extern/ffmpeg/libavcodec/mmvideo.c

   1 /*
   2  * American Laser Games MM Video Decoder
   3  * Copyright (c) 2006 Peter Ross
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 /**
  21  * @file mm.c
  22  * American Laser Games MM Video Decoder
  23  * by Peter Ross (suxen_drol at hotmail dot com)
  24  *
  25  * The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,
  26  * including Mad Dog McCree and Crime Patrol.
  27  *
  28  * Technical details here:
  29  *  http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
  30  */
  31
  32 #include "avcodec.h"
  33
  34 #define MM_PREAMBLE_SIZE    6
  35
  36 #define MM_TYPE_INTER       0x5
  37 #define MM_TYPE_INTRA       0x8
  38 #define MM_TYPE_INTRA_HH    0xc
  39 #define MM_TYPE_INTER_HH    0xd
  40 #define MM_TYPE_INTRA_HHV   0xe
  41 #define MM_TYPE_INTER_HHV   0xf
  42
  43 typedef struct MmContext {
  44     AVCodecContext *avctx;
  45     AVFrame frame;
  46 } MmContext;
  47
  48 static int mm_decode_init(AVCodecContext *avctx)
  49 {
  50     MmContext *s = avctx->priv_data;
  51
  52     s->avctx = avctx;
  53
  54     if (s->avctx->palctrl == NULL) {
  55         av_log(avctx, AV_LOG_ERROR, "mmvideo: palette expected.\n");
  56         return -1;
  57     }
  58
  59     avctx->pix_fmt = PIX_FMT_PAL8;
  60     avctx->has_b_frames = 0;
  61
  62     if (avcodec_check_dimensions(avctx, avctx->width, avctx->height))
  63         return -1;
  64
  65     s->frame.reference = 1;
  66     if (avctx->get_buffer(avctx, &s->frame)) {
  67         av_log(s->avctx, AV_LOG_ERROR, "mmvideo: get_buffer() failed\n");
  68         return -1;
  69     }
  70
  71     return 0;
  72 }
  73
  74 static void mm_decode_intra(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size)
  75 {
  76     int i, x, y;
  77     i=0; x=0; y=0;
  78
  79     while(i<buf_size) {
  80         int run_length, color;
  81
  82         if (buf[i] & 0x80) {
  83             run_length = 1;
  84             color = buf[i];
  85             i++;
  86         }else{
  87             run_length = (buf[i] & 0x7f) + 2;
  88             color = buf[i+1];
  89             i+=2;
  90         }
  91
  92         if (half_horiz)
  93             run_length *=2;
  94
  95         if (color) {
  96             memset(s->frame.data[0] + y*s->frame.linesize[0] + x, color, run_length);
  97             if (half_vert)
  98                 memset(s->frame.data[0] + (y+1)*s->frame.linesize[0] + x, color, run_length);
  99         }
 100         x+= run_length;
 101
 102         if (x >= s->avctx->width) {
 103             x=0;
 104             y += half_vert ? 2 : 1;
 105         }
 106     }
 107 }
 108
 109 static void mm_decode_inter(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size)
 110 {
 111     const int data_ptr = 2 + LE_16(&buf[0]);
 112     int d, r, y;
 113     d = data_ptr; r = 2; y = 0;
 114
 115     while(r < data_ptr) {
 116         int i, j;
 117         int length = buf[r] & 0x7f;
 118         int x = buf[r+1] + ((buf[r] & 0x80) << 1);
 119         r += 2;
 120
 121         if (length==0) {
 122             y += x;
 123             continue;
 124         }
 125
 126         for(i=0; i<length; i++) {
 127             for(j=0; j<8; j++) {
 128                 int replace = (buf[r+i] >> (7-j)) & 1;
 129                 if (replace) {
 130                     int color = buf[d];
 131                     s->frame.data[0][y*s->frame.linesize[0] + x] = color;
 132                     if (half_horiz)
 133                         s->frame.data[0][y*s->frame.linesize[0] + x + 1] = color;
 134                     if (half_vert) {
 135                         s->frame.data[0][(y+1)*s->frame.linesize[0] + x] = color;
 136                         if (half_horiz)
 137                             s->frame.data[0][(y+1)*s->frame.linesize[0] + x + 1] = color;
 138                     }
 139                     d++;
 140                 }
 141                 x += half_horiz ? 2 : 1;
 142             }
 143         }
 144
 145         r += length;
 146         y += half_vert ? 2 : 1;
 147     }
 148 }
 149
 150 static int mm_decode_frame(AVCodecContext *avctx,
 151                             void *data, int *data_size,
 152                             uint8_t *buf, int buf_size)
 153 {
 154     MmContext *s = avctx->priv_data;
 155     AVPaletteControl *palette_control = avctx->palctrl;
 156     int type;
 157
 158     if (palette_control->palette_changed) {
 159         memcpy(s->frame.data[1], palette_control->palette, AVPALETTE_SIZE);
 160         palette_control->palette_changed = 0;
 161     }
 162
 163     type = LE_16(&buf[0]);
 164     buf += MM_PREAMBLE_SIZE;
 165     buf_size -= MM_PREAMBLE_SIZE;
 166
 167     switch(type) {
 168     case MM_TYPE_INTRA     : mm_decode_intra(s, 0, 0, buf, buf_size); break;
 169     case MM_TYPE_INTRA_HH  : mm_decode_intra(s, 1, 0, buf, buf_size); break;
 170     case MM_TYPE_INTRA_HHV : mm_decode_intra(s, 1, 1, buf, buf_size); break;
 171     case MM_TYPE_INTER     : mm_decode_inter(s, 0, 0, buf, buf_size); break;
 172     case MM_TYPE_INTER_HH  : mm_decode_inter(s, 1, 0, buf, buf_size); break;
 173     case MM_TYPE_INTER_HHV : mm_decode_inter(s, 1, 1, buf, buf_size); break;
 174     default :
 175         return -1;
 176     }
 177
 178     *data_size = sizeof(AVFrame);
 179     *(AVFrame*)data = s->frame;
 180
 181     return buf_size;
 182 }
 183
 184 static int mm_decode_end(AVCodecContext *avctx)
 185 {
 186     MmContext *s = avctx->priv_data;
 187
 188     if(s->frame.data[0])
 189         avctx->release_buffer(avctx, &s->frame);
 190
 191     return 0;
 192 }
 193
 194 AVCodec mmvideo_decoder = {
 195     "mmvideo",
 196     CODEC_TYPE_VIDEO,
 197     CODEC_ID_MMVIDEO,
 198     sizeof(MmContext),
 199     mm_decode_init,
 200     NULL,
 201     mm_decode_end,
 202     mm_decode_frame,
 203     CODEC_CAP_DR1,
 204 };