Revision 40d26273

View differences:

libavcodec/Makefile
67 67
OBJS-$(CONFIG_EIGHTBPS_DECODER)        += 8bps.o
68 68
OBJS-$(CONFIG_EIGHTSVX_EXP_DECODER)    += 8svx.o
69 69
OBJS-$(CONFIG_EIGHTSVX_FIB_DECODER)    += 8svx.o
70
OBJS-$(CONFIG_ESCAPE124_DECODER)       += escape124.o
70 71
OBJS-$(CONFIG_FFV1_DECODER)            += ffv1.o rangecoder.o golomb.o
71 72
OBJS-$(CONFIG_FFV1_ENCODER)            += ffv1.o rangecoder.o
72 73
OBJS-$(CONFIG_FFVHUFF_DECODER)         += huffyuv.o
libavcodec/allcodecs.c
80 80
    REGISTER_DECODER (EIGHTBPS, eightbps);
81 81
    REGISTER_DECODER (EIGHTSVX_EXP, eightsvx_exp);
82 82
    REGISTER_DECODER (EIGHTSVX_FIB, eightsvx_fib);
83
    REGISTER_DECODER (ESCAPE124, escape124);
83 84
    REGISTER_ENCDEC  (FFV1, ffv1);
84 85
    REGISTER_ENCDEC  (FFVHUFF, ffvhuff);
85 86
    REGISTER_ENCDEC  (FLASHSV, flashsv);
libavcodec/avcodec.h
181 181
    CODEC_ID_RL2,
182 182
    CODEC_ID_8SVX_EXP,
183 183
    CODEC_ID_8SVX_FIB,
184
    CODEC_ID_ESCAPE124,
184 185

  
185 186
    /* various PCM "codecs" */
186 187
    CODEC_ID_PCM_S16LE= 0x10000,
libavcodec/escape124.c
1
/*
2
 * Escape 124 Video Decoder
3
 * Copyright (C) 2008 Eli Friedman (eli.friedman@gmail.com)
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
#include "avcodec.h"
23

  
24
#define ALT_BITSTREAM_READER_LE
25
#include "bitstream.h"
26

  
27
typedef union MacroBlock {
28
    uint16_t pixels[4];
29
    uint32_t pixels32[2];
30
} MacroBlock;
31

  
32
typedef union SuperBlock {
33
    uint16_t pixels[64];
34
    uint32_t pixels32[32];
35
} SuperBlock;
36

  
37
typedef struct CodeBook {
38
    unsigned depth;
39
    unsigned size;
40
    MacroBlock blocks[];
41
} CodeBook;
42

  
43
typedef struct Escape124Context {
44
    AVFrame frame;
45

  
46
    unsigned num_superblocks;
47

  
48
    CodeBook* codebooks[3];
49
} Escape124Context;
50

  
51
static int can_safely_read(GetBitContext* gb, int bits) {
52
    return get_bits_count(gb) + bits <= gb->size_in_bits;
53
}
54

  
55
/**
56
 * Initialize the decoder
57
 * @param avctx decoder context
58
 * @return 0 success, negative on error
59
 */
60
static av_cold int escape124_decode_init(AVCodecContext *avctx)
61
{
62
    Escape124Context *s = avctx->priv_data;
63

  
64
    avctx->pix_fmt = PIX_FMT_RGB555;
65

  
66
    s->num_superblocks = ((unsigned)avctx->width / 8) *
67
                         ((unsigned)avctx->height / 8);
68

  
69
    return 0;
70
}
71

  
72
static av_cold int escape124_decode_close(AVCodecContext *avctx)
73
{
74
    unsigned i;
75
    Escape124Context *s = avctx->priv_data;
76

  
77
    for (i = 0; i < 3; i++)
78
        av_free(s->codebooks[i]);
79

  
80
    if (s->frame.data[0])
81
        avctx->release_buffer(avctx, &s->frame);
82

  
83
    return 0;
84
}
85

  
86
static CodeBook* unpack_codebook(GetBitContext* gb, unsigned depth,
87
                                 unsigned size)
88
{
89
    unsigned i, j;
90
    CodeBook* cb;
91

  
92
    if (!can_safely_read(gb, size * 34))
93
        return NULL;
94

  
95
    if (size >= (INT_MAX - sizeof(CodeBook)) / sizeof(MacroBlock))
96
        return NULL;
97
    cb = av_malloc(size * sizeof(MacroBlock) + sizeof(CodeBook));
98
    if (!cb)
99
        return NULL;
100

  
101
    cb->depth = depth;
102
    cb->size = size;
103
    for (i = 0; i < size; i++) {
104
        unsigned mask_bits = get_bits(gb, 4);
105
        unsigned color0 = get_bits(gb, 15);
106
        unsigned color1 = get_bits(gb, 15);
107

  
108
        for (j = 0; j < 4; j++) {
109
            if (mask_bits & (1 << j))
110
                cb->blocks[i].pixels[j] = color1;
111
            else
112
                cb->blocks[i].pixels[j] = color0;
113
        }
114
    }
115
    return cb;
116
}
117

  
118
static unsigned decode_skip_count(GetBitContext* gb)
119
{
120
    unsigned value;
121
    // This function reads a maximum of 23 bits,
122
    // which is within the padding space
123
    if (!can_safely_read(gb, 1))
124
        return -1;
125
    value = get_bits1(gb);
126
    if (!value)
127
        return value;
128

  
129
    value += get_bits(gb, 3);
130
    if (value != (1 + ((1 << 3) - 1)))
131
        return value;
132

  
133
    value += get_bits(gb, 7);
134
    if (value != (1 + ((1 << 3) - 1)) + ((1 << 7) - 1))
135
        return value;
136

  
137
    return value + get_bits(gb, 12);
138
}
139

  
140
static MacroBlock decode_macroblock(Escape124Context* s, GetBitContext* gb,
141
                                    int* codebook_index, int superblock_index)
142
{
143
    // This function reads a maximum of 22 bits; the callers
144
    // guard this function appropriately
145
    unsigned block_index, depth;
146

  
147
    if (get_bits1(gb)) {
148
        static const char transitions[3][2] = { {2, 1}, {0, 2}, {1, 0} };
149
        *codebook_index = transitions[*codebook_index][get_bits1(gb)];
150
    }
151

  
152
    depth = s->codebooks[*codebook_index]->depth;
153

  
154
    // depth = 0 means that this shouldn't read any bits;
155
    // in theory, this is the same as get_bits(gb, 0), but
156
    // that doesn't actually work.
157
    block_index = depth ? get_bits(gb, depth) : 0;
158

  
159
    if (*codebook_index == 1) {
160
        block_index += superblock_index << s->codebooks[1]->depth;
161
    }
162

  
163
    // This condition can occur with invalid bitstreams and
164
    // *codebook_index == 2
165
    if (block_index >= s->codebooks[*codebook_index]->size)
166
        return (MacroBlock) { { 0 } };
167

  
168
    return s->codebooks[*codebook_index]->blocks[block_index];
169
}
170

  
171
static void insert_mb_into_sb(SuperBlock* sb, MacroBlock mb, unsigned index) {
172
   // Formula: ((index / 4) * 16 + (index % 4) * 2) / 2
173
   uint32_t *dst = sb->pixels32 + index + (index & -4);
174

  
175
   // This technically violates C99 aliasing rules, but it should be safe.
176
   dst[0] = mb.pixels32[0];
177
   dst[4] = mb.pixels32[1];
178
}
179

  
180
static void copy_superblock(uint16_t* dest, unsigned dest_stride,
181
                            uint16_t* src, unsigned src_stride)
182
{
183
    unsigned y;
184
    if (src)
185
        for (y = 0; y < 8; y++)
186
            memcpy(dest + y * dest_stride, src + y * src_stride,
187
                   sizeof(uint16_t) * 8);
188
    else
189
        for (y = 0; y < 8; y++)
190
            memset(dest + y * dest_stride, 0, sizeof(uint16_t) * 8);
191
}
192

  
193
static const uint16_t mask_matrix[] = {0x1,   0x2,   0x10,   0x20,
194
                                       0x4,   0x8,   0x40,   0x80,
195
                                       0x100, 0x200, 0x1000, 0x2000,
196
                                       0x400, 0x800, 0x4000, 0x8000};
197

  
198
/**
199
 * Decode a single frame
200
 * @param avctx decoder context
201
 * @param data decoded frame
202
 * @param data_size size of the decoded frame
203
 * @param buf input buffer
204
 * @param buf_size input buffer size
205
 * @return 0 success, -1 on error
206
 */
207
static int escape124_decode_frame(AVCodecContext *avctx,
208
                                  void *data, int *data_size,
209
                                  const uint8_t *buf, int buf_size)
210
{
211
    Escape124Context *s = avctx->priv_data;
212

  
213
    GetBitContext gb;
214
    unsigned frame_flags, frame_size;
215
    unsigned i;
216

  
217
    unsigned superblock_index, cb_index = 1,
218
             superblock_col_index = 0,
219
             superblocks_per_row = avctx->width / 8, skip = -1;
220

  
221
    uint16_t* old_frame_data, *new_frame_data;
222
    unsigned old_stride, new_stride;
223

  
224
    AVFrame new_frame = { { 0 } };
225

  
226
    init_get_bits(&gb, buf, buf_size * 8);
227

  
228
    // This call also guards the potential depth reads for the
229
    // codebook unpacking.
230
    if (!can_safely_read(&gb, 64))
231
        return -1;
232

  
233
    frame_flags = get_bits_long(&gb, 32);
234
    frame_size  = get_bits_long(&gb, 32);
235

  
236
    // Leave last frame unchanged
237
    // FIXME: Is this necessary?  I haven't seen it in any real samples
238
    if (!(frame_flags & 0x114) || !(frame_flags & 0x7800000)) {
239
        av_log(NULL, AV_LOG_DEBUG, "Skipping frame\n");
240

  
241
        *data_size = sizeof(AVFrame);
242
        *(AVFrame*)data = s->frame;
243

  
244
        return frame_size;
245
    }
246

  
247
    for (i = 0; i < 3; i++) {
248
        if (frame_flags & (1 << (17 + i))) {
249
            unsigned cb_depth, cb_size;
250
            if (i == 2) {
251
                // This codebook can be cut off at places other than
252
                // powers of 2, leaving some of the entries undefined.
253
                cb_size = get_bits_long(&gb, 20);
254
                cb_depth = av_log2(cb_size - 1) + 1;
255
            } else {
256
                cb_depth = get_bits(&gb, 4);
257
                if (i == 0) {
258
                    // This is the most basic codebook: pow(2,depth) entries
259
                    // for a depth-length key
260
                    cb_size = 1 << cb_depth;
261
                } else {
262
                    // This codebook varies per superblock
263
                    // FIXME: I don't think this handles integer overflow
264
                    // properly
265
                    cb_size = s->num_superblocks << cb_depth;
266
                }
267
            }
268
            av_free(s->codebooks[i]);
269
            s->codebooks[i] = unpack_codebook(&gb, cb_depth, cb_size);
270
            if (!s->codebooks[i])
271
                return -1;
272
        }
273
    }
274

  
275
    new_frame.reference = 3;
276
    if (avctx->get_buffer(avctx, &new_frame)) {
277
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
278
        return -1;
279
    }
280

  
281
    new_frame_data = (uint16_t*)new_frame.data[0];
282
    new_stride = new_frame.linesize[0] / 2;
283
    old_frame_data = (uint16_t*)s->frame.data[0];
284
    old_stride = s->frame.linesize[0] / 2;
285

  
286
    for (superblock_index = 0; superblock_index < s->num_superblocks;
287
         superblock_index++) {
288
        MacroBlock mb;
289
        SuperBlock sb;
290
        unsigned multi_mask = 0;
291

  
292
        if (skip == -1) {
293
            // Note that this call will make us skip the rest of the blocks
294
            // if the frame prematurely ends
295
            skip = decode_skip_count(&gb);
296
        }
297

  
298
        if (skip) {
299
            copy_superblock(new_frame_data, new_stride,
300
                            old_frame_data, old_stride);
301
        } else {
302
            copy_superblock(sb.pixels, 8,
303
                            old_frame_data, old_stride);
304

  
305
            while (can_safely_read(&gb, 1) && !get_bits1(&gb)) {
306
                unsigned mask;
307
                mb = decode_macroblock(s, &gb, &cb_index, superblock_index);
308
                mask = get_bits(&gb, 16);
309
                multi_mask |= mask;
310
                for (i = 0; i < 16; i++) {
311
                    if (mask & mask_matrix[i]) {
312
                        insert_mb_into_sb(&sb, mb, i);
313
                    }
314
                }
315
            }
316

  
317
            if (can_safely_read(&gb, 1) && !get_bits1(&gb)) {
318
                unsigned inv_mask = get_bits(&gb, 4);
319
                for (i = 0; i < 4; i++) {
320
                    if (inv_mask & (1 << i)) {
321
                        multi_mask ^= 0xF << i*4;
322
                    } else {
323
                        multi_mask ^= get_bits(&gb, 4) << i*4;
324
                    }
325
                }
326

  
327
                for (i = 0; i < 16; i++) {
328
                    if (multi_mask & mask_matrix[i]) {
329
                        if (!can_safely_read(&gb, 1))
330
                            break;
331
                        mb = decode_macroblock(s, &gb, &cb_index,
332
                                               superblock_index);
333
                        insert_mb_into_sb(&sb, mb, i);
334
                    }
335
                }
336
            } else if (frame_flags & (1 << 16)) {
337
                while (can_safely_read(&gb, 1) && !get_bits1(&gb)) {
338
                    mb = decode_macroblock(s, &gb, &cb_index, superblock_index);
339
                    insert_mb_into_sb(&sb, mb, get_bits(&gb, 4));
340
                }
341
            }
342

  
343
            copy_superblock(new_frame_data, new_stride, sb.pixels, 8);
344
        }
345

  
346
        superblock_col_index++;
347
        new_frame_data += 8;
348
        if (old_frame_data)
349
            old_frame_data += 8;
350
        if (superblock_col_index == superblocks_per_row) {
351
            new_frame_data += new_stride * 8 - superblocks_per_row * 8;
352
            if (old_frame_data)
353
                old_frame_data += old_stride * 8 - superblocks_per_row * 8;
354
            superblock_col_index = 0;
355
        }
356
        skip--;
357
    }
358

  
359
    av_log(NULL, AV_LOG_DEBUG,
360
           "Escape sizes: %i, %i, %i\n",
361
           frame_size, buf_size, get_bits_count(&gb) / 8);
362

  
363
    if (s->frame.data[0])
364
        avctx->release_buffer(avctx, &s->frame);
365

  
366
    *(AVFrame*)data = s->frame = new_frame;
367
    *data_size = sizeof(AVFrame);
368

  
369
    return frame_size;
370
}
371

  
372

  
373
AVCodec escape124_decoder = {
374
    "escape124",
375
    CODEC_TYPE_VIDEO,
376
    CODEC_ID_ESCAPE124,
377
    sizeof(Escape124Context),
378
    escape124_decode_init,
379
    NULL,
380
    escape124_decode_close,
381
    escape124_decode_frame,
382
    CODEC_CAP_DR1,
383
};
384

  

Also available in: Unified diff