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
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
|
/*
* Escape 130 Video Decoder
* Copyright (C) 2008 Eli Friedman (eli.friedman <at> gmail.com)
*
* 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
*/
#include "avcodec.h"
#define BITSTREAM_READER_LE
#include "get_bits.h"
typedef struct Escape130Context {
AVFrame frame;
uint8_t *bases;
} Escape130Context;
/**
* Initialize the decoder
* @param avctx decoder context
* @return 0 success, negative on error
*/
static av_cold int escape130_decode_init(AVCodecContext *avctx)
{
Escape130Context *s = avctx->priv_data;
avctx->pix_fmt = AV_PIX_FMT_YUV420P;
if((avctx->width&1) || (avctx->height&1)){
av_log(avctx, AV_LOG_ERROR, "Dimensions are not a multiple of the block size\n");
return AVERROR(EINVAL);
}
s->bases= av_malloc(avctx->width * avctx->height /4);
return 0;
}
static av_cold int escape130_decode_close(AVCodecContext *avctx)
{
Escape130Context *s = avctx->priv_data;
if (s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
av_freep(&s->bases);
return 0;
}
static unsigned decode_skip_count(GetBitContext* gb) {
unsigned value;
// This function reads a maximum of 27 bits,
// which is within the padding space
if (get_bits_left(gb) < 1+3)
return -1;
value = get_bits1(gb);
if (value)
return 0;
value = get_bits(gb, 3);
if (value)
return value;
value = get_bits(gb, 8);
if (value)
return value + 7;
value = get_bits(gb, 15);
if (value)
return value + 262;
return -1;
}
/**
* Decode a single frame
* @param avctx decoder context
* @param data decoded frame
* @param data_size size of the decoded frame
* @param buf input buffer
* @param buf_size input buffer size
* @return 0 success, -1 on error
*/
static int escape130_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
Escape130Context *s = avctx->priv_data;
GetBitContext gb;
unsigned i;
uint8_t *old_y, *old_cb, *old_cr,
*new_y, *new_cb, *new_cr;
unsigned old_y_stride, old_cb_stride, old_cr_stride,
new_y_stride, new_cb_stride, new_cr_stride;
unsigned total_blocks = avctx->width * avctx->height / 4,
block_index, row_index = 0;
unsigned y[4] = {0}, cb = 16, cr = 16;
unsigned skip = -1;
unsigned y_base = 0;
uint8_t *yb= s->bases;
AVFrame new_frame = { { 0 } };
init_get_bits(&gb, buf, buf_size * 8);
if (get_bits_left(&gb) < 128)
return -1;
// Header; no useful information in here
skip_bits_long(&gb, 128);
new_frame.reference = 3;
if (avctx->get_buffer(avctx, &new_frame)) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return -1;
}
new_y = new_frame.data[0];
new_cb = new_frame.data[1];
new_cr = new_frame.data[2];
new_y_stride = new_frame.linesize[0];
new_cb_stride = new_frame.linesize[1];
new_cr_stride = new_frame.linesize[2];
old_y = s->frame.data[0];
old_cb = s->frame.data[1];
old_cr = s->frame.data[2];
old_y_stride = s->frame.linesize[0];
old_cb_stride = s->frame.linesize[1];
old_cr_stride = s->frame.linesize[2];
av_log(avctx, AV_LOG_DEBUG,
"Strides: %i, %i\n",
new_y_stride, new_cb_stride);
for (block_index = 0; block_index < total_blocks; block_index++) {
// Note that this call will make us skip the rest of the blocks
// if the frame prematurely ends
if (skip == -1)
skip = decode_skip_count(&gb);
if (skip) {
if (old_y) {
y[0] = old_y[0] / 4;
y[1] = old_y[1] / 4;
y[2] = old_y[old_y_stride] / 4;
y[3] = old_y[old_y_stride+1] / 4;
y_base= yb[0];
cb = old_cb[0] / 8;
cr = old_cr[0] / 8;
} else {
y_base=y[0] = y[1] = y[2] = y[3] = 0;
cb = cr = 16;
}
} else {
if (get_bits1(&gb)) {
static const uint8_t offset_table[] = {2, 4, 10, 20};
static const int8_t sign_table[64][4] =
{ {0, 0, 0, 0},
{-1, 1, 0, 0},
{1, -1, 0, 0},
{-1, 0, 1, 0},
{-1, 1, 1, 0},
{0, -1, 1, 0},
{1, -1, 1, 0},
{-1, -1, 1, 0},
{1, 0, -1, 0},
{0, 1, -1, 0},
{1, 1, -1, 0},
{-1, 1, -1, 0},
{1, -1, -1, 0},
{-1, 0, 0, 1},
{-1, 1, 0, 1},
{0, -1, 0, 1},
{0, 0, 0, 0},
{1, -1, 0, 1},
{-1, -1, 0, 1},
{-1, 0, 1, 1},
{-1, 1, 1, 1},
{0, -1, 1, 1},
{1, -1, 1, 1},
{-1, -1, 1, 1},
{0, 0, -1, 1},
{1, 0, -1, 1},
{-1, 0, -1, 1},
{0, 1, -1, 1},
{1, 1, -1, 1},
{-1, 1, -1, 1},
{0, -1, -1, 1},
{1, -1, -1, 1},
{0, 0, 0, 0},
{-1, -1, -1, 1},
{1, 0, 0, -1},
{0, 1, 0, -1},
{1, 1, 0, -1},
{-1, 1, 0, -1},
{1, -1, 0, -1},
{0, 0, 1, -1},
{1, 0, 1, -1},
{-1, 0, 1, -1},
{0, 1, 1, -1},
{1, 1, 1, -1},
{-1, 1, 1, -1},
{0, -1, 1, -1},
{1, -1, 1, -1},
{-1, -1, 1, -1},
{0, 0, 0, 0},
{1, 0, -1, -1},
{0, 1, -1, -1},
{1, 1, -1, -1},
{-1, 1, -1, -1},
{1, -1, -1, -1} };
unsigned sign_selector = get_bits(&gb, 6);
unsigned difference_selector = get_bits(&gb, 2);
y_base = 2 * get_bits(&gb, 5);
for (i = 0; i < 4; i++) {
y[i] = av_clip((int)y_base + offset_table[difference_selector] *
sign_table[sign_selector][i], 0, 63);
}
} else if (get_bits1(&gb)) {
if (get_bits1(&gb)) {
y_base = get_bits(&gb, 6);
} else {
unsigned adjust_index = get_bits(&gb, 3);
static const int8_t adjust[] = {-4, -3, -2, -1, 1, 2, 3, 4};
y_base = (y_base + adjust[adjust_index]) & 63;
}
for (i = 0; i < 4; i++)
y[i] = y_base;
}
if (get_bits1(&gb)) {
if (get_bits1(&gb)) {
cb = get_bits(&gb, 5);
cr = get_bits(&gb, 5);
} else {
unsigned adjust_index = get_bits(&gb, 3);
static const int8_t adjust[2][8] =
{ { 1, 1, 0, -1, -1, -1, 0, 1 },
{ 0, 1, 1, 1, 0, -1, -1, -1 } };
cb = (cb + adjust[0][adjust_index]) & 31;
cr = (cr + adjust[1][adjust_index]) & 31;
}
}
}
*yb++= y_base;
new_y[0] = y[0] * 4;
new_y[1] = y[1] * 4;
new_y[new_y_stride] = y[2] * 4;
new_y[new_y_stride + 1] = y[3] * 4;
*new_cb = cb * 8;
*new_cr = cr * 8;
if (old_y)
old_y += 2, old_cb++, old_cr++;
new_y += 2, new_cb++, new_cr++;
row_index++;
if (avctx->width / 2 == row_index) {
row_index = 0;
if (old_y) {
old_y += old_y_stride * 2 - avctx->width;
old_cb += old_cb_stride - avctx->width / 2;
old_cr += old_cr_stride - avctx->width / 2;
}
new_y += new_y_stride * 2 - avctx->width;
new_cb += new_cb_stride - avctx->width / 2;
new_cr += new_cr_stride - avctx->width / 2;
}
skip--;
}
av_log(avctx, AV_LOG_DEBUG,
"Escape sizes: %i, %i\n",
buf_size, get_bits_count(&gb) / 8);
if (s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
*(AVFrame*)data = s->frame = new_frame;
*data_size = sizeof(AVFrame);
return buf_size;
}
AVCodec ff_escape130_decoder = {
.name = "escape130",
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_ESCAPE130,
.priv_data_size = sizeof(Escape130Context),
.init = escape130_decode_init,
.close = escape130_decode_close,
.decode = escape130_decode_frame,
.capabilities = CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("Escape 130"),
};
|
