gif: add loop private option.
[libav.git] / libavformat / gif.c
1 /*
2 * Animated GIF muxer
3 * Copyright (c) 2000 Fabrice Bellard
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; 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 "libavutil/log.h"
44 #include "libavutil/opt.h"
45
46 /* The GIF format uses reversed order for bitstreams... */
47 /* at least they don't use PDP_ENDIAN :) */
48 #define BITSTREAM_WRITER_LE
49
50 #include "libavcodec/put_bits.h"
51
52 /* bitstream minipacket size */
53 #define GIF_CHUNKS 100
54
55 /* slows down the decoding (and some browsers don't like it) */
56 /* 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 */
57 #define GIF_ADD_APP_HEADER // required to enable looping of animated gif
58
59 typedef struct {
60 unsigned char r;
61 unsigned char g;
62 unsigned char b;
63 } rgb_triplet;
64
65 /* we use the standard 216 color palette */
66
67 /* this script was used to create the palette:
68 * 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
69 * echo -n "{ 0x$r, 0x$g, 0x$b }, "; done; echo ""; done; done
70 */
71
72 static const rgb_triplet gif_clut[216] = {
73 { 0x00, 0x00, 0x00 }, { 0x00, 0x00, 0x33 }, { 0x00, 0x00, 0x66 }, { 0x00, 0x00, 0x99 }, { 0x00, 0x00, 0xcc }, { 0x00, 0x00, 0xff },
74 { 0x00, 0x33, 0x00 }, { 0x00, 0x33, 0x33 }, { 0x00, 0x33, 0x66 }, { 0x00, 0x33, 0x99 }, { 0x00, 0x33, 0xcc }, { 0x00, 0x33, 0xff },
75 { 0x00, 0x66, 0x00 }, { 0x00, 0x66, 0x33 }, { 0x00, 0x66, 0x66 }, { 0x00, 0x66, 0x99 }, { 0x00, 0x66, 0xcc }, { 0x00, 0x66, 0xff },
76 { 0x00, 0x99, 0x00 }, { 0x00, 0x99, 0x33 }, { 0x00, 0x99, 0x66 }, { 0x00, 0x99, 0x99 }, { 0x00, 0x99, 0xcc }, { 0x00, 0x99, 0xff },
77 { 0x00, 0xcc, 0x00 }, { 0x00, 0xcc, 0x33 }, { 0x00, 0xcc, 0x66 }, { 0x00, 0xcc, 0x99 }, { 0x00, 0xcc, 0xcc }, { 0x00, 0xcc, 0xff },
78 { 0x00, 0xff, 0x00 }, { 0x00, 0xff, 0x33 }, { 0x00, 0xff, 0x66 }, { 0x00, 0xff, 0x99 }, { 0x00, 0xff, 0xcc }, { 0x00, 0xff, 0xff },
79 { 0x33, 0x00, 0x00 }, { 0x33, 0x00, 0x33 }, { 0x33, 0x00, 0x66 }, { 0x33, 0x00, 0x99 }, { 0x33, 0x00, 0xcc }, { 0x33, 0x00, 0xff },
80 { 0x33, 0x33, 0x00 }, { 0x33, 0x33, 0x33 }, { 0x33, 0x33, 0x66 }, { 0x33, 0x33, 0x99 }, { 0x33, 0x33, 0xcc }, { 0x33, 0x33, 0xff },
81 { 0x33, 0x66, 0x00 }, { 0x33, 0x66, 0x33 }, { 0x33, 0x66, 0x66 }, { 0x33, 0x66, 0x99 }, { 0x33, 0x66, 0xcc }, { 0x33, 0x66, 0xff },
82 { 0x33, 0x99, 0x00 }, { 0x33, 0x99, 0x33 }, { 0x33, 0x99, 0x66 }, { 0x33, 0x99, 0x99 }, { 0x33, 0x99, 0xcc }, { 0x33, 0x99, 0xff },
83 { 0x33, 0xcc, 0x00 }, { 0x33, 0xcc, 0x33 }, { 0x33, 0xcc, 0x66 }, { 0x33, 0xcc, 0x99 }, { 0x33, 0xcc, 0xcc }, { 0x33, 0xcc, 0xff },
84 { 0x33, 0xff, 0x00 }, { 0x33, 0xff, 0x33 }, { 0x33, 0xff, 0x66 }, { 0x33, 0xff, 0x99 }, { 0x33, 0xff, 0xcc }, { 0x33, 0xff, 0xff },
85 { 0x66, 0x00, 0x00 }, { 0x66, 0x00, 0x33 }, { 0x66, 0x00, 0x66 }, { 0x66, 0x00, 0x99 }, { 0x66, 0x00, 0xcc }, { 0x66, 0x00, 0xff },
86 { 0x66, 0x33, 0x00 }, { 0x66, 0x33, 0x33 }, { 0x66, 0x33, 0x66 }, { 0x66, 0x33, 0x99 }, { 0x66, 0x33, 0xcc }, { 0x66, 0x33, 0xff },
87 { 0x66, 0x66, 0x00 }, { 0x66, 0x66, 0x33 }, { 0x66, 0x66, 0x66 }, { 0x66, 0x66, 0x99 }, { 0x66, 0x66, 0xcc }, { 0x66, 0x66, 0xff },
88 { 0x66, 0x99, 0x00 }, { 0x66, 0x99, 0x33 }, { 0x66, 0x99, 0x66 }, { 0x66, 0x99, 0x99 }, { 0x66, 0x99, 0xcc }, { 0x66, 0x99, 0xff },
89 { 0x66, 0xcc, 0x00 }, { 0x66, 0xcc, 0x33 }, { 0x66, 0xcc, 0x66 }, { 0x66, 0xcc, 0x99 }, { 0x66, 0xcc, 0xcc }, { 0x66, 0xcc, 0xff },
90 { 0x66, 0xff, 0x00 }, { 0x66, 0xff, 0x33 }, { 0x66, 0xff, 0x66 }, { 0x66, 0xff, 0x99 }, { 0x66, 0xff, 0xcc }, { 0x66, 0xff, 0xff },
91 { 0x99, 0x00, 0x00 }, { 0x99, 0x00, 0x33 }, { 0x99, 0x00, 0x66 }, { 0x99, 0x00, 0x99 }, { 0x99, 0x00, 0xcc }, { 0x99, 0x00, 0xff },
92 { 0x99, 0x33, 0x00 }, { 0x99, 0x33, 0x33 }, { 0x99, 0x33, 0x66 }, { 0x99, 0x33, 0x99 }, { 0x99, 0x33, 0xcc }, { 0x99, 0x33, 0xff },
93 { 0x99, 0x66, 0x00 }, { 0x99, 0x66, 0x33 }, { 0x99, 0x66, 0x66 }, { 0x99, 0x66, 0x99 }, { 0x99, 0x66, 0xcc }, { 0x99, 0x66, 0xff },
94 { 0x99, 0x99, 0x00 }, { 0x99, 0x99, 0x33 }, { 0x99, 0x99, 0x66 }, { 0x99, 0x99, 0x99 }, { 0x99, 0x99, 0xcc }, { 0x99, 0x99, 0xff },
95 { 0x99, 0xcc, 0x00 }, { 0x99, 0xcc, 0x33 }, { 0x99, 0xcc, 0x66 }, { 0x99, 0xcc, 0x99 }, { 0x99, 0xcc, 0xcc }, { 0x99, 0xcc, 0xff },
96 { 0x99, 0xff, 0x00 }, { 0x99, 0xff, 0x33 }, { 0x99, 0xff, 0x66 }, { 0x99, 0xff, 0x99 }, { 0x99, 0xff, 0xcc }, { 0x99, 0xff, 0xff },
97 { 0xcc, 0x00, 0x00 }, { 0xcc, 0x00, 0x33 }, { 0xcc, 0x00, 0x66 }, { 0xcc, 0x00, 0x99 }, { 0xcc, 0x00, 0xcc }, { 0xcc, 0x00, 0xff },
98 { 0xcc, 0x33, 0x00 }, { 0xcc, 0x33, 0x33 }, { 0xcc, 0x33, 0x66 }, { 0xcc, 0x33, 0x99 }, { 0xcc, 0x33, 0xcc }, { 0xcc, 0x33, 0xff },
99 { 0xcc, 0x66, 0x00 }, { 0xcc, 0x66, 0x33 }, { 0xcc, 0x66, 0x66 }, { 0xcc, 0x66, 0x99 }, { 0xcc, 0x66, 0xcc }, { 0xcc, 0x66, 0xff },
100 { 0xcc, 0x99, 0x00 }, { 0xcc, 0x99, 0x33 }, { 0xcc, 0x99, 0x66 }, { 0xcc, 0x99, 0x99 }, { 0xcc, 0x99, 0xcc }, { 0xcc, 0x99, 0xff },
101 { 0xcc, 0xcc, 0x00 }, { 0xcc, 0xcc, 0x33 }, { 0xcc, 0xcc, 0x66 }, { 0xcc, 0xcc, 0x99 }, { 0xcc, 0xcc, 0xcc }, { 0xcc, 0xcc, 0xff },
102 { 0xcc, 0xff, 0x00 }, { 0xcc, 0xff, 0x33 }, { 0xcc, 0xff, 0x66 }, { 0xcc, 0xff, 0x99 }, { 0xcc, 0xff, 0xcc }, { 0xcc, 0xff, 0xff },
103 { 0xff, 0x00, 0x00 }, { 0xff, 0x00, 0x33 }, { 0xff, 0x00, 0x66 }, { 0xff, 0x00, 0x99 }, { 0xff, 0x00, 0xcc }, { 0xff, 0x00, 0xff },
104 { 0xff, 0x33, 0x00 }, { 0xff, 0x33, 0x33 }, { 0xff, 0x33, 0x66 }, { 0xff, 0x33, 0x99 }, { 0xff, 0x33, 0xcc }, { 0xff, 0x33, 0xff },
105 { 0xff, 0x66, 0x00 }, { 0xff, 0x66, 0x33 }, { 0xff, 0x66, 0x66 }, { 0xff, 0x66, 0x99 }, { 0xff, 0x66, 0xcc }, { 0xff, 0x66, 0xff },
106 { 0xff, 0x99, 0x00 }, { 0xff, 0x99, 0x33 }, { 0xff, 0x99, 0x66 }, { 0xff, 0x99, 0x99 }, { 0xff, 0x99, 0xcc }, { 0xff, 0x99, 0xff },
107 { 0xff, 0xcc, 0x00 }, { 0xff, 0xcc, 0x33 }, { 0xff, 0xcc, 0x66 }, { 0xff, 0xcc, 0x99 }, { 0xff, 0xcc, 0xcc }, { 0xff, 0xcc, 0xff },
108 { 0xff, 0xff, 0x00 }, { 0xff, 0xff, 0x33 }, { 0xff, 0xff, 0x66 }, { 0xff, 0xff, 0x99 }, { 0xff, 0xff, 0xcc }, { 0xff, 0xff, 0xff },
109 };
110
111 /* GIF header */
112 static int gif_image_write_header(AVIOContext *pb,
113 int width, int height, int loop_count,
114 uint32_t *palette)
115 {
116 int i;
117 unsigned int v;
118
119 avio_write(pb, "GIF", 3);
120 avio_write(pb, "89a", 3);
121 avio_wl16(pb, width);
122 avio_wl16(pb, height);
123
124 avio_w8(pb, 0xf7); /* flags: global clut, 256 entries */
125 avio_w8(pb, 0x1f); /* background color index */
126 avio_w8(pb, 0); /* aspect ratio */
127
128 /* the global palette */
129 if (!palette) {
130 avio_write(pb, (const unsigned char *)gif_clut, 216*3);
131 for(i=0;i<((256-216)*3);i++)
132 avio_w8(pb, 0);
133 } else {
134 for(i=0;i<256;i++) {
135 v = palette[i];
136 avio_w8(pb, (v >> 16) & 0xff);
137 avio_w8(pb, (v >> 8) & 0xff);
138 avio_w8(pb, (v) & 0xff);
139 }
140 }
141
142 /* update: this is the 'NETSCAPE EXTENSION' that allows for looped animated gif
143 see http://members.aol.com/royalef/gifabout.htm#net-extension
144
145 byte 1 : 33 (hex 0x21) GIF Extension code
146 byte 2 : 255 (hex 0xFF) Application Extension Label
147 byte 3 : 11 (hex (0x0B) Length of Application Block
148 (eleven bytes of data to follow)
149 bytes 4 to 11 : "NETSCAPE"
150 bytes 12 to 14 : "2.0"
151 byte 15 : 3 (hex 0x03) Length of Data Sub-Block
152 (three bytes of data to follow)
153 byte 16 : 1 (hex 0x01)
154 bytes 17 to 18 : 0 to 65535, an unsigned integer in
155 lo-hi byte format. This indicate the
156 number of iterations the loop should
157 be executed.
158 bytes 19 : 0 (hex 0x00) a Data Sub-block Terminator
159 */
160
161 /* application extension header */
162 #ifdef GIF_ADD_APP_HEADER
163 if (loop_count >= 0 && loop_count <= 65535) {
164 avio_w8(pb, 0x21);
165 avio_w8(pb, 0xff);
166 avio_w8(pb, 0x0b);
167 avio_write(pb, "NETSCAPE2.0", sizeof("NETSCAPE2.0") - 1); // bytes 4 to 14
168 avio_w8(pb, 0x03); // byte 15
169 avio_w8(pb, 0x01); // byte 16
170 avio_wl16(pb, (uint16_t)loop_count);
171 avio_w8(pb, 0x00); // byte 19
172 }
173 #endif
174 return 0;
175 }
176
177 /* this is maybe slow, but allows for extensions */
178 static inline unsigned char gif_clut_index(uint8_t r, uint8_t g, uint8_t b)
179 {
180 return (((r) / 47) % 6) * 6 * 6 + (((g) / 47) % 6) * 6 + (((b) / 47) % 6);
181 }
182
183
184 static int gif_image_write_image(AVIOContext *pb,
185 int x1, int y1, int width, int height,
186 const uint8_t *buf, int linesize, int pix_fmt)
187 {
188 PutBitContext p;
189 uint8_t buffer[200]; /* 100 * 9 / 8 = 113 */
190 int i, left, w, v;
191 const uint8_t *ptr;
192 /* image block */
193
194 avio_w8(pb, 0x2c);
195 avio_wl16(pb, x1);
196 avio_wl16(pb, y1);
197 avio_wl16(pb, width);
198 avio_wl16(pb, height);
199 avio_w8(pb, 0x00); /* flags */
200 /* no local clut */
201
202 avio_w8(pb, 0x08);
203
204 left= width * height;
205
206 init_put_bits(&p, buffer, 130);
207
208 /*
209 * the thing here is the bitstream is written as little packets, with a size byte before
210 * but it's still the same bitstream between packets (no flush !)
211 */
212 ptr = buf;
213 w = width;
214 while(left>0) {
215
216 put_bits(&p, 9, 0x0100); /* clear code */
217
218 for(i=(left<GIF_CHUNKS)?left:GIF_CHUNKS;i;i--) {
219 if (pix_fmt == PIX_FMT_RGB24) {
220 v = gif_clut_index(ptr[0], ptr[1], ptr[2]);
221 ptr+=3;
222 } else {
223 v = *ptr++;
224 }
225 put_bits(&p, 9, v);
226 if (--w == 0) {
227 w = width;
228 buf += linesize;
229 ptr = buf;
230 }
231 }
232
233 if(left<=GIF_CHUNKS) {
234 put_bits(&p, 9, 0x101); /* end of stream */
235 flush_put_bits(&p);
236 }
237 if(put_bits_ptr(&p) - p.buf > 0) {
238 avio_w8(pb, put_bits_ptr(&p) - p.buf); /* byte count of the packet */
239 avio_write(pb, p.buf, put_bits_ptr(&p) - p.buf); /* the actual buffer */
240 p.buf_ptr = p.buf; /* dequeue the bytes off the bitstream */
241 }
242 left-=GIF_CHUNKS;
243 }
244 avio_w8(pb, 0x00); /* end of image block */
245
246 return 0;
247 }
248
249 typedef struct {
250 AVClass *class; /** Class for private options. */
251 int64_t time, file_time;
252 uint8_t buffer[100]; /* data chunks */
253 int loop;
254 } GIFContext;
255
256 static int gif_write_header(AVFormatContext *s)
257 {
258 GIFContext *gif = s->priv_data;
259 AVIOContext *pb = s->pb;
260 AVCodecContext *enc, *video_enc;
261 int i, width, height /*, rate*/;
262
263 /* XXX: do we reject audio streams or just ignore them ?
264 if(s->nb_streams > 1)
265 return -1;
266 */
267 gif->time = 0;
268 gif->file_time = 0;
269
270 video_enc = NULL;
271 for(i=0;i<s->nb_streams;i++) {
272 enc = s->streams[i]->codec;
273 if (enc->codec_type != AVMEDIA_TYPE_AUDIO)
274 video_enc = enc;
275 }
276
277 if (!video_enc) {
278 av_free(gif);
279 return -1;
280 } else {
281 width = video_enc->width;
282 height = video_enc->height;
283 // rate = video_enc->time_base.den;
284 }
285
286 if (video_enc->pix_fmt != PIX_FMT_RGB24) {
287 av_log(s, AV_LOG_ERROR, "ERROR: gif only handles the rgb24 pixel format. Use -pix_fmt rgb24.\n");
288 return AVERROR(EIO);
289 }
290
291 #if FF_API_LOOP_OUTPUT
292 if (s->loop_output)
293 gif->loop = s->loop_output;
294 #endif
295
296 gif_image_write_header(pb, width, height, gif->loop, NULL);
297
298 avio_flush(s->pb);
299 return 0;
300 }
301
302 static int gif_write_video(AVFormatContext *s,
303 AVCodecContext *enc, const uint8_t *buf, int size)
304 {
305 AVIOContext *pb = s->pb;
306 int jiffies;
307
308 /* graphic control extension block */
309 avio_w8(pb, 0x21);
310 avio_w8(pb, 0xf9);
311 avio_w8(pb, 0x04); /* block size */
312 avio_w8(pb, 0x04); /* flags */
313
314 /* 1 jiffy is 1/70 s */
315 /* the delay_time field indicates the number of jiffies - 1 */
316 /* XXX: should use delay, in order to be more accurate */
317 /* instead of using the same rounded value each time */
318 /* XXX: don't even remember if I really use it for now */
319 jiffies = (70*enc->time_base.num/enc->time_base.den) - 1;
320
321 avio_wl16(pb, jiffies);
322
323 avio_w8(pb, 0x1f); /* transparent color index */
324 avio_w8(pb, 0x00);
325
326 gif_image_write_image(pb, 0, 0, enc->width, enc->height,
327 buf, enc->width * 3, PIX_FMT_RGB24);
328
329 avio_flush(s->pb);
330 return 0;
331 }
332
333 static int gif_write_packet(AVFormatContext *s, AVPacket *pkt)
334 {
335 AVCodecContext *codec = s->streams[pkt->stream_index]->codec;
336 if (codec->codec_type == AVMEDIA_TYPE_AUDIO)
337 return 0; /* just ignore audio */
338 else
339 return gif_write_video(s, codec, pkt->data, pkt->size);
340 }
341
342 static int gif_write_trailer(AVFormatContext *s)
343 {
344 AVIOContext *pb = s->pb;
345
346 avio_w8(pb, 0x3b);
347 avio_flush(s->pb);
348 return 0;
349 }
350
351 #define OFFSET(x) offsetof(GIFContext, x)
352 #define ENC AV_OPT_FLAG_ENCODING_PARAM
353 static const AVOption options[] = {
354 { "loop", "Number of times to loop the output.", OFFSET(loop), FF_OPT_TYPE_INT, {0}, 0, 65535, ENC },
355 { NULL },
356 };
357
358 static const AVClass gif_muxer_class = {
359 .class_name = "GIF muxer",
360 .item_name = av_default_item_name,
361 .version = LIBAVUTIL_VERSION_INT,
362 .option = options,
363 };
364
365 AVOutputFormat ff_gif_muxer = {
366 "gif",
367 NULL_IF_CONFIG_SMALL("GIF Animation"),
368 "image/gif",
369 "gif",
370 sizeof(GIFContext),
371 CODEC_ID_NONE,
372 CODEC_ID_RAWVIDEO,
373 gif_write_header,
374 gif_write_packet,
375 gif_write_trailer,
376 .priv_class = &gif_muxer_class,
377 };