0c6686feada7eab077560c25318689c53a3a7e49
[libav.git] / libavformat / gif.c
1 /*
2 * Animated GIF muxer
3 * Copyright (c) 2000 Fabrice Bellard.
4 *
5 * This file is part of FFmpeg.
6 *
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.
11 *
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.
16 *
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
20 */
21
22 /*
23 * First version by Francois Revol revol@free.fr
24 *
25 * Features and limitations:
26 * - currently no compression is performed,
27 * in fact the size of the data is 9/8 the size of the image in 8bpp
28 * - uses only a global standard palette
29 * - tested with IE 5.0, Opera for BeOS, NetPositive (BeOS), and Mozilla (BeOS).
30 *
31 * Reference documents:
32 * http://www.goice.co.jp/member/mo/formats/gif.html
33 * http://astronomy.swin.edu.au/pbourke/dataformats/gif/
34 * http://www.dcs.ed.ac.uk/home/mxr/gfx/2d/GIF89a.txt
35 *
36 * this url claims to have an LZW algorithm not covered by Unisys patent:
37 * http://www.msg.net/utility/whirlgif/gifencod.html
38 * could help reduce the size of the files _a lot_...
39 * some sites mentions an RLE type compression also.
40 */
41
42 #include "avformat.h"
43 #include "libavcodec/bitstream.h"
44
45 /* bitstream minipacket size */
46 #define GIF_CHUNKS 100
47
48 /* slows down the decoding (and some browsers don't like it) */
49 /* update on the 'some browsers don't like it issue from above: this was probably due to missing 'Data Sub-block Terminator' (byte 19) in the app_header */
50 #define GIF_ADD_APP_HEADER // required to enable looping of animated gif
51
52 typedef struct {
53 unsigned char r;
54 unsigned char g;
55 unsigned char b;
56 } rgb_triplet;
57
58 /* we use the standard 216 color palette */
59
60 /* this script was used to create the palette:
61 * for r in 00 33 66 99 cc ff; do for g in 00 33 66 99 cc ff; do echo -n " "; for b in 00 33 66 99 cc ff; do
62 * echo -n "{ 0x$r, 0x$g, 0x$b }, "; done; echo ""; done; done
63 */
64
65 static const rgb_triplet gif_clut[216] = {
66 { 0x00, 0x00, 0x00 }, { 0x00, 0x00, 0x33 }, { 0x00, 0x00, 0x66 }, { 0x00, 0x00, 0x99 }, { 0x00, 0x00, 0xcc }, { 0x00, 0x00, 0xff },
67 { 0x00, 0x33, 0x00 }, { 0x00, 0x33, 0x33 }, { 0x00, 0x33, 0x66 }, { 0x00, 0x33, 0x99 }, { 0x00, 0x33, 0xcc }, { 0x00, 0x33, 0xff },
68 { 0x00, 0x66, 0x00 }, { 0x00, 0x66, 0x33 }, { 0x00, 0x66, 0x66 }, { 0x00, 0x66, 0x99 }, { 0x00, 0x66, 0xcc }, { 0x00, 0x66, 0xff },
69 { 0x00, 0x99, 0x00 }, { 0x00, 0x99, 0x33 }, { 0x00, 0x99, 0x66 }, { 0x00, 0x99, 0x99 }, { 0x00, 0x99, 0xcc }, { 0x00, 0x99, 0xff },
70 { 0x00, 0xcc, 0x00 }, { 0x00, 0xcc, 0x33 }, { 0x00, 0xcc, 0x66 }, { 0x00, 0xcc, 0x99 }, { 0x00, 0xcc, 0xcc }, { 0x00, 0xcc, 0xff },
71 { 0x00, 0xff, 0x00 }, { 0x00, 0xff, 0x33 }, { 0x00, 0xff, 0x66 }, { 0x00, 0xff, 0x99 }, { 0x00, 0xff, 0xcc }, { 0x00, 0xff, 0xff },
72 { 0x33, 0x00, 0x00 }, { 0x33, 0x00, 0x33 }, { 0x33, 0x00, 0x66 }, { 0x33, 0x00, 0x99 }, { 0x33, 0x00, 0xcc }, { 0x33, 0x00, 0xff },
73 { 0x33, 0x33, 0x00 }, { 0x33, 0x33, 0x33 }, { 0x33, 0x33, 0x66 }, { 0x33, 0x33, 0x99 }, { 0x33, 0x33, 0xcc }, { 0x33, 0x33, 0xff },
74 { 0x33, 0x66, 0x00 }, { 0x33, 0x66, 0x33 }, { 0x33, 0x66, 0x66 }, { 0x33, 0x66, 0x99 }, { 0x33, 0x66, 0xcc }, { 0x33, 0x66, 0xff },
75 { 0x33, 0x99, 0x00 }, { 0x33, 0x99, 0x33 }, { 0x33, 0x99, 0x66 }, { 0x33, 0x99, 0x99 }, { 0x33, 0x99, 0xcc }, { 0x33, 0x99, 0xff },
76 { 0x33, 0xcc, 0x00 }, { 0x33, 0xcc, 0x33 }, { 0x33, 0xcc, 0x66 }, { 0x33, 0xcc, 0x99 }, { 0x33, 0xcc, 0xcc }, { 0x33, 0xcc, 0xff },
77 { 0x33, 0xff, 0x00 }, { 0x33, 0xff, 0x33 }, { 0x33, 0xff, 0x66 }, { 0x33, 0xff, 0x99 }, { 0x33, 0xff, 0xcc }, { 0x33, 0xff, 0xff },
78 { 0x66, 0x00, 0x00 }, { 0x66, 0x00, 0x33 }, { 0x66, 0x00, 0x66 }, { 0x66, 0x00, 0x99 }, { 0x66, 0x00, 0xcc }, { 0x66, 0x00, 0xff },
79 { 0x66, 0x33, 0x00 }, { 0x66, 0x33, 0x33 }, { 0x66, 0x33, 0x66 }, { 0x66, 0x33, 0x99 }, { 0x66, 0x33, 0xcc }, { 0x66, 0x33, 0xff },
80 { 0x66, 0x66, 0x00 }, { 0x66, 0x66, 0x33 }, { 0x66, 0x66, 0x66 }, { 0x66, 0x66, 0x99 }, { 0x66, 0x66, 0xcc }, { 0x66, 0x66, 0xff },
81 { 0x66, 0x99, 0x00 }, { 0x66, 0x99, 0x33 }, { 0x66, 0x99, 0x66 }, { 0x66, 0x99, 0x99 }, { 0x66, 0x99, 0xcc }, { 0x66, 0x99, 0xff },
82 { 0x66, 0xcc, 0x00 }, { 0x66, 0xcc, 0x33 }, { 0x66, 0xcc, 0x66 }, { 0x66, 0xcc, 0x99 }, { 0x66, 0xcc, 0xcc }, { 0x66, 0xcc, 0xff },
83 { 0x66, 0xff, 0x00 }, { 0x66, 0xff, 0x33 }, { 0x66, 0xff, 0x66 }, { 0x66, 0xff, 0x99 }, { 0x66, 0xff, 0xcc }, { 0x66, 0xff, 0xff },
84 { 0x99, 0x00, 0x00 }, { 0x99, 0x00, 0x33 }, { 0x99, 0x00, 0x66 }, { 0x99, 0x00, 0x99 }, { 0x99, 0x00, 0xcc }, { 0x99, 0x00, 0xff },
85 { 0x99, 0x33, 0x00 }, { 0x99, 0x33, 0x33 }, { 0x99, 0x33, 0x66 }, { 0x99, 0x33, 0x99 }, { 0x99, 0x33, 0xcc }, { 0x99, 0x33, 0xff },
86 { 0x99, 0x66, 0x00 }, { 0x99, 0x66, 0x33 }, { 0x99, 0x66, 0x66 }, { 0x99, 0x66, 0x99 }, { 0x99, 0x66, 0xcc }, { 0x99, 0x66, 0xff },
87 { 0x99, 0x99, 0x00 }, { 0x99, 0x99, 0x33 }, { 0x99, 0x99, 0x66 }, { 0x99, 0x99, 0x99 }, { 0x99, 0x99, 0xcc }, { 0x99, 0x99, 0xff },
88 { 0x99, 0xcc, 0x00 }, { 0x99, 0xcc, 0x33 }, { 0x99, 0xcc, 0x66 }, { 0x99, 0xcc, 0x99 }, { 0x99, 0xcc, 0xcc }, { 0x99, 0xcc, 0xff },
89 { 0x99, 0xff, 0x00 }, { 0x99, 0xff, 0x33 }, { 0x99, 0xff, 0x66 }, { 0x99, 0xff, 0x99 }, { 0x99, 0xff, 0xcc }, { 0x99, 0xff, 0xff },
90 { 0xcc, 0x00, 0x00 }, { 0xcc, 0x00, 0x33 }, { 0xcc, 0x00, 0x66 }, { 0xcc, 0x00, 0x99 }, { 0xcc, 0x00, 0xcc }, { 0xcc, 0x00, 0xff },
91 { 0xcc, 0x33, 0x00 }, { 0xcc, 0x33, 0x33 }, { 0xcc, 0x33, 0x66 }, { 0xcc, 0x33, 0x99 }, { 0xcc, 0x33, 0xcc }, { 0xcc, 0x33, 0xff },
92 { 0xcc, 0x66, 0x00 }, { 0xcc, 0x66, 0x33 }, { 0xcc, 0x66, 0x66 }, { 0xcc, 0x66, 0x99 }, { 0xcc, 0x66, 0xcc }, { 0xcc, 0x66, 0xff },
93 { 0xcc, 0x99, 0x00 }, { 0xcc, 0x99, 0x33 }, { 0xcc, 0x99, 0x66 }, { 0xcc, 0x99, 0x99 }, { 0xcc, 0x99, 0xcc }, { 0xcc, 0x99, 0xff },
94 { 0xcc, 0xcc, 0x00 }, { 0xcc, 0xcc, 0x33 }, { 0xcc, 0xcc, 0x66 }, { 0xcc, 0xcc, 0x99 }, { 0xcc, 0xcc, 0xcc }, { 0xcc, 0xcc, 0xff },
95 { 0xcc, 0xff, 0x00 }, { 0xcc, 0xff, 0x33 }, { 0xcc, 0xff, 0x66 }, { 0xcc, 0xff, 0x99 }, { 0xcc, 0xff, 0xcc }, { 0xcc, 0xff, 0xff },
96 { 0xff, 0x00, 0x00 }, { 0xff, 0x00, 0x33 }, { 0xff, 0x00, 0x66 }, { 0xff, 0x00, 0x99 }, { 0xff, 0x00, 0xcc }, { 0xff, 0x00, 0xff },
97 { 0xff, 0x33, 0x00 }, { 0xff, 0x33, 0x33 }, { 0xff, 0x33, 0x66 }, { 0xff, 0x33, 0x99 }, { 0xff, 0x33, 0xcc }, { 0xff, 0x33, 0xff },
98 { 0xff, 0x66, 0x00 }, { 0xff, 0x66, 0x33 }, { 0xff, 0x66, 0x66 }, { 0xff, 0x66, 0x99 }, { 0xff, 0x66, 0xcc }, { 0xff, 0x66, 0xff },
99 { 0xff, 0x99, 0x00 }, { 0xff, 0x99, 0x33 }, { 0xff, 0x99, 0x66 }, { 0xff, 0x99, 0x99 }, { 0xff, 0x99, 0xcc }, { 0xff, 0x99, 0xff },
100 { 0xff, 0xcc, 0x00 }, { 0xff, 0xcc, 0x33 }, { 0xff, 0xcc, 0x66 }, { 0xff, 0xcc, 0x99 }, { 0xff, 0xcc, 0xcc }, { 0xff, 0xcc, 0xff },
101 { 0xff, 0xff, 0x00 }, { 0xff, 0xff, 0x33 }, { 0xff, 0xff, 0x66 }, { 0xff, 0xff, 0x99 }, { 0xff, 0xff, 0xcc }, { 0xff, 0xff, 0xff },
102 };
103
104 /* The GIF format uses reversed order for bitstreams... */
105 /* at least they don't use PDP_ENDIAN :) */
106 /* so we 'extend' PutBitContext. hmmm, OOP :) */
107 /* seems this thing changed slightly since I wrote it... */
108
109 #ifdef ALT_BITSTREAM_WRITER
110 # error no ALT_BITSTREAM_WRITER support for now
111 #endif
112
113 static void gif_put_bits_rev(PutBitContext *s, int n, unsigned int value)
114 {
115 unsigned int bit_buf;
116 int bit_cnt;
117
118 // printf("put_bits=%d %x\n", n, value);
119 assert(n == 32 || value < (1U << n));
120
121 bit_buf = s->bit_buf;
122 bit_cnt = 32 - s->bit_left; /* XXX:lazyness... was = s->bit_cnt; */
123
124 // printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
125 /* XXX: optimize */
126 if (n < (32-bit_cnt)) {
127 bit_buf |= value << (bit_cnt);
128 bit_cnt+=n;
129 } else {
130 bit_buf |= value << (bit_cnt);
131
132 *s->buf_ptr = bit_buf & 0xff;
133 s->buf_ptr[1] = (bit_buf >> 8) & 0xff;
134 s->buf_ptr[2] = (bit_buf >> 16) & 0xff;
135 s->buf_ptr[3] = (bit_buf >> 24) & 0xff;
136
137 //printf("bitbuf = %08x\n", bit_buf);
138 s->buf_ptr+=4;
139 if (s->buf_ptr >= s->buf_end)
140 abort();
141 // flush_buffer_rev(s);
142 bit_cnt=bit_cnt + n - 32;
143 if (bit_cnt == 0) {
144 bit_buf = 0;
145 } else {
146 bit_buf = value >> (n - bit_cnt);
147 }
148 }
149
150 s->bit_buf = bit_buf;
151 s->bit_left = 32 - bit_cnt;
152 }
153
154 /* pad the end of the output stream with zeros */
155 static void gif_flush_put_bits_rev(PutBitContext *s)
156 {
157 while (s->bit_left < 32) {
158 /* XXX: should test end of buffer */
159 *s->buf_ptr++=s->bit_buf & 0xff;
160 s->bit_buf>>=8;
161 s->bit_left+=8;
162 }
163 // flush_buffer_rev(s);
164 s->bit_left=32;
165 s->bit_buf=0;
166 }
167
168 /* !RevPutBitContext */
169
170 /* GIF header */
171 static int gif_image_write_header(ByteIOContext *pb,
172 int width, int height, int loop_count,
173 uint32_t *palette)
174 {
175 int i;
176 unsigned int v;
177
178 put_tag(pb, "GIF");
179 put_tag(pb, "89a");
180 put_le16(pb, width);
181 put_le16(pb, height);
182
183 put_byte(pb, 0xf7); /* flags: global clut, 256 entries */
184 put_byte(pb, 0x1f); /* background color index */
185 put_byte(pb, 0); /* aspect ratio */
186
187 /* the global palette */
188 if (!palette) {
189 put_buffer(pb, (const unsigned char *)gif_clut, 216*3);
190 for(i=0;i<((256-216)*3);i++)
191 put_byte(pb, 0);
192 } else {
193 for(i=0;i<256;i++) {
194 v = palette[i];
195 put_byte(pb, (v >> 16) & 0xff);
196 put_byte(pb, (v >> 8) & 0xff);
197 put_byte(pb, (v) & 0xff);
198 }
199 }
200
201 /* update: this is the 'NETSCAPE EXTENSION' that allows for looped animated gif
202 see http://members.aol.com/royalef/gifabout.htm#net-extension
203
204 byte 1 : 33 (hex 0x21) GIF Extension code
205 byte 2 : 255 (hex 0xFF) Application Extension Label
206 byte 3 : 11 (hex (0x0B) Length of Application Block
207 (eleven bytes of data to follow)
208 bytes 4 to 11 : "NETSCAPE"
209 bytes 12 to 14 : "2.0"
210 byte 15 : 3 (hex 0x03) Length of Data Sub-Block
211 (three bytes of data to follow)
212 byte 16 : 1 (hex 0x01)
213 bytes 17 to 18 : 0 to 65535, an unsigned integer in
214 lo-hi byte format. This indicate the
215 number of iterations the loop should
216 be executed.
217 bytes 19 : 0 (hex 0x00) a Data Sub-block Terminator
218 */
219
220 /* application extension header */
221 #ifdef GIF_ADD_APP_HEADER
222 if (loop_count >= 0 && loop_count <= 65535) {
223 put_byte(pb, 0x21);
224 put_byte(pb, 0xff);
225 put_byte(pb, 0x0b);
226 put_tag(pb, "NETSCAPE2.0"); // bytes 4 to 14
227 put_byte(pb, 0x03); // byte 15
228 put_byte(pb, 0x01); // byte 16
229 put_le16(pb, (uint16_t)loop_count);
230 put_byte(pb, 0x00); // byte 19
231 }
232 #endif
233 return 0;
234 }
235
236 /* this is maybe slow, but allows for extensions */
237 static inline unsigned char gif_clut_index(uint8_t r, uint8_t g, uint8_t b)
238 {
239 return (((r) / 47) % 6) * 6 * 6 + (((g) / 47) % 6) * 6 + (((b) / 47) % 6);
240 }
241
242
243 static int gif_image_write_image(ByteIOContext *pb,
244 int x1, int y1, int width, int height,
245 const uint8_t *buf, int linesize, int pix_fmt)
246 {
247 PutBitContext p;
248 uint8_t buffer[200]; /* 100 * 9 / 8 = 113 */
249 int i, left, w, v;
250 const uint8_t *ptr;
251 /* image block */
252
253 put_byte(pb, 0x2c);
254 put_le16(pb, x1);
255 put_le16(pb, y1);
256 put_le16(pb, width);
257 put_le16(pb, height);
258 put_byte(pb, 0x00); /* flags */
259 /* no local clut */
260
261 put_byte(pb, 0x08);
262
263 left= width * height;
264
265 init_put_bits(&p, buffer, 130);
266
267 /*
268 * the thing here is the bitstream is written as little packets, with a size byte before
269 * but it's still the same bitstream between packets (no flush !)
270 */
271 ptr = buf;
272 w = width;
273 while(left>0) {
274
275 gif_put_bits_rev(&p, 9, 0x0100); /* clear code */
276
277 for(i=(left<GIF_CHUNKS)?left:GIF_CHUNKS;i;i--) {
278 if (pix_fmt == PIX_FMT_RGB24) {
279 v = gif_clut_index(ptr[0], ptr[1], ptr[2]);
280 ptr+=3;
281 } else {
282 v = *ptr++;
283 }
284 gif_put_bits_rev(&p, 9, v);
285 if (--w == 0) {
286 w = width;
287 buf += linesize;
288 ptr = buf;
289 }
290 }
291
292 if(left<=GIF_CHUNKS) {
293 gif_put_bits_rev(&p, 9, 0x101); /* end of stream */
294 gif_flush_put_bits_rev(&p);
295 }
296 if(pbBufPtr(&p) - p.buf > 0) {
297 put_byte(pb, pbBufPtr(&p) - p.buf); /* byte count of the packet */
298 put_buffer(pb, p.buf, pbBufPtr(&p) - p.buf); /* the actual buffer */
299 p.buf_ptr = p.buf; /* dequeue the bytes off the bitstream */
300 }
301 left-=GIF_CHUNKS;
302 }
303 put_byte(pb, 0x00); /* end of image block */
304
305 return 0;
306 }
307
308 typedef struct {
309 int64_t time, file_time;
310 uint8_t buffer[100]; /* data chunks */
311 } GIFContext;
312
313 static int gif_write_header(AVFormatContext *s)
314 {
315 GIFContext *gif = s->priv_data;
316 ByteIOContext *pb = s->pb;
317 AVCodecContext *enc, *video_enc;
318 int i, width, height, loop_count /*, rate*/;
319
320 /* XXX: do we reject audio streams or just ignore them ?
321 if(s->nb_streams > 1)
322 return -1;
323 */
324 gif->time = 0;
325 gif->file_time = 0;
326
327 video_enc = NULL;
328 for(i=0;i<s->nb_streams;i++) {
329 enc = s->streams[i]->codec;
330 if (enc->codec_type != CODEC_TYPE_AUDIO)
331 video_enc = enc;
332 }
333
334 if (!video_enc) {
335 av_free(gif);
336 return -1;
337 } else {
338 width = video_enc->width;
339 height = video_enc->height;
340 loop_count = s->loop_output;
341 // rate = video_enc->time_base.den;
342 }
343
344 if (video_enc->pix_fmt != PIX_FMT_RGB24) {
345 av_log(s, AV_LOG_ERROR, "ERROR: gif only handles the rgb24 pixel format. Use -pix_fmt rgb24.\n");
346 return AVERROR(EIO);
347 }
348
349 gif_image_write_header(pb, width, height, loop_count, NULL);
350
351 put_flush_packet(s->pb);
352 return 0;
353 }
354
355 static int gif_write_video(AVFormatContext *s,
356 AVCodecContext *enc, const uint8_t *buf, int size)
357 {
358 ByteIOContext *pb = s->pb;
359 GIFContext *gif = s->priv_data;
360 int jiffies;
361 int64_t delay;
362
363 /* graphic control extension block */
364 put_byte(pb, 0x21);
365 put_byte(pb, 0xf9);
366 put_byte(pb, 0x04); /* block size */
367 put_byte(pb, 0x04); /* flags */
368
369 /* 1 jiffy is 1/70 s */
370 /* the delay_time field indicates the number of jiffies - 1 */
371 delay = gif->file_time - gif->time;
372
373 /* XXX: should use delay, in order to be more accurate */
374 /* instead of using the same rounded value each time */
375 /* XXX: don't even remember if I really use it for now */
376 jiffies = (70*enc->time_base.num/enc->time_base.den) - 1;
377
378 put_le16(pb, jiffies);
379
380 put_byte(pb, 0x1f); /* transparent color index */
381 put_byte(pb, 0x00);
382
383 gif_image_write_image(pb, 0, 0, enc->width, enc->height,
384 buf, enc->width * 3, PIX_FMT_RGB24);
385
386 put_flush_packet(s->pb);
387 return 0;
388 }
389
390 static int gif_write_packet(AVFormatContext *s, AVPacket *pkt)
391 {
392 AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
393 if (codec->codec_type == CODEC_TYPE_AUDIO)
394 return 0; /* just ignore audio */
395 else
396 return gif_write_video(s, codec, pkt->data, pkt->size);
397 }
398
399 static int gif_write_trailer(AVFormatContext *s)
400 {
401 ByteIOContext *pb = s->pb;
402
403 put_byte(pb, 0x3b);
404 put_flush_packet(s->pb);
405 return 0;
406 }
407
408 AVOutputFormat gif_muxer = {
409 "gif",
410 NULL_IF_CONFIG_SMALL("GIF Animation"),
411 "image/gif",
412 "gif",
413 sizeof(GIFContext),
414 CODEC_ID_NONE,
415 CODEC_ID_RAWVIDEO,
416 gif_write_header,
417 gif_write_packet,
418 gif_write_trailer,
419 };