| /* |
| * AST demuxer |
| * Copyright (c) 2012 Paul B Mahol |
| * |
| * 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 |
| */ |
| |
| #include "libavutil/channel_layout.h" |
| #include "libavutil/intreadwrite.h" |
| #include "avformat.h" |
| #include "internal.h" |
| #include "ast.h" |
| |
| static int ast_probe(const AVProbeData *p) |
| { |
| if (AV_RL32(p->buf) != MKTAG('S','T','R','M')) |
| return 0; |
| |
| if (!AV_RB16(p->buf + 10) || |
| !AV_RB16(p->buf + 12) || AV_RB16(p->buf + 12) > 256 || |
| !AV_RB32(p->buf + 16) || AV_RB32(p->buf + 16) > 8*48000) |
| return AVPROBE_SCORE_MAX / 8; |
| |
| return AVPROBE_SCORE_MAX / 3 * 2; |
| } |
| |
| static int ast_read_header(AVFormatContext *s) |
| { |
| int depth; |
| AVStream *st; |
| |
| st = avformat_new_stream(s, NULL); |
| if (!st) |
| return AVERROR(ENOMEM); |
| |
| avio_skip(s->pb, 8); |
| st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO; |
| st->codecpar->codec_id = ff_codec_get_id(ff_codec_ast_tags, avio_rb16(s->pb)); |
| |
| depth = avio_rb16(s->pb); |
| if (depth != 16) { |
| avpriv_request_sample(s, "depth %d", depth); |
| return AVERROR_INVALIDDATA; |
| } |
| |
| st->codecpar->channels = avio_rb16(s->pb); |
| if (!st->codecpar->channels) |
| return AVERROR_INVALIDDATA; |
| |
| if (st->codecpar->channels == 2) |
| st->codecpar->channel_layout = AV_CH_LAYOUT_STEREO; |
| else if (st->codecpar->channels == 4) |
| st->codecpar->channel_layout = AV_CH_LAYOUT_4POINT0; |
| |
| avio_skip(s->pb, 2); |
| st->codecpar->sample_rate = avio_rb32(s->pb); |
| if (st->codecpar->sample_rate <= 0) |
| return AVERROR_INVALIDDATA; |
| st->start_time = 0; |
| st->duration = avio_rb32(s->pb); |
| avio_skip(s->pb, 40); |
| avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate); |
| |
| return 0; |
| } |
| |
| static int ast_read_packet(AVFormatContext *s, AVPacket *pkt) |
| { |
| uint32_t type, size; |
| int64_t pos; |
| int ret; |
| |
| if (avio_feof(s->pb)) |
| return AVERROR_EOF; |
| |
| pos = avio_tell(s->pb); |
| type = avio_rl32(s->pb); |
| size = avio_rb32(s->pb); |
| if (!s->streams[0]->codecpar->channels || size > INT_MAX / s->streams[0]->codecpar->channels) |
| return AVERROR_INVALIDDATA; |
| |
| size *= s->streams[0]->codecpar->channels; |
| if ((ret = avio_skip(s->pb, 24)) < 0) // padding |
| return ret; |
| |
| if (type == MKTAG('B','L','C','K')) { |
| ret = av_get_packet(s->pb, pkt, size); |
| pkt->stream_index = 0; |
| pkt->pos = pos; |
| } else { |
| av_log(s, AV_LOG_ERROR, "unknown chunk %"PRIx32"\n", type); |
| avio_skip(s->pb, size); |
| ret = AVERROR_INVALIDDATA; |
| } |
| |
| return ret; |
| } |
| |
| AVInputFormat ff_ast_demuxer = { |
| .name = "ast", |
| .long_name = NULL_IF_CONFIG_SMALL("AST (Audio Stream)"), |
| .read_probe = ast_probe, |
| .read_header = ast_read_header, |
| .read_packet = ast_read_packet, |
| .extensions = "ast", |
| .flags = AVFMT_GENERIC_INDEX, |
| .codec_tag = (const AVCodecTag* const []){ff_codec_ast_tags, 0}, |
| }; |