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 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
  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 "codec_internal.h"
  38 #include "decode.h"
  39
  40 #define MM_PREAMBLE_SIZE    6
  41
  42 #define MM_TYPE_RAW         0x2
  43 #define MM_TYPE_INTER       0x5
  44 #define MM_TYPE_INTRA       0x8
  45 #define MM_TYPE_INTRA_HH    0xc
  46 #define MM_TYPE_INTER_HH    0xd
  47 #define MM_TYPE_INTRA_HHV   0xe
  48 #define MM_TYPE_INTER_HHV   0xf
  49 #define MM_TYPE_PALETTE     0x31
  50
  51 typedef struct MmContext {
  52     AVCodecContext *avctx;
  53     AVFrame *frame;
  54     unsigned int palette[AVPALETTE_COUNT];
  55     GetByteContext gb;
  56 } MmContext;
  57
  58 static av_cold int mm_decode_init(AVCodecContext *avctx)
  59 {
  60     MmContext *s = avctx->priv_data;
  61
  62     s->avctx = avctx;
  63
  64     avctx->pix_fmt = AV_PIX_FMT_PAL8;
  65
  66     if (!avctx->width || !avctx->height ||
  67         (avctx->width & 1) || (avctx->height & 1)) {
  68         av_log(avctx, AV_LOG_ERROR, "Invalid video dimensions: %dx%d\n",
  69                avctx->width, avctx->height);
  70         return AVERROR(EINVAL);
  71     }
  72
  73     s->frame = av_frame_alloc();
  74     if (!s->frame)
  75         return AVERROR(ENOMEM);
  76
  77     return 0;
  78 }
  79
  80 static int mm_decode_raw(MmContext * s)
  81 {
  82     if (bytestream2_get_bytes_left(&s->gb) < s->avctx->width * s->avctx->height)
  83         return AVERROR_INVALIDDATA;
  84     for (int y = 0; y < s->avctx->height; y++)
  85         bytestream2_get_buffer(&s->gb, s->frame->data[0] + y*s->frame->linesize[0], s->avctx->width);
  86     return 0;
  87 }
  88
  89 static void mm_decode_pal(MmContext *s)
  90 {
  91     int start = bytestream2_get_le16(&s->gb);
  92     int count = bytestream2_get_le16(&s->gb);
  93     for (int i = 0; i < count; i++)
  94         s->palette[start+i] = 0xFFU << 24 | (bytestream2_get_be24(&s->gb) << 2);
  95 }
  96
  97 /**
  98  * @param half_horiz Half horizontal resolution (0 or 1)
  99  * @param half_vert Half vertical resolution (0 or 1)
 100  */
 101 static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert)
 102 {
 103     int x = 0, y = 0;
 104
 105     while (bytestream2_get_bytes_left(&s->gb) > 0) {
 106         int run_length, color;
 107
 108         if (y >= s->avctx->height)
 109             return 0;
 110
 111         color = bytestream2_get_byte(&s->gb);
 112         if (color & 0x80) {
 113             run_length = 1;
 114         }else{
 115             run_length = (color & 0x7f) + 2;
 116             color = bytestream2_get_byte(&s->gb);
 117         }
 118
 119         if (half_horiz)
 120             run_length *=2;
 121
 122         if (run_length > s->avctx->width - x)
 123             return AVERROR_INVALIDDATA;
 124
 125         if (color) {
 126             memset(s->frame->data[0] + y*s->frame->linesize[0] + x, color, run_length);
 127             if (half_vert && y + half_vert < s->avctx->height)
 128                 memset(s->frame->data[0] + (y+1)*s->frame->linesize[0] + x, color, run_length);
 129         }
 130         x+= run_length;
 131
 132         if (x >= s->avctx->width) {
 133             x=0;
 134             y += 1 + half_vert;
 135         }
 136     }
 137
 138     return 0;
 139 }
 140
 141 /**
 142  * @param half_horiz Half horizontal resolution (0 or 1)
 143  * @param half_vert Half vertical resolution (0 or 1)
 144  */
 145 static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert)
 146 {
 147     int data_off = bytestream2_get_le16(&s->gb);
 148     int y = 0;
 149     GetByteContext data_ptr;
 150
 151     if (bytestream2_get_bytes_left(&s->gb) < data_off)
 152         return AVERROR_INVALIDDATA;
 153
 154     bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off);
 155     while (s->gb.buffer < data_ptr.buffer_start) {
 156         int i, j;
 157         int length = bytestream2_get_byte(&s->gb);
 158         int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1);
 159         length &= 0x7F;
 160
 161         if (length==0) {
 162             y += x;
 163             continue;
 164         }
 165
 166         if (y + half_vert >= s->avctx->height)
 167             return 0;
 168
 169         for(i=0; i<length; i++) {
 170             int replace_array = bytestream2_get_byte(&s->gb);
 171             for(j=0; j<8; j++) {
 172                 int replace = (replace_array >> (7-j)) & 1;
 173                 if (x + half_horiz >= s->avctx->width)
 174                     break;
 175                 if (replace) {
 176                     int color = bytestream2_get_byte(&data_ptr);
 177                     s->frame->data[0][y*s->frame->linesize[0] + x] = color;
 178                     if (half_horiz)
 179                         s->frame->data[0][y*s->frame->linesize[0] + x + 1] = color;
 180                     if (half_vert) {
 181                         s->frame->data[0][(y+1)*s->frame->linesize[0] + x] = color;
 182                         if (half_horiz)
 183                             s->frame->data[0][(y+1)*s->frame->linesize[0] + x + 1] = color;
 184                     }
 185                 }
 186                 x += 1 + half_horiz;
 187             }
 188         }
 189
 190         y += 1 + half_vert;
 191     }
 192
 193     return 0;
 194 }
 195
 196 static int mm_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
 197                            int *got_frame, AVPacket *avpkt)
 198 {
 199     const uint8_t *buf = avpkt->data;
 200     int buf_size = avpkt->size;
 201     MmContext *s = avctx->priv_data;
 202     int type, res;
 203
 204     if (buf_size < MM_PREAMBLE_SIZE)
 205         return AVERROR_INVALIDDATA;
 206     type = AV_RL16(&buf[0]);
 207     buf += MM_PREAMBLE_SIZE;
 208     buf_size -= MM_PREAMBLE_SIZE;
 209     bytestream2_init(&s->gb, buf, buf_size);
 210
 211     if ((res = ff_reget_buffer(avctx, s->frame, 0)) < 0)
 212         return res;
 213
 214     switch(type) {
 215     case MM_TYPE_RAW       : res = mm_decode_raw(s); break;
 216     case MM_TYPE_PALETTE   : mm_decode_pal(s); return avpkt->size;
 217     case MM_TYPE_INTRA     : res = mm_decode_intra(s, 0, 0); break;
 218     case MM_TYPE_INTRA_HH  : res = mm_decode_intra(s, 1, 0); break;
 219     case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break;
 220     case MM_TYPE_INTER     : res = mm_decode_inter(s, 0, 0); break;
 221     case MM_TYPE_INTER_HH  : res = mm_decode_inter(s, 1, 0); break;
 222     case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break;
 223     default:
 224         res = AVERROR_INVALIDDATA;
 225         break;
 226     }
 227     if (res < 0)
 228         return res;
 229
 230     memcpy(s->frame->data[1], s->palette, AVPALETTE_SIZE);
 231
 232     if ((res = av_frame_ref(rframe, s->frame)) < 0)
 233         return res;
 234
 235     *got_frame      = 1;
 236
 237     return avpkt->size;
 238 }
 239
 240 static av_cold int mm_decode_end(AVCodecContext *avctx)
 241 {
 242     MmContext *s = avctx->priv_data;
 243
 244     av_frame_free(&s->frame);
 245
 246     return 0;
 247 }
 248
 249 const FFCodec ff_mmvideo_decoder = {
 250     .p.name         = "mmvideo",
 251     CODEC_LONG_NAME("American Laser Games MM Video"),
 252     .p.type         = AVMEDIA_TYPE_VIDEO,
 253     .p.id           = AV_CODEC_ID_MMVIDEO,
 254     .priv_data_size = sizeof(MmContext),
 255     .init           = mm_decode_init,
 256     .close          = mm_decode_end,
 257     FF_CODEC_DECODE_CB(mm_decode_frame),
 258     .p.capabilities = AV_CODEC_CAP_DR1,
 259 };