From 461ecea0680606875cb28a6b98ac1df25ae8a3c6 Mon Sep 17 00:00:00 2001 From: Paul B Mahol Date: Wed, 14 Nov 2012 17:53:22 +0000 Subject: AST demuxer Signed-off-by: Paul B Mahol --- libavformat/ast.c | 117 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 117 insertions(+) create mode 100644 libavformat/ast.c (limited to 'libavformat/ast.c') diff --git a/libavformat/ast.c b/libavformat/ast.c new file mode 100644 index 0000000000..a15054588f --- /dev/null +++ b/libavformat/ast.c @@ -0,0 +1,117 @@ +/* + * 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" + +static int ast_probe(AVProbeData *p) +{ + if (AV_RL32(p->buf) == MKTAG('S', 'T', 'R', 'M')) + return AVPROBE_SCORE_MAX / 2; + return 0; +} + +static int ast_read_header(AVFormatContext *s) +{ + int codec; + AVStream *st; + + st = avformat_new_stream(s, NULL); + if (!st) + return AVERROR(ENOMEM); + + avio_skip(s->pb, 8); + codec = avio_rb16(s->pb); + switch (codec) { + case 1: + st->codec->codec_id = AV_CODEC_ID_PCM_S16BE_PLANAR; + break; + default: + av_log(s, AV_LOG_ERROR, "unsupported codec %d\n", codec); + } + + avio_skip(s->pb, 2); + + st->codec->codec_type = AVMEDIA_TYPE_AUDIO; + st->codec->channels = avio_rb16(s->pb); + if (!st->codec->channels) + return AVERROR_INVALIDDATA; + + if (st->codec->channels == 2) + st->codec->channel_layout = AV_CH_LAYOUT_STEREO; + else if (st->codec->channels == 4) + st->codec->channel_layout = AV_CH_LAYOUT_4POINT0; + + avio_skip(s->pb, 2); + st->codec->sample_rate = avio_rb32(s->pb); + if (st->codec->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->codec->sample_rate); + + return 0; +} + +static int ast_read_packet(AVFormatContext *s, AVPacket *pkt) +{ + uint32_t type, size; + int64_t pos; + int ret; + + if (url_feof(s->pb)) + return AVERROR_EOF; + + pos = avio_tell(s->pb); + type = avio_rl32(s->pb); + size = avio_rb32(s->pb); + if (size > INT_MAX / s->streams[0]->codec->channels) + return AVERROR_INVALIDDATA; + + size *= s->streams[0]->codec->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 %x\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, +}; -- cgit v1.2.3