libavformat/mm.c

   1 /*
   2  * American Laser Games MM Format Demuxer
   3  * Copyright (c) 2006 Peter Ross
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file libavformat/mm.c
  24  * American Laser Games MM Format Demuxer
  25  * by Peter Ross (suxen_drol at hotmail dot com)
  26  *
  27  * The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,
  28  * including Mad Dog McCree and Crime Patrol.
  29  *
  30  * Technical details here:
  31  *  http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
  32  */
  33
  34 #include "libavutil/intreadwrite.h"
  35 #include "avformat.h"
  36
  37 #define MM_PREAMBLE_SIZE    6
  38
  39 #define MM_TYPE_HEADER      0x0
  40 #define MM_TYPE_INTER       0x5
  41 #define MM_TYPE_INTRA       0x8
  42 #define MM_TYPE_INTRA_HH    0xc
  43 #define MM_TYPE_INTER_HH    0xd
  44 #define MM_TYPE_INTRA_HHV   0xe
  45 #define MM_TYPE_INTER_HHV   0xf
  46 #define MM_TYPE_AUDIO       0x15
  47 #define MM_TYPE_PALETTE     0x31
  48
  49 #define MM_HEADER_LEN_V     0x16    /* video only */
  50 #define MM_HEADER_LEN_AV    0x18    /* video + audio */
  51
  52 #define MM_PALETTE_COUNT    128
  53 #define MM_PALETTE_SIZE     (MM_PALETTE_COUNT*3)
  54
  55 typedef struct {
  56   unsigned int audio_pts, video_pts;
  57 } MmDemuxContext;
  58
  59 static int mm_probe(AVProbeData *p)
  60 {
  61     /* the first chunk is always the header */
  62     if (AV_RL16(&p->buf[0]) != MM_TYPE_HEADER)
  63         return 0;
  64     if (AV_RL32(&p->buf[2]) != MM_HEADER_LEN_V && AV_RL32(&p->buf[2]) != MM_HEADER_LEN_AV)
  65         return 0;
  66
  67     /* only return half certainty since this check is a bit sketchy */
  68     return AVPROBE_SCORE_MAX / 2;
  69 }
  70
  71 static int mm_read_header(AVFormatContext *s,
  72                            AVFormatParameters *ap)
  73 {
  74     MmDemuxContext *mm = s->priv_data;
  75     ByteIOContext *pb = s->pb;
  76     AVStream *st;
  77
  78     unsigned int type, length;
  79     unsigned int frame_rate, width, height;
  80
  81     type = get_le16(pb);
  82     length = get_le32(pb);
  83
  84     if (type != MM_TYPE_HEADER)
  85         return AVERROR_INVALIDDATA;
  86
  87     /* read header */
  88     get_le16(pb);   /* total number of chunks */
  89     frame_rate = get_le16(pb);
  90     get_le16(pb);   /* ibm-pc video bios mode */
  91     width = get_le16(pb);
  92     height = get_le16(pb);
  93     url_fseek(pb, length - 10, SEEK_CUR);  /* unknown data */
  94
  95     /* video stream */
  96     st = av_new_stream(s, 0);
  97     if (!st)
  98         return AVERROR(ENOMEM);
  99     st->codec->codec_type = CODEC_TYPE_VIDEO;
 100     st->codec->codec_id = CODEC_ID_MMVIDEO;
 101     st->codec->codec_tag = 0;  /* no fourcc */
 102     st->codec->width = width;
 103     st->codec->height = height;
 104     av_set_pts_info(st, 64, 1, frame_rate);
 105
 106     /* audio stream */
 107     if (length == MM_HEADER_LEN_AV) {
 108         st = av_new_stream(s, 0);
 109         if (!st)
 110             return AVERROR(ENOMEM);
 111         st->codec->codec_type = CODEC_TYPE_AUDIO;
 112         st->codec->codec_tag = 0; /* no fourcc */
 113         st->codec->codec_id = CODEC_ID_PCM_U8;
 114         st->codec->channels = 1;
 115         st->codec->sample_rate = 8000;
 116         av_set_pts_info(st, 64, 1, 8000); /* 8000 hz */
 117     }
 118
 119     mm->audio_pts = 0;
 120     mm->video_pts = 0;
 121     return 0;
 122 }
 123
 124 static int mm_read_packet(AVFormatContext *s,
 125                            AVPacket *pkt)
 126 {
 127     MmDemuxContext *mm = s->priv_data;
 128     ByteIOContext *pb = s->pb;
 129     unsigned char preamble[MM_PREAMBLE_SIZE];
 130     unsigned int type, length;
 131
 132     while(1) {
 133
 134         if (get_buffer(pb, preamble, MM_PREAMBLE_SIZE) != MM_PREAMBLE_SIZE) {
 135             return AVERROR(EIO);
 136         }
 137
 138         type = AV_RL16(&preamble[0]);
 139         length = AV_RL16(&preamble[2]);
 140
 141         switch(type) {
 142         case MM_TYPE_PALETTE :
 143         case MM_TYPE_INTER :
 144         case MM_TYPE_INTRA :
 145         case MM_TYPE_INTRA_HH :
 146         case MM_TYPE_INTER_HH :
 147         case MM_TYPE_INTRA_HHV :
 148         case MM_TYPE_INTER_HHV :
 149             /* output preamble + data */
 150             if (av_new_packet(pkt, length + MM_PREAMBLE_SIZE))
 151                 return AVERROR(ENOMEM);
 152             memcpy(pkt->data, preamble, MM_PREAMBLE_SIZE);
 153             if (get_buffer(pb, pkt->data + MM_PREAMBLE_SIZE, length) != length)
 154                 return AVERROR(EIO);
 155             pkt->size = length + MM_PREAMBLE_SIZE;
 156             pkt->stream_index = 0;
 157             pkt->pts = mm->video_pts;
 158             if (type!=MM_TYPE_PALETTE)
 159                 mm->video_pts++;
 160             return 0;
 161
 162         case MM_TYPE_AUDIO :
 163             if (av_get_packet(s->pb, pkt, length)<0)
 164                 return AVERROR(ENOMEM);
 165             pkt->size = length;
 166             pkt->stream_index = 1;
 167             pkt->pts = mm->audio_pts++;
 168             return 0;
 169
 170         default :
 171             av_log(s, AV_LOG_INFO, "unknown chunk type 0x%x\n", type);
 172             url_fseek(pb, length, SEEK_CUR);
 173         }
 174     }
 175
 176     return 0;
 177 }
 178
 179 AVInputFormat mm_demuxer = {
 180     "mm",
 181     NULL_IF_CONFIG_SMALL("American Laser Games MM format"),
 182     sizeof(MmDemuxContext),
 183     mm_probe,
 184     mm_read_header,
 185     mm_read_packet,
 186 };