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ffmpeg/libavcodec/shorten.c

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/*
* Shorten decoder
* Copyright (c) 2005 Jeff Muizelaar
*
* 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 libavcodec/shorten.c
* Shorten decoder
* @author Jeff Muizelaar
*
*/
#define DEBUG
#include <limits.h>
#include "avcodec.h"
#include "get_bits.h"
#include "golomb.h"
#define MAX_CHANNELS 8
#define MAX_BLOCKSIZE 65535
#define OUT_BUFFER_SIZE 16384
#define ULONGSIZE 2
#define WAVE_FORMAT_PCM 0x0001
#define DEFAULT_BLOCK_SIZE 256
#define TYPESIZE 4
#define CHANSIZE 0
#define LPCQSIZE 2
#define ENERGYSIZE 3
#define BITSHIFTSIZE 2
#define TYPE_S16HL 3
#define TYPE_S16LH 5
#define NWRAP 3
#define NSKIPSIZE 1
#define LPCQUANT 5
#define V2LPCQOFFSET (1 << LPCQUANT)
#define FNSIZE 2
#define FN_DIFF0 0
#define FN_DIFF1 1
#define FN_DIFF2 2
#define FN_DIFF3 3
#define FN_QUIT 4
#define FN_BLOCKSIZE 5
#define FN_BITSHIFT 6
#define FN_QLPC 7
#define FN_ZERO 8
#define FN_VERBATIM 9
#define VERBATIM_CKSIZE_SIZE 5
#define VERBATIM_BYTE_SIZE 8
#define CANONICAL_HEADER_SIZE 44
typedef struct ShortenContext {
AVCodecContext *avctx;
GetBitContext gb;
int min_framesize, max_framesize;
int channels;
int32_t *decoded[MAX_CHANNELS];
int32_t *offset[MAX_CHANNELS];
uint8_t *bitstream;
int bitstream_size;
int bitstream_index;
unsigned int allocated_bitstream_size;
int header_size;
uint8_t header[OUT_BUFFER_SIZE];
int version;
int cur_chan;
int bitshift;
int nmean;
int internal_ftype;
int nwrap;
int blocksize;
int bitindex;
int32_t lpcqoffset;
} ShortenContext;
static av_cold int shorten_decode_init(AVCodecContext * avctx)
{
ShortenContext *s = avctx->priv_data;
s->avctx = avctx;
avctx->sample_fmt = SAMPLE_FMT_S16;
return 0;
}
static int allocate_buffers(ShortenContext *s)
{
int i, chan;
for (chan=0; chan<s->channels; chan++) {
if(FFMAX(1, s->nmean) >= UINT_MAX/sizeof(int32_t)){
av_log(s->avctx, AV_LOG_ERROR, "nmean too large\n");
return -1;
}
if(s->blocksize + s->nwrap >= UINT_MAX/sizeof(int32_t) || s->blocksize + s->nwrap <= (unsigned)s->nwrap){
av_log(s->avctx, AV_LOG_ERROR, "s->blocksize + s->nwrap too large\n");
return -1;
}
s->offset[chan] = av_realloc(s->offset[chan], sizeof(int32_t)*FFMAX(1, s->nmean));
s->decoded[chan] = av_realloc(s->decoded[chan], sizeof(int32_t)*(s->blocksize + s->nwrap));
for (i=0; i<s->nwrap; i++)
s->decoded[chan][i] = 0;
s->decoded[chan] += s->nwrap;
}
return 0;
}
static inline unsigned int get_uint(ShortenContext *s, int k)
{
if (s->version != 0)
k = get_ur_golomb_shorten(&s->gb, ULONGSIZE);
return get_ur_golomb_shorten(&s->gb, k);
}
static void fix_bitshift(ShortenContext *s, int32_t *buffer)
{
int i;
if (s->bitshift != 0)
for (i = 0; i < s->blocksize; i++)
buffer[s->nwrap + i] <<= s->bitshift;
}
static void init_offset(ShortenContext *s)
{
int32_t mean = 0;
int chan, i;
int nblock = FFMAX(1, s->nmean);
/* initialise offset */
switch (s->internal_ftype)
{
case TYPE_S16HL:
case TYPE_S16LH:
mean = 0;
break;
default:
av_log(s->avctx, AV_LOG_ERROR, "unknown audio type");
abort();
}
for (chan = 0; chan < s->channels; chan++)
for (i = 0; i < nblock; i++)
s->offset[chan][i] = mean;
}
static inline int get_le32(GetBitContext *gb)
{
return bswap_32(get_bits_long(gb, 32));
}
static inline short get_le16(GetBitContext *gb)
{
return bswap_16(get_bits_long(gb, 16));
}
static int decode_wave_header(AVCodecContext *avctx, uint8_t *header, int header_size)
{
GetBitContext hb;
int len;
int chunk_size;
short wave_format;
init_get_bits(&hb, header, header_size*8);
if (get_le32(&hb) != MKTAG('R','I','F','F')) {
av_log(avctx, AV_LOG_ERROR, "missing RIFF tag\n");
return -1;
}
chunk_size = get_le32(&hb);
if (get_le32(&hb) != MKTAG('W','A','V','E')) {
av_log(avctx, AV_LOG_ERROR, "missing WAVE tag\n");
return -1;
}
while (get_le32(&hb) != MKTAG('f','m','t',' ')) {
len = get_le32(&hb);
skip_bits(&hb, 8*len);
}
len = get_le32(&hb);
if (len < 16) {
av_log(avctx, AV_LOG_ERROR, "fmt chunk was too short\n");
return -1;
}
wave_format = get_le16(&hb);
switch (wave_format) {
case WAVE_FORMAT_PCM:
break;
default:
av_log(avctx, AV_LOG_ERROR, "unsupported wave format\n");
return -1;
}
avctx->channels = get_le16(&hb);
avctx->sample_rate = get_le32(&hb);
avctx->bit_rate = get_le32(&hb) * 8;
avctx->block_align = get_le16(&hb);
avctx->bits_per_coded_sample = get_le16(&hb);
if (avctx->bits_per_coded_sample != 16) {
av_log(avctx, AV_LOG_ERROR, "unsupported number of bits per sample\n");
return -1;
}
len -= 16;
if (len > 0)
av_log(avctx, AV_LOG_INFO, "%d header bytes unparsed\n", len);
return 0;
}
static int16_t * interleave_buffer(int16_t *samples, int nchan, int blocksize, int32_t **buffer) {
int i, chan;
for (i=0; i<blocksize; i++)
for (chan=0; chan < nchan; chan++)
*samples++ = FFMIN(buffer[chan][i], 32768);
return samples;
}
static void decode_subframe_lpc(ShortenContext *s, int channel, int residual_size, int pred_order)
{
int sum, i, j;
int coeffs[pred_order];
for (i=0; i<pred_order; i++)
coeffs[i] = get_sr_golomb_shorten(&s->gb, LPCQUANT);
for (i=0; i < s->blocksize; i++) {
sum = s->lpcqoffset;
for (j=0; j<pred_order; j++)
sum += coeffs[j] * s->decoded[channel][i-j-1];
s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + (sum >> LPCQUANT);
}
}
static int shorten_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
ShortenContext *s = avctx->priv_data;
int i, input_buf_size = 0;
int16_t *samples = data;
if(s->max_framesize == 0){
s->max_framesize= 1024; // should hopefully be enough for the first header
s->bitstream= av_fast_realloc(s->bitstream, &s->allocated_bitstream_size, s->max_framesize);
}
if(1 && s->max_framesize){//FIXME truncated
buf_size= FFMIN(buf_size, s->max_framesize - s->bitstream_size);
input_buf_size= buf_size;
if(s->bitstream_index + s->bitstream_size + buf_size > s->allocated_bitstream_size){
// printf("memmove\n");
memmove(s->bitstream, &s->bitstream[s->bitstream_index], s->bitstream_size);
s->bitstream_index=0;
}
memcpy(&s->bitstream[s->bitstream_index + s->bitstream_size], buf, buf_size);
buf= &s->bitstream[s->bitstream_index];
buf_size += s->bitstream_size;
s->bitstream_size= buf_size;
if(buf_size < s->max_framesize){
//dprintf(avctx, "wanna more data ... %d\n", buf_size);
*data_size = 0;
return input_buf_size;
}
}
init_get_bits(&s->gb, buf, buf_size*8);
skip_bits(&s->gb, s->bitindex);
if (!s->blocksize)
{
int maxnlpc = 0;
/* shorten signature */
if (get_bits_long(&s->gb, 32) != AV_RB32("ajkg")) {
av_log(s->avctx, AV_LOG_ERROR, "missing shorten magic 'ajkg'\n");
return -1;
}
s->lpcqoffset = 0;
s->blocksize = DEFAULT_BLOCK_SIZE;
s->channels = 1;
s->nmean = -1;
s->version = get_bits(&s->gb, 8);
s->internal_ftype = get_uint(s, TYPESIZE);
s->channels = get_uint(s, CHANSIZE);
if (s->channels > MAX_CHANNELS) {
av_log(s->avctx, AV_LOG_ERROR, "too many channels: %d\n", s->channels);
return -1;
}
/* get blocksize if version > 0 */
if (s->version > 0) {
int skip_bytes;
s->blocksize = get_uint(s, av_log2(DEFAULT_BLOCK_SIZE));
maxnlpc = get_uint(s, LPCQSIZE);
s->nmean = get_uint(s, 0);
skip_bytes = get_uint(s, NSKIPSIZE);
for (i=0; i<skip_bytes; i++) {
skip_bits(&s->gb, 8);
}
}
s->nwrap = FFMAX(NWRAP, maxnlpc);
if (allocate_buffers(s))
return -1;
init_offset(s);
if (s->version > 1)
s->lpcqoffset = V2LPCQOFFSET;
if (get_ur_golomb_shorten(&s->gb, FNSIZE) != FN_VERBATIM) {
av_log(s->avctx, AV_LOG_ERROR, "missing verbatim section at beginning of stream\n");
return -1;
}
s->header_size = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
if (s->header_size >= OUT_BUFFER_SIZE || s->header_size < CANONICAL_HEADER_SIZE) {
av_log(s->avctx, AV_LOG_ERROR, "header is wrong size: %d\n", s->header_size);
return -1;
}
for (i=0; i<s->header_size; i++)
s->header[i] = (char)get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
if (decode_wave_header(avctx, s->header, s->header_size) < 0)
return -1;
s->cur_chan = 0;
s->bitshift = 0;
}
else
{
int cmd;
int len;
cmd = get_ur_golomb_shorten(&s->gb, FNSIZE);
switch (cmd) {
case FN_ZERO:
case FN_DIFF0:
case FN_DIFF1:
case FN_DIFF2:
case FN_DIFF3:
case FN_QLPC:
{
int residual_size = 0;
int channel = s->cur_chan;
int32_t coffset;
if (cmd != FN_ZERO) {
residual_size = get_ur_golomb_shorten(&s->gb, ENERGYSIZE);
/* this is a hack as version 0 differed in defintion of get_sr_golomb_shorten */
if (s->version == 0)
residual_size--;
}
if (s->nmean == 0)
coffset = s->offset[channel][0];
else {
int32_t sum = (s->version < 2) ? 0 : s->nmean / 2;
for (i=0; i<s->nmean; i++)
sum += s->offset[channel][i];
coffset = sum / s->nmean;
if (s->version >= 2)
coffset >>= FFMIN(1, s->bitshift);
}
switch (cmd) {
case FN_ZERO:
for (i=0; i<s->blocksize; i++)
s->decoded[channel][i] = 0;
break;
case FN_DIFF0:
for (i=0; i<s->blocksize; i++)
s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + coffset;
break;
case FN_DIFF1:
for (i=0; i<s->blocksize; i++)
s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + s->decoded[channel][i - 1];
break;
case FN_DIFF2:
for (i=0; i<s->blocksize; i++)
s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 2*s->decoded[channel][i-1]
- s->decoded[channel][i-2];
break;
case FN_DIFF3:
for (i=0; i<s->blocksize; i++)
s->decoded[channel][i] = get_sr_golomb_shorten(&s->gb, residual_size) + 3*s->decoded[channel][i-1]
- 3*s->decoded[channel][i-2]
+ s->decoded[channel][i-3];
break;
case FN_QLPC:
{
int pred_order = get_ur_golomb_shorten(&s->gb, LPCQSIZE);
for (i=0; i<pred_order; i++)
s->decoded[channel][i - pred_order] -= coffset;
decode_subframe_lpc(s, channel, residual_size, pred_order);
if (coffset != 0)
for (i=0; i < s->blocksize; i++)
s->decoded[channel][i] += coffset;
}
}
if (s->nmean > 0) {
int32_t sum = (s->version < 2) ? 0 : s->blocksize / 2;
for (i=0; i<s->blocksize; i++)
sum += s->decoded[channel][i];
for (i=1; i<s->nmean; i++)
s->offset[channel][i-1] = s->offset[channel][i];
if (s->version < 2)
s->offset[channel][s->nmean - 1] = sum / s->blocksize;
else
s->offset[channel][s->nmean - 1] = (sum / s->blocksize) << s->bitshift;
}
for (i=-s->nwrap; i<0; i++)
s->decoded[channel][i] = s->decoded[channel][i + s->blocksize];
fix_bitshift(s, s->decoded[channel]);
s->cur_chan++;
if (s->cur_chan == s->channels) {
samples = interleave_buffer(samples, s->channels, s->blocksize, s->decoded);
s->cur_chan = 0;
goto frame_done;
}
break;
}
break;
case FN_VERBATIM:
len = get_ur_golomb_shorten(&s->gb, VERBATIM_CKSIZE_SIZE);
while (len--) {
get_ur_golomb_shorten(&s->gb, VERBATIM_BYTE_SIZE);
}
break;
case FN_BITSHIFT:
s->bitshift = get_ur_golomb_shorten(&s->gb, BITSHIFTSIZE);
break;
case FN_BLOCKSIZE:
s->blocksize = get_uint(s, av_log2(s->blocksize));
break;
case FN_QUIT:
*data_size = 0;
return buf_size;
break;
default:
av_log(avctx, AV_LOG_ERROR, "unknown shorten function %d\n", cmd);
return -1;
break;
}
}
frame_done:
*data_size = (int8_t *)samples - (int8_t *)data;
// s->last_blocksize = s->blocksize;
s->bitindex = get_bits_count(&s->gb) - 8*((get_bits_count(&s->gb))/8);
i= (get_bits_count(&s->gb))/8;
if (i > buf_size) {
av_log(s->avctx, AV_LOG_ERROR, "overread: %d\n", i - buf_size);
s->bitstream_size=0;
s->bitstream_index=0;
return -1;
}
if (s->bitstream_size) {
s->bitstream_index += i;
s->bitstream_size -= i;
return input_buf_size;
} else
return i;
}
static av_cold int shorten_decode_close(AVCodecContext *avctx)
{
ShortenContext *s = avctx->priv_data;
int i;
for (i = 0; i < s->channels; i++) {
s->decoded[i] -= s->nwrap;
av_freep(&s->decoded[i]);
av_freep(&s->offset[i]);
}
av_freep(&s->bitstream);
return 0;
}
static void shorten_flush(AVCodecContext *avctx){
ShortenContext *s = avctx->priv_data;
s->bitstream_size=
s->bitstream_index= 0;
}
AVCodec shorten_decoder = {
"shorten",
CODEC_TYPE_AUDIO,
CODEC_ID_SHORTEN,
sizeof(ShortenContext),
shorten_decode_init,
NULL,
shorten_decode_close,
shorten_decode_frame,
.flush= shorten_flush,
.long_name= NULL_IF_CONFIG_SMALL("Shorten"),
};
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