip_bits(&s->gb, 8);
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s->nwrap = FFMAX(NWRAP, maxnlpc);
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s->lpcqoffset = V2LPCQOFFSET;
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if (get_ur_golomb_shorten(&s->gb, FNSIZE) != FN_VERBATIM) {
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av_log(s->avctx, AV_LOG_ERROR, "missing verbatim section at begining of stream\n");
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s->header_size = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
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if (s->header_size >= OUT_BUFFER_SIZE || s->header_size < CANONICAL_HEADER_SIZE) {
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av_log(s->avctx, AV_LOG_ERROR, "header is wrong size: %d\n", s->header_size);
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for (i=0; i<s->header_size; i++)
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s->header[i] = (char)get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
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if (decode_wave_header(avctx, s->header, s->header_size) < 0)
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cmd = get_ur_golomb_shorten(&s->gb, FNSIZE);
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int residual_size = 0;
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int channel = s->cur_chan;
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if (cmd != FN_ZERO) {
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residual_size = get_ur_golomb_shorten(&s->gb, ENERGYSIZE);
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/* this is a hack as version 0 differed in defintion of get_sr_golomb_shorten */
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coffset = s->offset[channel][0];
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int32_t sum = (s->version < 2) ? 0 : s->nmean / 2;
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for (i=0; i<s->nmean; i++)
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sum += s->offset[channel][i];
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coffset = sum / s->nmean;
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coffset >>= FFMIN(1, s->bitshift);
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for (i=0; i<s->blocksize; i++)
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s->decoded[channel][i] = 0;
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for (i=0; i<s->blocksize; i++)
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s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + coffset;
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for (i=0; i<s->blocksize; i++)
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s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + s->decoded[channel][i - 1];
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for (i=0; i<s->blocksize; i++)
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s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 2*s->decoded[channel][i-1]
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- s->decoded[channel][i-2];
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for (i=0; i<s->blocksize; i++)
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s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 3*s->decoded[channel][i-1]
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- 3*s->decoded[channel][i-2]
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+ s->decoded[channel][i-3];
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int pred_order = get_ur_golomb_shorten(&s->gb, LPCQSIZE);
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for (i=0; i<pred_order; i++)
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s->decoded[channel][i - pred_order] -= coffset;
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decode_subframe_lpc(s, channel, residual_size, pred_order);
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for (i=0; i < s->blocksize; i++)
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s->decoded[channel][i] += coffset;
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int32_t sum = (s->version < 2) ? 0 : s->blocksize / 2;
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for (i=0; i<s->blocksize; i++)
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sum += s->decoded[channel][i];
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for (i=1; i<s->nmean; i++)
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s->offset[channel][i-1] = s->offset[channel][i];
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s->offset[channel][s->nmean - 1] = sum / s->blocksize;
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s->offset[channel][s->nmean - 1] = (sum / s->blocksize) << s->bitshift;
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for (i=-s->nwrap; i<0; i++)
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s->decoded[channel][i] = s->decoded[channel][i + s->blocksize];
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fix_bitshift(s, s->decoded[channel]);
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if (s->cur_chan == s->channels) {
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samples = interleave_buffer(samples, s->channels, s->blocksize, s->decoded);
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len = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
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get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
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s->bitshift = get_ur_golomb_shorten(&s->gb, BITSHIFTSIZE);
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s->blocksize = get_uint(s, av_log2(s->blocksize));
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av_log(avctx, AV_LOG_ERROR, "unknown shorten function %d\n", cmd);
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*data_size = (int8_t *)samples - (int8_t *)data;
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// s->last_blocksize = s->blocksize;
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s->bitindex = get_bits_count(&s->gb) - 8*((get_bits_count(&s->gb))/8);
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i= (get_bits_count(&s->gb))/8;
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av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
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s->bitstream_index=0;
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if (s->bitstream_size) {
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s->bitstream_index += i;
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s->bitstream_size -= i;
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return input_buf_size;
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static int shorten_decode_close(AVCodecContext *avctx)
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ShortenContext *s = avctx->priv_data;
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for (i = 0; i < s->channels; i++) {
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s->decoded[i] -= s->nwrap;
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av_freep(&s->decoded[i]);
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av_freep(&s->offset[i]);
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av_freep(&s->bitstream);
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static void shorten_flush(AVCodecContext *avctx){
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ShortenContext *s = avctx->priv_data;
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s->bitstream_index= 0;
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AVCodec shorten_decoder = {
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sizeof(ShortenContext),
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shorten_decode_close,
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shorten_decode_frame,
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.flush= shorten_flush,