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ffmpeg / libavcodec / dvdsubdec.c @ 28e7453c

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1
/*
2
 * DVD subtitle decoding for ffmpeg
3
 * Copyright (c) 2005 Fabrice Bellard.
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
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20
 */
21
#include "avcodec.h"
22
#include "bitstream.h"
23
#include "colorspace.h"
24
#include "dsputil.h"
25

    
26
//#define DEBUG
27

    
28
static void yuv_a_to_rgba(const uint8_t *ycbcr, const uint8_t *alpha, uint32_t *rgba, int num_values)
29
{
30
    uint8_t *cm = ff_cropTbl + MAX_NEG_CROP;
31
    uint8_t r, g, b;
32
    int i, y, cb, cr;
33
    int r_add, g_add, b_add;
34

    
35
    for (i = num_values; i > 0; i--) {
36
        y = *ycbcr++;
37
        cb = *ycbcr++;
38
        cr = *ycbcr++;
39
        YUV_TO_RGB1_CCIR(cb, cr);
40
        YUV_TO_RGB2_CCIR(r, g, b, y);
41
        *rgba++ = (*alpha++ << 24) | (r << 16) | (g << 8) | b;
42
    }
43
}
44

    
45
static int decode_run_2bit(GetBitContext *gb, int *color)
46
{
47
    unsigned int v, t;
48

    
49
    v = 0;
50
    for (t = 1; v < t && t <= 0x40; t <<= 2)
51
        v = (v << 4) | get_bits(gb, 4);
52
    *color = v & 3;
53
    if (v < 4) { /* Code for fill rest of line */
54
        return INT_MAX;
55
    }
56
    return v >> 2;
57
}
58

    
59
static int decode_run_8bit(GetBitContext *gb, int *color)
60
{
61
    int len;
62
    int has_run = get_bits1(gb);
63
    if (get_bits1(gb))
64
        *color = get_bits(gb, 8);
65
    else
66
        *color = get_bits(gb, 2);
67
    if (has_run) {
68
        if (get_bits1(gb)) {
69
            len = get_bits(gb, 7);
70
            if (len == 0)
71
                len = INT_MAX;
72
            else
73
                len += 9;
74
        } else
75
            len = get_bits(gb, 3) + 2;
76
    } else
77
        len = 1;
78
    return len;
79
}
80

    
81
static int decode_rle(uint8_t *bitmap, int linesize, int w, int h,
82
                      const uint8_t *buf, int start, int buf_size, int is_8bit)
83
{
84
    GetBitContext gb;
85
    int bit_len;
86
    int x, y, len, color;
87
    uint8_t *d;
88

    
89
    bit_len = (buf_size - start) * 8;
90
    init_get_bits(&gb, buf + start, bit_len);
91

    
92
    x = 0;
93
    y = 0;
94
    d = bitmap;
95
    for(;;) {
96
        if (get_bits_count(&gb) > bit_len)
97
            return -1;
98
        if (is_8bit)
99
            len = decode_run_8bit(&gb, &color);
100
        else
101
            len = decode_run_2bit(&gb, &color);
102
        len = FFMIN(len, w - x);
103
        memset(d + x, color, len);
104
        x += len;
105
        if (x >= w) {
106
            y++;
107
            if (y >= h)
108
                break;
109
            d += linesize;
110
            x = 0;
111
            /* byte align */
112
            align_get_bits(&gb);
113
        }
114
    }
115
    return 0;
116
}
117

    
118
static void guess_palette(uint32_t *rgba_palette,
119
                          uint8_t *colormap,
120
                          uint8_t *alpha,
121
                          uint32_t subtitle_color)
122
{
123
    uint8_t color_used[16];
124
    int nb_opaque_colors, i, level, j, r, g, b;
125

    
126
    for(i = 0; i < 4; i++)
127
        rgba_palette[i] = 0;
128

    
129
    memset(color_used, 0, 16);
130
    nb_opaque_colors = 0;
131
    for(i = 0; i < 4; i++) {
132
        if (alpha[i] != 0 && !color_used[colormap[i]]) {
133
            color_used[colormap[i]] = 1;
134
            nb_opaque_colors++;
135
        }
136
    }
137

    
138
    if (nb_opaque_colors == 0)
139
        return;
140

    
141
    j = nb_opaque_colors;
142
    memset(color_used, 0, 16);
143
    for(i = 0; i < 4; i++) {
144
        if (alpha[i] != 0) {
145
            if (!color_used[colormap[i]])  {
146
                level = (0xff * j) / nb_opaque_colors;
147
                r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
148
                g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
149
                b = (((subtitle_color >> 0) & 0xff) * level) >> 8;
150
                rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);
151
                color_used[colormap[i]] = (i + 1);
152
                j--;
153
            } else {
154
                rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) |
155
                                    ((alpha[i] * 17) << 24);
156
            }
157
        }
158
    }
159
}
160

    
161
#define READ_OFFSET(a) (big_offsets ? AV_RB32(a) : AV_RB16(a))
162

    
163
static int decode_dvd_subtitles(AVSubtitle *sub_header,
164
                                const uint8_t *buf, int buf_size)
165
{
166
    int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;
167
    int big_offsets, offset_size, is_8bit = 0;
168
    const uint8_t *yuv_palette = 0;
169
    uint8_t colormap[4], alpha[256];
170
    int date;
171
    int i;
172
    int is_menu = 0;
173

    
174
    if (buf_size < 10)
175
        return -1;
176
    sub_header->rects = NULL;
177
    sub_header->num_rects = 0;
178
    sub_header->start_display_time = 0;
179
    sub_header->end_display_time = 0;
180

    
181
    if (AV_RB16(buf) == 0) {   /* HD subpicture with 4-byte offsets */
182
        big_offsets = 1;
183
        offset_size = 4;
184
        cmd_pos = 6;
185
    } else {
186
        big_offsets = 0;
187
        offset_size = 2;
188
        cmd_pos = 2;
189
    }
190

    
191
    cmd_pos = READ_OFFSET(buf + cmd_pos);
192

    
193
    while ((cmd_pos + 2 + offset_size) < buf_size) {
194
        date = AV_RB16(buf + cmd_pos);
195
        next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);
196
#ifdef DEBUG
197
        av_log(NULL, AV_LOG_INFO, "cmd_pos=0x%04x next=0x%04x date=%d\n",
198
               cmd_pos, next_cmd_pos, date);
199
#endif
200
        pos = cmd_pos + 2 + offset_size;
201
        offset1 = -1;
202
        offset2 = -1;
203
        x1 = y1 = x2 = y2 = 0;
204
        while (pos < buf_size) {
205
            cmd = buf[pos++];
206
#ifdef DEBUG
207
            av_log(NULL, AV_LOG_INFO, "cmd=%02x\n", cmd);
208
#endif
209
            switch(cmd) {
210
            case 0x00:
211
                /* menu subpicture */
212
                is_menu = 1;
213
                break;
214
            case 0x01:
215
                /* set start date */
216
                sub_header->start_display_time = (date << 10) / 90;
217
                break;
218
            case 0x02:
219
                /* set end date */
220
                sub_header->end_display_time = (date << 10) / 90;
221
                break;
222
            case 0x03:
223
                /* set colormap */
224
                if ((buf_size - pos) < 2)
225
                    goto fail;
226
                colormap[3] = buf[pos] >> 4;
227
                colormap[2] = buf[pos] & 0x0f;
228
                colormap[1] = buf[pos + 1] >> 4;
229
                colormap[0] = buf[pos + 1] & 0x0f;
230
                pos += 2;
231
                break;
232
            case 0x04:
233
                /* set alpha */
234
                if ((buf_size - pos) < 2)
235
                    goto fail;
236
                alpha[3] = buf[pos] >> 4;
237
                alpha[2] = buf[pos] & 0x0f;
238
                alpha[1] = buf[pos + 1] >> 4;
239
                alpha[0] = buf[pos + 1] & 0x0f;
240
                pos += 2;
241
#ifdef DEBUG
242
            av_log(NULL, AV_LOG_INFO, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
243
#endif
244
                break;
245
            case 0x05:
246
            case 0x85:
247
                if ((buf_size - pos) < 6)
248
                    goto fail;
249
                x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
250
                x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
251
                y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
252
                y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
253
                if (cmd & 0x80)
254
                    is_8bit = 1;
255
#ifdef DEBUG
256
                av_log(NULL, AV_LOG_INFO, "x1=%d x2=%d y1=%d y2=%d\n",
257
                       x1, x2, y1, y2);
258
#endif
259
                pos += 6;
260
                break;
261
            case 0x06:
262
                if ((buf_size - pos) < 4)
263
                    goto fail;
264
                offset1 = AV_RB16(buf + pos);
265
                offset2 = AV_RB16(buf + pos + 2);
266
#ifdef DEBUG
267
                av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
268
#endif
269
                pos += 4;
270
                break;
271
            case 0x86:
272
                if ((buf_size - pos) < 8)
273
                    goto fail;
274
                offset1 = AV_RB32(buf + pos);
275
                offset2 = AV_RB32(buf + pos + 4);
276
#ifdef DEBUG
277
                av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
278
#endif
279
                pos += 8;
280
                break;
281

    
282
            case 0x83:
283
                /* HD set palette */
284
                if ((buf_size - pos) < 768)
285
                    goto fail;
286
                yuv_palette = buf + pos;
287
                pos += 768;
288
                break;
289
            case 0x84:
290
                /* HD set contrast (alpha) */
291
                if ((buf_size - pos) < 256)
292
                    goto fail;
293
                for (i = 0; i < 256; i++)
294
                    alpha[i] = 0xFF - buf[pos+i];
295
                pos += 256;
296
                break;
297

    
298
            case 0xff:
299
                goto the_end;
300
            default:
301
#ifdef DEBUG
302
                av_log(NULL, AV_LOG_INFO, "unrecognised subpicture command 0x%x\n", cmd);
303
#endif
304
                goto the_end;
305
            }
306
        }
307
    the_end:
308
        if (offset1 >= 0) {
309
            int w, h;
310
            uint8_t *bitmap;
311

    
312
            /* decode the bitmap */
313
            w = x2 - x1 + 1;
314
            if (w < 0)
315
                w = 0;
316
            h = y2 - y1;
317
            if (h < 0)
318
                h = 0;
319
            if (w > 0 && h > 0) {
320
                if (sub_header->rects != NULL) {
321
                    for (i = 0; i < sub_header->num_rects; i++) {
322
                        av_free(sub_header->rects[i].bitmap);
323
                        av_free(sub_header->rects[i].rgba_palette);
324
                    }
325
                    av_freep(&sub_header->rects);
326
                    sub_header->num_rects = 0;
327
                }
328

    
329
                bitmap = av_malloc(w * h);
330
                sub_header->rects = av_mallocz(sizeof(AVSubtitleRect));
331
                sub_header->num_rects = 1;
332
                sub_header->rects[0].bitmap = bitmap;
333
                decode_rle(bitmap, w * 2, w, (h + 1) / 2,
334
                           buf, offset1, buf_size, is_8bit);
335
                decode_rle(bitmap + w, w * 2, w, h / 2,
336
                           buf, offset2, buf_size, is_8bit);
337
                if (is_8bit) {
338
                    if (yuv_palette == 0)
339
                        goto fail;
340
                    sub_header->rects[0].rgba_palette = av_malloc(256 * 4);
341
                    sub_header->rects[0].nb_colors = 256;
342
                    yuv_a_to_rgba(yuv_palette, alpha, sub_header->rects[0].rgba_palette, 256);
343
                } else {
344
                    sub_header->rects[0].rgba_palette = av_malloc(4 * 4);
345
                    sub_header->rects[0].nb_colors = 4;
346
                    guess_palette(sub_header->rects[0].rgba_palette,
347
                                  colormap, alpha, 0xffff00);
348
                }
349
                sub_header->rects[0].x = x1;
350
                sub_header->rects[0].y = y1;
351
                sub_header->rects[0].w = w;
352
                sub_header->rects[0].h = h;
353
                sub_header->rects[0].linesize = w;
354
            }
355
        }
356
        if (next_cmd_pos == cmd_pos)
357
            break;
358
        cmd_pos = next_cmd_pos;
359
    }
360
    if (sub_header->num_rects > 0)
361
        return is_menu;
362
 fail:
363
    if (sub_header->rects != NULL) {
364
        for (i = 0; i < sub_header->num_rects; i++) {
365
            av_free(sub_header->rects[i].bitmap);
366
            av_free(sub_header->rects[i].rgba_palette);
367
        }
368
        av_freep(&sub_header->rects);
369
        sub_header->num_rects = 0;
370
    }
371
    return -1;
372
}
373

    
374
static int is_transp(const uint8_t *buf, int pitch, int n,
375
                     const uint8_t *transp_color)
376
{
377
    int i;
378
    for(i = 0; i < n; i++) {
379
        if (!transp_color[*buf])
380
            return 0;
381
        buf += pitch;
382
    }
383
    return 1;
384
}
385

    
386
/* return 0 if empty rectangle, 1 if non empty */
387
static int find_smallest_bounding_rectangle(AVSubtitle *s)
388
{
389
    uint8_t transp_color[256];
390
    int y1, y2, x1, x2, y, w, h, i;
391
    uint8_t *bitmap;
392

    
393
    if (s->num_rects == 0 || s->rects == NULL || s->rects[0].w <= 0 || s->rects[0].h <= 0)
394
        return 0;
395

    
396
    memset(transp_color, 0, 256);
397
    for(i = 0; i < s->rects[0].nb_colors; i++) {
398
        if ((s->rects[0].rgba_palette[i] >> 24) == 0)
399
            transp_color[i] = 1;
400
    }
401
    y1 = 0;
402
    while (y1 < s->rects[0].h && is_transp(s->rects[0].bitmap + y1 * s->rects[0].linesize,
403
                                  1, s->rects[0].w, transp_color))
404
        y1++;
405
    if (y1 == s->rects[0].h) {
406
        av_freep(&s->rects[0].bitmap);
407
        s->rects[0].w = s->rects[0].h = 0;
408
        return 0;
409
    }
410

    
411
    y2 = s->rects[0].h - 1;
412
    while (y2 > 0 && is_transp(s->rects[0].bitmap + y2 * s->rects[0].linesize, 1,
413
                               s->rects[0].w, transp_color))
414
        y2--;
415
    x1 = 0;
416
    while (x1 < (s->rects[0].w - 1) && is_transp(s->rects[0].bitmap + x1, s->rects[0].linesize,
417
                                        s->rects[0].h, transp_color))
418
        x1++;
419
    x2 = s->rects[0].w - 1;
420
    while (x2 > 0 && is_transp(s->rects[0].bitmap + x2, s->rects[0].linesize, s->rects[0].h,
421
                                  transp_color))
422
        x2--;
423
    w = x2 - x1 + 1;
424
    h = y2 - y1 + 1;
425
    bitmap = av_malloc(w * h);
426
    if (!bitmap)
427
        return 1;
428
    for(y = 0; y < h; y++) {
429
        memcpy(bitmap + w * y, s->rects[0].bitmap + x1 + (y1 + y) * s->rects[0].linesize, w);
430
    }
431
    av_freep(&s->rects[0].bitmap);
432
    s->rects[0].bitmap = bitmap;
433
    s->rects[0].linesize = w;
434
    s->rects[0].w = w;
435
    s->rects[0].h = h;
436
    s->rects[0].x += x1;
437
    s->rects[0].y += y1;
438
    return 1;
439
}
440

    
441
#ifdef DEBUG
442
#undef fprintf
443
static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
444
                     uint32_t *rgba_palette)
445
{
446
    int x, y, v;
447
    FILE *f;
448

    
449
    f = fopen(filename, "w");
450
    if (!f) {
451
        perror(filename);
452
        exit(1);
453
    }
454
    fprintf(f, "P6\n"
455
            "%d %d\n"
456
            "%d\n",
457
            w, h, 255);
458
    for(y = 0; y < h; y++) {
459
        for(x = 0; x < w; x++) {
460
            v = rgba_palette[bitmap[y * w + x]];
461
            putc((v >> 16) & 0xff, f);
462
            putc((v >> 8) & 0xff, f);
463
            putc((v >> 0) & 0xff, f);
464
        }
465
    }
466
    fclose(f);
467
}
468
#endif
469

    
470
static int dvdsub_decode(AVCodecContext *avctx,
471
                         void *data, int *data_size,
472
                         uint8_t *buf, int buf_size)
473
{
474
    AVSubtitle *sub = (void *)data;
475
    int is_menu;
476

    
477
    is_menu = decode_dvd_subtitles(sub, buf, buf_size);
478

    
479
    if (is_menu < 0) {
480
    no_subtitle:
481
        *data_size = 0;
482

    
483
        return buf_size;
484
    }
485
    if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
486
        goto no_subtitle;
487

    
488
#if defined(DEBUG)
489
    av_log(NULL, AV_LOG_INFO, "start=%d ms end =%d ms\n",
490
           sub->start_display_time,
491
           sub->end_display_time);
492
    ppm_save("/tmp/a.ppm", sub->rects[0].bitmap,
493
             sub->rects[0].w, sub->rects[0].h, sub->rects[0].rgba_palette);
494
#endif
495

    
496
    *data_size = 1;
497
    return buf_size;
498
}
499

    
500
AVCodec dvdsub_decoder = {
501
    "dvdsub",
502
    CODEC_TYPE_SUBTITLE,
503
    CODEC_ID_DVD_SUBTITLE,
504
    0,
505
    NULL,
506
    NULL,
507
    NULL,
508
    dvdsub_decode,
509
};