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ffmpeg / libavcodec / dvdsubdec.c @ 1aadf63f

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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
 *
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 * 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 dvdsub_init_decoder(AVCodecContext *avctx)
46
{
47
    return 0;
48
}
49

    
50
static int decode_run_2bit(GetBitContext *gb, int *color)
51
{
52
    unsigned int v, t;
53

    
54
    v = 0;
55
    for (t = 1; v < t && t <= 0x40; t <<= 2)
56
        v = (v << 4) | get_bits(gb, 4);
57
    *color = v & 3;
58
    if (v < 4) { /* Code for fill rest of line */
59
        return INT_MAX;
60
    }
61
    return v >> 2;
62
}
63

    
64
static int decode_run_8bit(GetBitContext *gb, int *color)
65
{
66
    int len;
67
    int has_run = get_bits1(gb);
68
    if (get_bits1(gb))
69
        *color = get_bits(gb, 8);
70
    else
71
        *color = get_bits(gb, 2);
72
    if (has_run) {
73
        if (get_bits1(gb)) {
74
            len = get_bits(gb, 7);
75
            if (len == 0)
76
                len = INT_MAX;
77
            else
78
                len += 9;
79
        } else
80
            len = get_bits(gb, 3) + 2;
81
    } else
82
        len = 1;
83
    return len;
84
}
85

    
86
static int decode_rle(uint8_t *bitmap, int linesize, int w, int h,
87
                      const uint8_t *buf, int start, int buf_size, int is_8bit)
88
{
89
    GetBitContext gb;
90
    int bit_len;
91
    int x, y, len, color;
92
    uint8_t *d;
93

    
94
    bit_len = (buf_size - start) * 8;
95
    init_get_bits(&gb, buf + start, bit_len);
96

    
97
    x = 0;
98
    y = 0;
99
    d = bitmap;
100
    for(;;) {
101
        if (get_bits_count(&gb) > bit_len)
102
            return -1;
103
        if (is_8bit)
104
            len = decode_run_8bit(&gb, &color);
105
        else
106
            len = decode_run_2bit(&gb, &color);
107
        len = FFMIN(len, w - x);
108
        memset(d + x, color, len);
109
        x += len;
110
        if (x >= w) {
111
            y++;
112
            if (y >= h)
113
                break;
114
            d += linesize;
115
            x = 0;
116
            /* byte align */
117
            align_get_bits(&gb);
118
        }
119
    }
120
    return 0;
121
}
122

    
123
static void guess_palette(uint32_t *rgba_palette,
124
                          uint8_t *colormap,
125
                          uint8_t *alpha,
126
                          uint32_t subtitle_color)
127
{
128
    uint8_t color_used[16];
129
    int nb_opaque_colors, i, level, j, r, g, b;
130

    
131
    for(i = 0; i < 4; i++)
132
        rgba_palette[i] = 0;
133

    
134
    memset(color_used, 0, 16);
135
    nb_opaque_colors = 0;
136
    for(i = 0; i < 4; i++) {
137
        if (alpha[i] != 0 && !color_used[colormap[i]]) {
138
            color_used[colormap[i]] = 1;
139
            nb_opaque_colors++;
140
        }
141
    }
142

    
143
    if (nb_opaque_colors == 0)
144
        return;
145

    
146
    j = nb_opaque_colors;
147
    memset(color_used, 0, 16);
148
    for(i = 0; i < 4; i++) {
149
        if (alpha[i] != 0) {
150
            if (!color_used[colormap[i]])  {
151
                level = (0xff * j) / nb_opaque_colors;
152
                r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
153
                g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
154
                b = (((subtitle_color >> 0) & 0xff) * level) >> 8;
155
                rgba_palette[i] = b | (g << 8) | (r << 16) | ((alpha[i] * 17) << 24);
156
                color_used[colormap[i]] = (i + 1);
157
                j--;
158
            } else {
159
                rgba_palette[i] = (rgba_palette[color_used[colormap[i]] - 1] & 0x00ffffff) |
160
                                    ((alpha[i] * 17) << 24);
161
            }
162
        }
163
    }
164
}
165

    
166
#define READ_OFFSET(a) (big_offsets ? AV_RB32(a) : AV_RB16(a))
167

    
168
static int decode_dvd_subtitles(AVSubtitle *sub_header,
169
                                const uint8_t *buf, int buf_size)
170
{
171
    int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;
172
    int big_offsets, offset_size, is_8bit = 0;
173
    const uint8_t *yuv_palette = 0;
174
    uint8_t colormap[4], alpha[256];
175
    int date;
176
    int i;
177
    int is_menu = 0;
178

    
179
    if (buf_size < 10)
180
        return -1;
181
    sub_header->rects = NULL;
182
    sub_header->num_rects = 0;
183
    sub_header->start_display_time = 0;
184
    sub_header->end_display_time = 0;
185

    
186
    if (AV_RB16(buf) == 0) {   /* HD subpicture with 4-byte offsets */
187
        big_offsets = 1;
188
        offset_size = 4;
189
        cmd_pos = 6;
190
    } else {
191
        big_offsets = 0;
192
        offset_size = 2;
193
        cmd_pos = 2;
194
    }
195

    
196
    cmd_pos = READ_OFFSET(buf + cmd_pos);
197

    
198
    while ((cmd_pos + 2 + offset_size) < buf_size) {
199
        date = AV_RB16(buf + cmd_pos);
200
        next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);
201
#ifdef DEBUG
202
        av_log(NULL, AV_LOG_INFO, "cmd_pos=0x%04x next=0x%04x date=%d\n",
203
               cmd_pos, next_cmd_pos, date);
204
#endif
205
        pos = cmd_pos + 2 + offset_size;
206
        offset1 = -1;
207
        offset2 = -1;
208
        x1 = y1 = x2 = y2 = 0;
209
        while (pos < buf_size) {
210
            cmd = buf[pos++];
211
#ifdef DEBUG
212
            av_log(NULL, AV_LOG_INFO, "cmd=%02x\n", cmd);
213
#endif
214
            switch(cmd) {
215
            case 0x00:
216
                /* menu subpicture */
217
                is_menu = 1;
218
                break;
219
            case 0x01:
220
                /* set start date */
221
                sub_header->start_display_time = (date << 10) / 90;
222
                break;
223
            case 0x02:
224
                /* set end date */
225
                sub_header->end_display_time = (date << 10) / 90;
226
                break;
227
            case 0x03:
228
                /* set colormap */
229
                if ((buf_size - pos) < 2)
230
                    goto fail;
231
                colormap[3] = buf[pos] >> 4;
232
                colormap[2] = buf[pos] & 0x0f;
233
                colormap[1] = buf[pos + 1] >> 4;
234
                colormap[0] = buf[pos + 1] & 0x0f;
235
                pos += 2;
236
                break;
237
            case 0x04:
238
                /* set alpha */
239
                if ((buf_size - pos) < 2)
240
                    goto fail;
241
                alpha[3] = buf[pos] >> 4;
242
                alpha[2] = buf[pos] & 0x0f;
243
                alpha[1] = buf[pos + 1] >> 4;
244
                alpha[0] = buf[pos + 1] & 0x0f;
245
                pos += 2;
246
#ifdef DEBUG
247
            av_log(NULL, AV_LOG_INFO, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
248
#endif
249
                break;
250
            case 0x05:
251
            case 0x85:
252
                if ((buf_size - pos) < 6)
253
                    goto fail;
254
                x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
255
                x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
256
                y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
257
                y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
258
                if (cmd & 0x80)
259
                    is_8bit = 1;
260
#ifdef DEBUG
261
                av_log(NULL, AV_LOG_INFO, "x1=%d x2=%d y1=%d y2=%d\n",
262
                       x1, x2, y1, y2);
263
#endif
264
                pos += 6;
265
                break;
266
            case 0x06:
267
                if ((buf_size - pos) < 4)
268
                    goto fail;
269
                offset1 = AV_RB16(buf + pos);
270
                offset2 = AV_RB16(buf + pos + 2);
271
#ifdef DEBUG
272
                av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
273
#endif
274
                pos += 4;
275
                break;
276
            case 0x86:
277
                if ((buf_size - pos) < 8)
278
                    goto fail;
279
                offset1 = AV_RB32(buf + pos);
280
                offset2 = AV_RB32(buf + pos + 4);
281
#ifdef DEBUG
282
                av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
283
#endif
284
                pos += 8;
285
                break;
286

    
287
            case 0x83:
288
                /* HD set palette */
289
                if ((buf_size - pos) < 768)
290
                    goto fail;
291
                yuv_palette = buf + pos;
292
                pos += 768;
293
                break;
294
            case 0x84:
295
                /* HD set contrast (alpha) */
296
                if ((buf_size - pos) < 256)
297
                    goto fail;
298
                for (i = 0; i < 256; i++)
299
                    alpha[i] = 0xFF - buf[pos+i];
300
                pos += 256;
301
                break;
302

    
303
            case 0xff:
304
                goto the_end;
305
            default:
306
#ifdef DEBUG
307
                av_log(NULL, AV_LOG_INFO, "unrecognised subpicture command 0x%x\n", cmd);
308
#endif
309
                goto the_end;
310
            }
311
        }
312
    the_end:
313
        if (offset1 >= 0) {
314
            int w, h;
315
            uint8_t *bitmap;
316

    
317
            /* decode the bitmap */
318
            w = x2 - x1 + 1;
319
            if (w < 0)
320
                w = 0;
321
            h = y2 - y1;
322
            if (h < 0)
323
                h = 0;
324
            if (w > 0 && h > 0) {
325
                if (sub_header->rects != NULL) {
326
                    for (i = 0; i < sub_header->num_rects; i++) {
327
                        av_free(sub_header->rects[i].bitmap);
328
                        av_free(sub_header->rects[i].rgba_palette);
329
                    }
330
                    av_freep(&sub_header->rects);
331
                    sub_header->num_rects = 0;
332
                }
333

    
334
                bitmap = av_malloc(w * h);
335
                sub_header->rects = av_mallocz(sizeof(AVSubtitleRect));
336
                sub_header->num_rects = 1;
337
                sub_header->rects[0].bitmap = bitmap;
338
                decode_rle(bitmap, w * 2, w, (h + 1) / 2,
339
                           buf, offset1, buf_size, is_8bit);
340
                decode_rle(bitmap + w, w * 2, w, h / 2,
341
                           buf, offset2, buf_size, is_8bit);
342
                if (is_8bit) {
343
                    if (yuv_palette == 0)
344
                        goto fail;
345
                    sub_header->rects[0].rgba_palette = av_malloc(256 * 4);
346
                    sub_header->rects[0].nb_colors = 256;
347
                    yuv_a_to_rgba(yuv_palette, alpha, sub_header->rects[0].rgba_palette, 256);
348
                } else {
349
                    sub_header->rects[0].rgba_palette = av_malloc(4 * 4);
350
                    sub_header->rects[0].nb_colors = 4;
351
                guess_palette(sub_header->rects[0].rgba_palette,
352
                              colormap, alpha, 0xffff00);
353
                }
354
                sub_header->rects[0].x = x1;
355
                sub_header->rects[0].y = y1;
356
                sub_header->rects[0].w = w;
357
                sub_header->rects[0].h = h;
358
                sub_header->rects[0].linesize = w;
359
            }
360
        }
361
        if (next_cmd_pos == cmd_pos)
362
            break;
363
        cmd_pos = next_cmd_pos;
364
    }
365
    if (sub_header->num_rects > 0)
366
        return is_menu;
367
 fail:
368
    if (sub_header->rects != NULL) {
369
        for (i = 0; i < sub_header->num_rects; i++) {
370
            av_free(sub_header->rects[i].bitmap);
371
            av_free(sub_header->rects[i].rgba_palette);
372
        }
373
        av_freep(&sub_header->rects);
374
        sub_header->num_rects = 0;
375
    }
376
    return -1;
377
}
378

    
379
static int is_transp(const uint8_t *buf, int pitch, int n,
380
                     const uint8_t *transp_color)
381
{
382
    int i;
383
    for(i = 0; i < n; i++) {
384
        if (!transp_color[*buf])
385
            return 0;
386
        buf += pitch;
387
    }
388
    return 1;
389
}
390

    
391
/* return 0 if empty rectangle, 1 if non empty */
392
static int find_smallest_bounding_rectangle(AVSubtitle *s)
393
{
394
    uint8_t transp_color[256];
395
    int y1, y2, x1, x2, y, w, h, i;
396
    uint8_t *bitmap;
397

    
398
    if (s->num_rects == 0 || s->rects == NULL || s->rects[0].w <= 0 || s->rects[0].h <= 0)
399
        return 0;
400

    
401
    memset(transp_color, 0, 256);
402
    for(i = 0; i < s->rects[0].nb_colors; i++) {
403
        if ((s->rects[0].rgba_palette[i] >> 24) == 0)
404
            transp_color[i] = 1;
405
    }
406
    y1 = 0;
407
    while (y1 < s->rects[0].h && is_transp(s->rects[0].bitmap + y1 * s->rects[0].linesize,
408
                                  1, s->rects[0].w, transp_color))
409
        y1++;
410
    if (y1 == s->rects[0].h) {
411
        av_freep(&s->rects[0].bitmap);
412
        s->rects[0].w = s->rects[0].h = 0;
413
        return 0;
414
    }
415

    
416
    y2 = s->rects[0].h - 1;
417
    while (y2 > 0 && is_transp(s->rects[0].bitmap + y2 * s->rects[0].linesize, 1,
418
                               s->rects[0].w, transp_color))
419
        y2--;
420
    x1 = 0;
421
    while (x1 < (s->rects[0].w - 1) && is_transp(s->rects[0].bitmap + x1, s->rects[0].linesize,
422
                                        s->rects[0].h, transp_color))
423
        x1++;
424
    x2 = s->rects[0].w - 1;
425
    while (x2 > 0 && is_transp(s->rects[0].bitmap + x2, s->rects[0].linesize, s->rects[0].h,
426
                                  transp_color))
427
        x2--;
428
    w = x2 - x1 + 1;
429
    h = y2 - y1 + 1;
430
    bitmap = av_malloc(w * h);
431
    if (!bitmap)
432
        return 1;
433
    for(y = 0; y < h; y++) {
434
        memcpy(bitmap + w * y, s->rects[0].bitmap + x1 + (y1 + y) * s->rects[0].linesize, w);
435
    }
436
    av_freep(&s->rects[0].bitmap);
437
    s->rects[0].bitmap = bitmap;
438
    s->rects[0].linesize = w;
439
    s->rects[0].w = w;
440
    s->rects[0].h = h;
441
    s->rects[0].x += x1;
442
    s->rects[0].y += y1;
443
    return 1;
444
}
445

    
446
static int dvdsub_close_decoder(AVCodecContext *avctx)
447
{
448
    return 0;
449
}
450

    
451
#ifdef DEBUG
452
#undef fprintf
453
static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
454
                     uint32_t *rgba_palette)
455
{
456
    int x, y, v;
457
    FILE *f;
458

    
459
    f = fopen(filename, "w");
460
    if (!f) {
461
        perror(filename);
462
        exit(1);
463
    }
464
    fprintf(f, "P6\n"
465
            "%d %d\n"
466
            "%d\n",
467
            w, h, 255);
468
    for(y = 0; y < h; y++) {
469
        for(x = 0; x < w; x++) {
470
            v = rgba_palette[bitmap[y * w + x]];
471
            putc((v >> 16) & 0xff, f);
472
            putc((v >> 8) & 0xff, f);
473
            putc((v >> 0) & 0xff, f);
474
        }
475
    }
476
    fclose(f);
477
}
478
#endif
479

    
480
static int dvdsub_decode(AVCodecContext *avctx,
481
                         void *data, int *data_size,
482
                         uint8_t *buf, int buf_size)
483
{
484
    AVSubtitle *sub = (void *)data;
485
    int is_menu;
486

    
487
    is_menu = decode_dvd_subtitles(sub, buf, buf_size);
488

    
489
    if (is_menu < 0) {
490
    no_subtitle:
491
        *data_size = 0;
492

    
493
        return buf_size;
494
    }
495
    if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
496
        goto no_subtitle;
497

    
498
#if defined(DEBUG)
499
    av_log(NULL, AV_LOG_INFO, "start=%d ms end =%d ms\n",
500
           sub->start_display_time,
501
           sub->end_display_time);
502
    ppm_save("/tmp/a.ppm", sub->rects[0].bitmap,
503
             sub->rects[0].w, sub->rects[0].h, sub->rects[0].rgba_palette);
504
#endif
505

    
506
    *data_size = 1;
507
    return buf_size;
508
}
509

    
510
AVCodec dvdsub_decoder = {
511
    "dvdsub",
512
    CODEC_TYPE_SUBTITLE,
513
    CODEC_ID_DVD_SUBTITLE,
514
    0,
515
    dvdsub_init_decoder,
516
    NULL,
517
    dvdsub_close_decoder,
518
    dvdsub_decode,
519
};