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
206
207
208
209
210
211
212
213
214
215
216
217
218
219
|
/*
* Micrsoft RLE Video Decoder
* Copyright (C) 2003 the ffmpeg project
*
* This library 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 of the License, or (at your option) any later version.
*
* This library 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 this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/**
* @file msrle.c
* MS RLE Video Decoder by Mike Melanson (melanson@pcisys.net)
* For more information about the MS RLE format, visit:
* http://www.pcisys.net/~melanson/codecs/
*
* The MS RLE decoder outputs PAL8 colorspace data.
*
* Note that this decoder expects the palette colors from the end of the
* BITMAPINFO header passed through extradata.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "common.h"
#include "avcodec.h"
#include "dsputil.h"
typedef struct MsrleContext {
AVCodecContext *avctx;
AVFrame frame;
AVFrame prev_frame;
unsigned char *buf;
int size;
unsigned int palette[256];
} MsrleContext;
#define FETCH_NEXT_STREAM_BYTE() \
if (stream_ptr >= s->size) \
{ \
printf(" MS RLE: stream ptr just went out of bounds (1)\n"); \
return; \
} \
stream_byte = s->buf[stream_ptr++];
static void msrle_decode_pal8(MsrleContext *s)
{
int stream_ptr = 0;
unsigned char rle_code;
unsigned char extra_byte;
unsigned char stream_byte;
int pixel_ptr = 0;
int row_dec = s->frame.linesize[0];
int row_ptr = (s->avctx->height - 1) * row_dec;
int frame_size = row_dec * s->avctx->height;
while (row_ptr >= 0) {
FETCH_NEXT_STREAM_BYTE();
rle_code = stream_byte;
if (rle_code == 0) {
/* fetch the next byte to see how to handle escape code */
FETCH_NEXT_STREAM_BYTE();
if (stream_byte == 0) {
/* line is done, goto the next one */
row_ptr -= row_dec;
pixel_ptr = 0;
} else if (stream_byte == 1) {
/* decode is done */
return;
} else if (stream_byte == 2) {
/* reposition frame decode coordinates */
FETCH_NEXT_STREAM_BYTE();
pixel_ptr += stream_byte;
FETCH_NEXT_STREAM_BYTE();
row_ptr -= stream_byte * row_dec;
} else {
/* copy pixels from encoded stream */
if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
(row_ptr < 0)) {
printf(" MS RLE: frame ptr just went out of bounds (1)\n");
return;
}
rle_code = stream_byte;
extra_byte = stream_byte & 0x01;
if (stream_ptr + rle_code + extra_byte > s->size) {
printf(" MS RLE: stream ptr just went out of bounds (2)\n");
return;
}
while (rle_code--) {
FETCH_NEXT_STREAM_BYTE();
s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
pixel_ptr++;
}
/* if the RLE code is odd, skip a byte in the stream */
if (extra_byte)
stream_ptr++;
}
} else {
/* decode a run of data */
if ((row_ptr + pixel_ptr + stream_byte > frame_size) ||
(row_ptr < 0)) {
printf(" MS RLE: frame ptr just went out of bounds (2)\n");
return;
}
FETCH_NEXT_STREAM_BYTE();
while(rle_code--) {
s->frame.data[0][row_ptr + pixel_ptr] = stream_byte;
pixel_ptr++;
}
}
}
/* make the palette available */
memcpy(s->frame.data[1], s->palette, 256 * 4);
/* one last sanity check on the way out */
if (stream_ptr < s->size)
printf(" MS RLE: ended frame decode with bytes left over (%d < %d)\n",
stream_ptr, s->size);
}
static int msrle_decode_init(AVCodecContext *avctx)
{
MsrleContext *s = (MsrleContext *)avctx->priv_data;
int i, j;
unsigned char *palette;
s->avctx = avctx;
avctx->pix_fmt = PIX_FMT_PAL8;
avctx->has_b_frames = 0;
s->frame.data[0] = s->prev_frame.data[0] = NULL;
/* convert palette */
palette = (unsigned char *)s->avctx->extradata;
memset (s->palette, 0, 256 * 4);
for (i = 0, j = 0; i < s->avctx->extradata_size / 4; i++, j += 4)
s->palette[i] =
(palette[j + 2] << 16) |
(palette[j + 1] << 8) |
(palette[j + 0] << 0);
return 0;
}
static int msrle_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
uint8_t *buf, int buf_size)
{
MsrleContext *s = (MsrleContext *)avctx->priv_data;
s->buf = buf;
s->size = buf_size;
if (avctx->get_buffer(avctx, &s->frame)) {
printf (" MS RLE: get_buffer() failed\n");
return -1;
}
/* grossly inefficient, but...oh well */
memcpy(s->frame.data[0], s->prev_frame.data[0],
s->frame.linesize[0] * s->avctx->height);
msrle_decode_pal8(s);
if (s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
/* shuffle frames */
s->prev_frame = s->frame;
*data_size = sizeof(AVFrame);
*(AVFrame*)data = s->frame;
/* report that the buffer was completely consumed */
return buf_size;
}
static int msrle_decode_end(AVCodecContext *avctx)
{
MsrleContext *s = (MsrleContext *)avctx->priv_data;
/* release the last frame */
if (s->prev_frame.data[0])
avctx->release_buffer(avctx, &s->prev_frame);
return 0;
}
AVCodec msrle_decoder = {
"msrle",
CODEC_TYPE_VIDEO,
CODEC_ID_MSRLE,
sizeof(MsrleContext),
msrle_decode_init,
NULL,
msrle_decode_end,
msrle_decode_frame,
CODEC_CAP_DR1,
};
|
