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 "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 49typedef struct MmContext { 50 AVCodecContext *avctx; 51 AVFrame *frame; 52 int palette[AVPALETTE_COUNT]; 53 GetByteContext gb; 54} MmContext; 55 56static 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 s->frame = av_frame_alloc(); 65 if (!s->frame) 66 return AVERROR(ENOMEM); 67 68 return 0; 69} 70 71static int mm_decode_pal(MmContext *s) 72{ 73 int i; 74 75 bytestream2_skip(&s->gb, 4); 76 for (i = 0; i < 128; i++) { 77 s->palette[i] = 0xFFU << 24 | bytestream2_get_be24(&s->gb); 78 s->palette[i+128] = s->palette[i]<<2; 79 } 80 81 return 0; 82} 83 84/** 85 * @param half_horiz Half horizontal resolution (0 or 1) 86 * @param half_vert Half vertical resolution (0 or 1) 87 */ 88static int mm_decode_intra(MmContext * s, int half_horiz, int half_vert) 89{ 90 int x = 0, y = 0; 91 92 while (bytestream2_get_bytes_left(&s->gb) > 0) { 93 int run_length, color; 94 95 if (y >= s->avctx->height) 96 return 0; 97 98 color = bytestream2_get_byte(&s->gb); 99 if (color & 0x80) { 100 run_length = 1; 101 }else{ 102 run_length = (color & 0x7f) + 2; 103 color = bytestream2_get_byte(&s->gb); 104 } 105 106 if (half_horiz) 107 run_length *=2; 108 109 if (run_length > s->avctx->width - x) 110 return AVERROR_INVALIDDATA; 111 112 if (color) { 113 memset(s->frame->data[0] + y*s->frame->linesize[0] + x, color, run_length); 114 if (half_vert) 115 memset(s->frame->data[0] + (y+1)*s->frame->linesize[0] + x, color, run_length); 116 } 117 x+= run_length; 118 119 if (x >= s->avctx->width) { 120 x=0; 121 y += 1 + half_vert; 122 } 123 } 124 125 return 0; 126} 127 128/** 129 * @param half_horiz Half horizontal resolution (0 or 1) 130 * @param half_vert Half vertical resolution (0 or 1) 131 */ 132static int mm_decode_inter(MmContext * s, int half_horiz, int half_vert) 133{ 134 int data_off = bytestream2_get_le16(&s->gb); 135 int y = 0; 136 GetByteContext data_ptr; 137 138 if (bytestream2_get_bytes_left(&s->gb) < data_off) 139 return AVERROR_INVALIDDATA; 140 141 bytestream2_init(&data_ptr, s->gb.buffer + data_off, bytestream2_get_bytes_left(&s->gb) - data_off); 142 while (s->gb.buffer < data_ptr.buffer_start) { 143 int i, j; 144 int length = bytestream2_get_byte(&s->gb); 145 int x = bytestream2_get_byte(&s->gb) + ((length & 0x80) << 1); 146 length &= 0x7F; 147 148 if (length==0) { 149 y += x; 150 continue; 151 } 152 153 if (y + half_vert >= s->avctx->height) 154 return 0; 155 156 for(i=0; i<length; i++) { 157 int replace_array = bytestream2_get_byte(&s->gb); 158 for(j=0; j<8; j++) { 159 int replace = (replace_array >> (7-j)) & 1; 160 if (x + half_horiz >= s->avctx->width) 161 return AVERROR_INVALIDDATA; 162 if (replace) { 163 int color = bytestream2_get_byte(&data_ptr); 164 s->frame->data[0][y*s->frame->linesize[0] + x] = color; 165 if (half_horiz) 166 s->frame->data[0][y*s->frame->linesize[0] + x + 1] = color; 167 if (half_vert) { 168 s->frame->data[0][(y+1)*s->frame->linesize[0] + x] = color; 169 if (half_horiz) 170 s->frame->data[0][(y+1)*s->frame->linesize[0] + x + 1] = color; 171 } 172 } 173 x += 1 + half_horiz; 174 } 175 } 176 177 y += 1 + half_vert; 178 } 179 180 return 0; 181} 182 183static int mm_decode_frame(AVCodecContext *avctx, 184 void *data, int *got_frame, 185 AVPacket *avpkt) 186{ 187 const uint8_t *buf = avpkt->data; 188 int buf_size = avpkt->size; 189 MmContext *s = avctx->priv_data; 190 int type, res; 191 192 if (buf_size < MM_PREAMBLE_SIZE) 193 return AVERROR_INVALIDDATA; 194 type = AV_RL16(&buf[0]); 195 buf += MM_PREAMBLE_SIZE; 196 buf_size -= MM_PREAMBLE_SIZE; 197 bytestream2_init(&s->gb, buf, buf_size); 198 199 if ((res = ff_reget_buffer(avctx, s->frame)) < 0) 200 return res; 201 202 switch(type) { 203 case MM_TYPE_PALETTE : res = mm_decode_pal(s); return avpkt->size; 204 case MM_TYPE_INTRA : res = mm_decode_intra(s, 0, 0); break; 205 case MM_TYPE_INTRA_HH : res = mm_decode_intra(s, 1, 0); break; 206 case MM_TYPE_INTRA_HHV : res = mm_decode_intra(s, 1, 1); break; 207 case MM_TYPE_INTER : res = mm_decode_inter(s, 0, 0); break; 208 case MM_TYPE_INTER_HH : res = mm_decode_inter(s, 1, 0); break; 209 case MM_TYPE_INTER_HHV : res = mm_decode_inter(s, 1, 1); break; 210 default: 211 res = AVERROR_INVALIDDATA; 212 break; 213 } 214 if (res < 0) 215 return res; 216 217 memcpy(s->frame->data[1], s->palette, AVPALETTE_SIZE); 218 219 if ((res = av_frame_ref(data, s->frame)) < 0) 220 return res; 221 222 *got_frame = 1; 223 224 return avpkt->size; 225} 226 227static av_cold int mm_decode_end(AVCodecContext *avctx) 228{ 229 MmContext *s = avctx->priv_data; 230 231 av_frame_free(&s->frame); 232 233 return 0; 234} 235 236AVCodec ff_mmvideo_decoder = { 237 .name = "mmvideo", 238 .long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"), 239 .type = AVMEDIA_TYPE_VIDEO, 240 .id = AV_CODEC_ID_MMVIDEO, 241 .priv_data_size = sizeof(MmContext), 242 .init = mm_decode_init, 243 .close = mm_decode_end, 244 .decode = mm_decode_frame, 245 .capabilities = CODEC_CAP_DR1, 246}; 247