mirror of
https://github.com/FFmpeg/FFmpeg.git
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120 lines
3.4 KiB
C
120 lines
3.4 KiB
C
/*
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* AST demuxer
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* Copyright (c) 2012 Paul B Mahol
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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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#include "libavutil/channel_layout.h"
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#include "libavutil/intreadwrite.h"
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#include "avformat.h"
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#include "internal.h"
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#include "ast.h"
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static int ast_probe(AVProbeData *p)
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{
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if (AV_RL32(p->buf) == MKTAG('S','T','R','M') &&
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AV_RB16(p->buf + 10) &&
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AV_RB16(p->buf + 12) &&
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AV_RB32(p->buf + 16))
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return AVPROBE_SCORE_MAX / 3 * 2;
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return 0;
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}
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static int ast_read_header(AVFormatContext *s)
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{
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int depth;
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AVStream *st;
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st = avformat_new_stream(s, NULL);
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if (!st)
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return AVERROR(ENOMEM);
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avio_skip(s->pb, 8);
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st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
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st->codec->codec_id = ff_codec_get_id(ff_codec_ast_tags, avio_rb16(s->pb));
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depth = avio_rb16(s->pb);
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if (depth != 16) {
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avpriv_request_sample(s, "depth %d", depth);
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return AVERROR_INVALIDDATA;
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}
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st->codec->channels = avio_rb16(s->pb);
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if (!st->codec->channels)
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return AVERROR_INVALIDDATA;
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if (st->codec->channels == 2)
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st->codec->channel_layout = AV_CH_LAYOUT_STEREO;
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else if (st->codec->channels == 4)
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st->codec->channel_layout = AV_CH_LAYOUT_4POINT0;
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avio_skip(s->pb, 2);
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st->codec->sample_rate = avio_rb32(s->pb);
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if (st->codec->sample_rate <= 0)
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return AVERROR_INVALIDDATA;
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st->start_time = 0;
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st->duration = avio_rb32(s->pb);
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avio_skip(s->pb, 40);
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avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
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return 0;
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}
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static int ast_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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uint32_t type, size;
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int64_t pos;
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int ret;
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if (url_feof(s->pb))
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return AVERROR_EOF;
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pos = avio_tell(s->pb);
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type = avio_rl32(s->pb);
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size = avio_rb32(s->pb);
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if (size > INT_MAX / s->streams[0]->codec->channels)
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return AVERROR_INVALIDDATA;
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size *= s->streams[0]->codec->channels;
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if ((ret = avio_skip(s->pb, 24)) < 0) // padding
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return ret;
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if (type == MKTAG('B','L','C','K')) {
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ret = av_get_packet(s->pb, pkt, size);
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pkt->stream_index = 0;
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pkt->pos = pos;
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} else {
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av_log(s, AV_LOG_ERROR, "unknown chunk %x\n", type);
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avio_skip(s->pb, size);
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ret = AVERROR_INVALIDDATA;
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}
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return ret;
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}
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AVInputFormat ff_ast_demuxer = {
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.name = "ast",
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.long_name = NULL_IF_CONFIG_SMALL("AST (Audio Stream)"),
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.read_probe = ast_probe,
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.read_header = ast_read_header,
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.read_packet = ast_read_packet,
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.extensions = "ast",
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.flags = AVFMT_GENERIC_INDEX,
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.codec_tag = (const AVCodecTag* const []){ff_codec_ast_tags, 0},
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};
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