/* * Linux Media Labs MPEG-4 demuxer * Copyright (c) 2008 Ivo van Poorten * * Due to a lack of sample files, only files with one channel are supported. * u-law and ADPCM audio are unsupported for the same reason. * * 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 "avformat.h"#define LMLM4_I_FRAME   0x00#define LMLM4_P_FRAME   0x01#define LMLM4_B_FRAME   0x02#define LMLM4_INVALID   0x03#define LMLM4_MPEG1L2   0x04#define LMLM4_MAX_PACKET_SIZE   1024 * 1024static int lmlm4_probe(AVProbeData * pd) {    unsigned char *buf = pd->buf;    unsigned int frame_type, packet_size;    frame_type  = AV_RB16(buf+2);    packet_size = AV_RB32(buf+4);    if (!AV_RB16(buf) && frame_type <= LMLM4_MPEG1L2 && packet_size &&        frame_type != LMLM4_INVALID && packet_size <= LMLM4_MAX_PACKET_SIZE) {        if (frame_type == LMLM4_MPEG1L2) {            if ((AV_RB16(buf+8) & 0xfffe) != 0xfffc)                return 0;            /* I could calculate the audio framesize and compare with             * packet_size-8, but that seems overkill */            return AVPROBE_SCORE_MAX / 3;        } else if (AV_RB24(buf+8) == 0x000001) {    /* PES Signal */            return AVPROBE_SCORE_MAX / 5;        }    }    return 0;}static int lmlm4_read_header(AVFormatContext *s, AVFormatParameters *ap) {    AVStream *st;    if (!(st = av_new_stream(s, 0)))        return AVERROR(ENOMEM);    st->codec->codec_type = CODEC_TYPE_VIDEO;    st->codec->codec_id   = CODEC_ID_MPEG4;    st->need_parsing      = AVSTREAM_PARSE_HEADERS;    av_set_pts_info(st, 64, 1001, 30000);    if (!(st = av_new_stream(s, 1)))        return AVERROR(ENOMEM);    st->codec->codec_type = CODEC_TYPE_AUDIO;    st->codec->codec_id   = CODEC_ID_MP2;    st->need_parsing      = AVSTREAM_PARSE_HEADERS;    /* the parameters will be extracted from the compressed bitstream */    return 0;}static int lmlm4_read_packet(AVFormatContext *s, AVPacket *pkt) {    ByteIOContext *pb = s->pb;    int ret;    unsigned int frame_type, packet_size, padding, frame_size;    get_be16(pb);                       /* channel number */    frame_type  = get_be16(pb);    packet_size = get_be32(pb);    padding     = -packet_size & 511;    frame_size  = packet_size - 8;    if (frame_type > LMLM4_MPEG1L2 || frame_type == LMLM4_INVALID) {        av_log(s, AV_LOG_ERROR, "invalid or unsupported frame_type\n");        return AVERROR(EIO);    }    if (packet_size > LMLM4_MAX_PACKET_SIZE) {        av_log(s, AV_LOG_ERROR, "packet size exceeds maximum\n");        return AVERROR(EIO);    }    if ((ret = av_get_packet(pb, pkt, frame_size)) <= 0)        return AVERROR(EIO);    url_fskip(pb, padding);    switch (frame_type) {        case LMLM4_I_FRAME:            pkt->flags = PKT_FLAG_KEY;        case LMLM4_P_FRAME:        case LMLM4_B_FRAME:            pkt->stream_index = 0;            break;        case LMLM4_MPEG1L2:            pkt->stream_index = 1;            break;    }    return ret;}AVInputFormat lmlm4_demuxer = {    "lmlm4",    NULL_IF_CONFIG_SMALL("lmlm4 raw format"),    0,    lmlm4_probe,    lmlm4_read_header,    lmlm4_read_packet,};