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