libavcodec/mmvideo.c

   1 /*
   2  * American Laser Games MM Video Decoder
   3  * Copyright (c) 2006,2008 Peter Ross
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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
  24  * American Laser Games MM Video Decoder
  25  * by Peter Ross (pross@xvid.org)
  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 "avcodec.h"
  36 #include "bytestream.h"
  37 #include "internal.h"
  38
  39 #define MM_PREAMBLE_SIZE    6
  40
  41 #define MM_TYPE_INTER       0x5
  42 #define MM_TYPE_INTRA       0x8
  43 #define MM_TYPE_INTRA_HH    0xc
  44 #define MM_TYPE_INTER_HH    0xd
  45 #define MM_TYPE_INTRA_HHV   0xe
  46 #define MM_TYPE_INTER_HHV   0xf
  47 #define MM_TYPE_PALETTE     0x31
  48
  49 typedef struct MmContext {
  50     AVCodecContext *avctx;
  51     AVFrame frame;
  52     int palette[AVPALETTE_COUNT];
  53     GetByteContext gb;
  54 } MmContext;
  55
  56 static av_cold int mm_decode_init(AVCodecContext *avctx)
  57 {
  58     MmContext *s = avctx->priv_data;
  59
  60     s->avctx = avctx;
  61
  62     avctx->pix_fmt = AV_PIX_FMT_PAL8;
  63
  64     avcodec_get_frame_defaults(&s->frame);
  65
  66     return 0;
  67 }
  68
  69 static int mm_decode_pal(MmContext *s)
  70 {
  71     int i;
  72
  73     bytestream2_skip(&s->gb, 4);
  74     for (i = 0; i < 128; i++) {
  75         s->palette[i] = bytestream2_get_be24(&s->gb);
  76         s->palette[i+128] = s->palette[i]<<2;
  77     }
  78
  79     return 0;
  80 }
  81
  82 /**
  83  * @param half_horiz Half horizontal resolution (0 or 1)
  84  * @param half_vert Half vertical resolution (0 or 1)
  85  */
  86 static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
  87 {
  88     int x = 0, y = 0;
  89
  90     while (bytestream2_get_bytes_left(&s->gb) > 0) {
  91         int run_length, color;
  92
  93         if (y >= s->avctx->height)
  94             return 0;
  95
  96         color = bytestream2_get_byte(&s->gb);
  97         if (color & 0x80) {
  98             run_length = 1;
  99         }else{
 100             run_length = (color & 0x7f) + 2;
 101             color = bytestream2_get_byte(&s->gb);
 102         }
 103
 104         if (half_horiz)
 105             run_length *=2;
 106
 107         if (color) {
 108             memset(s->frame.data[0] + y*s->frame.linesize[0] + x, color, run_length);
 109             if (half_vert)
 110                 memset(s->frame.data[0] + (y+1)*s->frame.linesize[0] + x, color, run_length);
 111         }
 112         x+= run_length;
 113
 114         if (x >= s->avctx->width) {
 115             x=0;
 116             y += 1 + half_vert;
 117         }
 118     }
 119
 120     return 0;
 121 }
 122
 123 /*
 124  * @param half_horiz Half horizontal resolution (0 or 1)
 125  * @param half_vert Half vertical resolution (0 or 1)
 126  */
 127 static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
 128 {
 129     int data_off = bytestream2_get_le16(&s->gb), y;
 130     GetByteContext data_ptr;
 131
 132     if (bytestream2_get_bytes_left(&s->gb) < data_off)
 133         return AVERROR_INVALIDDATA;
 134
 135     bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
 136     while (s->gb.buffer < data_ptr.buffer_start) {
 137         int i, j;
 138         int length = bytestream2_get_byte(&s->gb);
 139         int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
 140         length &= 0x7F;
 141
 142         if (length==0) {
 143             y += x;
 144             continue;
 145         }
 146
 147         if (y + half_vert >= s->avctx->height)
 148             return 0;
 149
 150         for(i=0; i<length; i++) {
 151             int replace_array = bytestream2_get_byte(&s->gb);
 152             for(j=0; j<8; j++) {
 153                 int replace = (replace_array >> (7-j)) & 1;
 154                 if (replace) {
 155                     int color = bytestream2_get_byte(&data_ptr);
 156                     s->frame.data[0][y*s->frame.linesize[0] + x] = color;
 157                     if (half_horiz)
 158                         s->frame.data[0][y*s->frame.linesize[0] + x + 1] = color;
 159                     if (half_vert) {
 160                         s->frame.data[0][(y+1)*s->frame.linesize[0] + x] = color;
 161                         if (half_horiz)
 162                             s->frame.data[0][(y+1)*s->frame.linesize[0] + x + 1] = color;
 163                     }
 164                 }
 165                 x += 1 + half_horiz;
 166             }
 167         }
 168
 169         y += 1 + half_vert;
 170     }
 171
 172     return 0;
 173 }
 174
 175 static int mm_decode_frame(AVCodecContext *avctx,
 176                             void *data, int *got_frame,
 177                             AVPacket *avpkt)
 178 {
 179     const uint8_t *buf = avpkt->data;
 180     int buf_size = avpkt->size;
 181     MmContext *s = avctx->priv_data;
 182     int type, res;
 183
 184     if (buf_size < MM_PREAMBLE_SIZE)
 185         return AVERROR_INVALIDDATA;
 186     type = AV_RL16(&buf[0]);
 187     buf += MM_PREAMBLE_SIZE;
 188     buf_size -= MM_PREAMBLE_SIZE;
 189     bytestream2_init(&s->gb, buf, buf_size);
 190
 191     if ((res = ff_reget_buffer(avctx, &s->frame)) < 0) {
 192         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
 193         return res;
 194     }
 195
 196     switch(type) {
 197     case MM_TYPE_PALETTE   : res = mm_decode_pal(s); return buf_size;
 198     case MM_TYPE_INTRA     : res = mm_decode_intra(s, 0, 0); break;
 199     case MM_TYPE_INTRA_HH  : res = mm_decode_intra(s, 1, 0); break;
 200     case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
 201     case MM_TYPE_INTER     : res = mm_decode_inter(s, 0, 0); break;
 202     case MM_TYPE_INTER_HH  : res = mm_decode_inter(s, 1, 0); break;
 203     case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
 204     default:
 205         res = AVERROR_INVALIDDATA;
 206         break;
 207     }
 208     if (res < 0)
 209         return res;
 210
 211     memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
 212
 213     if ((res = av_frame_ref(data, &s->frame)) < 0)
 214         return res;
 215
 216     *got_frame      = 1;
 217
 218     return buf_size;
 219 }
 220
 221 static av_cold int mm_decode_end(AVCodecContext *avctx)
 222 {
 223     MmContext *s = avctx->priv_data;
 224
 225     av_frame_unref(&s->frame);
 226
 227     return 0;
 228 }
 229
 230 AVCodec ff_mmvideo_decoder = {
 231     .name           = "mmvideo",
 232     .long_name      = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),
 233     .type           = AVMEDIA_TYPE_VIDEO,
 234     .id             = AV_CODEC_ID_MMVIDEO,
 235     .priv_data_size = sizeof(MmContext),
 236     .init           = mm_decode_init,
 237     .close          = mm_decode_end,
 238     .decode         = mm_decode_frame,
 239     .capabilities   = CODEC_CAP_DR1,
 240 };