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ffmpeg / libavcodec / dvdsubdec.c @ 2912e87a

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1
/*
2
 * DVD subtitle decoding for ffmpeg
3
 * Copyright (c) 2005 Fabrice Bellard
4
 *
5
 * This file is part of Libav.
6
 *
7
 * Libav 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
 * Libav 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 Libav; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "avcodec.h"
22
#include "get_bits.h"
23
#include "dsputil.h"
24
#include "libavutil/colorspace.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,
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                          uint8_t *alpha,
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                          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
    memset(sub_header, 0, sizeof(*sub_header));
177

    
178
    if (AV_RB16(buf) == 0) {   /* HD subpicture with 4-byte offsets */
179
        big_offsets = 1;
180
        offset_size = 4;
181
        cmd_pos = 6;
182
    } else {
183
        big_offsets = 0;
184
        offset_size = 2;
185
        cmd_pos = 2;
186
    }
187

    
188
    cmd_pos = READ_OFFSET(buf + cmd_pos);
189

    
190
    while (cmd_pos > 0 && cmd_pos < buf_size - 2 - offset_size) {
191
        date = AV_RB16(buf + cmd_pos);
192
        next_cmd_pos = READ_OFFSET(buf + cmd_pos + 2);
193
        av_dlog(NULL, "cmd_pos=0x%04x next=0x%04x date=%d\n",
194
                cmd_pos, next_cmd_pos, date);
195
        pos = cmd_pos + 2 + offset_size;
196
        offset1 = -1;
197
        offset2 = -1;
198
        x1 = y1 = x2 = y2 = 0;
199
        while (pos < buf_size) {
200
            cmd = buf[pos++];
201
            av_dlog(NULL, "cmd=%02x\n", cmd);
202
            switch(cmd) {
203
            case 0x00:
204
                /* menu subpicture */
205
                is_menu = 1;
206
                break;
207
            case 0x01:
208
                /* set start date */
209
                sub_header->start_display_time = (date << 10) / 90;
210
                break;
211
            case 0x02:
212
                /* set end date */
213
                sub_header->end_display_time = (date << 10) / 90;
214
                break;
215
            case 0x03:
216
                /* set colormap */
217
                if ((buf_size - pos) < 2)
218
                    goto fail;
219
                colormap[3] = buf[pos] >> 4;
220
                colormap[2] = buf[pos] & 0x0f;
221
                colormap[1] = buf[pos + 1] >> 4;
222
                colormap[0] = buf[pos + 1] & 0x0f;
223
                pos += 2;
224
                break;
225
            case 0x04:
226
                /* set alpha */
227
                if ((buf_size - pos) < 2)
228
                    goto fail;
229
                alpha[3] = buf[pos] >> 4;
230
                alpha[2] = buf[pos] & 0x0f;
231
                alpha[1] = buf[pos + 1] >> 4;
232
                alpha[0] = buf[pos + 1] & 0x0f;
233
                pos += 2;
234
            av_dlog(NULL, "alpha=%x%x%x%x\n", alpha[0],alpha[1],alpha[2],alpha[3]);
235
                break;
236
            case 0x05:
237
            case 0x85:
238
                if ((buf_size - pos) < 6)
239
                    goto fail;
240
                x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
241
                x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
242
                y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
243
                y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
244
                if (cmd & 0x80)
245
                    is_8bit = 1;
246
                av_dlog(NULL, "x1=%d x2=%d y1=%d y2=%d\n", x1, x2, y1, y2);
247
                pos += 6;
248
                break;
249
            case 0x06:
250
                if ((buf_size - pos) < 4)
251
                    goto fail;
252
                offset1 = AV_RB16(buf + pos);
253
                offset2 = AV_RB16(buf + pos + 2);
254
                av_dlog(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
255
                pos += 4;
256
                break;
257
            case 0x86:
258
                if ((buf_size - pos) < 8)
259
                    goto fail;
260
                offset1 = AV_RB32(buf + pos);
261
                offset2 = AV_RB32(buf + pos + 4);
262
                av_dlog(NULL, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
263
                pos += 8;
264
                break;
265

    
266
            case 0x83:
267
                /* HD set palette */
268
                if ((buf_size - pos) < 768)
269
                    goto fail;
270
                yuv_palette = buf + pos;
271
                pos += 768;
272
                break;
273
            case 0x84:
274
                /* HD set contrast (alpha) */
275
                if ((buf_size - pos) < 256)
276
                    goto fail;
277
                for (i = 0; i < 256; i++)
278
                    alpha[i] = 0xFF - buf[pos+i];
279
                pos += 256;
280
                break;
281

    
282
            case 0xff:
283
                goto the_end;
284
            default:
285
                av_dlog(NULL, "unrecognised subpicture command 0x%x\n", cmd);
286
                goto the_end;
287
            }
288
        }
289
    the_end:
290
        if (offset1 >= 0) {
291
            int w, h;
292
            uint8_t *bitmap;
293

    
294
            /* decode the bitmap */
295
            w = x2 - x1 + 1;
296
            if (w < 0)
297
                w = 0;
298
            h = y2 - y1;
299
            if (h < 0)
300
                h = 0;
301
            if (w > 0 && h > 0) {
302
                if (sub_header->rects != NULL) {
303
                    for (i = 0; i < sub_header->num_rects; i++) {
304
                        av_freep(&sub_header->rects[i]->pict.data[0]);
305
                        av_freep(&sub_header->rects[i]->pict.data[1]);
306
                        av_freep(&sub_header->rects[i]);
307
                    }
308
                    av_freep(&sub_header->rects);
309
                    sub_header->num_rects = 0;
310
                }
311

    
312
                bitmap = av_malloc(w * h);
313
                sub_header->rects = av_mallocz(sizeof(*sub_header->rects));
314
                sub_header->rects[0] = av_mallocz(sizeof(AVSubtitleRect));
315
                sub_header->num_rects = 1;
316
                sub_header->rects[0]->pict.data[0] = bitmap;
317
                decode_rle(bitmap, w * 2, w, (h + 1) / 2,
318
                           buf, offset1, buf_size, is_8bit);
319
                decode_rle(bitmap + w, w * 2, w, h / 2,
320
                           buf, offset2, buf_size, is_8bit);
321
                sub_header->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE);
322
                if (is_8bit) {
323
                    if (yuv_palette == 0)
324
                        goto fail;
325
                    sub_header->rects[0]->nb_colors = 256;
326
                    yuv_a_to_rgba(yuv_palette, alpha, (uint32_t*)sub_header->rects[0]->pict.data[1], 256);
327
                } else {
328
                    sub_header->rects[0]->nb_colors = 4;
329
                    guess_palette((uint32_t*)sub_header->rects[0]->pict.data[1],
330
                                  colormap, alpha, 0xffff00);
331
                }
332
                sub_header->rects[0]->x = x1;
333
                sub_header->rects[0]->y = y1;
334
                sub_header->rects[0]->w = w;
335
                sub_header->rects[0]->h = h;
336
                sub_header->rects[0]->type = SUBTITLE_BITMAP;
337
                sub_header->rects[0]->pict.linesize[0] = w;
338
            }
339
        }
340
        if (next_cmd_pos == cmd_pos)
341
            break;
342
        cmd_pos = next_cmd_pos;
343
    }
344
    if (sub_header->num_rects > 0)
345
        return is_menu;
346
 fail:
347
    if (sub_header->rects != NULL) {
348
        for (i = 0; i < sub_header->num_rects; i++) {
349
            av_freep(&sub_header->rects[i]->pict.data[0]);
350
            av_freep(&sub_header->rects[i]->pict.data[1]);
351
            av_freep(&sub_header->rects[i]);
352
        }
353
        av_freep(&sub_header->rects);
354
        sub_header->num_rects = 0;
355
    }
356
    return -1;
357
}
358

    
359
static int is_transp(const uint8_t *buf, int pitch, int n,
360
                     const uint8_t *transp_color)
361
{
362
    int i;
363
    for(i = 0; i < n; i++) {
364
        if (!transp_color[*buf])
365
            return 0;
366
        buf += pitch;
367
    }
368
    return 1;
369
}
370

    
371
/* return 0 if empty rectangle, 1 if non empty */
372
static int find_smallest_bounding_rectangle(AVSubtitle *s)
373
{
374
    uint8_t transp_color[256];
375
    int y1, y2, x1, x2, y, w, h, i;
376
    uint8_t *bitmap;
377

    
378
    if (s->num_rects == 0 || s->rects == NULL || s->rects[0]->w <= 0 || s->rects[0]->h <= 0)
379
        return 0;
380

    
381
    memset(transp_color, 0, 256);
382
    for(i = 0; i < s->rects[0]->nb_colors; i++) {
383
        if ((((uint32_t*)s->rects[0]->pict.data[1])[i] >> 24) == 0)
384
            transp_color[i] = 1;
385
    }
386
    y1 = 0;
387
    while (y1 < s->rects[0]->h && is_transp(s->rects[0]->pict.data[0] + y1 * s->rects[0]->pict.linesize[0],
388
                                  1, s->rects[0]->w, transp_color))
389
        y1++;
390
    if (y1 == s->rects[0]->h) {
391
        av_freep(&s->rects[0]->pict.data[0]);
392
        s->rects[0]->w = s->rects[0]->h = 0;
393
        return 0;
394
    }
395

    
396
    y2 = s->rects[0]->h - 1;
397
    while (y2 > 0 && is_transp(s->rects[0]->pict.data[0] + y2 * s->rects[0]->pict.linesize[0], 1,
398
                               s->rects[0]->w, transp_color))
399
        y2--;
400
    x1 = 0;
401
    while (x1 < (s->rects[0]->w - 1) && is_transp(s->rects[0]->pict.data[0] + x1, s->rects[0]->pict.linesize[0],
402
                                        s->rects[0]->h, transp_color))
403
        x1++;
404
    x2 = s->rects[0]->w - 1;
405
    while (x2 > 0 && is_transp(s->rects[0]->pict.data[0] + x2, s->rects[0]->pict.linesize[0], s->rects[0]->h,
406
                                  transp_color))
407
        x2--;
408
    w = x2 - x1 + 1;
409
    h = y2 - y1 + 1;
410
    bitmap = av_malloc(w * h);
411
    if (!bitmap)
412
        return 1;
413
    for(y = 0; y < h; y++) {
414
        memcpy(bitmap + w * y, s->rects[0]->pict.data[0] + x1 + (y1 + y) * s->rects[0]->pict.linesize[0], w);
415
    }
416
    av_freep(&s->rects[0]->pict.data[0]);
417
    s->rects[0]->pict.data[0] = bitmap;
418
    s->rects[0]->pict.linesize[0] = w;
419
    s->rects[0]->w = w;
420
    s->rects[0]->h = h;
421
    s->rects[0]->x += x1;
422
    s->rects[0]->y += y1;
423
    return 1;
424
}
425

    
426
#ifdef DEBUG
427
#undef fprintf
428
#undef perror
429
#undef exit
430
static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
431
                     uint32_t *rgba_palette)
432
{
433
    int x, y, v;
434
    FILE *f;
435

    
436
    f = fopen(filename, "w");
437
    if (!f) {
438
        perror(filename);
439
        exit(1);
440
    }
441
    fprintf(f, "P6\n"
442
            "%d %d\n"
443
            "%d\n",
444
            w, h, 255);
445
    for(y = 0; y < h; y++) {
446
        for(x = 0; x < w; x++) {
447
            v = rgba_palette[bitmap[y * w + x]];
448
            putc((v >> 16) & 0xff, f);
449
            putc((v >> 8) & 0xff, f);
450
            putc((v >> 0) & 0xff, f);
451
        }
452
    }
453
    fclose(f);
454
}
455
#endif
456

    
457
static int dvdsub_decode(AVCodecContext *avctx,
458
                         void *data, int *data_size,
459
                         AVPacket *avpkt)
460
{
461
    const uint8_t *buf = avpkt->data;
462
    int buf_size = avpkt->size;
463
    AVSubtitle *sub = data;
464
    int is_menu;
465

    
466
    is_menu = decode_dvd_subtitles(sub, buf, buf_size);
467

    
468
    if (is_menu < 0) {
469
    no_subtitle:
470
        *data_size = 0;
471

    
472
        return buf_size;
473
    }
474
    if (!is_menu && find_smallest_bounding_rectangle(sub) == 0)
475
        goto no_subtitle;
476

    
477
#if defined(DEBUG)
478
    av_dlog(NULL, "start=%d ms end =%d ms\n",
479
            sub->start_display_time,
480
            sub->end_display_time);
481
    ppm_save("/tmp/a.ppm", sub->rects[0]->pict.data[0],
482
             sub->rects[0]->w, sub->rects[0]->h, sub->rects[0]->pict.data[1]);
483
#endif
484

    
485
    *data_size = 1;
486
    return buf_size;
487
}
488

    
489
AVCodec ff_dvdsub_decoder = {
490
    "dvdsub",
491
    AVMEDIA_TYPE_SUBTITLE,
492
    CODEC_ID_DVD_SUBTITLE,
493
    0,
494
    NULL,
495
    NULL,
496
    NULL,
497
    dvdsub_decode,
498
    .long_name = NULL_IF_CONFIG_SMALL("DVD subtitles"),
499
};