yading@11: /*
yading@11:  * AST demuxer
yading@11:  * Copyright (c) 2012 Paul B Mahol
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: #include "libavutil/channel_layout.h"
yading@11: #include "libavutil/intreadwrite.h"
yading@11: #include "avformat.h"
yading@11: #include "internal.h"
yading@11: #include "ast.h"
yading@11: 
yading@11: static int ast_probe(AVProbeData *p)
yading@11: {
yading@11:     if (AV_RL32(p->buf) == MKTAG('S','T','R','M') &&
yading@11:         AV_RB16(p->buf + 10) &&
yading@11:         AV_RB16(p->buf + 12) &&
yading@11:         AV_RB32(p->buf + 16))
yading@11:         return AVPROBE_SCORE_MAX / 3 * 2;
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static int ast_read_header(AVFormatContext *s)
yading@11: {
yading@11:     int depth;
yading@11:     AVStream *st;
yading@11: 
yading@11:     st = avformat_new_stream(s, NULL);
yading@11:     if (!st)
yading@11:         return AVERROR(ENOMEM);
yading@11: 
yading@11:     avio_skip(s->pb, 8);
yading@11:     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
yading@11:     st->codec->codec_id   = ff_codec_get_id(ff_codec_ast_tags, avio_rb16(s->pb));
yading@11: 
yading@11:     depth = avio_rb16(s->pb);
yading@11:     if (depth != 16) {
yading@11:         avpriv_request_sample(s, "depth %d", depth);
yading@11:         return AVERROR_INVALIDDATA;
yading@11:     }
yading@11: 
yading@11:     st->codec->channels = avio_rb16(s->pb);
yading@11:     if (!st->codec->channels)
yading@11:         return AVERROR_INVALIDDATA;
yading@11: 
yading@11:     if (st->codec->channels == 2)
yading@11:         st->codec->channel_layout = AV_CH_LAYOUT_STEREO;
yading@11:     else if (st->codec->channels == 4)
yading@11:         st->codec->channel_layout = AV_CH_LAYOUT_4POINT0;
yading@11: 
yading@11:     avio_skip(s->pb, 2);
yading@11:     st->codec->sample_rate = avio_rb32(s->pb);
yading@11:     if (st->codec->sample_rate <= 0)
yading@11:         return AVERROR_INVALIDDATA;
yading@11:     st->start_time         = 0;
yading@11:     st->duration           = avio_rb32(s->pb);
yading@11:     avio_skip(s->pb, 40);
yading@11:     avpriv_set_pts_info(st, 64, 1, st->codec->sample_rate);
yading@11: 
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static int ast_read_packet(AVFormatContext *s, AVPacket *pkt)
yading@11: {
yading@11:     uint32_t type, size;
yading@11:     int64_t pos;
yading@11:     int ret;
yading@11: 
yading@11:     if (url_feof(s->pb))
yading@11:         return AVERROR_EOF;
yading@11: 
yading@11:     pos  = avio_tell(s->pb);
yading@11:     type = avio_rl32(s->pb);
yading@11:     size = avio_rb32(s->pb);
yading@11:     if (size > INT_MAX / s->streams[0]->codec->channels)
yading@11:         return AVERROR_INVALIDDATA;
yading@11: 
yading@11:     size *= s->streams[0]->codec->channels;
yading@11:     if ((ret = avio_skip(s->pb, 24)) < 0) // padding
yading@11:         return ret;
yading@11: 
yading@11:     if (type == MKTAG('B','L','C','K')) {
yading@11:         ret = av_get_packet(s->pb, pkt, size);
yading@11:         pkt->stream_index = 0;
yading@11:         pkt->pos = pos;
yading@11:     } else {
yading@11:         av_log(s, AV_LOG_ERROR, "unknown chunk %x\n", type);
yading@11:         avio_skip(s->pb, size);
yading@11:         ret = AVERROR_INVALIDDATA;
yading@11:     }
yading@11: 
yading@11:     return ret;
yading@11: }
yading@11: 
yading@11: AVInputFormat ff_ast_demuxer = {
yading@11:     .name           = "ast",
yading@11:     .long_name      = NULL_IF_CONFIG_SMALL("AST (Audio Stream)"),
yading@11:     .read_probe     = ast_probe,
yading@11:     .read_header    = ast_read_header,
yading@11:     .read_packet    = ast_read_packet,
yading@11:     .extensions     = "ast",
yading@11:     .flags          = AVFMT_GENERIC_INDEX,
yading@11:     .codec_tag      = (const AVCodecTag* const []){ff_codec_ast_tags, 0},
yading@11: };