Imported Debian version 2.5.3~trusty1
[deb_ffmpeg.git] / ffmpeg / libavcodec / gifdec.c
CommitLineData
2ba45a60
DM
1/*
2 * GIF decoder
3 * Copyright (c) 2003 Fabrice Bellard
4 * Copyright (c) 2006 Baptiste Coudurier
5 * Copyright (c) 2012 Vitaliy E Sugrobov
6 *
7 * This file is part of FFmpeg.
8 *
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24#include "libavutil/imgutils.h"
25#include "libavutil/opt.h"
26#include "avcodec.h"
27#include "bytestream.h"
28#include "internal.h"
29#include "lzw.h"
30#include "gif.h"
31
32/* This value is intentionally set to "transparent white" color.
33 * It is much better to have white background instead of black
34 * when gif image converted to format which not support transparency.
35 */
36#define GIF_TRANSPARENT_COLOR 0x00ffffff
37
38typedef struct GifState {
39 const AVClass *class;
40 AVFrame *frame;
41 int screen_width;
42 int screen_height;
43 int has_global_palette;
44 int bits_per_pixel;
45 uint32_t bg_color;
46 int background_color_index;
47 int transparent_color_index;
48 int color_resolution;
49 /* intermediate buffer for storing color indices
50 * obtained from lzw-encoded data stream */
51 uint8_t *idx_line;
52 int idx_line_size;
53
54 /* after the frame is displayed, the disposal method is used */
55 int gce_prev_disposal;
56 int gce_disposal;
57 /* rectangle describing area that must be disposed */
58 int gce_l, gce_t, gce_w, gce_h;
59 /* depending on disposal method we store either part of the image
60 * drawn on the canvas or background color that
61 * should be used upon disposal */
62 uint32_t * stored_img;
63 int stored_img_size;
64 int stored_bg_color;
65
66 GetByteContext gb;
67 LZWState *lzw;
68
69 /* aux buffers */
70 uint32_t global_palette[256];
71 uint32_t local_palette[256];
72
73 AVCodecContext *avctx;
74 int keyframe;
75 int keyframe_ok;
76 int trans_color; /**< color value that is used instead of transparent color */
77} GifState;
78
79static void gif_read_palette(GifState *s, uint32_t *pal, int nb)
80{
81 int i;
82
83 for (i = 0; i < nb; i++, pal++)
84 *pal = (0xffu << 24) | bytestream2_get_be24u(&s->gb);
85}
86
87static void gif_fill(AVFrame *picture, uint32_t color)
88{
89 uint32_t *p = (uint32_t *)picture->data[0];
90 uint32_t *p_end = p + (picture->linesize[0] / sizeof(uint32_t)) * picture->height;
91
92 for (; p < p_end; p++)
93 *p = color;
94}
95
96static void gif_fill_rect(AVFrame *picture, uint32_t color, int l, int t, int w, int h)
97{
98 const int linesize = picture->linesize[0] / sizeof(uint32_t);
99 const uint32_t *py = (uint32_t *)picture->data[0] + t * linesize;
100 const uint32_t *pr, *pb = py + h * linesize;
101 uint32_t *px;
102
103 for (; py < pb; py += linesize) {
104 px = (uint32_t *)py + l;
105 pr = px + w;
106
107 for (; px < pr; px++)
108 *px = color;
109 }
110}
111
112static void gif_copy_img_rect(const uint32_t *src, uint32_t *dst,
113 int linesize, int l, int t, int w, int h)
114{
115 const int y_start = t * linesize;
116 const uint32_t *src_px,
117 *src_py = src + y_start,
118 *dst_py = dst + y_start;
119 const uint32_t *src_pb = src_py + h * linesize;
120 uint32_t *dst_px;
121
122 for (; src_py < src_pb; src_py += linesize, dst_py += linesize) {
123 src_px = src_py + l;
124 dst_px = (uint32_t *)dst_py + l;
125
126 memcpy(dst_px, src_px, w * sizeof(uint32_t));
127 }
128}
129
130static int gif_read_image(GifState *s, AVFrame *frame)
131{
132 int left, top, width, height, bits_per_pixel, code_size, flags, pw;
133 int is_interleaved, has_local_palette, y, pass, y1, linesize, pal_size;
134 uint32_t *ptr, *pal, *px, *pr, *ptr1;
135 int ret;
136 uint8_t *idx;
137
138 /* At least 9 bytes of Image Descriptor. */
139 if (bytestream2_get_bytes_left(&s->gb) < 9)
140 return AVERROR_INVALIDDATA;
141
142 left = bytestream2_get_le16u(&s->gb);
143 top = bytestream2_get_le16u(&s->gb);
144 width = bytestream2_get_le16u(&s->gb);
145 height = bytestream2_get_le16u(&s->gb);
146 flags = bytestream2_get_byteu(&s->gb);
147 is_interleaved = flags & 0x40;
148 has_local_palette = flags & 0x80;
149 bits_per_pixel = (flags & 0x07) + 1;
150
151 av_dlog(s->avctx, "image x=%d y=%d w=%d h=%d\n", left, top, width, height);
152
153 if (has_local_palette) {
154 pal_size = 1 << bits_per_pixel;
155
156 if (bytestream2_get_bytes_left(&s->gb) < pal_size * 3)
157 return AVERROR_INVALIDDATA;
158
159 gif_read_palette(s, s->local_palette, pal_size);
160 pal = s->local_palette;
161 } else {
162 if (!s->has_global_palette) {
163 av_log(s->avctx, AV_LOG_ERROR, "picture doesn't have either global or local palette.\n");
164 return AVERROR_INVALIDDATA;
165 }
166
167 pal = s->global_palette;
168 }
169
170 if (s->keyframe) {
171 if (s->transparent_color_index == -1 && s->has_global_palette) {
172 /* transparency wasn't set before the first frame, fill with background color */
173 gif_fill(frame, s->bg_color);
174 } else {
175 /* otherwise fill with transparent color.
176 * this is necessary since by default picture filled with 0x80808080. */
177 gif_fill(frame, s->trans_color);
178 }
179 }
180
181 /* verify that all the image is inside the screen dimensions */
182 if (!width || width > s->screen_width || left >= s->screen_width) {
183 av_log(s->avctx, AV_LOG_ERROR, "Invalid image width.\n");
184 return AVERROR_INVALIDDATA;
185 }
186 if (!height || height > s->screen_height || top >= s->screen_height) {
187 av_log(s->avctx, AV_LOG_ERROR, "Invalid image height.\n");
188 return AVERROR_INVALIDDATA;
189 }
190 if (left + width > s->screen_width) {
191 /* width must be kept around to avoid lzw vs line desync */
192 pw = s->screen_width - left;
193 av_log(s->avctx, AV_LOG_WARNING, "Image too wide by %d, truncating.\n",
194 left + width - s->screen_width);
195 } else {
196 pw = width;
197 }
198 if (top + height > s->screen_height) {
199 /* we don't care about the extra invisible lines */
200 av_log(s->avctx, AV_LOG_WARNING, "Image too high by %d, truncating.\n",
201 top + height - s->screen_height);
202 height = s->screen_height - top;
203 }
204
205 /* process disposal method */
206 if (s->gce_prev_disposal == GCE_DISPOSAL_BACKGROUND) {
207 gif_fill_rect(frame, s->stored_bg_color, s->gce_l, s->gce_t, s->gce_w, s->gce_h);
208 } else if (s->gce_prev_disposal == GCE_DISPOSAL_RESTORE) {
209 gif_copy_img_rect(s->stored_img, (uint32_t *)frame->data[0],
210 frame->linesize[0] / sizeof(uint32_t), s->gce_l, s->gce_t, s->gce_w, s->gce_h);
211 }
212
213 s->gce_prev_disposal = s->gce_disposal;
214
215 if (s->gce_disposal != GCE_DISPOSAL_NONE) {
216 s->gce_l = left; s->gce_t = top;
217 s->gce_w = pw; s->gce_h = height;
218
219 if (s->gce_disposal == GCE_DISPOSAL_BACKGROUND) {
220 if (s->transparent_color_index >= 0)
221 s->stored_bg_color = s->trans_color;
222 else
223 s->stored_bg_color = s->bg_color;
224 } else if (s->gce_disposal == GCE_DISPOSAL_RESTORE) {
225 av_fast_malloc(&s->stored_img, &s->stored_img_size, frame->linesize[0] * frame->height);
226 if (!s->stored_img)
227 return AVERROR(ENOMEM);
228
229 gif_copy_img_rect((uint32_t *)frame->data[0], s->stored_img,
230 frame->linesize[0] / sizeof(uint32_t), left, top, pw, height);
231 }
232 }
233
234 /* Expect at least 2 bytes: 1 for lzw code size and 1 for block size. */
235 if (bytestream2_get_bytes_left(&s->gb) < 2)
236 return AVERROR_INVALIDDATA;
237
238 /* now get the image data */
239 code_size = bytestream2_get_byteu(&s->gb);
240 if ((ret = ff_lzw_decode_init(s->lzw, code_size, s->gb.buffer,
241 bytestream2_get_bytes_left(&s->gb), FF_LZW_GIF)) < 0) {
242 av_log(s->avctx, AV_LOG_ERROR, "LZW init failed\n");
243 return ret;
244 }
245
246 /* read all the image */
247 linesize = frame->linesize[0] / sizeof(uint32_t);
248 ptr1 = (uint32_t *)frame->data[0] + top * linesize + left;
249 ptr = ptr1;
250 pass = 0;
251 y1 = 0;
252 for (y = 0; y < height; y++) {
253 int count = ff_lzw_decode(s->lzw, s->idx_line, width);
254 if (count != width) {
255 if (count)
256 av_log(s->avctx, AV_LOG_ERROR, "LZW decode failed\n");
257 goto decode_tail;
258 }
259
260 pr = ptr + pw;
261
262 for (px = ptr, idx = s->idx_line; px < pr; px++, idx++) {
263 if (*idx != s->transparent_color_index)
264 *px = pal[*idx];
265 }
266
267 if (is_interleaved) {
268 switch(pass) {
269 default:
270 case 0:
271 case 1:
272 y1 += 8;
273 ptr += linesize * 8;
274 break;
275 case 2:
276 y1 += 4;
277 ptr += linesize * 4;
278 break;
279 case 3:
280 y1 += 2;
281 ptr += linesize * 2;
282 break;
283 }
284 while (y1 >= height) {
285 y1 = 4 >> pass;
286 ptr = ptr1 + linesize * y1;
287 pass++;
288 }
289 } else {
290 ptr += linesize;
291 }
292 }
293
294 decode_tail:
295 /* read the garbage data until end marker is found */
296 ff_lzw_decode_tail(s->lzw);
297
298 /* Graphic Control Extension's scope is single frame.
299 * Remove its influence. */
300 s->transparent_color_index = -1;
301 s->gce_disposal = GCE_DISPOSAL_NONE;
302
303 return 0;
304}
305
306static int gif_read_extension(GifState *s)
307{
308 int ext_code, ext_len, gce_flags, gce_transparent_index;
309
310 /* There must be at least 2 bytes:
311 * 1 for extension label and 1 for extension length. */
312 if (bytestream2_get_bytes_left(&s->gb) < 2)
313 return AVERROR_INVALIDDATA;
314
315 ext_code = bytestream2_get_byteu(&s->gb);
316 ext_len = bytestream2_get_byteu(&s->gb);
317
318 av_dlog(s->avctx, "ext_code=0x%x len=%d\n", ext_code, ext_len);
319
320 switch(ext_code) {
321 case GIF_GCE_EXT_LABEL:
322 if (ext_len != 4)
323 goto discard_ext;
324
325 /* We need at least 5 bytes more: 4 is for extension body
326 * and 1 for next block size. */
327 if (bytestream2_get_bytes_left(&s->gb) < 5)
328 return AVERROR_INVALIDDATA;
329
330 gce_flags = bytestream2_get_byteu(&s->gb);
331 bytestream2_skipu(&s->gb, 2); // delay during which the frame is shown
332 gce_transparent_index = bytestream2_get_byteu(&s->gb);
333 if (gce_flags & 0x01)
334 s->transparent_color_index = gce_transparent_index;
335 else
336 s->transparent_color_index = -1;
337 s->gce_disposal = (gce_flags >> 2) & 0x7;
338
339 av_dlog(s->avctx, "gce_flags=%x tcolor=%d disposal=%d\n",
340 gce_flags,
341 s->transparent_color_index, s->gce_disposal);
342
343 if (s->gce_disposal > 3) {
344 s->gce_disposal = GCE_DISPOSAL_NONE;
345 av_dlog(s->avctx, "invalid value in gce_disposal (%d). Using default value of 0.\n", ext_len);
346 }
347
348 ext_len = bytestream2_get_byteu(&s->gb);
349 break;
350 }
351
352 /* NOTE: many extension blocks can come after */
353 discard_ext:
354 while (ext_len) {
355 /* There must be at least ext_len bytes and 1 for next block size byte. */
356 if (bytestream2_get_bytes_left(&s->gb) < ext_len + 1)
357 return AVERROR_INVALIDDATA;
358
359 bytestream2_skipu(&s->gb, ext_len);
360 ext_len = bytestream2_get_byteu(&s->gb);
361
362 av_dlog(s->avctx, "ext_len1=%d\n", ext_len);
363 }
364 return 0;
365}
366
367static int gif_read_header1(GifState *s)
368{
369 uint8_t sig[6];
370 int v, n;
371 int background_color_index;
372
373 if (bytestream2_get_bytes_left(&s->gb) < 13)
374 return AVERROR_INVALIDDATA;
375
376 /* read gif signature */
377 bytestream2_get_bufferu(&s->gb, sig, 6);
378 if (memcmp(sig, gif87a_sig, 6) &&
379 memcmp(sig, gif89a_sig, 6))
380 return AVERROR_INVALIDDATA;
381
382 /* read screen header */
383 s->transparent_color_index = -1;
384 s->screen_width = bytestream2_get_le16u(&s->gb);
385 s->screen_height = bytestream2_get_le16u(&s->gb);
386
387 v = bytestream2_get_byteu(&s->gb);
388 s->color_resolution = ((v & 0x70) >> 4) + 1;
389 s->has_global_palette = (v & 0x80);
390 s->bits_per_pixel = (v & 0x07) + 1;
391 background_color_index = bytestream2_get_byteu(&s->gb);
392 n = bytestream2_get_byteu(&s->gb);
393 if (n) {
394 s->avctx->sample_aspect_ratio.num = n + 15;
395 s->avctx->sample_aspect_ratio.den = 64;
396 }
397
398 av_dlog(s->avctx, "screen_w=%d screen_h=%d bpp=%d global_palette=%d\n",
399 s->screen_width, s->screen_height, s->bits_per_pixel,
400 s->has_global_palette);
401
402 if (s->has_global_palette) {
403 s->background_color_index = background_color_index;
404 n = 1 << s->bits_per_pixel;
405 if (bytestream2_get_bytes_left(&s->gb) < n * 3)
406 return AVERROR_INVALIDDATA;
407
408 gif_read_palette(s, s->global_palette, n);
409 s->bg_color = s->global_palette[s->background_color_index];
410 } else
411 s->background_color_index = -1;
412
413 return 0;
414}
415
416static int gif_parse_next_image(GifState *s, AVFrame *frame)
417{
418 while (bytestream2_get_bytes_left(&s->gb) > 0) {
419 int code = bytestream2_get_byte(&s->gb);
420 int ret;
421
422 av_log(s->avctx, AV_LOG_DEBUG, "code=%02x '%c'\n", code, code);
423
424 switch (code) {
425 case GIF_IMAGE_SEPARATOR:
426 return gif_read_image(s, frame);
427 case GIF_EXTENSION_INTRODUCER:
428 if ((ret = gif_read_extension(s)) < 0)
429 return ret;
430 break;
431 case GIF_TRAILER:
432 /* end of image */
433 return AVERROR_EOF;
434 default:
435 /* erroneous block label */
436 return AVERROR_INVALIDDATA;
437 }
438 }
439 return AVERROR_EOF;
440}
441
442static av_cold int gif_decode_init(AVCodecContext *avctx)
443{
444 GifState *s = avctx->priv_data;
445
446 s->avctx = avctx;
447
448 avctx->pix_fmt = AV_PIX_FMT_RGB32;
449 s->frame = av_frame_alloc();
450 if (!s->frame)
451 return AVERROR(ENOMEM);
452 ff_lzw_decode_open(&s->lzw);
453 return 0;
454}
455
456static int gif_decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
457{
458 GifState *s = avctx->priv_data;
459 int ret;
460
461 bytestream2_init(&s->gb, avpkt->data, avpkt->size);
462
463 s->frame->pts = avpkt->pts;
464 s->frame->pkt_pts = avpkt->pts;
465 s->frame->pkt_dts = avpkt->dts;
466 av_frame_set_pkt_duration(s->frame, avpkt->duration);
467
468 if (avpkt->size >= 6) {
469 s->keyframe = memcmp(avpkt->data, gif87a_sig, 6) == 0 ||
470 memcmp(avpkt->data, gif89a_sig, 6) == 0;
471 } else {
472 s->keyframe = 0;
473 }
474
475 if (s->keyframe) {
476 s->keyframe_ok = 0;
477 s->gce_prev_disposal = GCE_DISPOSAL_NONE;
478 if ((ret = gif_read_header1(s)) < 0)
479 return ret;
480
481 if ((ret = ff_set_dimensions(avctx, s->screen_width, s->screen_height)) < 0)
482 return ret;
483
484 av_frame_unref(s->frame);
485 if ((ret = ff_get_buffer(avctx, s->frame, 0)) < 0)
486 return ret;
487
488 av_fast_malloc(&s->idx_line, &s->idx_line_size, s->screen_width);
489 if (!s->idx_line)
490 return AVERROR(ENOMEM);
491
492 s->frame->pict_type = AV_PICTURE_TYPE_I;
493 s->frame->key_frame = 1;
494 s->keyframe_ok = 1;
495 } else {
496 if (!s->keyframe_ok) {
497 av_log(avctx, AV_LOG_ERROR, "cannot decode frame without keyframe\n");
498 return AVERROR_INVALIDDATA;
499 }
500
501 if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
502 return ret;
503
504 s->frame->pict_type = AV_PICTURE_TYPE_P;
505 s->frame->key_frame = 0;
506 }
507
508 ret = gif_parse_next_image(s, s->frame);
509 if (ret < 0)
510 return ret;
511
512 if ((ret = av_frame_ref(data, s->frame)) < 0)
513 return ret;
514 *got_frame = 1;
515
516 return bytestream2_tell(&s->gb);
517}
518
519static av_cold int gif_decode_close(AVCodecContext *avctx)
520{
521 GifState *s = avctx->priv_data;
522
523 ff_lzw_decode_close(&s->lzw);
524 av_frame_free(&s->frame);
525 av_freep(&s->idx_line);
526 av_freep(&s->stored_img);
527
528 return 0;
529}
530
531static const AVOption options[] = {
532 { "trans_color", "color value (ARGB) that is used instead of transparent color",
533 offsetof(GifState, trans_color), AV_OPT_TYPE_INT,
534 {.i64 = GIF_TRANSPARENT_COLOR}, 0, 0xffffffff,
535 AV_OPT_FLAG_DECODING_PARAM|AV_OPT_FLAG_VIDEO_PARAM },
536 { NULL },
537};
538
539static const AVClass decoder_class = {
540 .class_name = "gif decoder",
541 .item_name = av_default_item_name,
542 .option = options,
543 .version = LIBAVUTIL_VERSION_INT,
544 .category = AV_CLASS_CATEGORY_DECODER,
545};
546
547AVCodec ff_gif_decoder = {
548 .name = "gif",
549 .long_name = NULL_IF_CONFIG_SMALL("GIF (Graphics Interchange Format)"),
550 .type = AVMEDIA_TYPE_VIDEO,
551 .id = AV_CODEC_ID_GIF,
552 .priv_data_size = sizeof(GifState),
553 .init = gif_decode_init,
554 .close = gif_decode_close,
555 .decode = gif_decode_frame,
556 .capabilities = CODEC_CAP_DR1,
557 .priv_class = &decoder_class,
558};