/*
* 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
* @see http://www.true-audio.com/
* @see http://tta.corecodec.org/
* @author Alex Beregszaszi
*/
#define BITSTREAM_READER_LE
//#define DEBUG
#include <limits.h>
#include "avcodec.h"
#include "get_bits.h"
#include "internal.h"
#include "libavutil/crc.h"
#define FORMAT_SIMPLE 1
#define FORMAT_ENCRYPTED 2
#define MAX_ORDER 16
typedef struct TTAFilter {
int32_t shift, round, error;
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;
AVFrame frame;
GetBitContext gb;
const AVCRC *crc_table;
int format, channels, bps;
unsigned data_length;
int frame_length, last_frame_length;
int32_t *decode_buffer;
TTAChannel *ch_ctx;
} TTAContext;
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;
static const int32_t ttafilter_configs[4] = {
10,
9,
10,
12
};
static void ttafilter_init(TTAFilter *c, int32_t shift) {
memset(c, 0, sizeof(TTAFilter));
c->shift = shift;
c->round = shift_1[shift-1];
// c->round = 1 << (shift - 1);
}
static inline void ttafilter_process(TTAFilter *c, int32_t *in)
{
register int32_t *dl = c->dl, *qm = c->qm, *dx = c->dx, sum = c->round;
if (c->error < 0) {
qm[0] -= dx[0]; qm[1] -= dx[1]; qm[2] -= dx[2]; qm[3] -= dx[3];
qm[4] -= dx[4]; qm[5] -= dx[5]; qm[6] -= dx[6]; qm[7] -= dx[7];
} else if (c->error > 0) {
qm[0] += dx[0]; qm[1] += dx[1]; qm[2] += dx[2]; qm[3] += dx[3];
qm[4] += dx[4]; qm[5] += dx[5]; qm[6] += dx[6]; qm[7] += dx[7];
}
sum += dl[0] * qm[0] + dl[1] * qm[1] + dl[2] * qm[2] + dl[3] * qm[3] +
dl[4] * qm[4] + dl[5] * qm[5] + dl[6] * qm[6] + dl[7] * qm[7];
dx[0] = dx[1]; dx[1] = dx[2]; dx[2] = dx[3]; dx[3] = dx[4];
dl[0] = dl[1]; dl[1] = dl[2]; dl[2] = dl[3]; dl[3] = dl[4];
dx[4] = ((dl[4] >> 30) | 1);
dx[5] = ((dl[5] >> 30) | 2) & ~1;
dx[6] = ((dl[6] >> 30) | 2) & ~1;
dx[7] = ((dl[7] >> 30) | 4) & ~3;
c->error = *in;
*in += (sum >> c->shift);
dl[4] = -dl[5]; dl[5] = -dl[6];
dl[6] = *in - dl[7]; dl[7] = *in;
dl[5] += dl[6]; dl[4] += dl[5];
}
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_bits_left(gb) > 0 && get_bits1(gb))
ret++;
return ret;
}
static const int64_t tta_channel_layouts[7] = {
AV_CH_LAYOUT_STEREO,
AV_CH_LAYOUT_STEREO|AV_CH_LOW_FREQUENCY,
AV_CH_LAYOUT_QUAD,
0,
AV_CH_LAYOUT_5POINT1_BACK,
AV_CH_LAYOUT_5POINT1_BACK|AV_CH_BACK_CENTER,
AV_CH_LAYOUT_7POINT1_WIDE
};
static int tta_check_crc(TTAContext *s, const uint8_t *buf, int buf_size)
{
uint32_t crc, CRC;
CRC = AV_RL32(buf + buf_size);
crc = av_crc(s->crc_table, 0xFFFFFFFFU, buf, buf_size);
if (CRC != (crc ^ 0xFFFFFFFFU)) {
av_log(s->avctx, AV_LOG_ERROR, "CRC error\n");
return AVERROR_INVALIDDATA;
}
return 0;
}
static av_cold int tta_decode_init(AVCodecContext * avctx)
{
TTAContext *s = avctx->priv_data;
int total_frames;
s->avctx = avctx;
// 30bytes includes a seektable with one frame
if (avctx->extradata_size < 30)
return AVERROR_INVALIDDATA;
init_get_bits(&s->gb, avctx->extradata, avctx->extradata_size * 8);
if (show_bits_long(&s->gb, 32) == AV_RL32("TTA1"))
{
if (avctx->err_recognition & AV_EF_CRCCHECK) {
s->crc_table = av_crc_get_table(AV_CRC_32_IEEE_LE);
tta_check_crc(s, avctx->extradata, 18);
}
/* signature */
skip_bits_long(&s->gb, 32);
s->format = get_bits(&s->gb, 16);
if (s->format > 2) {
av_log(s->avctx, AV_LOG_ERROR, "Invalid format\n");
return AVERROR_INVALIDDATA;
}
if (s->format == FORMAT_ENCRYPTED) {
av_log_missing_feature(s->avctx, "Encrypted TTA", 0);
return AVERROR_PATCHWELCOME;
}
avctx->channels = s->channels = get_bits(&s->gb, 16);
if (s->channels > 1 && s->channels < 9)
avctx->channel_layout = tta_channel_layouts[s->channels-2];
avctx->bits_per_raw_sample = get_bits(&s->gb, 16);
s->bps = (avctx->bits_per_raw_sample + 7) / 8;
avctx->sample_rate = get_bits_long(&s->gb, 32);
s->data_length = get_bits_long(&s->gb, 32);
skip_bits_long(&s->gb, 32); // CRC32 of header
if (s->channels == 0) {
av_log(s->avctx, AV_LOG_ERROR, "Invalid number of channels\n");
return AVERROR_INVALIDDATA;
} else if (avctx->sample_rate == 0) {
av_log(s->avctx, AV_LOG_ERROR, "Invalid samplerate\n");
return AVERROR_INVALIDDATA;
}
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_S32;
break;
//case 4: avctx->sample_fmt = AV_SAMPLE_FMT_S32; break;
default:
av_log(avctx, AV_LOG_ERROR, "Invalid/unsupported sample format.\n");
return AVERROR_INVALIDDATA;
}
// prevent overflow
if (avctx->sample_rate > 0x7FFFFFu) {
av_log(avctx, AV_LOG_ERROR, "sample_rate too large\n");
return AVERROR(EINVAL);
}
s->frame_length = 256 * avctx->sample_rate / 245;
s->last_frame_length = s->data_length % s->frame_length;
total_frames = s->data_length / s->frame_length +
(s->last_frame_length ? 1 : 0);
av_log(s->avctx, AV_LOG_DEBUG, "format: %d chans: %d bps: %d rate: %d block: %d\n",
s->format, 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, total_frames);
// FIXME: seek table
if (avctx->extradata_size <= 26 || total_frames > INT_MAX / 4 ||
avctx->extradata_size - 26 < total_frames * 4)
av_log(avctx, AV_LOG_WARNING, "Seek table missing or too small\n");
else if (avctx->err_recognition & AV_EF_CRCCHECK) {
if (tta_check_crc(s, avctx->extradata + 22, total_frames * 4))
return AVERROR_INVALIDDATA;
}
skip_bits_long(&s->gb, 32 * total_frames);
skip_bits_long(&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 AVERROR_INVALIDDATA;
}
if (s->bps < 3) {
s->decode_buffer = av_mallocz(sizeof(int32_t)*s->frame_length*s->channels);
if (!s->decode_buffer)
return AVERROR(ENOMEM);
} else
s->decode_buffer = NULL;
s->ch_ctx = av_malloc(avctx->channels * sizeof(*s->ch_ctx));
if (!s->ch_ctx) {
av_freep(&s->decode_buffer);
return AVERROR(ENOMEM);
}
} else {
av_log(avctx, AV_LOG_ERROR, "Wrong extradata present\n");
return AVERROR_INVALIDDATA;
}
avcodec_get_frame_defaults(&s->frame);
avctx->coded_frame = &s->frame;
return 0;
}
static int tta_decode_frame(AVCodecContext *avctx, void *data,
int *got_frame_ptr, AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
TTAContext *s = avctx->priv_data;
int i, ret;
int cur_chan = 0, framelen = s->frame_length;
int32_t *p;
if (avctx->err_recognition & AV_EF_CRCCHECK) {
if (buf_size < 4 || tta_check_crc(s, buf, buf_size - 4))
return AVERROR_INVALIDDATA;
}
init_get_bits(&s->gb, buf, buf_size*8);
/* get output buffer */
s->frame.nb_samples = framelen;
if ((ret = ff_get_buffer(avctx, &s->frame)) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return ret;
}
// decode directly to output buffer for 24-bit sample format
if (s->bps == 3)
s->decode_buffer = (int32_t *)s->frame.data[0];
// 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]);
rice_init(&s->ch_ctx[i].rice, 10, 10);
}
i = 0;
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) {
ret = AVERROR_INVALIDDATA;
goto error;
}
if (k) {
if (k > MIN_CACHE_BITS) {
ret = AVERROR_INVALIDDATA;
goto error;
}
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
*p = 1 + ((value >> 1) ^ ((value & 1) - 1));
// run hybrid filter
ttafilter_process(filter, p);
// 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;
// flip channels
if (cur_chan < (s->channels-1))
cur_chan++;
else {
// decorrelate in case of multiple channels
if (s->channels > 1) {
int32_t *r = p - 1;
for (*p += *r / 2; r > p - s->channels; r--)
*r = *(r + 1) - *r;
}
cur_chan = 0;
i++;
// check for last frame
if (i == s->last_frame_length && get_bits_left(&s->gb) / 8 == 4) {
s->frame.nb_samples = framelen = s->last_frame_length;
break;
}
}
}
align_get_bits(&s->gb);
if (get_bits_left(&s->gb) < 32) {
ret = AVERROR_INVALIDDATA;
goto error;
}
skip_bits_long(&s->gb, 32); // frame crc
// convert to output buffer
switch (s->bps) {
case 1: {
uint8_t *samples = (uint8_t *)s->frame.data[0];
for (p = s->decode_buffer; p < s->decode_buffer + (framelen * s->channels); p++)
*samples++ = *p + 0x80;
break;
}
case 2: {
int16_t *samples = (int16_t *)s->frame.data[0];
for (p = s->decode_buffer; p < s->decode_buffer + (framelen * s->channels); p++)
*samples++ = *p;
break;
}
case 3: {
// shift samples for 24-bit sample format
int32_t *samples = (int32_t *)s->frame.data[0];
for (p = s->decode_buffer; p < s->decode_buffer + (framelen * s->channels); p++)
*samples++ <<= 8;
// reset decode buffer
s->decode_buffer = NULL;
break;
}
}
*got_frame_ptr = 1;
*(AVFrame *)data = s->frame;
return buf_size;
error:
// reset decode buffer
if (s->bps == 3)
s->decode_buffer = NULL;
return ret;
}
static av_cold int tta_decode_close(AVCodecContext *avctx) {
TTAContext *s = avctx->priv_data;
if (s->bps < 3)
av_free(s->decode_buffer);
s->decode_buffer = NULL;
av_freep(&s->ch_ctx);
return 0;
}
AVCodec ff_tta_decoder = {
.name = "tta",
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_TTA,
.priv_data_size = sizeof(TTAContext),
.init = tta_decode_init,
.close = tta_decode_close,
.decode = tta_decode_frame,
.capabilities = CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("TTA (True Audio)"),
};