2 * American Laser Games MM Video Decoder
3 * Copyright (c) 2006,2008 Peter Ross
5 * This file is part of FFmpeg.
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.
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.
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
23 * @file libavcodec/mmvideo.c
24 * American Laser Games MM Video Decoder
25 * by Peter Ross (pross@xvid.org)
27 * The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,
28 * including Mad Dog McCree and Crime Patrol.
30 * Technical details here:
31 * http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
34 #include "libavutil/intreadwrite.h"
37 #define MM_PREAMBLE_SIZE 6
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
47 typedef struct MmContext {
48 AVCodecContext *avctx;
50 int palette[AVPALETTE_COUNT];
53 static av_cold int mm_decode_init(AVCodecContext *avctx)
55 MmContext *s = avctx->priv_data;
59 avctx->pix_fmt = PIX_FMT_PAL8;
61 s->frame.reference = 1;
62 if (avctx->get_buffer(avctx, &s->frame)) {
63 av_log(s->avctx, AV_LOG_ERROR, "mmvideo: get_buffer() failed\n");
70 static void mm_decode_pal(MmContext *s, const uint8_t *buf, const uint8_t *buf_end)
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;
81 static void mm_decode_intra(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size)
87 int run_length, color;
94 run_length = (buf[i] & 0x7f) + 2;
103 memset(s->frame.data[0] + y*s->frame.linesize[0] + x, color, run_length);
105 memset(s->frame.data[0] + (y+1)*s->frame.linesize[0] + x, color, run_length);
109 if (x >= s->avctx->width) {
111 y += half_vert ? 2 : 1;
116 static void mm_decode_inter(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size)
118 const int data_ptr = 2 + AV_RL16(&buf[0]);
120 d = data_ptr; r = 2; y = 0;
122 while(r < data_ptr) {
124 int length = buf[r] & 0x7f;
125 int x = buf[r+1] + ((buf[r] & 0x80) << 1);
133 for(i=0; i<length; i++) {
135 int replace = (buf[r+i] >> (7-j)) & 1;
138 s->frame.data[0][y*s->frame.linesize[0] + x] = color;
140 s->frame.data[0][y*s->frame.linesize[0] + x + 1] = color;
142 s->frame.data[0][(y+1)*s->frame.linesize[0] + x] = color;
144 s->frame.data[0][(y+1)*s->frame.linesize[0] + x + 1] = color;
148 x += half_horiz ? 2 : 1;
153 y += half_vert ? 2 : 1;
157 static int mm_decode_frame(AVCodecContext *avctx,
158 void *data, int *data_size,
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;
167 type = AV_RL16(&buf[0]);
168 buf += MM_PREAMBLE_SIZE;
169 buf_size -= MM_PREAMBLE_SIZE;
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;
183 memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
185 *data_size = sizeof(AVFrame);
186 *(AVFrame*)data = s->frame;
191 static av_cold int mm_decode_end(AVCodecContext *avctx)
193 MmContext *s = avctx->priv_data;
196 avctx->release_buffer(avctx, &s->frame);
201 AVCodec mmvideo_decoder = {
211 .long_name = NULL_IF_CONFIG_SMALL("American Laser Games MM Video"),