1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
|
/*
* American Laser Games MM Video Decoder
* Copyright (c) 2006 Peter Ross
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file mm.c
* American Laser Games MM Video Decoder
* by Peter Ross (suxen_drol at hotmail dot com)
*
* The MM format was used by IBM-PC ports of ALG's "arcade shooter" games,
* including Mad Dog McCree and Crime Patrol.
*
* Technical details here:
* http://wiki.multimedia.cx/index.php?title=American_Laser_Games_MM
*/
#include "avcodec.h"
#define MM_PREAMBLE_SIZE 6
#define MM_TYPE_INTER 0x5
#define MM_TYPE_INTRA 0x8
#define MM_TYPE_INTRA_HH 0xc
#define MM_TYPE_INTER_HH 0xd
#define MM_TYPE_INTRA_HHV 0xe
#define MM_TYPE_INTER_HHV 0xf
typedef struct MmContext {
AVCodecContext *avctx;
AVFrame frame;
} MmContext;
static av_cold int mm_decode_init(AVCodecContext *avctx)
{
MmContext *s = avctx->priv_data;
s->avctx = avctx;
if (s->avctx->palctrl == NULL) {
av_log(avctx, AV_LOG_ERROR, "mmvideo: palette expected.\n");
return -1;
}
avctx->pix_fmt = PIX_FMT_PAL8;
if (avcodec_check_dimensions(avctx, avctx->width, avctx->height))
return -1;
s->frame.reference = 1;
if (avctx->get_buffer(avctx, &s->frame)) {
av_log(s->avctx, AV_LOG_ERROR, "mmvideo: get_buffer() failed\n");
return -1;
}
return 0;
}
static void mm_decode_intra(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size)
{
int i, x, y;
i=0; x=0; y=0;
while(i<buf_size) {
int run_length, color;
if (buf[i] & 0x80) {
run_length = 1;
color = buf[i];
i++;
}else{
run_length = (buf[i] & 0x7f) + 2;
color = buf[i+1];
i+=2;
}
if (half_horiz)
run_length *=2;
if (color) {
memset(s->frame.data[0] + y*s->frame.linesize[0] + x, color, run_length);
if (half_vert)
memset(s->frame.data[0] + (y+1)*s->frame.linesize[0] + x, color, run_length);
}
x+= run_length;
if (x >= s->avctx->width) {
x=0;
y += half_vert ? 2 : 1;
}
}
}
static void mm_decode_inter(MmContext * s, int half_horiz, int half_vert, const uint8_t *buf, int buf_size)
{
const int data_ptr = 2 + AV_RL16(&buf[0]);
int d, r, y;
d = data_ptr; r = 2; y = 0;
while(r < data_ptr) {
int i, j;
int length = buf[r] & 0x7f;
int x = buf[r+1] + ((buf[r] & 0x80) << 1);
r += 2;
if (length==0) {
y += x;
continue;
}
for(i=0; i<length; i++) {
for(j=0; j<8; j++) {
int replace = (buf[r+i] >> (7-j)) & 1;
if (replace) {
int color = buf[d];
s->frame.data[0][y*s->frame.linesize[0] + x] = color;
if (half_horiz)
s->frame.data[0][y*s->frame.linesize[0] + x + 1] = color;
if (half_vert) {
s->frame.data[0][(y+1)*s->frame.linesize[0] + x] = color;
if (half_horiz)
s->frame.data[0][(y+1)*s->frame.linesize[0] + x + 1] = color;
}
d++;
}
x += half_horiz ? 2 : 1;
}
}
r += length;
y += half_vert ? 2 : 1;
}
}
static int mm_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
const uint8_t *buf, int buf_size)
{
MmContext *s = avctx->priv_data;
AVPaletteControl *palette_control = avctx->palctrl;
int type;
if (palette_control->palette_changed) {
memcpy(s->frame.data[1], palette_control->palette, AVPALETTE_SIZE);
palette_control->palette_changed = 0;
}
type = AV_RL16(&buf[0]);
buf += MM_PREAMBLE_SIZE;
buf_size -= MM_PREAMBLE_SIZE;
switch(type) {
case MM_TYPE_INTRA : mm_decode_intra(s, 0, 0, buf, buf_size); break;
case MM_TYPE_INTRA_HH : mm_decode_intra(s, 1, 0, buf, buf_size); break;
case MM_TYPE_INTRA_HHV : mm_decode_intra(s, 1, 1, buf, buf_size); break;
case MM_TYPE_INTER : mm_decode_inter(s, 0, 0, buf, buf_size); break;
case MM_TYPE_INTER_HH : mm_decode_inter(s, 1, 0, buf, buf_size); break;
case MM_TYPE_INTER_HHV : mm_decode_inter(s, 1, 1, buf, buf_size); break;
default :
return -1;
}
*data_size = sizeof(AVFrame);
*(AVFrame*)data = s->frame;
return buf_size;
}
static av_cold int mm_decode_end(AVCodecContext *avctx)
{
MmContext *s = avctx->priv_data;
if(s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
return 0;
}
AVCodec mmvideo_decoder = {
"mmvideo",
CODEC_TYPE_VIDEO,
CODEC_ID_MMVIDEO,
sizeof(MmContext),
mm_decode_init,
NULL,
mm_decode_end,
mm_decode_frame,
CODEC_CAP_DR1,
};
|
