changing AVCodecContext codec -> *codec in AVStream so additions to AVCodecContext...
[libav.git] / libavformat / gifdec.c
CommitLineData
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1/*
2 * GIF decoder
3 * Copyright (c) 2003 Fabrice Bellard.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19#include "avformat.h"
20
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21int gif_write(ByteIOContext *pb, AVImageInfo *info);
22
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23//#define DEBUG
24
25#define MAXBITS 12
26#define SIZTABLE (1<<MAXBITS)
27
28#define GCE_DISPOSAL_NONE 0
29#define GCE_DISPOSAL_INPLACE 1
30#define GCE_DISPOSAL_BACKGROUND 2
31#define GCE_DISPOSAL_RESTORE 3
32
33typedef struct GifState {
34 int screen_width;
35 int screen_height;
36 int bits_per_pixel;
37 int background_color_index;
38 int transparent_color_index;
39 int color_resolution;
12b64a22 40 uint8_t *image_buf;
fcfa89e8 41 int image_linesize;
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42 uint32_t *image_palette;
43 int pix_fmt;
44
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45 /* after the frame is displayed, the disposal method is used */
46 int gce_disposal;
47 /* delay during which the frame is shown */
48 int gce_delay;
49
50 /* LZW compatible decoder */
51 ByteIOContext *f;
52 int eob_reached;
53 uint8_t *pbuf, *ebuf;
54 int bbits;
55 unsigned int bbuf;
56
57 int cursize; /* The current code size */
58 int curmask;
59 int codesize;
60 int clear_code;
61 int end_code;
62 int newcodes; /* First available code */
63 int top_slot; /* Highest code for current size */
64 int slot; /* Last read code */
65 int fc, oc;
66 uint8_t *sp;
67 uint8_t stack[SIZTABLE];
68 uint8_t suffix[SIZTABLE];
69 uint16_t prefix[SIZTABLE];
70
71 /* aux buffers */
72 uint8_t global_palette[256 * 3];
73 uint8_t local_palette[256 * 3];
74 uint8_t buf[256];
75} GifState;
76
77
78static const uint8_t gif87a_sig[6] = "GIF87a";
79static const uint8_t gif89a_sig[6] = "GIF89a";
80
81static const uint16_t mask[17] =
82{
83 0x0000, 0x0001, 0x0003, 0x0007,
84 0x000F, 0x001F, 0x003F, 0x007F,
85 0x00FF, 0x01FF, 0x03FF, 0x07FF,
86 0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF
87};
88
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89/* Probe gif video format or gif image format. The current heuristic
90 supposes the gif87a is always a single image. For gif89a, we
91 consider it as a video only if a GCE extension is present in the
92 first kilobyte. */
93static int gif_video_probe(AVProbeData * pd)
94{
95 const uint8_t *p, *p_end;
96 int bits_per_pixel, has_global_palette, ext_code, ext_len;
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97 int gce_flags, gce_disposal;
98
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99 if (pd->buf_size < 24 ||
100 memcmp(pd->buf, gif89a_sig, 6) != 0)
101 return 0;
102 p_end = pd->buf + pd->buf_size;
103 p = pd->buf + 6;
104 bits_per_pixel = (p[4] & 0x07) + 1;
105 has_global_palette = (p[4] & 0x80);
106 p += 7;
107 if (has_global_palette)
108 p += (1 << bits_per_pixel) * 3;
109 for(;;) {
110 if (p >= p_end)
111 return 0;
112 if (*p != '!')
113 break;
114 p++;
115 if (p >= p_end)
116 return 0;
117 ext_code = *p++;
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118 if (p >= p_end)
119 return 0;
120 ext_len = *p++;
121 if (ext_code == 0xf9) {
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122 if (p >= p_end)
123 return 0;
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124 /* if GCE extension found with gce_disposal != 0: it is
125 likely to be an animation */
126 gce_flags = *p++;
127 gce_disposal = (gce_flags >> 2) & 0x7;
128 if (gce_disposal != 0)
129 return AVPROBE_SCORE_MAX;
130 else
131 return 0;
132 }
133 for(;;) {
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134 if (ext_len == 0)
135 break;
136 p += ext_len;
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137 if (p >= p_end)
138 return 0;
139 ext_len = *p++;
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140 }
141 }
142 return 0;
143}
144
145static int gif_image_probe(AVProbeData * pd)
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146{
147 if (pd->buf_size >= 24 &&
148 (memcmp(pd->buf, gif87a_sig, 6) == 0 ||
149 memcmp(pd->buf, gif89a_sig, 6) == 0))
fcfa89e8 150 return AVPROBE_SCORE_MAX - 1;
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151 else
152 return 0;
153}
154
fcfa89e8 155
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156static void GLZWDecodeInit(GifState * s, int csize)
157{
158 /* read buffer */
159 s->eob_reached = 0;
160 s->pbuf = s->buf;
161 s->ebuf = s->buf;
162 s->bbuf = 0;
163 s->bbits = 0;
164
165 /* decoder */
166 s->codesize = csize;
167 s->cursize = s->codesize + 1;
168 s->curmask = mask[s->cursize];
169 s->top_slot = 1 << s->cursize;
170 s->clear_code = 1 << s->codesize;
171 s->end_code = s->clear_code + 1;
172 s->slot = s->newcodes = s->clear_code + 2;
173 s->oc = s->fc = 0;
174 s->sp = s->stack;
175}
176
177/* XXX: optimize */
178static inline int GetCode(GifState * s)
179{
180 int c, sizbuf;
181 uint8_t *ptr;
182
183 while (s->bbits < s->cursize) {
184 ptr = s->pbuf;
185 if (ptr >= s->ebuf) {
186 if (!s->eob_reached) {
187 sizbuf = get_byte(s->f);
188 s->ebuf = s->buf + sizbuf;
189 s->pbuf = s->buf;
190 if (sizbuf > 0) {
191 get_buffer(s->f, s->buf, sizbuf);
192 } else {
193 s->eob_reached = 1;
194 }
195 }
196 ptr = s->pbuf;
197 }
198 s->bbuf |= ptr[0] << s->bbits;
199 ptr++;
200 s->pbuf = ptr;
201 s->bbits += 8;
202 }
203 c = s->bbuf & s->curmask;
204 s->bbuf >>= s->cursize;
205 s->bbits -= s->cursize;
206 return c;
207}
208
209/* NOTE: the algorithm here is inspired from the LZW GIF decoder
210 written by Steven A. Bennett in 1987. */
211/* return the number of byte decoded */
212static int GLZWDecode(GifState * s, uint8_t * buf, int len)
213{
214 int l, c, code, oc, fc;
215 uint8_t *sp;
216
217 if (s->end_code < 0)
218 return 0;
219
220 l = len;
221 sp = s->sp;
222 oc = s->oc;
223 fc = s->fc;
224
225 while (sp > s->stack) {
226 *buf++ = *(--sp);
227 if ((--l) == 0)
228 goto the_end;
229 }
230
231 for (;;) {
232 c = GetCode(s);
233 if (c == s->end_code) {
234 s->end_code = -1;
235 break;
236 } else if (c == s->clear_code) {
237 s->cursize = s->codesize + 1;
238 s->curmask = mask[s->cursize];
239 s->slot = s->newcodes;
240 s->top_slot = 1 << s->cursize;
241 while ((c = GetCode(s)) == s->clear_code);
242 if (c == s->end_code) {
243 s->end_code = -1;
244 break;
245 }
246 /* test error */
247 if (c >= s->slot)
248 c = 0;
249 fc = oc = c;
250 *buf++ = c;
251 if ((--l) == 0)
252 break;
253 } else {
254 code = c;
255 if (code >= s->slot) {
256 *sp++ = fc;
257 code = oc;
258 }
259 while (code >= s->newcodes) {
260 *sp++ = s->suffix[code];
261 code = s->prefix[code];
262 }
263 *sp++ = code;
264 if (s->slot < s->top_slot) {
265 s->suffix[s->slot] = fc = code;
266 s->prefix[s->slot++] = oc;
267 oc = c;
268 }
269 if (s->slot >= s->top_slot) {
270 if (s->cursize < MAXBITS) {
271 s->top_slot <<= 1;
272 s->curmask = mask[++s->cursize];
273 }
274 }
275 while (sp > s->stack) {
276 *buf++ = *(--sp);
277 if ((--l) == 0)
278 goto the_end;
279 }
280 }
281 }
282 the_end:
283 s->sp = sp;
284 s->oc = oc;
285 s->fc = fc;
286 return len - l;
287}
288
fcfa89e8 289static int gif_read_image(GifState *s)
12b64a22 290{
fcfa89e8 291 ByteIOContext *f = s->f;
12b64a22 292 int left, top, width, height, bits_per_pixel, code_size, flags;
84ab361f 293 int is_interleaved, has_local_palette, y, x, pass, y1, linesize, n, i;
fcfa89e8 294 uint8_t *ptr, *line, *d, *spal, *palette, *sptr, *ptr1;
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295
296 left = get_le16(f);
297 top = get_le16(f);
298 width = get_le16(f);
299 height = get_le16(f);
300 flags = get_byte(f);
301 is_interleaved = flags & 0x40;
302 has_local_palette = flags & 0x80;
303 bits_per_pixel = (flags & 0x07) + 1;
304#ifdef DEBUG
305 printf("gif: image x=%d y=%d w=%d h=%d\n", left, top, width, height);
306#endif
307
308 if (has_local_palette) {
309 get_buffer(f, s->local_palette, 3 * (1 << bits_per_pixel));
310 palette = s->local_palette;
311 } else {
312 palette = s->global_palette;
84ab361f 313 bits_per_pixel = s->bits_per_pixel;
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314 }
315
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316 /* verify that all the image is inside the screen dimensions */
317 if (left + width > s->screen_width ||
318 top + height > s->screen_height)
319 return -EINVAL;
12b64a22 320
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321 /* build the palette */
322 if (s->pix_fmt == PIX_FMT_RGB24) {
323 line = av_malloc(width);
324 if (!line)
325 return -ENOMEM;
326 } else {
327 n = (1 << bits_per_pixel);
328 spal = palette;
329 for(i = 0; i < n; i++) {
330 s->image_palette[i] = (0xff << 24) |
331 (spal[0] << 16) | (spal[1] << 8) | (spal[2]);
332 spal += 3;
333 }
334 for(; i < 256; i++)
335 s->image_palette[i] = (0xff << 24);
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336 /* handle transparency */
337 if (s->transparent_color_index >= 0)
338 s->image_palette[s->transparent_color_index] = 0;
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339 line = NULL;
340 }
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341
342 /* now get the image data */
343 s->f = f;
344 code_size = get_byte(f);
345 GLZWDecodeInit(s, code_size);
346
84ab361f 347 /* read all the image */
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348 linesize = s->image_linesize;
349 ptr1 = s->image_buf + top * linesize + (left * 3);
350 ptr = ptr1;
351 pass = 0;
352 y1 = 0;
12b64a22 353 for (y = 0; y < height; y++) {
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354 if (s->pix_fmt == PIX_FMT_RGB24) {
355 /* transcode to RGB24 */
356 GLZWDecode(s, line, width);
357 d = ptr;
358 sptr = line;
359 for(x = 0; x < width; x++) {
360 spal = palette + sptr[0] * 3;
361 d[0] = spal[0];
362 d[1] = spal[1];
363 d[2] = spal[2];
364 d += 3;
365 sptr++;
366 }
367 } else {
368 GLZWDecode(s, ptr, width);
12b64a22 369 }
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370 if (is_interleaved) {
371 switch(pass) {
372 default:
373 case 0:
374 case 1:
375 y1 += 8;
376 ptr += linesize * 8;
377 if (y1 >= height) {
378 y1 = 4;
379 if (pass == 0)
380 ptr = ptr1 + linesize * 4;
381 else
382 ptr = ptr1 + linesize * 2;
383 pass++;
384 }
385 break;
386 case 2:
387 y1 += 4;
388 ptr += linesize * 4;
389 if (y1 >= height) {
390 y1 = 1;
391 ptr = ptr1 + linesize;
392 pass++;
393 }
394 break;
395 case 3:
396 y1 += 2;
397 ptr += linesize * 2;
398 break;
399 }
400 } else {
401 ptr += linesize;
402 }
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403 }
404 av_free(line);
405
406 /* read the garbage data until end marker is found */
407 while (!s->eob_reached)
408 GetCode(s);
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409 return 0;
410}
411
fcfa89e8 412static int gif_read_extension(GifState *s)
12b64a22 413{
fcfa89e8 414 ByteIOContext *f = s->f;
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415 int ext_code, ext_len, i, gce_flags, gce_transparent_index;
416
417 /* extension */
418 ext_code = get_byte(f);
419 ext_len = get_byte(f);
420#ifdef DEBUG
421 printf("gif: ext_code=0x%x len=%d\n", ext_code, ext_len);
422#endif
423 switch(ext_code) {
424 case 0xf9:
425 if (ext_len != 4)
426 goto discard_ext;
427 s->transparent_color_index = -1;
428 gce_flags = get_byte(f);
429 s->gce_delay = get_le16(f);
430 gce_transparent_index = get_byte(f);
431 if (gce_flags & 0x01)
432 s->transparent_color_index = gce_transparent_index;
433 else
434 s->transparent_color_index = -1;
435 s->gce_disposal = (gce_flags >> 2) & 0x7;
436#ifdef DEBUG
437 printf("gif: gce_flags=%x delay=%d tcolor=%d disposal=%d\n",
438 gce_flags, s->gce_delay,
439 s->transparent_color_index, s->gce_disposal);
440#endif
441 ext_len = get_byte(f);
442 break;
443 }
444
445 /* NOTE: many extension blocks can come after */
446 discard_ext:
447 while (ext_len != 0) {
448 for (i = 0; i < ext_len; i++)
449 get_byte(f);
450 ext_len = get_byte(f);
451#ifdef DEBUG
452 printf("gif: ext_len1=%d\n", ext_len);
453#endif
454 }
455 return 0;
456}
457
fcfa89e8 458static int gif_read_header1(GifState *s)
12b64a22 459{
fcfa89e8 460 ByteIOContext *f = s->f;
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461 uint8_t sig[6];
462 int ret, v, n;
463 int has_global_palette;
464
465 /* read gif signature */
466 ret = get_buffer(f, sig, 6);
467 if (ret != 6)
468 return -1;
469 if (memcmp(sig, gif87a_sig, 6) != 0 &&
470 memcmp(sig, gif89a_sig, 6) != 0)
471 return -1;
472
473 /* read screen header */
474 s->transparent_color_index = -1;
475 s->screen_width = get_le16(f);
476 s->screen_height = get_le16(f);
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477 if( (unsigned)s->screen_width > 32767
478 || (unsigned)s->screen_height > 32767){
479 av_log(NULL, AV_LOG_ERROR, "picture size too large\n");
480 return -1;
481 }
482
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483 v = get_byte(f);
484 s->color_resolution = ((v & 0x70) >> 4) + 1;
485 has_global_palette = (v & 0x80);
486 s->bits_per_pixel = (v & 0x07) + 1;
487 s->background_color_index = get_byte(f);
488 get_byte(f); /* ignored */
489#ifdef DEBUG
490 printf("gif: screen_w=%d screen_h=%d bpp=%d global_palette=%d\n",
491 s->screen_width, s->screen_height, s->bits_per_pixel,
492 has_global_palette);
493#endif
494 if (has_global_palette) {
495 n = 1 << s->bits_per_pixel;
496 get_buffer(f, s->global_palette, n * 3);
497 }
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498 return 0;
499}
500
fcfa89e8 501static int gif_parse_next_image(GifState *s)
12b64a22 502{
fcfa89e8 503 ByteIOContext *f = s->f;
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504 int ret, code;
505
506 for (;;) {
507 code = url_fgetc(f);
508#ifdef DEBUG
509 printf("gif: code=%02x '%c'\n", code, code);
510#endif
511 switch (code) {
512 case ',':
fcfa89e8 513 if (gif_read_image(s) < 0)
0bd586c5 514 return AVERROR_IO;
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515 ret = 0;
516 goto the_end;
517 case ';':
518 /* end of image */
0bd586c5 519 ret = AVERROR_IO;
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520 goto the_end;
521 case '!':
fcfa89e8 522 if (gif_read_extension(s) < 0)
0bd586c5 523 return AVERROR_IO;
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524 break;
525 case EOF:
526 default:
527 /* error or errneous EOF */
0bd586c5 528 ret = AVERROR_IO;
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529 goto the_end;
530 }
531 }
532 the_end:
533 return ret;
534}
535
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536static int gif_read_header(AVFormatContext * s1,
537 AVFormatParameters * ap)
538{
539 GifState *s = s1->priv_data;
540 ByteIOContext *f = &s1->pb;
541 AVStream *st;
542
543 s->f = f;
544 if (gif_read_header1(s) < 0)
545 return -1;
546
547 /* allocate image buffer */
548 s->image_linesize = s->screen_width * 3;
549 s->image_buf = av_malloc(s->screen_height * s->image_linesize);
550 if (!s->image_buf)
551 return -ENOMEM;
84ab361f 552 s->pix_fmt = PIX_FMT_RGB24;
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553 /* now we are ready: build format streams */
554 st = av_new_stream(s1, 0);
555 if (!st)
556 return -1;
557
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558 st->codec->codec_type = CODEC_TYPE_VIDEO;
559 st->codec->codec_id = CODEC_ID_RAWVIDEO;
560 st->codec->time_base.den = 5;
561 st->codec->time_base.num = 1;
fcfa89e8 562 /* XXX: check if screen size is always valid */
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563 st->codec->width = s->screen_width;
564 st->codec->height = s->screen_height;
565 st->codec->pix_fmt = PIX_FMT_RGB24;
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566 return 0;
567}
568
569static int gif_read_packet(AVFormatContext * s1,
570 AVPacket * pkt)
571{
572 GifState *s = s1->priv_data;
573 int ret;
574
575 ret = gif_parse_next_image(s);
576 if (ret < 0)
577 return ret;
578
579 /* XXX: avoid copying */
580 if (av_new_packet(pkt, s->screen_width * s->screen_height * 3)) {
0bd586c5 581 return AVERROR_IO;
fcfa89e8
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582 }
583 pkt->stream_index = 0;
584 memcpy(pkt->data, s->image_buf, s->screen_width * s->screen_height * 3);
585 return 0;
586}
587
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588static int gif_read_close(AVFormatContext *s1)
589{
590 GifState *s = s1->priv_data;
591 av_free(s->image_buf);
592 return 0;
593}
594
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595/* read gif as image */
596static int gif_read(ByteIOContext *f,
597 int (*alloc_cb)(void *opaque, AVImageInfo *info), void *opaque)
598{
599 GifState s1, *s = &s1;
600 AVImageInfo info1, *info = &info1;
601 int ret;
602
603 memset(s, 0, sizeof(GifState));
604 s->f = f;
605 if (gif_read_header1(s) < 0)
606 return -1;
607 info->width = s->screen_width;
608 info->height = s->screen_height;
84ab361f 609 info->pix_fmt = PIX_FMT_PAL8;
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610 ret = alloc_cb(opaque, info);
611 if (ret)
612 return ret;
613 s->image_buf = info->pict.data[0];
614 s->image_linesize = info->pict.linesize[0];
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615 s->image_palette = (uint32_t *)info->pict.data[1];
616
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617 if (gif_parse_next_image(s) < 0)
618 return -1;
619 return 0;
620}
621
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622AVInputFormat gif_iformat =
623{
624 "gif",
625 "gif format",
626 sizeof(GifState),
fcfa89e8 627 gif_video_probe,
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628 gif_read_header,
629 gif_read_packet,
630 gif_read_close,
631};
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632
633AVImageFormat gif_image_format = {
634 "gif",
635 "gif",
636 gif_image_probe,
637 gif_read,
84ab361f 638 (1 << PIX_FMT_PAL8),
fcfa89e8
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639 gif_write,
640};