/* * TTA (The Lossless True Audio) decoder * Copyright (c) 2006 Alex Beregszaszi * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; 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 "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, total_frames; 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); } // 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; } 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) { 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); c->error = *in; *in += (sum >> c->shift); *dl = *in; *(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_bits_left(gb) > 0 && get_bits1(gb)) ret++; return ret; } 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; 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 * 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 -1; } 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); 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); 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 2: avctx->sample_fmt = AV_SAMPLE_FMT_S16; avctx->bits_per_raw_sample = 16; break; case 3: avctx->sample_fmt = AV_SAMPLE_FMT_S32; avctx->bits_per_raw_sample = 24; 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; s->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, s->total_frames); // FIXME: seek table if (avctx->extradata_size <= 26 || s->total_frames > INT_MAX / 4 || avctx->extradata_size - 26 < s->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, s->total_frames * 4)) return AVERROR_INVALIDDATA; } skip_bits_long(&s->gb, 32 * s->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 -1; } if (s->bps == 2) { s->decode_buffer = av_mallocz(sizeof(int32_t)*s->frame_length*s->channels); if (!s->decode_buffer) return AVERROR(ENOMEM); } 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 -1; } 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); // FIXME: seeking s->total_frames--; if (!s->total_frames && s->last_frame_length) framelen = s->last_frame_length; /* get output buffer */ s->frame.nb_samples = framelen; if ((ret = avctx->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); } 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; } } if (get_bits_left(&s->gb) < 32) { ret = AVERROR_INVALIDDATA; goto error; } skip_bits_long(&s->gb, 32); // frame crc // convert to output buffer if (s->bps == 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; } else { // shift samples for 24-bit sample format int32_t *samples = (int32_t *)s->frame.data[0]; for (i = 0; i < framelen * s->channels; i++) *samples++ <<= 8; // reset decode buffer s->decode_buffer = NULL; } *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; av_free(s->decode_buffer); 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)"), };