/*
  * 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 "libavutil/intreadwrite.h"

 #include "avformat.h"

 #include "internal.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 * 1024
 
 static int lmlm4_probe(AVProbeData * pd) {

     const 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) {

     AVStream *st;
 

     if (!(st = avformat_new_stream(s, NULL)))

         return AVERROR(ENOMEM);

     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

     st->codec->codec_id   = AV_CODEC_ID_MPEG4;

     st->need_parsing      = AVSTREAM_PARSE_HEADERS;

     avpriv_set_pts_info(st, 64, 1001, 30000);

     if (!(st = avformat_new_stream(s, NULL)))

         return AVERROR(ENOMEM);

     st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

     st->codec->codec_id   = AV_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) {

     AVIOContext *pb = s->pb;

     int ret;
     unsigned int frame_type, packet_size, padding, frame_size;
 

     avio_rb16(pb);                       /* channel number */
     frame_type  = avio_rb16(pb);
     packet_size = avio_rb32(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 || packet_size<=8) {
         av_log(s, AV_LOG_ERROR, "packet size %d is invalid\n", packet_size);

         return AVERROR(EIO);
     }
 
     if ((ret = av_get_packet(pb, pkt, frame_size)) <= 0)
         return AVERROR(EIO);
 

     avio_skip(pb, padding);

 
     switch (frame_type) {
         case LMLM4_I_FRAME:

             pkt->flags = AV_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 ff_lmlm4_demuxer = {

     .name           = "lmlm4",

     .long_name      = NULL_IF_CONFIG_SMALL("raw lmlm4"),

     .read_probe     = lmlm4_probe,
     .read_header    = lmlm4_read_header,
     .read_packet    = lmlm4_read_packet,

 };