lavc decoders: work with refcounted frames.
[libav.git] / libavcodec / gifdec.c
1 /*
2 * GIF decoder
3 * Copyright (c) 2003 Fabrice Bellard
4 * Copyright (c) 2006 Baptiste Coudurier
5 *
6 * This file is part of Libav.
7 *
8 * Libav is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * Libav is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with Libav; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 //#define DEBUG
24
25 #include "libavutil/imgutils.h"
26 #include "avcodec.h"
27 #include "bytestream.h"
28 #include "internal.h"
29 #include "lzw.h"
30
31 #define GCE_DISPOSAL_NONE 0
32 #define GCE_DISPOSAL_INPLACE 1
33 #define GCE_DISPOSAL_BACKGROUND 2
34 #define GCE_DISPOSAL_RESTORE 3
35
36 typedef struct GifState {
37 int screen_width;
38 int screen_height;
39 int bits_per_pixel;
40 int background_color_index;
41 int transparent_color_index;
42 int color_resolution;
43 uint32_t *image_palette;
44
45 /* after the frame is displayed, the disposal method is used */
46 int gce_disposal;
47 /* delay during which the frame is shown */
48 int gce_delay;
49
50 /* LZW compatible decoder */
51 const uint8_t *bytestream;
52 const uint8_t *bytestream_end;
53 LZWState *lzw;
54
55 /* aux buffers */
56 uint8_t global_palette[256 * 3];
57 uint8_t local_palette[256 * 3];
58
59 AVCodecContext* avctx;
60 } GifState;
61
62 static const uint8_t gif87a_sig[6] = "GIF87a";
63 static const uint8_t gif89a_sig[6] = "GIF89a";
64
65 static int gif_read_image(GifState *s, AVFrame *frame)
66 {
67 int left, top, width, height, bits_per_pixel, code_size, flags;
68 int is_interleaved, has_local_palette, y, pass, y1, linesize, n, i;
69 uint8_t *ptr, *spal, *palette, *ptr1;
70
71 left = bytestream_get_le16(&s->bytestream);
72 top = bytestream_get_le16(&s->bytestream);
73 width = bytestream_get_le16(&s->bytestream);
74 height = bytestream_get_le16(&s->bytestream);
75 flags = bytestream_get_byte(&s->bytestream);
76 is_interleaved = flags & 0x40;
77 has_local_palette = flags & 0x80;
78 bits_per_pixel = (flags & 0x07) + 1;
79
80 av_dlog(s->avctx, "gif: image x=%d y=%d w=%d h=%d\n", left, top, width, height);
81
82 if (has_local_palette) {
83 bytestream_get_buffer(&s->bytestream, s->local_palette, 3 * (1 << bits_per_pixel));
84 palette = s->local_palette;
85 } else {
86 palette = s->global_palette;
87 bits_per_pixel = s->bits_per_pixel;
88 }
89
90 /* verify that all the image is inside the screen dimensions */
91 if (left + width > s->screen_width ||
92 top + height > s->screen_height)
93 return AVERROR(EINVAL);
94
95 /* build the palette */
96 n = (1 << bits_per_pixel);
97 spal = palette;
98 for(i = 0; i < n; i++) {
99 s->image_palette[i] = (0xffu << 24) | AV_RB24(spal);
100 spal += 3;
101 }
102 for(; i < 256; i++)
103 s->image_palette[i] = (0xffu << 24);
104 /* handle transparency */
105 if (s->transparent_color_index >= 0)
106 s->image_palette[s->transparent_color_index] = 0;
107
108 /* now get the image data */
109 code_size = bytestream_get_byte(&s->bytestream);
110 ff_lzw_decode_init(s->lzw, code_size, s->bytestream,
111 s->bytestream_end - s->bytestream, FF_LZW_GIF);
112
113 /* read all the image */
114 linesize = frame->linesize[0];
115 ptr1 = frame->data[0] + top * linesize + left;
116 ptr = ptr1;
117 pass = 0;
118 y1 = 0;
119 for (y = 0; y < height; y++) {
120 ff_lzw_decode(s->lzw, ptr, width);
121 if (is_interleaved) {
122 switch(pass) {
123 default:
124 case 0:
125 case 1:
126 y1 += 8;
127 ptr += linesize * 8;
128 if (y1 >= height) {
129 y1 = pass ? 2 : 4;
130 ptr = ptr1 + linesize * y1;
131 pass++;
132 }
133 break;
134 case 2:
135 y1 += 4;
136 ptr += linesize * 4;
137 if (y1 >= height) {
138 y1 = 1;
139 ptr = ptr1 + linesize;
140 pass++;
141 }
142 break;
143 case 3:
144 y1 += 2;
145 ptr += linesize * 2;
146 break;
147 }
148 } else {
149 ptr += linesize;
150 }
151 }
152 /* read the garbage data until end marker is found */
153 ff_lzw_decode_tail(s->lzw);
154 s->bytestream = ff_lzw_cur_ptr(s->lzw);
155 return 0;
156 }
157
158 static int gif_read_extension(GifState *s)
159 {
160 int ext_code, ext_len, i, gce_flags, gce_transparent_index;
161
162 /* extension */
163 ext_code = bytestream_get_byte(&s->bytestream);
164 ext_len = bytestream_get_byte(&s->bytestream);
165
166 av_dlog(s->avctx, "gif: ext_code=0x%x len=%d\n", ext_code, ext_len);
167
168 switch(ext_code) {
169 case 0xf9:
170 if (ext_len != 4)
171 goto discard_ext;
172 s->transparent_color_index = -1;
173 gce_flags = bytestream_get_byte(&s->bytestream);
174 s->gce_delay = bytestream_get_le16(&s->bytestream);
175 gce_transparent_index = bytestream_get_byte(&s->bytestream);
176 if (gce_flags & 0x01)
177 s->transparent_color_index = gce_transparent_index;
178 else
179 s->transparent_color_index = -1;
180 s->gce_disposal = (gce_flags >> 2) & 0x7;
181
182 av_dlog(s->avctx, "gif: gce_flags=%x delay=%d tcolor=%d disposal=%d\n",
183 gce_flags, s->gce_delay,
184 s->transparent_color_index, s->gce_disposal);
185
186 ext_len = bytestream_get_byte(&s->bytestream);
187 break;
188 }
189
190 /* NOTE: many extension blocks can come after */
191 discard_ext:
192 while (ext_len != 0) {
193 for (i = 0; i < ext_len; i++)
194 bytestream_get_byte(&s->bytestream);
195 ext_len = bytestream_get_byte(&s->bytestream);
196
197 av_dlog(s->avctx, "gif: ext_len1=%d\n", ext_len);
198 }
199 return 0;
200 }
201
202 static int gif_read_header1(GifState *s)
203 {
204 uint8_t sig[6];
205 int v, n;
206 int has_global_palette;
207
208 if (s->bytestream_end < s->bytestream + 13)
209 return AVERROR_INVALIDDATA;
210
211 /* read gif signature */
212 bytestream_get_buffer(&s->bytestream, sig, 6);
213 if (memcmp(sig, gif87a_sig, 6) != 0 &&
214 memcmp(sig, gif89a_sig, 6) != 0)
215 return AVERROR_INVALIDDATA;
216
217 /* read screen header */
218 s->transparent_color_index = -1;
219 s->screen_width = bytestream_get_le16(&s->bytestream);
220 s->screen_height = bytestream_get_le16(&s->bytestream);
221 if( (unsigned)s->screen_width > 32767
222 || (unsigned)s->screen_height > 32767){
223 av_log(NULL, AV_LOG_ERROR, "picture size too large\n");
224 return AVERROR_INVALIDDATA;
225 }
226
227 v = bytestream_get_byte(&s->bytestream);
228 s->color_resolution = ((v & 0x70) >> 4) + 1;
229 has_global_palette = (v & 0x80);
230 s->bits_per_pixel = (v & 0x07) + 1;
231 s->background_color_index = bytestream_get_byte(&s->bytestream);
232 bytestream_get_byte(&s->bytestream); /* ignored */
233
234 av_dlog(s->avctx, "gif: screen_w=%d screen_h=%d bpp=%d global_palette=%d\n",
235 s->screen_width, s->screen_height, s->bits_per_pixel,
236 has_global_palette);
237
238 if (has_global_palette) {
239 n = 1 << s->bits_per_pixel;
240 if (s->bytestream_end < s->bytestream + n * 3)
241 return AVERROR_INVALIDDATA;
242 bytestream_get_buffer(&s->bytestream, s->global_palette, n * 3);
243 }
244 return 0;
245 }
246
247 static int gif_parse_next_image(GifState *s, AVFrame *frame)
248 {
249 while (s->bytestream < s->bytestream_end) {
250 int code = bytestream_get_byte(&s->bytestream);
251 int ret;
252
253 av_dlog(s->avctx, "gif: code=%02x '%c'\n", code, code);
254
255 switch (code) {
256 case ',':
257 return gif_read_image(s, frame);
258 case '!':
259 if ((ret = gif_read_extension(s)) < 0)
260 return ret;
261 break;
262 case ';':
263 /* end of image */
264 default:
265 /* error or erroneous EOF */
266 return AVERROR_INVALIDDATA;
267 }
268 }
269 return AVERROR_INVALIDDATA;
270 }
271
272 static av_cold int gif_decode_init(AVCodecContext *avctx)
273 {
274 GifState *s = avctx->priv_data;
275
276 s->avctx = avctx;
277
278 ff_lzw_decode_open(&s->lzw);
279 return 0;
280 }
281
282 static int gif_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
283 AVPacket *avpkt)
284 {
285 const uint8_t *buf = avpkt->data;
286 int buf_size = avpkt->size;
287 GifState *s = avctx->priv_data;
288 AVFrame *picture = data;
289 int ret;
290
291 s->bytestream = buf;
292 s->bytestream_end = buf + buf_size;
293 if ((ret = gif_read_header1(s)) < 0)
294 return ret;
295
296 avctx->pix_fmt = AV_PIX_FMT_PAL8;
297 if ((ret = av_image_check_size(s->screen_width, s->screen_height, 0, avctx)) < 0)
298 return ret;
299 avcodec_set_dimensions(avctx, s->screen_width, s->screen_height);
300
301 if ((ret = ff_get_buffer(avctx, picture, 0)) < 0) {
302 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
303 return ret;
304 }
305 s->image_palette = (uint32_t *)picture->data[1];
306 ret = gif_parse_next_image(s, picture);
307 if (ret < 0)
308 return ret;
309
310 *got_frame = 1;
311 return s->bytestream - buf;
312 }
313
314 static av_cold int gif_decode_close(AVCodecContext *avctx)
315 {
316 GifState *s = avctx->priv_data;
317
318 ff_lzw_decode_close(&s->lzw);
319 return 0;
320 }
321
322 AVCodec ff_gif_decoder = {
323 .name = "gif",
324 .type = AVMEDIA_TYPE_VIDEO,
325 .id = AV_CODEC_ID_GIF,
326 .priv_data_size = sizeof(GifState),
327 .init = gif_decode_init,
328 .close = gif_decode_close,
329 .decode = gif_decode_frame,
330 .capabilities = CODEC_CAP_DR1,
331 .long_name = NULL_IF_CONFIG_SMALL("GIF (Graphics Interchange Format)"),
332 };