Imported Debian version 2.5.3~trusty1
[deb_ffmpeg.git] / ffmpeg / libavcodec / gif.c
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2ba45a60
DM
1/*
2 * Copyright (c) 2000 Fabrice Bellard
3 * Copyright (c) 2002 Francois Revol
4 * Copyright (c) 2006 Baptiste Coudurier
5 *
6 * first version by Francois Revol <revol@free.fr>
7 *
8 * This file is part of FFmpeg.
9 *
10 * FFmpeg is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU Lesser General Public
12 * License as published by the Free Software Foundation; either
13 * version 2.1 of the License, or (at your option) any later version.
14 *
15 * FFmpeg is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * Lesser General Public License for more details.
19 *
20 * You should have received a copy of the GNU Lesser General Public
21 * License along with FFmpeg; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25/**
26 * @file
27 * GIF encoder
28 * @see http://www.w3.org/Graphics/GIF/spec-gif89a.txt
29 */
30
31#define BITSTREAM_WRITER_LE
32#include "libavutil/opt.h"
33#include "libavutil/imgutils.h"
34#include "avcodec.h"
35#include "bytestream.h"
36#include "internal.h"
37#include "lzw.h"
38#include "gif.h"
39
40#include "put_bits.h"
41
42typedef struct {
43 const AVClass *class;
44 LZWState *lzw;
45 uint8_t *buf;
46 AVFrame *last_frame;
47 int flags;
48 uint32_t palette[AVPALETTE_COUNT]; ///< local reference palette for !pal8
49 uint8_t *tmpl; ///< temporary line buffer
50} GIFContext;
51
52enum {
53 GF_OFFSETTING = 1<<0,
54 GF_TRANSDIFF = 1<<1,
55};
56
57static int pick_palette_entry(const uint8_t *buf, int linesize, int w, int h)
58{
59 int histogram[AVPALETTE_COUNT] = {0};
60 int x, y, i;
61
62 for (y = 0; y < h; y++) {
63 for (x = 0; x < w; x++)
64 histogram[buf[x]]++;
65 buf += linesize;
66 }
67 for (i = 0; i < FF_ARRAY_ELEMS(histogram); i++)
68 if (!histogram[i])
69 return i;
70 return -1;
71}
72
73static int gif_image_write_image(AVCodecContext *avctx,
74 uint8_t **bytestream, uint8_t *end,
75 const uint32_t *palette,
76 const uint8_t *buf, const int linesize,
77 AVPacket *pkt)
78{
79 GIFContext *s = avctx->priv_data;
80 int len = 0, height = avctx->height, width = avctx->width, x, y;
81 int x_start = 0, y_start = 0, trans = -1;
82 const uint8_t *ptr;
83
84 /* Crop image */
85 // TODO support with palette change
86 if ((s->flags & GF_OFFSETTING) && s->last_frame && !palette) {
87 const uint8_t *ref = s->last_frame->data[0];
88 const int ref_linesize = s->last_frame->linesize[0];
89 int x_end = avctx->width - 1,
90 y_end = avctx->height - 1;
91
92 /* skip common lines */
93 while (y_start < y_end) {
94 if (memcmp(ref + y_start*ref_linesize, buf + y_start*linesize, width))
95 break;
96 y_start++;
97 }
98 while (y_end > y_start) {
99 if (memcmp(ref + y_end*ref_linesize, buf + y_end*linesize, width))
100 break;
101 y_end--;
102 }
103 height = y_end + 1 - y_start;
104
105 /* skip common columns */
106 while (x_start < x_end) {
107 int same_column = 1;
108 for (y = y_start; y < y_end; y++) {
109 if (ref[y*ref_linesize + x_start] != buf[y*linesize + x_start]) {
110 same_column = 0;
111 break;
112 }
113 }
114 if (!same_column)
115 break;
116 x_start++;
117 }
118 while (x_end > x_start) {
119 int same_column = 1;
120 for (y = y_start; y < y_end; y++) {
121 if (ref[y*ref_linesize + x_end] != buf[y*linesize + x_end]) {
122 same_column = 0;
123 break;
124 }
125 }
126 if (!same_column)
127 break;
128 x_end--;
129 }
130 width = x_end + 1 - x_start;
131
132 av_log(avctx, AV_LOG_DEBUG,"%dx%d image at pos (%d;%d) [area:%dx%d]\n",
133 width, height, x_start, y_start, avctx->width, avctx->height);
134 }
135
136 /* image block */
137 bytestream_put_byte(bytestream, GIF_IMAGE_SEPARATOR);
138 bytestream_put_le16(bytestream, x_start);
139 bytestream_put_le16(bytestream, y_start);
140 bytestream_put_le16(bytestream, width);
141 bytestream_put_le16(bytestream, height);
142
143 if (!palette) {
144 bytestream_put_byte(bytestream, 0x00); /* flags */
145 } else {
146 unsigned i;
147 bytestream_put_byte(bytestream, 1<<7 | 0x7); /* flags */
148 for (i = 0; i < AVPALETTE_COUNT; i++) {
149 const uint32_t v = palette[i];
150 bytestream_put_be24(bytestream, v);
151 }
152 }
153
154 /* TODO: support with palette change (pal8) */
155 if ((s->flags & GF_TRANSDIFF) && s->last_frame && !palette) {
156 trans = pick_palette_entry(buf + y_start*linesize + x_start,
157 linesize, width, height);
158 if (trans < 0) { // TODO, patch welcome
159 av_log(avctx, AV_LOG_DEBUG, "No available color, can not use transparency\n");
160 } else {
161 uint8_t *pal_exdata = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE);
162 if (!pal_exdata)
163 return AVERROR(ENOMEM);
164 memcpy(pal_exdata, s->palette, AVPALETTE_SIZE);
165 pal_exdata[trans*4 + 3*!HAVE_BIGENDIAN] = 0x00;
166 }
167 }
168
169 bytestream_put_byte(bytestream, 0x08);
170
171 ff_lzw_encode_init(s->lzw, s->buf, 2 * width * height,
172 12, FF_LZW_GIF, put_bits);
173
174 ptr = buf + y_start*linesize + x_start;
175 if (trans >= 0) {
176 const int ref_linesize = s->last_frame->linesize[0];
177 const uint8_t *ref = s->last_frame->data[0] + y_start*ref_linesize + x_start;
178
179 for (y = 0; y < height; y++) {
180 memcpy(s->tmpl, ptr, width);
181 for (x = 0; x < width; x++)
182 if (ref[x] == ptr[x])
183 s->tmpl[x] = trans;
184 len += ff_lzw_encode(s->lzw, s->tmpl, width);
185 ptr += linesize;
186 ref += ref_linesize;
187 }
188 } else {
189 for (y = 0; y < height; y++) {
190 len += ff_lzw_encode(s->lzw, ptr, width);
191 ptr += linesize;
192 }
193 }
194 len += ff_lzw_encode_flush(s->lzw, flush_put_bits);
195
196 ptr = s->buf;
197 while (len > 0) {
198 int size = FFMIN(255, len);
199 bytestream_put_byte(bytestream, size);
200 if (end - *bytestream < size)
201 return -1;
202 bytestream_put_buffer(bytestream, ptr, size);
203 ptr += size;
204 len -= size;
205 }
206 bytestream_put_byte(bytestream, 0x00); /* end of image block */
207 return 0;
208}
209
210static av_cold int gif_encode_init(AVCodecContext *avctx)
211{
212 GIFContext *s = avctx->priv_data;
213
214 if (avctx->width > 65535 || avctx->height > 65535) {
215 av_log(avctx, AV_LOG_ERROR, "GIF does not support resolutions above 65535x65535\n");
216 return AVERROR(EINVAL);
217 }
218
219 avctx->coded_frame = av_frame_alloc();
220 if (!avctx->coded_frame)
221 return AVERROR(ENOMEM);
222
223 avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
224 avctx->coded_frame->key_frame = 1;
225
226 s->lzw = av_mallocz(ff_lzw_encode_state_size);
227 s->buf = av_malloc(avctx->width*avctx->height*2);
228 s->tmpl = av_malloc(avctx->width);
229 if (!s->tmpl || !s->buf || !s->lzw)
230 return AVERROR(ENOMEM);
231
232 if (avpriv_set_systematic_pal2(s->palette, avctx->pix_fmt) < 0)
233 av_assert0(avctx->pix_fmt == AV_PIX_FMT_PAL8);
234
235 return 0;
236}
237
238static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
239 const AVFrame *pict, int *got_packet)
240{
241 GIFContext *s = avctx->priv_data;
242 uint8_t *outbuf_ptr, *end;
243 const uint32_t *palette = NULL;
244 int ret;
245
246 if ((ret = ff_alloc_packet2(avctx, pkt, avctx->width*avctx->height*7/5 + FF_MIN_BUFFER_SIZE)) < 0)
247 return ret;
248 outbuf_ptr = pkt->data;
249 end = pkt->data + pkt->size;
250
251 if (avctx->pix_fmt == AV_PIX_FMT_PAL8) {
252 uint8_t *pal_exdata = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE);
253 if (!pal_exdata)
254 return AVERROR(ENOMEM);
255 memcpy(pal_exdata, pict->data[1], AVPALETTE_SIZE);
256 palette = (uint32_t*)pict->data[1];
257 }
258
259 gif_image_write_image(avctx, &outbuf_ptr, end, palette,
260 pict->data[0], pict->linesize[0], pkt);
261 if (!s->last_frame) {
262 s->last_frame = av_frame_alloc();
263 if (!s->last_frame)
264 return AVERROR(ENOMEM);
265 }
266 av_frame_unref(s->last_frame);
267 ret = av_frame_ref(s->last_frame, (AVFrame*)pict);
268 if (ret < 0)
269 return ret;
270
271 pkt->size = outbuf_ptr - pkt->data;
272 pkt->flags |= AV_PKT_FLAG_KEY;
273 *got_packet = 1;
274
275 return 0;
276}
277
278static int gif_encode_close(AVCodecContext *avctx)
279{
280 GIFContext *s = avctx->priv_data;
281
282 av_frame_free(&avctx->coded_frame);
283
284 av_freep(&s->lzw);
285 av_freep(&s->buf);
286 av_frame_free(&s->last_frame);
287 av_freep(&s->tmpl);
288 return 0;
289}
290
291#define OFFSET(x) offsetof(GIFContext, x)
292#define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
293static const AVOption gif_options[] = {
294 { "gifflags", "set GIF flags", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = GF_OFFSETTING|GF_TRANSDIFF}, 0, INT_MAX, FLAGS, "flags" },
295 { "offsetting", "enable picture offsetting", 0, AV_OPT_TYPE_CONST, {.i64=GF_OFFSETTING}, INT_MIN, INT_MAX, FLAGS, "flags" },
296 { "transdiff", "enable transparency detection between frames", 0, AV_OPT_TYPE_CONST, {.i64=GF_TRANSDIFF}, INT_MIN, INT_MAX, FLAGS, "flags" },
297 { NULL }
298};
299
300static const AVClass gif_class = {
301 .class_name = "GIF encoder",
302 .item_name = av_default_item_name,
303 .option = gif_options,
304 .version = LIBAVUTIL_VERSION_INT,
305};
306
307AVCodec ff_gif_encoder = {
308 .name = "gif",
309 .long_name = NULL_IF_CONFIG_SMALL("GIF (Graphics Interchange Format)"),
310 .type = AVMEDIA_TYPE_VIDEO,
311 .id = AV_CODEC_ID_GIF,
312 .priv_data_size = sizeof(GIFContext),
313 .init = gif_encode_init,
314 .encode2 = gif_encode_frame,
315 .close = gif_encode_close,
316 .pix_fmts = (const enum AVPixelFormat[]){
317 AV_PIX_FMT_RGB8, AV_PIX_FMT_BGR8, AV_PIX_FMT_RGB4_BYTE, AV_PIX_FMT_BGR4_BYTE,
318 AV_PIX_FMT_GRAY8, AV_PIX_FMT_PAL8, AV_PIX_FMT_NONE
319 },
320 .priv_class = &gif_class,
321};