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 37#define MM_PREAMBLE_SIZE 6 38 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_PALETTE 0x31 46 47typedef struct MmContext { 48 AVCodecContext *avctx; 49 AVFrame frame; 50 int palette[AVPALETTE_COUNT]; 51} MmContext; 52 53static av_cold int mm_decode_init(AVCodecContext *avctx) 54{ 55 MmContext *s = avctx->priv_data; 56 57 s->avctx = avctx; 58 59 avctx->pix_fmt = PIX_FMT_PAL8; 60 61 s->frame.reference = 1; 62 if (avctx->get_buffer(avctx, &s->frame)) { 63 av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 64 return -1; 65 } 66 67 return 0; 68} 69 70static void mm_decode_pal(MmContext *s, const uint8_t *buf, const uint8_t *buf_end) 71{ 72 int i; 73 buf += 4; 74 for (i=0; i<128 && buf+2<buf_end; i++) { 75 s->palette[i] = AV_RB24(buf); 76 s->palette[i+128] = s->palette[i]<<2; 77 buf += 3; 78 } 79} 80 81static void mm_decode_intra(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size) 82{ 83 int i, x, y; 84 i=0; x=0; y=0; 85 86 while(i<buf_size) { 87 int run_length, color; 88 89 if (buf[i] & 0x80) { 90 run_length = 1; 91 color = buf[i]; 92 i++; 93 }else{ 94 run_length = (buf[i] & 0x7f) + 2; 95 color = buf[i+1]; 96 i+=2; 97 } 98 99 if (half_horiz) 100 run_length *=2; 101 102 if (color) { 103 memset(s->frame.data[0] + y*s->frame.linesize[0] + x, color, run_length); 104 if (half_vert) 105 memset(s->frame.data[0] + (y+1)*s->frame.linesize[0] + x, color, run_length); 106 } 107 x+= run_length; 108 109 if (x >= s->avctx->width) { 110 x=0; 111 y += half_vert ? 2 : 1; 112 } 113 } 114} 115 116static void mm_decode_inter(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size) 117{ 118 const int data_ptr = 2 + AV_RL16(&buf[0]); 119 int d, r, y; 120 d = data_ptr; r = 2; y = 0; 121 122 while(r < data_ptr) { 123 int i, j; 124 int length = buf[r] & 0x7f; 125 int x = buf[r+1] + ((buf[r] & 0x80) << 1); 126 r += 2; 127 128 if (length==0) { 129 y += x; 130 continue; 131 } 132 133 for(i=0; i<length; i++) { 134 for(j=0; j<8; j++) { 135 int replace = (buf[r+i] >> (7-j)) & 1; 136 if (replace) { 137 int color = buf[d]; 138 s->frame.data[0][y*s->frame.linesize[0] + x] = color; 139 if (half_horiz) 140 s->frame.data[0][y*s->frame.linesize[0] + x + 1] = color; 141 if (half_vert) { 142 s->frame.data[0][(y+1)*s->frame.linesize[0] + x] = color; 143 if (half_horiz) 144 s->frame.data[0][(y+1)*s->frame.linesize[0] + x + 1] = color; 145 } 146 d++; 147 } 148 x += half_horiz ? 2 : 1; 149 } 150 } 151 152 r += length; 153 y += half_vert ? 2 : 1; 154 } 155} 156 157static int mm_decode_frame(AVCodecContext *avctx, 158 void *data, int *data_size, 159 AVPacket *avpkt) 160{ 161 const uint8_t *buf = avpkt->data; 162 int buf_size = avpkt->size; 163 MmContext *s = avctx->priv_data; 164 const uint8_t *buf_end = buf+buf_size; 165 int type; 166 167 type = AV_RL16(&buf[0]); 168 buf += MM_PREAMBLE_SIZE; 169 buf_size -= MM_PREAMBLE_SIZE; 170 171 switch(type) { 172 case MM_TYPE_PALETTE : mm_decode_pal(s, buf, buf_end); return buf_size; 173 case MM_TYPE_INTRA : mm_decode_intra(s, 0, 0, buf, buf_size); break; 174 case MM_TYPE_INTRA_HH : mm_decode_intra(s, 1, 0, buf, buf_size); break; 175 case MM_TYPE_INTRA_HHV : mm_decode_intra(s, 1, 1, buf, buf_size); break; 176 case MM_TYPE_INTER : mm_decode_inter(s, 0, 0, buf, buf_size); break; 177 case MM_TYPE_INTER_HH : mm_decode_inter(s, 1, 0, buf, buf_size); break; 178 case MM_TYPE_INTER_HHV : mm_decode_inter(s, 1, 1, buf, buf_size); break; 179 default : 180 return -1; 181 } 182 183 memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE); 184 185 *data_size = sizeof(AVFrame); 186 *(AVFrame*)data = s->frame; 187 188 return buf_size; 189} 190 191static av_cold int mm_decode_end(AVCodecContext *avctx) 192{ 193 MmContext *s = avctx->priv_data; 194 195 if(s->frame.data[0]) 196 avctx->release_buffer(avctx, &s->frame); 197 198 return 0; 199} 200 201AVCodec mmvideo_decoder = { 202 "mmvideo", 203 AVMEDIA_TYPE_VIDEO, 204 CODEC_ID_MMVIDEO, 205 sizeof(MmContext), 206 mm_decode_init, 207 NULL, 208 mm_decode_end, 209 mm_decode_frame, 210 CODEC_CAP_DR1, 211 .long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"), 212}; 213