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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 | ||
42 | typedef 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 | ||
52 | enum { | |
53 | GF_OFFSETTING = 1<<0, | |
54 | GF_TRANSDIFF = 1<<1, | |
55 | }; | |
56 | ||
57 | static 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 | ||
73 | static 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 | ||
210 | static 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 | ||
238 | static 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 | ||
278 | static 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 | |
293 | static 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 | ||
300 | static 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 | ||
307 | AVCodec 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 | }; |