217 lines
6.4 KiB
C
Executable file
217 lines
6.4 KiB
C
Executable file
/*
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* MLP parser
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* Copyright (c) 2007 Ian Caulfield
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg 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 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg 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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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; 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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*/
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/**
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* @file
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* MLP parser
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*/
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#include <stdint.h>
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#include "libavutil/internal.h"
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#include "get_bits.h"
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#include "parser.h"
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#include "mlp_parse.h"
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#include "mlp.h"
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typedef struct MLPParseContext
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{
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ParseContext pc;
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int bytes_left;
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int in_sync;
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int num_substreams;
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} MLPParseContext;
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static av_cold int mlp_init(AVCodecParserContext *s)
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{
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ff_mlp_init_crc();
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return 0;
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}
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static int mlp_parse(AVCodecParserContext *s,
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AVCodecContext *avctx,
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const uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size)
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{
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MLPParseContext *mp = s->priv_data;
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int sync_present;
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uint8_t parity_bits;
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int next;
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int ret;
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int i, p = 0;
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s->key_frame = 0;
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*poutbuf_size = 0;
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*poutbuf = NULL;
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if (buf_size == 0)
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return 0;
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if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
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next = buf_size;
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} else {
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if (!mp->in_sync) {
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// Not in sync - find a major sync header
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for (i = 0; i < buf_size; i++) {
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mp->pc.state = (mp->pc.state << 8) | buf[i];
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if ((mp->pc.state & 0xfffffffe) == 0xf8726fba &&
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// ignore if we do not have the data for the start of header
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mp->pc.index + i >= 7) {
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mp->in_sync = 1;
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mp->bytes_left = 0;
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break;
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}
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}
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if (!mp->in_sync) {
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if (ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size) != -1)
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av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");
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return buf_size;
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}
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if ((ret = ff_combine_frame(&mp->pc, i - 7, &buf, &buf_size)) < 0) {
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av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");
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return ret;
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}
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return i - 7;
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}
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if (mp->bytes_left == 0) {
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// Find length of this packet
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/* Copy overread bytes from last frame into buffer. */
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for(; mp->pc.overread>0; mp->pc.overread--) {
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mp->pc.buffer[mp->pc.index++]= mp->pc.buffer[mp->pc.overread_index++];
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}
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if (mp->pc.index + buf_size < 2) {
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if (ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size) != -1)
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av_log(avctx, AV_LOG_WARNING, "ff_combine_frame failed\n");
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return buf_size;
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}
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mp->bytes_left = ((mp->pc.index > 0 ? mp->pc.buffer[0] : buf[0]) << 8)
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| (mp->pc.index > 1 ? mp->pc.buffer[1] : buf[1-mp->pc.index]);
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mp->bytes_left = (mp->bytes_left & 0xfff) * 2;
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if (mp->bytes_left <= 0) { // prevent infinite loop
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goto lost_sync;
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}
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mp->bytes_left -= mp->pc.index;
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}
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next = (mp->bytes_left > buf_size) ? END_NOT_FOUND : mp->bytes_left;
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if (ff_combine_frame(&mp->pc, next, &buf, &buf_size) < 0) {
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mp->bytes_left -= buf_size;
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return buf_size;
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}
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mp->bytes_left = 0;
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}
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sync_present = buf_size >= 8 && (AV_RB32(buf + 4) & 0xfffffffe) == 0xf8726fba;
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if (!sync_present) {
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/* The first nibble of a frame is a parity check of the 4-byte
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* access unit header and all the 2- or 4-byte substream headers. */
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// Only check when this isn't a sync frame - syncs have a checksum.
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s->key_frame = 0;
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parity_bits = 0;
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for (i = -1; i < mp->num_substreams; i++) {
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parity_bits ^= buf[p++];
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parity_bits ^= buf[p++];
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if (i < 0 || buf[p-2] & 0x80) {
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parity_bits ^= buf[p++];
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parity_bits ^= buf[p++];
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}
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}
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if ((((parity_bits >> 4) ^ parity_bits) & 0xF) != 0xF) {
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av_log(avctx, AV_LOG_INFO, "mlpparse: Parity check failed.\n");
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goto lost_sync;
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}
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} else {
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GetBitContext gb;
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MLPHeaderInfo mh;
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init_get_bits(&gb, buf + 4, (buf_size - 4) << 3);
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if (ff_mlp_read_major_sync(avctx, &mh, &gb) < 0)
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goto lost_sync;
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s->key_frame = 1;
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avctx->bits_per_raw_sample = mh.group1_bits;
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if (avctx->bits_per_raw_sample > 16)
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avctx->sample_fmt = AV_SAMPLE_FMT_S32;
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else
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avctx->sample_fmt = AV_SAMPLE_FMT_S16;
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avctx->sample_rate = mh.group1_samplerate;
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avctx->frame_size =
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s->duration = mh.access_unit_size;
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if(!avctx->channels || !avctx->channel_layout) {
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if (mh.stream_type == 0xbb) {
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/* MLP stream */
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avctx->channels = mh.channels_mlp;
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avctx->channel_layout = mh.channel_layout_mlp;
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} else { /* mh.stream_type == 0xba */
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/* TrueHD stream */
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if (!mh.channels_thd_stream2) {
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avctx->channels = mh.channels_thd_stream1;
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avctx->channel_layout = mh.channel_layout_thd_stream1;
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} else {
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avctx->channels = mh.channels_thd_stream2;
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avctx->channel_layout = mh.channel_layout_thd_stream2;
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}
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}
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}
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if (!mh.is_vbr) /* Stream is CBR */
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avctx->bit_rate = mh.peak_bitrate;
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mp->num_substreams = mh.num_substreams;
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}
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*poutbuf = buf;
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*poutbuf_size = buf_size;
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return next;
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lost_sync:
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mp->in_sync = 0;
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return 1;
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}
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AVCodecParser ff_mlp_parser = {
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.codec_ids = { AV_CODEC_ID_MLP, AV_CODEC_ID_TRUEHD },
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.priv_data_size = sizeof(MLPParseContext),
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.parser_init = mlp_init,
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.parser_parse = mlp_parse,
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.parser_close = ff_parse_close,
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};
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