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/*
* TTA (The Lossless True Audio) decoder
* Copyright (c) 2006 Alex Beregszaszi
*
* 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
* TTA (The Lossless True Audio) decoder
* (www.true-audio.com or tta.corecodec.org)
* @author Alex Beregszaszi
*
*/
#define ALT_BITSTREAM_READER_LE
//#define DEBUG
#include <limits.h>
#include "avcodec.h"
#include "get_bits.h"
#define FORMAT_INT 1
#define FORMAT_FLOAT 3
#define MAX_ORDER 16
typedef struct TTAFilter {
int32_t shift, round, error, mode;
int32_t qm[MAX_ORDER];
int32_t dx[MAX_ORDER];
int32_t dl[MAX_ORDER];
} TTAFilter;
typedef struct TTARice {
uint32_t k0, k1, sum0, sum1;
} TTARice;
typedef struct TTAChannel {
int32_t predictor;
TTAFilter filter;
TTARice rice;
} TTAChannel;
typedef struct TTAContext {
AVCodecContext *avctx;
GetBitContext gb;
int flags, channels, bps, is_float, data_length;
int frame_length, last_frame_length, total_frames;
int32_t *decode_buffer;
TTAChannel *ch_ctx;
} TTAContext;
#if 0
static inline int shift_1(int i)
{
if (i < 32)
return 1 << i;
else
return 0x80000000; // 16 << 31
}
static inline int shift_16(int i)
{
if (i < 28)
return 16 << i;
else
return 0x80000000; // 16 << 27
}
#else
static const uint32_t shift_1[] = {
0x00000001, 0x00000002, 0x00000004, 0x00000008,
0x00000010, 0x00000020, 0x00000040, 0x00000080,
0x00000100, 0x00000200, 0x00000400, 0x00000800,
0x00001000, 0x00002000, 0x00004000, 0x00008000,
0x00010000, 0x00020000, 0x00040000, 0x00080000,
0x00100000, 0x00200000, 0x00400000, 0x00800000,
0x01000000, 0x02000000, 0x04000000, 0x08000000,
0x10000000, 0x20000000, 0x40000000, 0x80000000,
0x80000000, 0x80000000, 0x80000000, 0x80000000,
0x80000000, 0x80000000, 0x80000000, 0x80000000
};
static const uint32_t * const shift_16 = shift_1 + 4;
#endif
static const int32_t ttafilter_configs[4][2] = {
{10, 1},
{9, 1},
{10, 1},
{12, 0}
};
static void ttafilter_init(TTAFilter *c, int32_t shift, int32_t mode) {
memset(c, 0, sizeof(TTAFilter));
c->shift = shift;
c->round = shift_1[shift-1];
// c->round = 1 << (shift - 1);
c->mode = mode;
}
// FIXME: copy paste from original
static inline void memshl(register int32_t *a, register int32_t *b) {
*a++ = *b++;
*a++ = *b++;
*a++ = *b++;
*a++ = *b++;
*a++ = *b++;
*a++ = *b++;
*a++ = *b++;
*a = *b;
}
// FIXME: copy paste from original
// mode=1 encoder, mode=0 decoder
static inline void ttafilter_process(TTAFilter *c, int32_t *in, int32_t mode) {
register int32_t *dl = c->dl, *qm = c->qm, *dx = c->dx, sum = c->round;
if (!c->error) {
sum += *dl++ * *qm, qm++;
sum += *dl++ * *qm, qm++;
sum += *dl++ * *qm, qm++;
sum += *dl++ * *qm, qm++;
sum += *dl++ * *qm, qm++;
sum += *dl++ * *qm, qm++;
sum += *dl++ * *qm, qm++;
sum += *dl++ * *qm, qm++;
dx += 8;
} else if(c->error < 0) {
sum += *dl++ * (*qm -= *dx++), qm++;
sum += *dl++ * (*qm -= *dx++), qm++;
sum += *dl++ * (*qm -= *dx++), qm++;
sum += *dl++ * (*qm -= *dx++), qm++;
sum += *dl++ * (*qm -= *dx++), qm++;
sum += *dl++ * (*qm -= *dx++), qm++;
sum += *dl++ * (*qm -= *dx++), qm++;
sum += *dl++ * (*qm -= *dx++), qm++;
} else {
sum += *dl++ * (*qm += *dx++), qm++;
sum += *dl++ * (*qm += *dx++), qm++;
sum += *dl++ * (*qm += *dx++), qm++;
sum += *dl++ * (*qm += *dx++), qm++;
sum += *dl++ * (*qm += *dx++), qm++;
sum += *dl++ * (*qm += *dx++), qm++;
sum += *dl++ * (*qm += *dx++), qm++;
sum += *dl++ * (*qm += *dx++), qm++;
}
*(dx-0) = ((*(dl-1) >> 30) | 1) << 2;
*(dx-1) = ((*(dl-2) >> 30) | 1) << 1;
*(dx-2) = ((*(dl-3) >> 30) | 1) << 1;
*(dx-3) = ((*(dl-4) >> 30) | 1);
// compress
if (mode) {
*dl = *in;
*in -= (sum >> c->shift);
c->error = *in;
} else {
c->error = *in;
*in += (sum >> c->shift);
*dl = *in;
}
if (c->mode) {
*(dl-1) = *dl - *(dl-1);
*(dl-2) = *(dl-1) - *(dl-2);
*(dl-3) = *(dl-2) - *(dl-3);
}
memshl(c->dl, c->dl + 1);
memshl(c->dx, c->dx + 1);
}
static void rice_init(TTARice *c, uint32_t k0, uint32_t k1)
{
c->k0 = k0;
c->k1 = k1;
c->sum0 = shift_16[k0];
c->sum1 = shift_16[k1];
}
static int tta_get_unary(GetBitContext *gb)
{
int ret = 0;
// count ones
while(get_bits1(gb))
ret++;
return ret;
}
static av_cold int tta_decode_init(AVCodecContext * avctx)
{
TTAContext *s = avctx->priv_data;
int i;
s->avctx = avctx;
// 30bytes includes a seektable with one frame
if (avctx->extradata_size < 30)
return -1;
init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size);
if (show_bits_long(&s->gb, 32) == AV_RL32("TTA1"))
{
/* signature */
skip_bits(&s->gb, 32);
// if (get_bits_long(&s->gb, 32) != av_bswap32(AV_RL32("TTA1"))) {
// av_log(s->avctx, AV_LOG_ERROR, "Missing magic\n");
// return -1;
// }
s->flags = get_bits(&s->gb, 16);
if (s->flags != 1 && s->flags != 3)
{
av_log(s->avctx, AV_LOG_ERROR, "Invalid flags\n");
return -1;
}
s->is_float = (s->flags == FORMAT_FLOAT);
avctx->channels = s->channels = get_bits(&s->gb, 16);
avctx->bits_per_coded_sample = get_bits(&s->gb, 16);
s->bps = (avctx->bits_per_coded_sample + 7) / 8;
avctx->sample_rate = get_bits_long(&s->gb, 32);
if(avctx->sample_rate > 1000000){ //prevent FRAME_TIME * avctx->sample_rate from overflowing and sanity check
av_log(avctx, AV_LOG_ERROR, "sample_rate too large\n");
return -1;
}
s->data_length = get_bits_long(&s->gb, 32);
skip_bits(&s->gb, 32); // CRC32 of header
if (s->is_float)
{
avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
av_log(s->avctx, AV_LOG_ERROR, "Unsupported sample format. Please contact the developers.\n");
return -1;
}
else switch(s->bps) {
// case 1: avctx->sample_fmt = AV_SAMPLE_FMT_U8; break;
case 2: avctx->sample_fmt = AV_SAMPLE_FMT_S16; break;
// case 3: avctx->sample_fmt = AV_SAMPLE_FMT_S24; break;
case 4: avctx->sample_fmt = AV_SAMPLE_FMT_S32; break;
default:
av_log(s->avctx, AV_LOG_ERROR, "Invalid/unsupported sample format. Please contact the developers.\n");
return -1;
}
// FIXME: horribly broken, but directly from reference source
#define FRAME_TIME 1.04489795918367346939
s->frame_length = (int)(FRAME_TIME * avctx->sample_rate);
s->last_frame_length = s->data_length % s->frame_length;
s->total_frames = s->data_length / s->frame_length +
(s->last_frame_length ? 1 : 0);
av_log(s->avctx, AV_LOG_DEBUG, "flags: %x chans: %d bps: %d rate: %d block: %d\n",
s->flags, avctx->channels, avctx->bits_per_coded_sample, avctx->sample_rate,
avctx->block_align);
av_log(s->avctx, AV_LOG_DEBUG, "data_length: %d frame_length: %d last: %d total: %d\n",
s->data_length, s->frame_length, s->last_frame_length, s->total_frames);
// FIXME: seek table
for (i = 0; i < s->total_frames; i++)
skip_bits(&s->gb, 32);
skip_bits(&s->gb, 32); // CRC32 of seektable
if(s->frame_length >= UINT_MAX / (s->channels * sizeof(int32_t))){
av_log(avctx, AV_LOG_ERROR, "frame_length too large\n");
return -1;
}
s->decode_buffer = av_mallocz(sizeof(int32_t)*s->frame_length*s->channels);
s->ch_ctx = av_malloc(avctx->channels * sizeof(*s->ch_ctx));
if (!s->ch_ctx)
return AVERROR(ENOMEM);
} else {
av_log(avctx, AV_LOG_ERROR, "Wrong extradata present\n");
return -1;
}
return 0;
}
static int tta_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
TTAContext *s = avctx->priv_data;
int i;
init_get_bits(&s->gb, buf, buf_size*8);
{
int cur_chan = 0, framelen = s->frame_length;
int32_t *p;
if (*data_size < (framelen * s->channels * 2)) {
av_log(avctx, AV_LOG_ERROR, "Output buffer size is too small.\n");
return -1;
}
// FIXME: seeking
s->total_frames--;
if (!s->total_frames && s->last_frame_length)
framelen = s->last_frame_length;
// init per channel states
for (i = 0; i < s->channels; i++) {
s->ch_ctx[i].predictor = 0;
ttafilter_init(&s->ch_ctx[i].filter, ttafilter_configs[s->bps-1][0], ttafilter_configs[s->bps-1][1]);
rice_init(&s->ch_ctx[i].rice, 10, 10);
}
for (p = s->decode_buffer; p < s->decode_buffer + (framelen * s->channels); p++) {
int32_t *predictor = &s->ch_ctx[cur_chan].predictor;
TTAFilter *filter = &s->ch_ctx[cur_chan].filter;
TTARice *rice = &s->ch_ctx[cur_chan].rice;
uint32_t unary, depth, k;
int32_t value;
unary = tta_get_unary(&s->gb);
if (unary == 0) {
depth = 0;
k = rice->k0;
} else {
depth = 1;
k = rice->k1;
unary--;
}
if (get_bits_left(&s->gb) < k)
return -1;
if (k) {
if (k > MIN_CACHE_BITS)
return -1;
value = (unary << k) + get_bits(&s->gb, k);
} else
value = unary;
// FIXME: copy paste from original
switch (depth) {
case 1:
rice->sum1 += value - (rice->sum1 >> 4);
if (rice->k1 > 0 && rice->sum1 < shift_16[rice->k1])
rice->k1--;
else if(rice->sum1 > shift_16[rice->k1 + 1])
rice->k1++;
value += shift_1[rice->k0];
default:
rice->sum0 += value - (rice->sum0 >> 4);
if (rice->k0 > 0 && rice->sum0 < shift_16[rice->k0])
rice->k0--;
else if(rice->sum0 > shift_16[rice->k0 + 1])
rice->k0++;
}
// extract coded value
#define UNFOLD(x) (((x)&1) ? (++(x)>>1) : (-(x)>>1))
*p = UNFOLD(value);
// run hybrid filter
ttafilter_process(filter, p, 0);
// fixed order prediction
#define PRED(x, k) (int32_t)((((uint64_t)x << k) - x) >> k)
switch (s->bps) {
case 1: *p += PRED(*predictor, 4); break;
case 2:
case 3: *p += PRED(*predictor, 5); break;
case 4: *p += *predictor; break;
}
*predictor = *p;
#if 0
// extract 32bit float from last two int samples
if (s->is_float && ((p - data) & 1)) {
uint32_t neg = *p & 0x80000000;
uint32_t hi = *(p - 1);
uint32_t lo = abs(*p) - 1;
hi += (hi || lo) ? 0x3f80 : 0;
// SWAP16: swap all the 16 bits
*(p - 1) = (hi << 16) | SWAP16(lo) | neg;
}
#endif
/*if ((get_bits_count(&s->gb)+7)/8 > buf_size)
{
av_log(NULL, AV_LOG_INFO, "overread!!\n");
break;
}*/
// flip channels
if (cur_chan < (s->channels-1))
cur_chan++;
else {
// decorrelate in case of stereo integer
if (!s->is_float && (s->channels > 1)) {
int32_t *r = p - 1;
for (*p += *r / 2; r > p - s->channels; r--)
*r = *(r + 1) - *r;
}
cur_chan = 0;
}
}
if (get_bits_left(&s->gb) < 32)
return -1;
skip_bits(&s->gb, 32); // frame crc
// convert to output buffer
switch(s->bps) {
case 2: {
uint16_t *samples = data;
for (p = s->decode_buffer; p < s->decode_buffer + (framelen * s->channels); p++) {
// *samples++ = (unsigned char)*p;
// *samples++ = (unsigned char)(*p >> 8);
*samples++ = *p;
}
*data_size = (uint8_t *)samples - (uint8_t *)data;
break;
}
default:
av_log(s->avctx, AV_LOG_ERROR, "Error, only 16bit samples supported!\n");
}
}
// return get_bits_count(&s->gb)+7)/8;
return buf_size;
}
static av_cold int tta_decode_close(AVCodecContext *avctx) {
TTAContext *s = avctx->priv_data;
if (s->decode_buffer)
av_free(s->decode_buffer);
av_freep(&s->ch_ctx);
return 0;
}
AVCodec tta_decoder = {
"tta",
AVMEDIA_TYPE_AUDIO,
CODEC_ID_TTA,
sizeof(TTAContext),
tta_decode_init,
NULL,
tta_decode_close,
tta_decode_frame,
.long_name = NULL_IF_CONFIG_SMALL("True Audio (TTA)"),
};
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