2 * DVD subtitle encoding
3 * Copyright (c) 2005 Wolfram Gloger
5 * This file is part of FFmpeg.
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.
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.
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
22 #include "bytestream.h"
24 #include "libavutil/avassert.h"
25 #include "libavutil/bprint.h"
26 #include "libavutil/imgutils.h"
27 #include "libavutil/opt.h"
31 uint32_t global_palette[16];
36 // ncnt is the nibble counter
37 #define PUTNIBBLE(val)\
40 *q++ = bitbuf | ((val) & 0x0f);\
45 static void dvd_encode_rle(uint8_t **pq,
46 const uint8_t *bitmap, int linesize,
51 unsigned int bitbuf = 0;
57 for (y = 0; y < h; ++y) {
59 for(x = 0; x < w; x += len) {
61 for (len=1; x+len < w; ++len)
62 if (bitmap[x+len] != color)
65 av_assert0(color < 4);
67 PUTNIBBLE((len << 2)|color);
68 } else if (len < 0x10) {
70 PUTNIBBLE((len << 2)|color);
71 } else if (len < 0x40) {
74 PUTNIBBLE((len << 2)|color);
75 } else if (x+len == w) {
86 PUTNIBBLE((len << 2)|color);
98 static int color_distance(uint32_t a, uint32_t b)
101 int alpha_a = 8, alpha_b = 8;
103 for (i = 24; i >= 0; i -= 8) {
104 d = alpha_a * (int)((a >> i) & 0xFF) -
105 alpha_b * (int)((b >> i) & 0xFF);
114 * Count colors used in a rectangle, quantizing alpha and grouping by
115 * nearest global palette entry.
117 static void count_colors(AVCodecContext *avctx, unsigned hits[33],
118 const AVSubtitleRect *r)
120 DVDSubtitleContext *dvdc = avctx->priv_data;
121 unsigned count[256] = { 0 };
122 uint32_t *palette = (uint32_t *)r->data[1];
124 int x, y, i, j, match, d, best_d, av_uninit(best_j);
125 uint8_t *p = r->data[0];
127 for (y = 0; y < r->h; y++) {
128 for (x = 0; x < r->w; x++)
130 p += r->linesize[0] - r->w;
132 for (i = 0; i < 256; i++) {
133 if (!count[i]) /* avoid useless search */
136 /* 0: transparent, 1-16: semi-transparent, 17-33 opaque */
137 match = color < 0x33000000 ? 0 : color < 0xCC000000 ? 1 : 17;
140 for (j = 0; j < 16; j++) {
141 d = color_distance(0xFF000000 | color,
142 0xFF000000 | dvdc->global_palette[j]);
150 hits[match] += count[i];
154 static void select_palette(AVCodecContext *avctx, int out_palette[4],
155 int out_alpha[4], unsigned hits[33])
157 DVDSubtitleContext *dvdc = avctx->priv_data;
158 int i, j, bright, mult;
160 int selected[4] = { 0 };
161 uint32_t pseudopal[33] = { 0 };
162 uint32_t refcolor[3] = { 0x00000000, 0xFFFFFFFF, 0xFF000000 };
164 /* Bonus for transparent: if the rectangle fits tightly the text, the
165 background color can be quite rare, but it would be ugly without it */
167 /* Bonus for bright colors */
168 for (i = 0; i < 16; i++) {
169 if (!(hits[1 + i] + hits[17 + i]))
170 continue; /* skip unused colors to gain time */
171 color = dvdc->global_palette[i];
173 for (j = 0; j < 3; j++, color >>= 8)
174 bright += (color & 0xFF) < 0x40 || (color & 0xFF) >= 0xC0;
175 mult = 2 + FFMIN(bright, 2);
176 hits[ 1 + i] *= mult;
177 hits[17 + i] *= mult;
180 /* Select four most frequent colors */
181 for (i = 0; i < 4; i++) {
182 for (j = 0; j < 33; j++)
183 if (hits[j] > hits[selected[i]])
185 hits[selected[i]] = 0;
188 /* Order the colors like in most DVDs:
189 0: background, 1: foreground, 2: outline */
190 for (i = 0; i < 16; i++) {
191 pseudopal[ 1 + i] = 0x80000000 | dvdc->global_palette[i];
192 pseudopal[17 + i] = 0xFF000000 | dvdc->global_palette[i];
194 for (i = 0; i < 3; i++) {
195 int best_d = color_distance(refcolor[i], pseudopal[selected[i]]);
196 for (j = i + 1; j < 4; j++) {
197 int d = color_distance(refcolor[i], pseudopal[selected[j]]);
199 FFSWAP(int, selected[i], selected[j]);
206 for (i = 0; i < 4; i++) {
207 out_palette[i] = selected[i] ? (selected[i] - 1) & 0xF : 0;
208 out_alpha [i] = !selected[i] ? 0 : selected[i] < 17 ? 0x80 : 0xFF;
212 static void build_color_map(AVCodecContext *avctx, int cmap[],
213 const uint32_t palette[],
214 const int out_palette[], unsigned int const out_alpha[])
216 DVDSubtitleContext *dvdc = avctx->priv_data;
218 uint32_t pseudopal[4];
220 for (i = 0; i < 4; i++)
221 pseudopal[i] = (out_alpha[i] << 24) |
222 dvdc->global_palette[out_palette[i]];
223 for (i = 0; i < 256; i++) {
225 for (j = 0; j < 4; j++) {
226 d = color_distance(pseudopal[j], palette[i]);
235 static void copy_rectangle(AVSubtitleRect *dst, AVSubtitleRect *src, int cmap[])
241 q = dst->data[0] + (src->x - dst->x) +
242 (src->y - dst->y) * dst->linesize[0];
243 for (y = 0; y < src->h; y++) {
244 for (x = 0; x < src->w; x++)
245 *(q++) = cmap[*(p++)];
246 p += src->linesize[0] - src->w;
247 q += dst->linesize[0] - src->w;
251 static int encode_dvd_subtitles(AVCodecContext *avctx,
252 uint8_t *outbuf, int outbuf_size,
255 DVDSubtitleContext *dvdc = avctx->priv_data;
257 int offset1, offset2;
258 int i, rects = h->num_rects, ret;
259 unsigned global_palette_hits[33] = { 0 };
263 AVSubtitleRect vrect;
264 uint8_t *vrect_data = NULL;
268 if (rects == 0 || !h->rects)
269 return AVERROR(EINVAL);
270 for (i = 0; i < rects; i++)
271 if (h->rects[i]->type != SUBTITLE_BITMAP) {
272 av_log(avctx, AV_LOG_ERROR, "Bitmap subtitle required\n");
273 return AVERROR(EINVAL);
275 /* Mark this subtitle forced if any of the rectangles is forced. */
276 for (i = 0; i < rects; i++)
277 if ((h->rects[i]->flags & AV_SUBTITLE_FLAG_FORCED) != 0) {
283 FF_DISABLE_DEPRECATION_WARNINGS
284 for (i = 0; i < rects; i++)
285 if (!h->rects[i]->data[0]) {
286 AVSubtitleRect *rect = h->rects[i];
288 for (j = 0; j < 4; j++) {
289 rect->data[j] = rect->pict.data[j];
290 rect->linesize[j] = rect->pict.linesize[j];
293 FF_ENABLE_DEPRECATION_WARNINGS
296 vrect = *h->rects[0];
299 /* DVD subtitles can have only one rectangle: build a virtual
300 rectangle containing all actual rectangles.
301 The data of the rectangles will be copied later, when the palette
302 is decided, because the rectangles may have different palettes. */
303 int xmin = h->rects[0]->x, xmax = xmin + h->rects[0]->w;
304 int ymin = h->rects[0]->y, ymax = ymin + h->rects[0]->h;
305 for (i = 1; i < rects; i++) {
306 xmin = FFMIN(xmin, h->rects[i]->x);
307 ymin = FFMIN(ymin, h->rects[i]->y);
308 xmax = FFMAX(xmax, h->rects[i]->x + h->rects[i]->w);
309 ymax = FFMAX(ymax, h->rects[i]->y + h->rects[i]->h);
313 vrect.w = xmax - xmin;
314 vrect.h = ymax - ymin;
315 if ((ret = av_image_check_size(vrect.w, vrect.h, 0, avctx)) < 0)
318 /* Count pixels outside the virtual rectangle as transparent */
319 global_palette_hits[0] = vrect.w * vrect.h;
320 for (i = 0; i < rects; i++)
321 global_palette_hits[0] -= h->rects[i]->w * h->rects[i]->h;
324 for (i = 0; i < rects; i++)
325 count_colors(avctx, global_palette_hits, h->rects[i]);
326 select_palette(avctx, out_palette, out_alpha, global_palette_hits);
329 if (!(vrect_data = av_calloc(vrect.w, vrect.h)))
330 return AVERROR(ENOMEM);
331 vrect.data [0] = vrect_data;
332 vrect.linesize[0] = vrect.w;
333 for (i = 0; i < rects; i++) {
334 build_color_map(avctx, cmap, (uint32_t *)h->rects[i]->data[1],
335 out_palette, out_alpha);
336 copy_rectangle(&vrect, h->rects[i], cmap);
338 for (i = 0; i < 4; i++)
341 build_color_map(avctx, cmap, (uint32_t *)h->rects[0]->data[1],
342 out_palette, out_alpha);
345 av_log(avctx, AV_LOG_DEBUG, "Selected palette:");
346 for (i = 0; i < 4; i++)
347 av_log(avctx, AV_LOG_DEBUG, " 0x%06"PRIx32"@@%02x (0x%x,0x%x)",
348 dvdc->global_palette[out_palette[i]], out_alpha[i],
349 out_palette[i], out_alpha[i] >> 4);
350 av_log(avctx, AV_LOG_DEBUG, "\n");
354 offset1 = q - outbuf;
355 // worst case memory requirement: 1 nibble per pixel..
356 if ((q - outbuf) + vrect.w * vrect.h / 2 + 17 + 21 > outbuf_size) {
357 av_log(NULL, AV_LOG_ERROR, "dvd_subtitle too big\n");
358 ret = AVERROR_BUFFER_TOO_SMALL;
361 dvd_encode_rle(&q, vrect.data[0], vrect.w * 2,
362 vrect.w, (vrect.h + 1) >> 1, cmap);
363 offset2 = q - outbuf;
364 dvd_encode_rle(&q, vrect.data[0] + vrect.w, vrect.w * 2,
365 vrect.w, vrect.h >> 1, cmap);
367 if (dvdc->even_rows_fix && (vrect.h & 1)) {
368 // Work-around for some players that want the height to be even.
370 *q++ = 0x00; // 0x00 0x00 == empty row, i.e. fully transparent
374 // set data packet size
376 bytestream_put_be16(&qq, q - outbuf);
378 // send start display command
379 bytestream_put_be16(&q, (h->start_display_time*90) >> 10);
380 bytestream_put_be16(&q, (q - outbuf) /*- 2 */ + 8 + 12 + 2);
381 *q++ = 0x03; // palette - 4 nibbles
382 *q++ = (out_palette[3] << 4) | out_palette[2];
383 *q++ = (out_palette[1] << 4) | out_palette[0];
384 *q++ = 0x04; // alpha - 4 nibbles
385 *q++ = (out_alpha[3] & 0xF0) | (out_alpha[2] >> 4);
386 *q++ = (out_alpha[1] & 0xF0) | (out_alpha[0] >> 4);
389 x2 = vrect.x + vrect.w - 1;
390 y2 = vrect.y + vrect.h - 1;
393 // x1 x2 -> 6 nibbles
395 *q++ = (vrect.x << 4) | ((x2 >> 8) & 0xf);
397 // y1 y2 -> 6 nibbles
399 *q++ = (vrect.y << 4) | ((y2 >> 8) & 0xf);
404 bytestream_put_be16(&q, offset1);
405 bytestream_put_be16(&q, offset2);
407 *q++ = forced ? 0x00 : 0x01; // start command
408 *q++ = 0xff; // terminating command
410 // send stop display command last
411 bytestream_put_be16(&q, (h->end_display_time*90) >> 10);
412 bytestream_put_be16(&q, (q - outbuf) - 2 /*+ 4*/);
413 *q++ = 0x02; // set end
414 *q++ = 0xff; // terminating command
417 bytestream_put_be16(&qq, q - outbuf);
419 av_log(NULL, AV_LOG_DEBUG, "subtitle_packet size=%"PTRDIFF_SPECIFIER"\n", q - outbuf);
427 static int bprint_to_extradata(AVCodecContext *avctx, struct AVBPrint *buf)
432 ret = av_bprint_finalize(buf, &str);
435 if (!av_bprint_is_complete(buf)) {
437 return AVERROR(ENOMEM);
440 avctx->extradata = str;
441 /* Note: the string is NUL terminated (so extradata can be read as a
442 * string), but the ending character is not accounted in the size (in
443 * binary formats you are likely not supposed to mux that character). When
444 * extradata is copied, it is also padded with AV_INPUT_BUFFER_PADDING_SIZE
446 avctx->extradata_size = buf->len;
450 static int dvdsub_init(AVCodecContext *avctx)
452 DVDSubtitleContext *dvdc = avctx->priv_data;
453 static const uint32_t default_palette[16] = {
454 0x000000, 0x0000FF, 0x00FF00, 0xFF0000,
455 0xFFFF00, 0xFF00FF, 0x00FFFF, 0xFFFFFF,
456 0x808000, 0x8080FF, 0x800080, 0x80FF80,
457 0x008080, 0xFF8080, 0x555555, 0xAAAAAA,
462 av_assert0(sizeof(dvdc->global_palette) == sizeof(default_palette));
463 if (dvdc->palette_str) {
464 ff_dvdsub_parse_palette(dvdc->global_palette, dvdc->palette_str);
466 memcpy(dvdc->global_palette, default_palette, sizeof(dvdc->global_palette));
469 av_bprint_init(&extradata, 0, AV_BPRINT_SIZE_AUTOMATIC);
470 if (avctx->width && avctx->height)
471 av_bprintf(&extradata, "size: %dx%d\n", avctx->width, avctx->height);
472 av_bprintf(&extradata, "palette:");
473 for (i = 0; i < 16; i++)
474 av_bprintf(&extradata, " %06"PRIx32"%c",
475 dvdc->global_palette[i] & 0xFFFFFF, i < 15 ? ',' : '\n');
477 ret = bprint_to_extradata(avctx, &extradata);
484 static int dvdsub_encode(AVCodecContext *avctx,
485 unsigned char *buf, int buf_size,
486 const AVSubtitle *sub)
488 //DVDSubtitleContext *s = avctx->priv_data;
491 ret = encode_dvd_subtitles(avctx, buf, buf_size, sub);
495 #define OFFSET(x) offsetof(DVDSubtitleContext, x)
496 #define SE AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_ENCODING_PARAM
497 static const AVOption options[] = {
498 {"palette", "set the global palette", OFFSET(palette_str), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, SE },
499 {"even_rows_fix", "Make number of rows even (workaround for some players)", OFFSET(even_rows_fix), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, SE},
503 static const AVClass dvdsubenc_class = {
504 .class_name = "VOBSUB subtitle encoder",
505 .item_name = av_default_item_name,
507 .version = LIBAVUTIL_VERSION_INT,
510 AVCodec ff_dvdsub_encoder = {
512 .long_name = NULL_IF_CONFIG_SMALL("DVD subtitles"),
513 .type = AVMEDIA_TYPE_SUBTITLE,
514 .id = AV_CODEC_ID_DVD_SUBTITLE,
516 .encode_sub = dvdsub_encode,
517 .priv_class = &dvdsubenc_class,
518 .priv_data_size = sizeof(DVDSubtitleContext),