GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/gif.c Lines: 187 253 73.9 %
Date: 2019-11-22 03:34:36 Branches: 111 188 59.0 %

Line Branch Exec Source
1
/*
2
 * Copyright (c) 2000 Fabrice Bellard
3
 * Copyright (c) 2002 Francois Revol
4
 * Copyright (c) 2006 Baptiste Coudurier
5
 * Copyright (c) 2018 Bjorn Roche
6
 * Copyright (c) 2018 Paul B Mahol
7
 *
8
 * first version by Francois Revol <revol@free.fr>
9
 *
10
 * This file is part of FFmpeg.
11
 *
12
 * FFmpeg is free software; you can redistribute it and/or
13
 * modify it under the terms of the GNU Lesser General Public
14
 * License as published by the Free Software Foundation; either
15
 * version 2.1 of the License, or (at your option) any later version.
16
 *
17
 * FFmpeg is distributed in the hope that it will be useful,
18
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
20
 * Lesser General Public License for more details.
21
 *
22
 * You should have received a copy of the GNU Lesser General Public
23
 * License along with FFmpeg; if not, write to the Free Software
24
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25
 */
26
27
/**
28
 * @file
29
 * GIF encoder
30
 * @see http://www.w3.org/Graphics/GIF/spec-gif89a.txt
31
 */
32
33
#define BITSTREAM_WRITER_LE
34
#include "libavutil/opt.h"
35
#include "libavutil/imgutils.h"
36
#include "avcodec.h"
37
#include "bytestream.h"
38
#include "internal.h"
39
#include "lzw.h"
40
#include "gif.h"
41
42
#include "put_bits.h"
43
44
#define DEFAULT_TRANSPARENCY_INDEX 0x1f
45
46
typedef struct GIFContext {
47
    const AVClass *class;
48
    LZWState *lzw;
49
    uint8_t *buf;
50
    int buf_size;
51
    AVFrame *last_frame;
52
    int flags;
53
    int image;
54
    uint32_t palette[AVPALETTE_COUNT];  ///< local reference palette for !pal8
55
    int palette_loaded;
56
    int transparent_index;
57
    uint8_t *tmpl;                      ///< temporary line buffer
58
} GIFContext;
59
60
enum {
61
    GF_OFFSETTING = 1<<0,
62
    GF_TRANSDIFF  = 1<<1,
63
};
64
65
1056
static int is_image_translucent(AVCodecContext *avctx,
66
                                const uint8_t *buf, const int linesize)
67
{
68
1056
    GIFContext *s = avctx->priv_data;
69
1056
    int trans = s->transparent_index;
70
71
1056
    if (trans < 0)
72
1056
        return 0;
73
74
    for (int y = 0; y < avctx->height; y++) {
75
        for (int x = 0; x < avctx->width; x++) {
76
            if (buf[x] == trans) {
77
                return 1;
78
            }
79
        }
80
        buf += linesize;
81
    }
82
83
    return 0;
84
}
85
86
39
static int get_palette_transparency_index(const uint32_t *palette)
87
{
88
39
    int transparent_color_index = -1;
89
39
    unsigned i, smallest_alpha = 0xff;
90
91
39
    if (!palette)
92
30
        return -1;
93
94
2313
    for (i = 0; i < AVPALETTE_COUNT; i++) {
95
2304
        const uint32_t v = palette[i];
96
2304
        if (v >> 24 < smallest_alpha) {
97
2
            smallest_alpha = v >> 24;
98
2
            transparent_color_index = i;
99
        }
100
    }
101
9
    return smallest_alpha < 128 ? transparent_color_index : -1;
102
}
103
104
1056
static int pick_palette_entry(const uint8_t *buf, int linesize, int w, int h)
105
{
106
1056
    int histogram[AVPALETTE_COUNT] = {0};
107
    int x, y, i;
108
109
33543
    for (y = 0; y < h; y++) {
110
3190262
        for (x = 0; x < w; x++)
111
3157775
            histogram[buf[x]]++;
112
32487
        buf += linesize;
113
    }
114
7312
    for (i = 0; i < FF_ARRAY_ELEMS(histogram); i++)
115
7288
        if (!histogram[i])
116
1032
            return i;
117
24
    return -1;
118
}
119
120
static void gif_crop_translucent(AVCodecContext *avctx,
121
                                 const uint8_t *buf, const int linesize,
122
                                 int *width, int *height,
123
                                 int *x_start, int *y_start)
124
{
125
    GIFContext *s = avctx->priv_data;
126
    int trans = s->transparent_index;
127
128
    /* Crop image */
129
    if ((s->flags & GF_OFFSETTING) && trans >= 0) {
130
        const int w = avctx->width;
131
        const int h = avctx->height;
132
        int x_end = w - 1,
133
            y_end = h - 1;
134
135
        // crop top
136
        while (*y_start < y_end) {
137
            int is_trans = 1;
138
            for (int i = 0; i < w; i++) {
139
                if (buf[linesize * *y_start + i] != trans) {
140
                    is_trans = 0;
141
                    break;
142
                }
143
            }
144
145
            if (!is_trans)
146
                break;
147
            (*y_start)++;
148
        }
149
150
        // crop bottom
151
        while (y_end > *y_start) {
152
            int is_trans = 1;
153
            for (int i = 0; i < w; i++) {
154
                if (buf[linesize * y_end + i] != trans) {
155
                    is_trans = 0;
156
                    break;
157
                }
158
            }
159
            if (!is_trans)
160
                break;
161
            y_end--;
162
        }
163
164
        // crop left
165
        while (*x_start < x_end) {
166
            int is_trans = 1;
167
            for (int i = *y_start; i < y_end; i++) {
168
                if (buf[linesize * i + *x_start] != trans) {
169
                    is_trans = 0;
170
                    break;
171
                }
172
            }
173
            if (!is_trans)
174
                break;
175
            (*x_start)++;
176
        }
177
178
        // crop right
179
        while (x_end > *x_start) {
180
            int is_trans = 1;
181
            for (int i = *y_start; i < y_end; i++) {
182
                if (buf[linesize * i + x_end] != trans) {
183
                    is_trans = 0;
184
                    break;
185
                }
186
            }
187
            if (!is_trans)
188
                break;
189
            x_end--;
190
        }
191
192
        *height = y_end + 1 - *y_start;
193
        *width  = x_end + 1 - *x_start;
194
        av_log(avctx, AV_LOG_DEBUG,"%dx%d image at pos (%d;%d) [area:%dx%d]\n",
195
               *width, *height, *x_start, *y_start, avctx->width, avctx->height);
196
    }
197
}
198
199
1063
static void gif_crop_opaque(AVCodecContext *avctx,
200
                            const uint32_t *palette,
201
                            const uint8_t *buf, const int linesize,
202
                            int *width, int *height, int *x_start, int *y_start)
203
{
204
1063
    GIFContext *s = avctx->priv_data;
205
206
    /* Crop image */
207

1063
    if ((s->flags & GF_OFFSETTING) && s->last_frame && !palette) {
208
1056
        const uint8_t *ref = s->last_frame->data[0];
209
1056
        const int ref_linesize = s->last_frame->linesize[0];
210
1056
        int x_end = avctx->width  - 1,
211
1056
            y_end = avctx->height - 1;
212
213
        /* skip common lines */
214
100704
        while (*y_start < y_end) {
215
100704
            if (memcmp(ref + *y_start*ref_linesize, buf + *y_start*linesize, *width))
216
1056
                break;
217
99648
            (*y_start)++;
218
        }
219
99777
        while (y_end > *y_start) {
220
99777
            if (memcmp(ref + y_end*ref_linesize, buf + y_end*linesize, *width))
221
1056
                break;
222
98721
            y_end--;
223
        }
224
1056
        *height = y_end + 1 - *y_start;
225
226
        /* skip common columns */
227
96923
        while (*x_start < x_end) {
228
96923
            int same_column = 1;
229
2498501
            for (int y = *y_start; y <= y_end; y++) {
230
2402634
                if (ref[y*ref_linesize + *x_start] != buf[y*linesize + *x_start]) {
231
1056
                    same_column = 0;
232
1056
                    break;
233
                }
234
            }
235
96923
            if (!same_column)
236
1056
                break;
237
95867
            (*x_start)++;
238
        }
239
104460
        while (x_end > *x_start) {
240
104460
            int same_column = 1;
241
2546113
            for (int y = *y_start; y <= y_end; y++) {
242
2442709
                if (ref[y*ref_linesize + x_end] != buf[y*linesize + x_end]) {
243
1056
                    same_column = 0;
244
1056
                    break;
245
                }
246
            }
247
104460
            if (!same_column)
248
1056
                break;
249
103404
            x_end--;
250
        }
251
1056
        *width = x_end + 1 - *x_start;
252
253
1056
        av_log(avctx, AV_LOG_DEBUG,"%dx%d image at pos (%d;%d) [area:%dx%d]\n",
254
               *width, *height, *x_start, *y_start, avctx->width, avctx->height);
255
    }
256
1063
}
257
258
1063
static int gif_image_write_image(AVCodecContext *avctx,
259
                                 uint8_t **bytestream, uint8_t *end,
260
                                 const uint32_t *palette,
261
                                 const uint8_t *buf, const int linesize,
262
                                 AVPacket *pkt)
263
{
264
1063
    GIFContext *s = avctx->priv_data;
265
1063
    int disposal, len = 0, height = avctx->height, width = avctx->width, x, y;
266
1063
    int x_start = 0, y_start = 0, trans = s->transparent_index;
267

1063
    int bcid = -1, honor_transparency = (s->flags & GF_TRANSDIFF) && s->last_frame && !palette;
268
    const uint8_t *ptr;
269
270

1063
    if (!s->image && avctx->frame_number && is_image_translucent(avctx, buf, linesize)) {
271
        gif_crop_translucent(avctx, buf, linesize, &width, &height, &x_start, &y_start);
272
        honor_transparency = 0;
273
        disposal = GCE_DISPOSAL_BACKGROUND;
274
    } else {
275
1063
        gif_crop_opaque(avctx, palette, buf, linesize, &width, &height, &x_start, &y_start);
276
1063
        disposal = GCE_DISPOSAL_INPLACE;
277
    }
278
279

1063
    if (s->image || !avctx->frame_number) { /* GIF header */
280
7
        const uint32_t *global_palette = palette ? palette : s->palette;
281
7
        const AVRational sar = avctx->sample_aspect_ratio;
282
7
        int64_t aspect = 0;
283
284

7
        if (sar.num > 0 && sar.den > 0) {
285
            aspect = sar.num * 64LL / sar.den - 15;
286
            if (aspect < 0 || aspect > 255)
287
                aspect = 0;
288
        }
289
290
7
        bytestream_put_buffer(bytestream, gif89a_sig, sizeof(gif89a_sig));
291
7
        bytestream_put_le16(bytestream, avctx->width);
292
7
        bytestream_put_le16(bytestream, avctx->height);
293
294
7
        bcid = get_palette_transparency_index(global_palette);
295
296
7
        bytestream_put_byte(bytestream, 0xf7); /* flags: global clut, 256 entries */
297
7
        bytestream_put_byte(bytestream, bcid < 0 ? DEFAULT_TRANSPARENCY_INDEX : bcid); /* background color index */
298
7
        bytestream_put_byte(bytestream, aspect);
299
1799
        for (int i = 0; i < 256; i++) {
300
1792
            const uint32_t v = global_palette[i] & 0xffffff;
301
1792
            bytestream_put_be24(bytestream, v);
302
        }
303
    }
304
305

1063
    if (honor_transparency && trans < 0) {
306
1056
        trans = pick_palette_entry(buf + y_start*linesize + x_start,
307
                                   linesize, width, height);
308
1056
        if (trans < 0) // TODO, patch welcome
309
24
            av_log(avctx, AV_LOG_DEBUG, "No available color, can not use transparency\n");
310
    }
311
312
1063
    if (trans < 0)
313
31
        honor_transparency = 0;
314
315

1063
    bcid = honor_transparency || disposal == GCE_DISPOSAL_BACKGROUND ? trans : get_palette_transparency_index(palette);
316
317
    /* graphic control extension */
318
1063
    bytestream_put_byte(bytestream, GIF_EXTENSION_INTRODUCER);
319
1063
    bytestream_put_byte(bytestream, GIF_GCE_EXT_LABEL);
320
1063
    bytestream_put_byte(bytestream, 0x04); /* block size */
321
1063
    bytestream_put_byte(bytestream, disposal<<2 | (bcid >= 0));
322
1063
    bytestream_put_le16(bytestream, 5); // default delay
323
1063
    bytestream_put_byte(bytestream, bcid < 0 ? DEFAULT_TRANSPARENCY_INDEX : bcid);
324
1063
    bytestream_put_byte(bytestream, 0x00);
325
326
    /* image block */
327
1063
    bytestream_put_byte(bytestream, GIF_IMAGE_SEPARATOR);
328
1063
    bytestream_put_le16(bytestream, x_start);
329
1063
    bytestream_put_le16(bytestream, y_start);
330
1063
    bytestream_put_le16(bytestream, width);
331
1063
    bytestream_put_le16(bytestream, height);
332
333
1063
    if (!palette) {
334
1062
        bytestream_put_byte(bytestream, 0x00); /* flags */
335
    } else {
336
        unsigned i;
337
1
        bytestream_put_byte(bytestream, 1<<7 | 0x7); /* flags */
338
257
        for (i = 0; i < AVPALETTE_COUNT; i++) {
339
256
            const uint32_t v = palette[i];
340
256
            bytestream_put_be24(bytestream, v);
341
        }
342
    }
343
344
1063
    bytestream_put_byte(bytestream, 0x08);
345
346
1063
    ff_lzw_encode_init(s->lzw, s->buf, s->buf_size,
347
                       12, FF_LZW_GIF, put_bits);
348
349
1063
    ptr = buf + y_start*linesize + x_start;
350
1063
    if (honor_transparency) {
351
1032
        const int ref_linesize = s->last_frame->linesize[0];
352
1032
        const uint8_t *ref = s->last_frame->data[0] + y_start*ref_linesize + x_start;
353
354
26607
        for (y = 0; y < height; y++) {
355
25575
            memcpy(s->tmpl, ptr, width);
356
750326
            for (x = 0; x < width; x++)
357
724751
                if (ref[x] == ptr[x])
358
367271
                    s->tmpl[x] = trans;
359
25575
            len += ff_lzw_encode(s->lzw, s->tmpl, width);
360
25575
            ptr += linesize;
361
25575
            ref += ref_linesize;
362
        }
363
    } else {
364
8533
        for (y = 0; y < height; y++) {
365
8502
            len += ff_lzw_encode(s->lzw, ptr, width);
366
8502
            ptr += linesize;
367
        }
368
    }
369
1063
    len += ff_lzw_encode_flush(s->lzw, flush_put_bits);
370
371
1063
    ptr = s->buf;
372
10314
    while (len > 0) {
373
9251
        int size = FFMIN(255, len);
374
9251
        bytestream_put_byte(bytestream, size);
375
9251
        if (end - *bytestream < size)
376
            return -1;
377
9251
        bytestream_put_buffer(bytestream, ptr, size);
378
9251
        ptr += size;
379
9251
        len -= size;
380
    }
381
1063
    bytestream_put_byte(bytestream, 0x00); /* end of image block */
382
1063
    return 0;
383
}
384
385
7
static av_cold int gif_encode_init(AVCodecContext *avctx)
386
{
387
7
    GIFContext *s = avctx->priv_data;
388
389

7
    if (avctx->width > 65535 || avctx->height > 65535) {
390
        av_log(avctx, AV_LOG_ERROR, "GIF does not support resolutions above 65535x65535\n");
391
        return AVERROR(EINVAL);
392
    }
393
394
7
    s->transparent_index = -1;
395
396
7
    s->lzw = av_mallocz(ff_lzw_encode_state_size);
397
7
    s->buf_size = avctx->width*avctx->height*2 + 1000;
398
7
    s->buf = av_malloc(s->buf_size);
399
7
    s->tmpl = av_malloc(avctx->width);
400

7
    if (!s->tmpl || !s->buf || !s->lzw)
401
        return AVERROR(ENOMEM);
402
403
7
    if (avpriv_set_systematic_pal2(s->palette, avctx->pix_fmt) < 0)
404
1
        av_assert0(avctx->pix_fmt == AV_PIX_FMT_PAL8);
405
406
7
    return 0;
407
}
408
409
1063
static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
410
                            const AVFrame *pict, int *got_packet)
411
{
412
1063
    GIFContext *s = avctx->priv_data;
413
    uint8_t *outbuf_ptr, *end;
414
1063
    const uint32_t *palette = NULL;
415
    int ret;
416
417
1063
    if ((ret = ff_alloc_packet2(avctx, pkt, avctx->width*avctx->height*7/5 + AV_INPUT_BUFFER_MIN_SIZE, 0)) < 0)
418
        return ret;
419
1063
    outbuf_ptr = pkt->data;
420
1063
    end        = pkt->data + pkt->size;
421
422
1063
    if (avctx->pix_fmt == AV_PIX_FMT_PAL8) {
423
173
        palette = (uint32_t*)pict->data[1];
424
425
173
        if (!s->palette_loaded) {
426
1
            memcpy(s->palette, palette, AVPALETTE_SIZE);
427
1
            s->transparent_index = get_palette_transparency_index(palette);
428
1
            s->palette_loaded = 1;
429
172
        } else if (!memcmp(s->palette, palette, AVPALETTE_SIZE)) {
430
172
            palette = NULL;
431
        }
432
    }
433
434
1063
    gif_image_write_image(avctx, &outbuf_ptr, end, palette,
435
1063
                          pict->data[0], pict->linesize[0], pkt);
436

1063
    if (!s->last_frame && !s->image) {
437
7
        s->last_frame = av_frame_alloc();
438
7
        if (!s->last_frame)
439
            return AVERROR(ENOMEM);
440
    }
441
442
1063
    if (!s->image) {
443
1063
        av_frame_unref(s->last_frame);
444
1063
        ret = av_frame_ref(s->last_frame, (AVFrame*)pict);
445
1063
        if (ret < 0)
446
            return ret;
447
    }
448
449
1063
    pkt->size   = outbuf_ptr - pkt->data;
450

1063
    if (s->image || !avctx->frame_number)
451
7
        pkt->flags |= AV_PKT_FLAG_KEY;
452
1063
    *got_packet = 1;
453
454
1063
    return 0;
455
}
456
457
7
static int gif_encode_close(AVCodecContext *avctx)
458
{
459
7
    GIFContext *s = avctx->priv_data;
460
461
7
    av_freep(&s->lzw);
462
7
    av_freep(&s->buf);
463
7
    s->buf_size = 0;
464
7
    av_frame_free(&s->last_frame);
465
7
    av_freep(&s->tmpl);
466
7
    return 0;
467
}
468
469
#define OFFSET(x) offsetof(GIFContext, x)
470
#define FLAGS AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
471
static const AVOption gif_options[] = {
472
    { "gifflags", "set GIF flags", OFFSET(flags), AV_OPT_TYPE_FLAGS, {.i64 = GF_OFFSETTING|GF_TRANSDIFF}, 0, INT_MAX, FLAGS, "flags" },
473
        { "offsetting", "enable picture offsetting", 0, AV_OPT_TYPE_CONST, {.i64=GF_OFFSETTING}, INT_MIN, INT_MAX, FLAGS, "flags" },
474
        { "transdiff", "enable transparency detection between frames", 0, AV_OPT_TYPE_CONST, {.i64=GF_TRANSDIFF}, INT_MIN, INT_MAX, FLAGS, "flags" },
475
    { "gifimage", "enable encoding only images per frame", OFFSET(image), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, FLAGS },
476
    { NULL }
477
};
478
479
static const AVClass gif_class = {
480
    .class_name = "GIF encoder",
481
    .item_name  = av_default_item_name,
482
    .option     = gif_options,
483
    .version    = LIBAVUTIL_VERSION_INT,
484
};
485
486
AVCodec ff_gif_encoder = {
487
    .name           = "gif",
488
    .long_name      = NULL_IF_CONFIG_SMALL("GIF (Graphics Interchange Format)"),
489
    .type           = AVMEDIA_TYPE_VIDEO,
490
    .id             = AV_CODEC_ID_GIF,
491
    .priv_data_size = sizeof(GIFContext),
492
    .init           = gif_encode_init,
493
    .encode2        = gif_encode_frame,
494
    .close          = gif_encode_close,
495
    .pix_fmts       = (const enum AVPixelFormat[]){
496
        AV_PIX_FMT_RGB8, AV_PIX_FMT_BGR8, AV_PIX_FMT_RGB4_BYTE, AV_PIX_FMT_BGR4_BYTE,
497
        AV_PIX_FMT_GRAY8, AV_PIX_FMT_PAL8, AV_PIX_FMT_NONE
498
    },
499
    .priv_class     = &gif_class,
500
};