FFmpeg  4.3
gif.c
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1 /*
2  * Copyright (c) 2000 Fabrice Bellard
3  * Copyright (c) 2002 Francois Revol
4  * Copyright (c) 2006 Baptiste Coudurier
5  * Copyright (c) 2018 Bjorn Roche
6  * Copyright (c) 2018 Paul B Mahol
7  *
8  * first version by Francois Revol <revol@free.fr>
9  *
10  * This file is part of FFmpeg.
11  *
12  * FFmpeg is free software; you can redistribute it and/or
13  * modify it under the terms of the GNU Lesser General Public
14  * License as published by the Free Software Foundation; either
15  * version 2.1 of the License, or (at your option) any later version.
16  *
17  * FFmpeg is distributed in the hope that it will be useful,
18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20  * Lesser General Public License for more details.
21  *
22  * You should have received a copy of the GNU Lesser General Public
23  * License along with FFmpeg; if not, write to the Free Software
24  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25  */
26 
27 /**
28  * @file
29  * GIF encoder
30  * @see http://www.w3.org/Graphics/GIF/spec-gif89a.txt
31  */
32 
33 #define BITSTREAM_WRITER_LE
34 #include "libavutil/opt.h"
35 #include "libavutil/imgutils.h"
36 #include "avcodec.h"
37 #include "bytestream.h"
38 #include "internal.h"
39 #include "lzw.h"
40 #include "gif.h"
41 
42 #include "put_bits.h"
43 
44 #define DEFAULT_TRANSPARENCY_INDEX 0x1f
45 
46 typedef struct GIFContext {
47  const AVClass *class;
50  int buf_size;
52  int flags;
53  int image;
54  uint32_t palette[AVPALETTE_COUNT]; ///< local reference palette for !pal8
57  uint8_t *tmpl; ///< temporary line buffer
58 } GIFContext;
59 
60 enum {
61  GF_OFFSETTING = 1<<0,
62  GF_TRANSDIFF = 1<<1,
63 };
64 
66  const uint8_t *buf, const int linesize)
67 {
68  GIFContext *s = avctx->priv_data;
69  int trans = s->transparent_index;
70 
71  if (trans < 0)
72  return 0;
73 
74  for (int y = 0; y < avctx->height; y++) {
75  for (int x = 0; x < avctx->width; x++) {
76  if (buf[x] == trans) {
77  return 1;
78  }
79  }
80  buf += linesize;
81  }
82 
83  return 0;
84 }
85 
86 static int get_palette_transparency_index(const uint32_t *palette)
87 {
88  int transparent_color_index = -1;
89  unsigned i, smallest_alpha = 0xff;
90 
91  if (!palette)
92  return -1;
93 
94  for (i = 0; i < AVPALETTE_COUNT; i++) {
95  const uint32_t v = palette[i];
96  if (v >> 24 < smallest_alpha) {
97  smallest_alpha = v >> 24;
98  transparent_color_index = i;
99  }
100  }
101  return smallest_alpha < 128 ? transparent_color_index : -1;
102 }
103 
104 static int pick_palette_entry(const uint8_t *buf, int linesize, int w, int h)
105 {
106  int histogram[AVPALETTE_COUNT] = {0};
107  int x, y, i;
108 
109  for (y = 0; y < h; y++) {
110  for (x = 0; x < w; x++)
111  histogram[buf[x]]++;
112  buf += linesize;
113  }
114  for (i = 0; i < FF_ARRAY_ELEMS(histogram); i++)
115  if (!histogram[i])
116  return i;
117  return -1;
118 }
119 
121  const uint8_t *buf, const int linesize,
122  int *width, int *height,
123  int *x_start, int *y_start)
124 {
125  GIFContext *s = avctx->priv_data;
126  int trans = s->transparent_index;
127 
128  /* Crop image */
129  if ((s->flags & GF_OFFSETTING) && trans >= 0) {
130  const int w = avctx->width;
131  const int h = avctx->height;
132  int x_end = w - 1,
133  y_end = h - 1;
134 
135  // crop top
136  while (*y_start < y_end) {
137  int is_trans = 1;
138  for (int i = 0; i < w; i++) {
139  if (buf[linesize * *y_start + i] != trans) {
140  is_trans = 0;
141  break;
142  }
143  }
144 
145  if (!is_trans)
146  break;
147  (*y_start)++;
148  }
149 
150  // crop bottom
151  while (y_end > *y_start) {
152  int is_trans = 1;
153  for (int i = 0; i < w; i++) {
154  if (buf[linesize * y_end + i] != trans) {
155  is_trans = 0;
156  break;
157  }
158  }
159  if (!is_trans)
160  break;
161  y_end--;
162  }
163 
164  // crop left
165  while (*x_start < x_end) {
166  int is_trans = 1;
167  for (int i = *y_start; i < y_end; i++) {
168  if (buf[linesize * i + *x_start] != trans) {
169  is_trans = 0;
170  break;
171  }
172  }
173  if (!is_trans)
174  break;
175  (*x_start)++;
176  }
177 
178  // crop right
179  while (x_end > *x_start) {
180  int is_trans = 1;
181  for (int i = *y_start; i < y_end; i++) {
182  if (buf[linesize * i + x_end] != trans) {
183  is_trans = 0;
184  break;
185  }
186  }
187  if (!is_trans)
188  break;
189  x_end--;
190  }
191 
192  *height = y_end + 1 - *y_start;
193  *width = x_end + 1 - *x_start;
194  av_log(avctx, AV_LOG_DEBUG,"%dx%d image at pos (%d;%d) [area:%dx%d]\n",
195  *width, *height, *x_start, *y_start, avctx->width, avctx->height);
196  }
197 }
198 
199 static void gif_crop_opaque(AVCodecContext *avctx,
200  const uint32_t *palette,
201  const uint8_t *buf, const int linesize,
202  int *width, int *height, int *x_start, int *y_start)
203 {
204  GIFContext *s = avctx->priv_data;
205 
206  /* Crop image */
207  if ((s->flags & GF_OFFSETTING) && s->last_frame && !palette) {
208  const uint8_t *ref = s->last_frame->data[0];
209  const int ref_linesize = s->last_frame->linesize[0];
210  int x_end = avctx->width - 1,
211  y_end = avctx->height - 1;
212 
213  /* skip common lines */
214  while (*y_start < y_end) {
215  if (memcmp(ref + *y_start*ref_linesize, buf + *y_start*linesize, *width))
216  break;
217  (*y_start)++;
218  }
219  while (y_end > *y_start) {
220  if (memcmp(ref + y_end*ref_linesize, buf + y_end*linesize, *width))
221  break;
222  y_end--;
223  }
224  *height = y_end + 1 - *y_start;
225 
226  /* skip common columns */
227  while (*x_start < x_end) {
228  int same_column = 1;
229  for (int y = *y_start; y <= y_end; y++) {
230  if (ref[y*ref_linesize + *x_start] != buf[y*linesize + *x_start]) {
231  same_column = 0;
232  break;
233  }
234  }
235  if (!same_column)
236  break;
237  (*x_start)++;
238  }
239  while (x_end > *x_start) {
240  int same_column = 1;
241  for (int y = *y_start; y <= y_end; y++) {
242  if (ref[y*ref_linesize + x_end] != buf[y*linesize + x_end]) {
243  same_column = 0;
244  break;
245  }
246  }
247  if (!same_column)
248  break;
249  x_end--;
250  }
251  *width = x_end + 1 - *x_start;
252 
253  av_log(avctx, AV_LOG_DEBUG,"%dx%d image at pos (%d;%d) [area:%dx%d]\n",
254  *width, *height, *x_start, *y_start, avctx->width, avctx->height);
255  }
256 }
257 
259  uint8_t **bytestream, uint8_t *end,
260  const uint32_t *palette,
261  const uint8_t *buf, const int linesize,
262  AVPacket *pkt)
263 {
264  GIFContext *s = avctx->priv_data;
265  int disposal, len = 0, height = avctx->height, width = avctx->width, x, y;
266  int x_start = 0, y_start = 0, trans = s->transparent_index;
267  int bcid = -1, honor_transparency = (s->flags & GF_TRANSDIFF) && s->last_frame && !palette;
268  const uint8_t *ptr;
269 
270  if (!s->image && avctx->frame_number && is_image_translucent(avctx, buf, linesize)) {
271  gif_crop_translucent(avctx, buf, linesize, &width, &height, &x_start, &y_start);
272  honor_transparency = 0;
273  disposal = GCE_DISPOSAL_BACKGROUND;
274  } else {
275  gif_crop_opaque(avctx, palette, buf, linesize, &width, &height, &x_start, &y_start);
276  disposal = GCE_DISPOSAL_INPLACE;
277  }
278 
279  if (s->image || !avctx->frame_number) { /* GIF header */
280  const uint32_t *global_palette = palette ? palette : s->palette;
281  const AVRational sar = avctx->sample_aspect_ratio;
282  int64_t aspect = 0;
283 
284  if (sar.num > 0 && sar.den > 0) {
285  aspect = sar.num * 64LL / sar.den - 15;
286  if (aspect < 0 || aspect > 255)
287  aspect = 0;
288  }
289 
290  bytestream_put_buffer(bytestream, gif89a_sig, sizeof(gif89a_sig));
291  bytestream_put_le16(bytestream, avctx->width);
292  bytestream_put_le16(bytestream, avctx->height);
293 
294  bcid = get_palette_transparency_index(global_palette);
295 
296  bytestream_put_byte(bytestream, 0xf7); /* flags: global clut, 256 entries */
297  bytestream_put_byte(bytestream, bcid < 0 ? DEFAULT_TRANSPARENCY_INDEX : bcid); /* background color index */
298  bytestream_put_byte(bytestream, aspect);
299  for (int i = 0; i < 256; i++) {
300  const uint32_t v = global_palette[i] & 0xffffff;
301  bytestream_put_be24(bytestream, v);
302  }
303  }
304 
305  if (honor_transparency && trans < 0) {
306  trans = pick_palette_entry(buf + y_start*linesize + x_start,
307  linesize, width, height);
308  if (trans < 0) // TODO, patch welcome
309  av_log(avctx, AV_LOG_DEBUG, "No available color, can not use transparency\n");
310  }
311 
312  if (trans < 0)
313  honor_transparency = 0;
314 
315  bcid = honor_transparency || disposal == GCE_DISPOSAL_BACKGROUND ? trans : get_palette_transparency_index(palette);
316 
317  /* graphic control extension */
318  bytestream_put_byte(bytestream, GIF_EXTENSION_INTRODUCER);
319  bytestream_put_byte(bytestream, GIF_GCE_EXT_LABEL);
320  bytestream_put_byte(bytestream, 0x04); /* block size */
321  bytestream_put_byte(bytestream, disposal<<2 | (bcid >= 0));
322  bytestream_put_le16(bytestream, 5); // default delay
323  bytestream_put_byte(bytestream, bcid < 0 ? DEFAULT_TRANSPARENCY_INDEX : bcid);
324  bytestream_put_byte(bytestream, 0x00);
325 
326  /* image block */
327  bytestream_put_byte(bytestream, GIF_IMAGE_SEPARATOR);
328  bytestream_put_le16(bytestream, x_start);
329  bytestream_put_le16(bytestream, y_start);
330  bytestream_put_le16(bytestream, width);
331  bytestream_put_le16(bytestream, height);
332 
333  if (!palette) {
334  bytestream_put_byte(bytestream, 0x00); /* flags */
335  } else {
336  unsigned i;
337  bytestream_put_byte(bytestream, 1<<7 | 0x7); /* flags */
338  for (i = 0; i < AVPALETTE_COUNT; i++) {
339  const uint32_t v = palette[i];
340  bytestream_put_be24(bytestream, v);
341  }
342  }
343 
344  bytestream_put_byte(bytestream, 0x08);
345 
346  ff_lzw_encode_init(s->lzw, s->buf, s->buf_size,
347  12, FF_LZW_GIF, put_bits);
348 
349  ptr = buf + y_start*linesize + x_start;
350  if (honor_transparency) {
351  const int ref_linesize = s->last_frame->linesize[0];
352  const uint8_t *ref = s->last_frame->data[0] + y_start*ref_linesize + x_start;
353 
354  for (y = 0; y < height; y++) {
355  memcpy(s->tmpl, ptr, width);
356  for (x = 0; x < width; x++)
357  if (ref[x] == ptr[x])
358  s->tmpl[x] = trans;
359  len += ff_lzw_encode(s->lzw, s->tmpl, width);
360  ptr += linesize;
361  ref += ref_linesize;
362  }
363  } else {
364  for (y = 0; y < height; y++) {
365  len += ff_lzw_encode(s->lzw, ptr, width);
366  ptr += linesize;
367  }
368  }
370 
371  ptr = s->buf;
372  while (len > 0) {
373  int size = FFMIN(255, len);
374  bytestream_put_byte(bytestream, size);
375  if (end - *bytestream < size)
376  return -1;
377  bytestream_put_buffer(bytestream, ptr, size);
378  ptr += size;
379  len -= size;
380  }
381  bytestream_put_byte(bytestream, 0x00); /* end of image block */
382  return 0;
383 }
384 
386 {
387  GIFContext *s = avctx->priv_data;
388 
389  if (avctx->width > 65535 || avctx->height > 65535) {
390  av_log(avctx, AV_LOG_ERROR, "GIF does not support resolutions above 65535x65535\n");
391  return AVERROR(EINVAL);
392  }
393 
394  s->transparent_index = -1;
395 
397  s->buf_size = avctx->width*avctx->height*2 + 1000;
398  s->buf = av_malloc(s->buf_size);
399  s->tmpl = av_malloc(avctx->width);
400  if (!s->tmpl || !s->buf || !s->lzw)
401  return AVERROR(ENOMEM);
402 
403  if (avpriv_set_systematic_pal2(s->palette, avctx->pix_fmt) < 0)
405 
406  return 0;
407 }
408 
410  const AVFrame *pict, int *got_packet)
411 {
412  GIFContext *s = avctx->priv_data;
413  uint8_t *outbuf_ptr, *end;
414  const uint32_t *palette = NULL;
415  int ret;
416 
417  if ((ret = ff_alloc_packet2(avctx, pkt, avctx->width*avctx->height*7/5 + AV_INPUT_BUFFER_MIN_SIZE, 0)) < 0)
418  return ret;
419  outbuf_ptr = pkt->data;
420  end = pkt->data + pkt->size;
421 
422  if (avctx->pix_fmt == AV_PIX_FMT_PAL8) {
423  palette = (uint32_t*)pict->data[1];
424 
425  if (!s->palette_loaded) {
426  memcpy(s->palette, palette, AVPALETTE_SIZE);
428  s->palette_loaded = 1;
429  } else if (!memcmp(s->palette, palette, AVPALETTE_SIZE)) {
430  palette = NULL;
431  }
432  }
433 
434  gif_image_write_image(avctx, &outbuf_ptr, end, palette,
435  pict->data[0], pict->linesize[0], pkt);
436  if (!s->last_frame && !s->image) {
437  s->last_frame = av_frame_alloc();
438  if (!s->last_frame)
439  return AVERROR(ENOMEM);
440  }
441 
442  if (!s->image) {
444  ret = av_frame_ref(s->last_frame, (AVFrame*)pict);
445  if (ret < 0)
446  return ret;
447  }
448 
449  pkt->size = outbuf_ptr - pkt->data;
450  if (s->image || !avctx->frame_number)
451  pkt->flags |= AV_PKT_FLAG_KEY;
452  *got_packet = 1;
453 
454  return 0;
455 }
456 
458 {
459  GIFContext *s = avctx->priv_data;
460 
461  av_freep(&s->lzw);
462  av_freep(&s->buf);
463  s->buf_size = 0;
465  av_freep(&s->tmpl);
466  return 0;
467 }
468 
469 #define OFFSET(x) offsetof(GIFContext, x)
470 #define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
471 static const AVOption gif_options[] = {
472  { "gifflags", "set GIF flags", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = GF_OFFSETTING|GF_TRANSDIFF}, 0, INT_MAX, FLAGS, "flags" },
473  { "offsetting", "enable picture offsetting", 0, AV_OPT_TYPE_CONST, {.i64=GF_OFFSETTING}, INT_MIN, INT_MAX, FLAGS, "flags" },
474  { "transdiff", "enable transparency detection between frames", 0, AV_OPT_TYPE_CONST, {.i64=GF_TRANSDIFF}, INT_MIN, INT_MAX, FLAGS, "flags" },
475  { "gifimage", "enable encoding only images per frame", OFFSET(image), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS },
476  { NULL }
477 };
478 
479 static const AVClass gif_class = {
480  .class_name = "GIF encoder",
481  .item_name = av_default_item_name,
482  .option = gif_options,
483  .version = LIBAVUTIL_VERSION_INT,
484 };
485 
487  .name = "gif",
488  .long_name = NULL_IF_CONFIG_SMALL("GIF (Graphics Interchange Format)"),
489  .type = AVMEDIA_TYPE_VIDEO,
490  .id = AV_CODEC_ID_GIF,
491  .priv_data_size = sizeof(GIFContext),
493  .encode2 = gif_encode_frame,
494  .close = gif_encode_close,
495  .pix_fmts = (const enum AVPixelFormat[]){
498  },
499  .priv_class = &gif_class,
500 };
#define NULL
Definition: coverity.c:32
int size
This structure describes decoded (raw) audio or video data.
Definition: frame.h:300
if(ret< 0)
Definition: vf_mcdeint.c:279
AVOption.
Definition: opt.h:246
uint32_t palette[AVPALETTE_COUNT]
local reference palette for !pal8
Definition: gif.c:54
misc image utilities
static void put_bits(Jpeg2000EncoderContext *s, int val, int n)
put n times val bit
Definition: j2kenc.c:208
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
static av_cold int init(AVCodecContext *avctx)
Definition: avrndec.c:35
#define GCE_DISPOSAL_BACKGROUND
Definition: gif.h:39
static int get_palette_transparency_index(const uint32_t *palette)
Definition: gif.c:86
int num
Numerator.
Definition: rational.h:59
int size
Definition: packet.h:356
static int gif_encode_close(AVCodecContext *avctx)
Definition: gif.c:457
static const AVClass gif_class
Definition: gif.c:479
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
int ff_lzw_encode(struct LZWEncodeState *s, const uint8_t *inbuf, int insize)
LZW main compress function.
Definition: lzwenc.c:227
#define GIF_GCE_EXT_LABEL
Definition: gif.h:45
AVRational sample_aspect_ratio
sample aspect ratio (0 if unknown) That is the width of a pixel divided by the height of the pixel...
Definition: avcodec.h:905
AVCodec ff_gif_encoder
Definition: gif.c:486
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:736
int image
Definition: gif.c:53
static AVPacket pkt
AVCodec.
Definition: codec.h:190
packed RGB 1:2:1, 8bpp, (msb)1B 2G 1R(lsb)
Definition: pixfmt.h:85
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
#define av_assert0(cond)
assert() equivalent, that is always enabled.
Definition: avassert.h:37
int ff_alloc_packet2(AVCodecContext *avctx, AVPacket *avpkt, int64_t size, int64_t min_size)
Check AVPacket size and/or allocate data.
Definition: encode.c:32
uint8_t
#define av_cold
Definition: attributes.h:88
#define av_malloc(s)
AVFrame * av_frame_alloc(void)
Allocate an AVFrame and set its fields to default values.
Definition: frame.c:190
8 bits with AV_PIX_FMT_RGB32 palette
Definition: pixfmt.h:77
AVOptions.
int avpriv_set_systematic_pal2(uint32_t pal[256], enum AVPixelFormat pix_fmt)
Definition: imgutils.c:152
#define AVPALETTE_SIZE
Definition: pixfmt.h:32
static av_cold int end(AVCodecContext *avctx)
Definition: avrndec.c:90
int av_frame_ref(AVFrame *dst, const AVFrame *src)
Set up a new reference to the data described by the source frame.
Definition: frame.c:444
int buf_size
Definition: gif.c:50
#define height
uint8_t * data
Definition: packet.h:355
static int gif_image_write_image(AVCodecContext *avctx, uint8_t **bytestream, uint8_t *end, const uint32_t *palette, const uint8_t *buf, const int linesize, AVPacket *pkt)
Definition: gif.c:258
uint8_t * tmpl
temporary line buffer
Definition: gif.c:57
int flags
Definition: gif.c:52
#define AV_INPUT_BUFFER_MIN_SIZE
minimum encoding buffer size Used to avoid some checks during header writing.
Definition: avcodec.h:222
#define av_log(a,...)
#define AV_PKT_FLAG_KEY
The packet contains a keyframe.
Definition: packet.h:388
#define FLAGS
Definition: gif.c:470
int ff_lzw_encode_flush(struct LZWEncodeState *s, void(*lzw_flush_put_bits)(struct PutBitContext *))
Definition: lzw.c:46
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
LZWState * lzw
Definition: gif.c:48
#define AVERROR(e)
Definition: error.h:43
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:203
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
#define AV_LOG_DEBUG
Stuff which is only useful for libav* developers.
Definition: log.h:197
Definition: gif.c:46
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:239
const char * name
Name of the codec implementation.
Definition: codec.h:197
int flags
A combination of AV_PKT_FLAG values.
Definition: packet.h:361
#define OFFSET(x)
Definition: gif.c:469
#define GIF_IMAGE_SEPARATOR
Definition: gif.h:44
#define FFMIN(a, b)
Definition: common.h:96
Definition: lzw.h:38
static int pick_palette_entry(const uint8_t *buf, int linesize, int w, int h)
Definition: gif.c:104
packed RGB 1:2:1, 8bpp, (msb)1R 2G 1B(lsb)
Definition: pixfmt.h:88
static void gif_crop_translucent(AVCodecContext *avctx, const uint8_t *buf, const int linesize, int *width, int *height, int *x_start, int *y_start)
Definition: gif.c:120
#define width
int width
picture width / height.
Definition: avcodec.h:699
uint8_t w
Definition: llviddspenc.c:38
#define s(width, name)
Definition: cbs_vp9.c:257
#define GIF_EXTENSION_INTRODUCER
Definition: gif.h:43
#define FF_ARRAY_ELEMS(a)
packed RGB 3:3:2, 8bpp, (msb)2B 3G 3R(lsb)
Definition: pixfmt.h:83
static void gif_crop_opaque(AVCodecContext *avctx, const uint32_t *palette, const uint8_t *buf, const int linesize, int *width, int *height, int *x_start, int *y_start)
Definition: gif.c:199
Libavcodec external API header.
int linesize[AV_NUM_DATA_POINTERS]
For video, size in bytes of each picture line.
Definition: frame.h:331
GIF format definitions.
main external API structure.
Definition: avcodec.h:526
static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt, const AVFrame *pict, int *got_packet)
Definition: gif.c:409
Describe the class of an AVClass context structure.
Definition: log.h:67
Rational number (pair of numerator and denominator).
Definition: rational.h:58
uint8_t * buf
Definition: gif.c:49
static enum AVPixelFormat pix_fmts[]
Definition: libkvazaar.c:275
#define AVPALETTE_COUNT
Definition: pixfmt.h:33
void av_frame_unref(AVFrame *frame)
Unreference all the buffers referenced by frame and reset the frame fields.
Definition: frame.c:554
uint8_t * data[AV_NUM_DATA_POINTERS]
pointer to the picture/channel planes.
Definition: frame.h:314
#define GCE_DISPOSAL_INPLACE
Definition: gif.h:38
LZW decoding routines.
static int is_image_translucent(AVCodecContext *avctx, const uint8_t *buf, const int linesize)
Definition: gif.c:65
Y , 8bpp.
Definition: pixfmt.h:74
void ff_lzw_encode_init(struct LZWEncodeState *s, uint8_t *outbuf, int outsize, int maxbits, enum FF_LZW_MODES mode, void(*lzw_put_bits)(struct PutBitContext *, int, unsigned int))
common internal api header.
static void flush_put_bits(PutBitContext *s)
Pad the end of the output stream with zeros.
Definition: put_bits.h:101
static int ref[MAX_W *MAX_W]
Definition: jpeg2000dwt.c:107
static const uint8_t gif89a_sig[6]
Definition: gif.h:35
packed RGB 3:3:2, 8bpp, (msb)2R 3G 3B(lsb)
Definition: pixfmt.h:86
int den
Denominator.
Definition: rational.h:60
static av_always_inline void bytestream_put_buffer(uint8_t **b, const uint8_t *src, unsigned int size)
Definition: bytestream.h:368
void * priv_data
Definition: avcodec.h:553
AVFrame * last_frame
Definition: gif.c:51
int len
static av_cold int gif_encode_init(AVCodecContext *avctx)
Definition: gif.c:385
int transparent_index
Definition: gif.c:56
int frame_number
Frame counter, set by libavcodec.
Definition: avcodec.h:1217
#define av_freep(p)
int palette_loaded
Definition: gif.c:55
const int ff_lzw_encode_state_size
Definition: lzwenc.c:67
static const AVOption gif_options[]
Definition: gif.c:471
AVPixelFormat
Pixel format.
Definition: pixfmt.h:64
This structure stores compressed data.
Definition: packet.h:332
#define DEFAULT_TRANSPARENCY_INDEX
Definition: gif.c:44
bitstream writer API