yading@11: /*
yading@11:  * Linux Media Labs MPEG-4 demuxer
yading@11:  * Copyright (c) 2008 Ivo van Poorten
yading@11:  *
yading@11:  * Due to a lack of sample files, only files with one channel are supported.
yading@11:  * u-law and ADPCM audio are unsupported for the same reason.
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/intreadwrite.h"
yading@11: #include "avformat.h"
yading@11: #include "internal.h"
yading@11: 
yading@11: #define LMLM4_I_FRAME   0x00
yading@11: #define LMLM4_P_FRAME   0x01
yading@11: #define LMLM4_B_FRAME   0x02
yading@11: #define LMLM4_INVALID   0x03
yading@11: #define LMLM4_MPEG1L2   0x04
yading@11: 
yading@11: #define LMLM4_MAX_PACKET_SIZE   1024 * 1024
yading@11: 
yading@11: static int lmlm4_probe(AVProbeData * pd) {
yading@11:     const unsigned char *buf = pd->buf;
yading@11:     unsigned int frame_type, packet_size;
yading@11: 
yading@11:     frame_type  = AV_RB16(buf+2);
yading@11:     packet_size = AV_RB32(buf+4);
yading@11: 
yading@11:     if (!AV_RB16(buf) && frame_type <= LMLM4_MPEG1L2 && packet_size &&
yading@11:         frame_type != LMLM4_INVALID && packet_size <= LMLM4_MAX_PACKET_SIZE) {
yading@11: 
yading@11:         if (frame_type == LMLM4_MPEG1L2) {
yading@11:             if ((AV_RB16(buf+8) & 0xfffe) != 0xfffc)
yading@11:                 return 0;
yading@11:             /* I could calculate the audio framesize and compare with
yading@11:              * packet_size-8, but that seems overkill */
yading@11:             return AVPROBE_SCORE_MAX / 3;
yading@11:         } else if (AV_RB24(buf+8) == 0x000001) {    /* PES Signal */
yading@11:             return AVPROBE_SCORE_MAX / 5;
yading@11:         }
yading@11:     }
yading@11: 
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static int lmlm4_read_header(AVFormatContext *s) {
yading@11:     AVStream *st;
yading@11: 
yading@11:     if (!(st = avformat_new_stream(s, NULL)))
yading@11:         return AVERROR(ENOMEM);
yading@11:     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
yading@11:     st->codec->codec_id   = AV_CODEC_ID_MPEG4;
yading@11:     st->need_parsing      = AVSTREAM_PARSE_HEADERS;
yading@11:     avpriv_set_pts_info(st, 64, 1001, 30000);
yading@11: 
yading@11:     if (!(st = avformat_new_stream(s, NULL)))
yading@11:         return AVERROR(ENOMEM);
yading@11:     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
yading@11:     st->codec->codec_id   = AV_CODEC_ID_MP2;
yading@11:     st->need_parsing      = AVSTREAM_PARSE_HEADERS;
yading@11: 
yading@11:     /* the parameters will be extracted from the compressed bitstream */
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static int lmlm4_read_packet(AVFormatContext *s, AVPacket *pkt) {
yading@11:     AVIOContext *pb = s->pb;
yading@11:     int ret;
yading@11:     unsigned int frame_type, packet_size, padding, frame_size;
yading@11: 
yading@11:     avio_rb16(pb);                       /* channel number */
yading@11:     frame_type  = avio_rb16(pb);
yading@11:     packet_size = avio_rb32(pb);
yading@11:     padding     = -packet_size & 511;
yading@11:     frame_size  = packet_size - 8;
yading@11: 
yading@11:     if (frame_type > LMLM4_MPEG1L2 || frame_type == LMLM4_INVALID) {
yading@11:         av_log(s, AV_LOG_ERROR, "invalid or unsupported frame_type\n");
yading@11:         return AVERROR(EIO);
yading@11:     }
yading@11:     if (packet_size > LMLM4_MAX_PACKET_SIZE || packet_size<=8) {
yading@11:         av_log(s, AV_LOG_ERROR, "packet size %d is invalid\n", packet_size);
yading@11:         return AVERROR(EIO);
yading@11:     }
yading@11: 
yading@11:     if ((ret = av_get_packet(pb, pkt, frame_size)) <= 0)
yading@11:         return AVERROR(EIO);
yading@11: 
yading@11:     avio_skip(pb, padding);
yading@11: 
yading@11:     switch (frame_type) {
yading@11:         case LMLM4_I_FRAME:
yading@11:             pkt->flags = AV_PKT_FLAG_KEY;
yading@11:         case LMLM4_P_FRAME:
yading@11:         case LMLM4_B_FRAME:
yading@11:             pkt->stream_index = 0;
yading@11:             break;
yading@11:         case LMLM4_MPEG1L2:
yading@11:             pkt->stream_index = 1;
yading@11:             break;
yading@11:     }
yading@11: 
yading@11:     return ret;
yading@11: }
yading@11: 
yading@11: AVInputFormat ff_lmlm4_demuxer = {
yading@11:     .name           = "lmlm4",
yading@11:     .long_name      = NULL_IF_CONFIG_SMALL("raw lmlm4"),
yading@11:     .read_probe     = lmlm4_probe,
yading@11:     .read_header    = lmlm4_read_header,
yading@11:     .read_packet    = lmlm4_read_packet,
yading@11: };