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 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 "avformat.h"
  35
  36 #define MM_PREAMBLE_SIZE    6
  37
  38 #define MM_TYPE_HEADER      0x0
  39 #define MM_TYPE_INTER       0x5
  40 #define MM_TYPE_INTRA       0x8
  41 #define MM_TYPE_INTRA_HH    0xc
  42 #define MM_TYPE_INTER_HH    0xd
  43 #define MM_TYPE_INTRA_HHV   0xe
  44 #define MM_TYPE_INTER_HHV   0xf
  45 #define MM_TYPE_AUDIO       0x15
  46 #define MM_TYPE_PALETTE     0x31
  47
  48 #define MM_HEADER_LEN_V     0x16    /* video only */
  49 #define MM_HEADER_LEN_AV    0x18    /* video + audio */
  50
  51 #define MM_PALETTE_COUNT    128
  52 #define MM_PALETTE_SIZE     (MM_PALETTE_COUNT*3)
  53
  54 typedef struct {
  55   unsigned int audio_pts, video_pts;
  56 } MmDemuxContext;
  57
  58 static int mm_probe(AVProbeData *p)
  59 {
  60     /* the first chunk is always the header */
  61     if (AV_RL16(&p->buf[0]) != MM_TYPE_HEADER)
  62         return 0;
  63     if (AV_RL32(&p->buf[2]) != MM_HEADER_LEN_V && AV_RL32(&p->buf[2]) != MM_HEADER_LEN_AV)
  64         return 0;
  65
  66     /* only return half certainty since this check is a bit sketchy */
  67     return AVPROBE_SCORE_MAX / 2;
  68 }
  69
  70 static int mm_read_header(AVFormatContext *s,
  71                            AVFormatParameters *ap)
  72 {
  73     MmDemuxContext *mm = s->priv_data;
  74     ByteIOContext *pb = s->pb;
  75     AVStream *st;
  76
  77     unsigned int type, length;
  78     unsigned int frame_rate, width, height;
  79
  80     type = get_le16(pb);
  81     length = get_le32(pb);
  82
  83     if (type != MM_TYPE_HEADER)
  84         return AVERROR_INVALIDDATA;
  85
  86     /* read header */
  87     get_le16(pb);   /* total number of chunks */
  88     frame_rate = get_le16(pb);
  89     get_le16(pb);   /* ibm-pc video bios mode */
  90     width = get_le16(pb);
  91     height = get_le16(pb);
  92     url_fseek(pb, length - 10, SEEK_CUR);  /* unknown data */
  93
  94     /* video stream */
  95     st = av_new_stream(s, 0);
  96     if (!st)
  97         return AVERROR(ENOMEM);
  98     st->codec->codec_type = CODEC_TYPE_VIDEO;
  99     st->codec->codec_id = CODEC_ID_MMVIDEO;
 100     st->codec->codec_tag = 0;  /* no fourcc */
 101     st->codec->width = width;
 102     st->codec->height = height;
 103     av_set_pts_info(st, 64, 1, frame_rate);
 104
 105     /* audio stream */
 106     if (length == MM_HEADER_LEN_AV) {
 107         st = av_new_stream(s, 0);
 108         if (!st)
 109             return AVERROR(ENOMEM);
 110         st->codec->codec_type = CODEC_TYPE_AUDIO;
 111         st->codec->codec_tag = 0; /* no fourcc */
 112         st->codec->codec_id = CODEC_ID_PCM_U8;
 113         st->codec->channels = 1;
 114         st->codec->sample_rate = 8000;
 115         av_set_pts_info(st, 64, 1, 8000); /* 8000 hz */
 116     }
 117
 118     mm->audio_pts = 0;
 119     mm->video_pts = 0;
 120     return 0;
 121 }
 122
 123 static int mm_read_packet(AVFormatContext *s,
 124                            AVPacket *pkt)
 125 {
 126     MmDemuxContext *mm = s->priv_data;
 127     ByteIOContext *pb = s->pb;
 128     unsigned char preamble[MM_PREAMBLE_SIZE];
 129     unsigned int type, length;
 130
 131     while(1) {
 132
 133         if (get_buffer(pb, preamble, MM_PREAMBLE_SIZE) != MM_PREAMBLE_SIZE) {
 134             return AVERROR(EIO);
 135         }
 136
 137         type = AV_RL16(&preamble[0]);
 138         length = AV_RL16(&preamble[2]);
 139
 140         switch(type) {
 141         case MM_TYPE_PALETTE :
 142         case MM_TYPE_INTER :
 143         case MM_TYPE_INTRA :
 144         case MM_TYPE_INTRA_HH :
 145         case MM_TYPE_INTER_HH :
 146         case MM_TYPE_INTRA_HHV :
 147         case MM_TYPE_INTER_HHV :
 148             /* output preamble + data */
 149             if (av_new_packet(pkt, length + MM_PREAMBLE_SIZE))
 150                 return AVERROR(ENOMEM);
 151             memcpy(pkt->data, preamble, MM_PREAMBLE_SIZE);
 152             if (get_buffer(pb, pkt->data + MM_PREAMBLE_SIZE, length) != length)
 153                 return AVERROR(EIO);
 154             pkt->size = length + MM_PREAMBLE_SIZE;
 155             pkt->stream_index = 0;
 156             pkt->pts = mm->video_pts;
 157             if (type!=MM_TYPE_PALETTE)
 158                 mm->video_pts++;
 159             return 0;
 160
 161         case MM_TYPE_AUDIO :
 162             if (av_get_packet(s->pb, pkt, length)<0)
 163                 return AVERROR(ENOMEM);
 164             pkt->size = length;
 165             pkt->stream_index = 1;
 166             pkt->pts = mm->audio_pts++;
 167             return 0;
 168
 169         default :
 170             av_log(NULL, AV_LOG_INFO, "mm: unknown chunk type 0x%x\n", type);
 171             url_fseek(pb, length, SEEK_CUR);
 172         }
 173     }
 174
 175     return 0;
 176 }
 177
 178 AVInputFormat mm_demuxer = {
 179     "mm",
 180     NULL_IF_CONFIG_SMALL("American Laser Games MM format"),
 181     sizeof(MmDemuxContext),
 182     mm_probe,
 183     mm_read_header,
 184     mm_read_packet,
 185 };