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