libavformat/lmlm4.c

   1 /*
   2  * Linux Media Labs MPEG-4 demuxer
   3  * Copyright (c) 2008 Ivo van Poorten
   4  *
   5  * Due to a lack of sample files, only files with one channel are supported.
   6  * u-law and ADPCM audio are unsupported for the same reason.
   7  *
   8  * This file is part of FFmpeg.
   9  *
  10  * FFmpeg is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU Lesser General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2.1 of the License, or (at your option) any later version.
  14  *
  15  * FFmpeg is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public
  21  * License along with FFmpeg; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  23  */
  24
  25 #include "avformat.h"
  26
  27 #define LMLM4_I_FRAME   0x00
  28 #define LMLM4_P_FRAME   0x01
  29 #define LMLM4_B_FRAME   0x02
  30 #define LMLM4_INVALID   0x03
  31 #define LMLM4_MPEG1L2   0x04
  32
  33 #define LMLM4_MAX_PACKET_SIZE   1024 * 1024
  34
  35 static int lmlm4_probe(AVProbeData * pd) {
  36     unsigned char *buf = pd->buf;
  37     unsigned int frame_type, packet_size;
  38
  39     frame_type  = AV_RB16(buf+2);
  40     packet_size = AV_RB32(buf+4);
  41
  42     if (!AV_RB16(buf) && frame_type <= LMLM4_MPEG1L2 && packet_size &&
  43         frame_type != LMLM4_INVALID && packet_size <= LMLM4_MAX_PACKET_SIZE) {
  44
  45         if (frame_type == LMLM4_MPEG1L2) {
  46             if ((AV_RB16(buf+8) & 0xfffe) != 0xfffc)
  47                 return 0;
  48             /* I could calculate the audio framesize and compare with
  49              * packet_size-8, but that seems overkill */
  50             return AVPROBE_SCORE_MAX / 3;
  51         } else if (AV_RB24(buf+8) == 0x000001) {    /* PES Signal */
  52             return AVPROBE_SCORE_MAX / 5;
  53         }
  54     }
  55
  56     return 0;
  57 }
  58
  59 static int lmlm4_read_header(AVFormatContext *s, AVFormatParameters *ap) {
  60     AVStream *st;
  61
  62     if (!(st = av_new_stream(s, 0)))
  63         return AVERROR(ENOMEM);
  64     st->codec->codec_type = CODEC_TYPE_VIDEO;
  65     st->codec->codec_id   = CODEC_ID_MPEG4;
  66     st->need_parsing      = AVSTREAM_PARSE_HEADERS;
  67     av_set_pts_info(st, 64, 1001, 30000);
  68
  69     if (!(st = av_new_stream(s, 1)))
  70         return AVERROR(ENOMEM);
  71     st->codec->codec_type = CODEC_TYPE_AUDIO;
  72     st->codec->codec_id   = CODEC_ID_MP2;
  73     st->need_parsing      = AVSTREAM_PARSE_HEADERS;
  74
  75     /* the parameters will be extracted from the compressed bitstream */
  76     return 0;
  77 }
  78
  79 static int lmlm4_read_packet(AVFormatContext *s, AVPacket *pkt) {
  80     ByteIOContext *pb = s->pb;
  81     int ret;
  82     unsigned int frame_type, packet_size, padding, frame_size;
  83
  84     get_be16(pb);                       /* channel number */
  85     frame_type  = get_be16(pb);
  86     packet_size = get_be32(pb);
  87     padding     = -packet_size & 511;
  88     frame_size  = packet_size - 8;
  89
  90     if (frame_type > LMLM4_MPEG1L2 || frame_type == LMLM4_INVALID) {
  91         av_log(s, AV_LOG_ERROR, "invalid or unsupported frame_type\n");
  92         return AVERROR(EIO);
  93     }
  94     if (packet_size > LMLM4_MAX_PACKET_SIZE) {
  95         av_log(s, AV_LOG_ERROR, "packet size exceeds maximum\n");
  96         return AVERROR(EIO);
  97     }
  98
  99     if ((ret = av_get_packet(pb, pkt, frame_size)) <= 0)
 100         return AVERROR(EIO);
 101
 102     url_fskip(pb, padding);
 103
 104     switch (frame_type) {
 105         case LMLM4_I_FRAME:
 106             pkt->flags = PKT_FLAG_KEY;
 107         case LMLM4_P_FRAME:
 108         case LMLM4_B_FRAME:
 109             pkt->stream_index = 0;
 110             break;
 111         case LMLM4_MPEG1L2:
 112             pkt->stream_index = 1;
 113             break;
 114     }
 115
 116     return ret;
 117 }
 118
 119 AVInputFormat lmlm4_demuxer = {
 120     "lmlm4",
 121     "lmlm4 raw format",
 122     0,
 123     lmlm4_probe,
 124     lmlm4_read_header,
 125     lmlm4_read_packet,
 126 };