FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavformat/gif.c
Date: 2026-04-17 20:31:08
Exec Total Coverage
Lines: 71 86 82.6%
Functions: 5 5 100.0%
Branches: 31 58 53.4%
Line Branch Exec Source
1 /*
2 * Animated GIF muxer
3 * Copyright (c) 2000 Fabrice Bellard
4 *
5 * first version by Francois Revol <revol@free.fr>
6 *
7 * This file is part of FFmpeg.
8 *
9 * FFmpeg is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
13 *
14 * FFmpeg is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
18 *
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with FFmpeg; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24 #include "avformat.h"
25 #include "internal.h"
26 #include "mux.h"
27 #include "libavutil/imgutils.h"
28 #include "libavutil/log.h"
29 #include "libavutil/opt.h"
30 #include "libavcodec/bytestream.h"
31 #include "libavcodec/gif.h"
32
33 typedef struct GIFContext {
34 AVClass *class;
35 int loop;
36 int last_delay;
37 int duration;
38 int64_t last_pos;
39 int have_end;
40 AVPacket *prev_pkt;
41 } GIFContext;
42
43 1 static av_cold int gif_init(AVFormatContext *s)
44 {
45 1 avpriv_set_pts_info(s->streams[0], 64, 1, 100);
46
47 1 return 0;
48 }
49
50 25 static int gif_parse_packet(AVFormatContext *s, const uint8_t *data, int size)
51 {
52 GetByteContext gb;
53 int x;
54
55 25 bytestream2_init(&gb, data, size);
56
57
1/2
✓ Branch 1 taken 25 times.
✗ Branch 2 not taken.
 25 while (bytestream2_get_bytes_left(&gb) > 0) {
58 25 x = bytestream2_get_byte(&gb);
59
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 25 times.
 25 if (x != GIF_EXTENSION_INTRODUCER)
60 ✗ return 0;
61
62 25 x = bytestream2_get_byte(&gb);
63
1/4
✗ Branch 0 not taken.
✓ Branch 1 taken 25 times.
✗ Branch 3 not taken.
✗ Branch 4 not taken.
 25 while (x != GIF_GCE_EXT_LABEL && bytestream2_get_bytes_left(&gb) > 0) {
64 ✗ int block_size = bytestream2_get_byte(&gb);
65 ✗ if (!block_size)
66 ✗ break;
67 ✗ bytestream2_skip(&gb, block_size);
68 }
69
70
1/2
✓ Branch 0 taken 25 times.
✗ Branch 1 not taken.
 25 if (x == GIF_GCE_EXT_LABEL)
71 25 return bytestream2_tell(&gb) + 2;
72 }
73
74 ✗ return 0;
75 }
76
77 25 static int gif_get_delay(GIFContext *gif, AVPacket *prev, AVPacket *new)
78 {
79
3/4
✓ Branch 0 taken 24 times.
✓ Branch 1 taken 1 times.
✓ Branch 2 taken 24 times.
✗ Branch 3 not taken.
 25 if (new && new->pts != AV_NOPTS_VALUE)
80 24 gif->duration = av_clip_uint16(new->pts - prev->pts);
81
2/4
✓ Branch 0 taken 1 times.
✗ Branch 1 not taken.
✗ Branch 2 not taken.
✓ Branch 3 taken 1 times.
 1 else if (!new && gif->last_delay >= 0)
82 ✗ gif->duration = gif->last_delay;
83
1/2
✓ Branch 0 taken 1 times.
✗ Branch 1 not taken.
 1 else if (prev->duration)
84 1 gif->duration = prev->duration;
85
86 25 return gif->duration;
87 }
88
89 26 static int gif_write_packet(AVFormatContext *s, AVPacket *new_pkt)
90 {
91 26 GIFContext *gif = s->priv_data;
92 26 AVIOContext *pb = s->pb;
93 26 AVPacket *pkt = gif->prev_pkt;
94
95
2/2
✓ Branch 0 taken 1 times.
✓ Branch 1 taken 25 times.
 26 if (!gif->prev_pkt) {
96 1 gif->prev_pkt = av_packet_alloc();
97
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 1 times.
 1 if (!gif->prev_pkt)
98 ✗ return AVERROR(ENOMEM);
99 1 return av_packet_ref(gif->prev_pkt, new_pkt);
100 }
101
102 25 gif->last_pos = avio_tell(pb);
103
1/2
✓ Branch 0 taken 25 times.
✗ Branch 1 not taken.
 25 if (pkt->size > 0)
104 25 gif->have_end = pkt->data[pkt->size - 1] == GIF_TRAILER;
105
106
2/2
✓ Branch 0 taken 1 times.
✓ Branch 1 taken 24 times.
 25 if (!gif->last_pos) {
107 int delay_pos;
108 1 int off = 13;
109
110
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 1 times.
 1 if (pkt->size < 13)
111 ✗ return AVERROR(EINVAL);
112
113
1/2
✓ Branch 0 taken 1 times.
✗ Branch 1 not taken.
 1 if (pkt->data[10] & 0x80)
114 1 off += 3 * (1 << ((pkt->data[10] & 0x07) + 1));
115
116
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 1 times.
 1 if (pkt->size < off + 2)
117 ✗ return AVERROR(EINVAL);
118
119 1 avio_write(pb, pkt->data, off);
120
121
2/4
✓ Branch 0 taken 1 times.
✗ Branch 1 not taken.
✗ Branch 2 not taken.
✓ Branch 3 taken 1 times.
 1 if (pkt->data[off] == GIF_EXTENSION_INTRODUCER && pkt->data[off + 1] == 0xff)
122 ✗ off += 19;
123
124
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 1 times.
 1 if (pkt->size <= off)
125 ✗ return AVERROR(EINVAL);
126
127 /* "NETSCAPE EXTENSION" for looped animation GIF */
128
1/2
✓ Branch 0 taken 1 times.
✗ Branch 1 not taken.
 1 if (gif->loop >= 0) {
129 1 avio_w8(pb, GIF_EXTENSION_INTRODUCER); /* GIF Extension code */
130 1 avio_w8(pb, GIF_APP_EXT_LABEL); /* Application Extension Label */
131 1 avio_w8(pb, 0x0b); /* Length of Application Block */
132 1 avio_write(pb, "NETSCAPE2.0", sizeof("NETSCAPE2.0") - 1);
133 1 avio_w8(pb, 0x03); /* Length of Data Sub-Block */
134 1 avio_w8(pb, 0x01);
135 1 avio_wl16(pb, (uint16_t)gif->loop);
136 1 avio_w8(pb, 0x00); /* Data Sub-block Terminator */
137 }
138
139 1 delay_pos = gif_parse_packet(s, pkt->data + off, pkt->size - off);
140
2/4
✓ Branch 0 taken 1 times.
✗ Branch 1 not taken.
✓ Branch 2 taken 1 times.
✗ Branch 3 not taken.
 1 if (delay_pos > 0 && delay_pos < pkt->size - off - 2) {
141 1 avio_write(pb, pkt->data + off, delay_pos);
142 1 avio_wl16(pb, gif_get_delay(gif, pkt, new_pkt));
143 1 avio_write(pb, pkt->data + off + delay_pos + 2, pkt->size - off - delay_pos - 2);
144 } else {
145 ✗ avio_write(pb, pkt->data + off, pkt->size - off);
146 }
147 } else {
148 24 int delay_pos = gif_parse_packet(s, pkt->data, pkt->size);
149
150
2/4
✓ Branch 0 taken 24 times.
✗ Branch 1 not taken.
✓ Branch 2 taken 24 times.
✗ Branch 3 not taken.
 24 if (delay_pos > 0 && delay_pos < pkt->size - 2) {
151 24 avio_write(pb, pkt->data, delay_pos);
152 24 avio_wl16(pb, gif_get_delay(gif, pkt, new_pkt));
153 24 avio_write(pb, pkt->data + delay_pos + 2, pkt->size - delay_pos - 2);
154 } else {
155 ✗ avio_write(pb, pkt->data, pkt->size);
156 }
157 }
158
159 25 av_packet_unref(gif->prev_pkt);
160
2/2
✓ Branch 0 taken 24 times.
✓ Branch 1 taken 1 times.
 25 if (new_pkt)
161 24 return av_packet_ref(gif->prev_pkt, new_pkt);
162
163 1 return 0;
164 }
165
166 1 static int gif_write_trailer(AVFormatContext *s)
167 {
168 1 GIFContext *gif = s->priv_data;
169 1 AVIOContext *pb = s->pb;
170
171
1/2
✗ Branch 0 not taken.
✓ Branch 1 taken 1 times.
 1 if (!gif->prev_pkt)
172 ✗ return AVERROR(EINVAL);
173
174 1 gif_write_packet(s, NULL);
175
176
1/2
✓ Branch 0 taken 1 times.
✗ Branch 1 not taken.
 1 if (!gif->have_end)
177 1 avio_w8(pb, GIF_TRAILER);
178 1 av_packet_free(&gif->prev_pkt);
179
180 1 return 0;
181 }
182
183 #define OFFSET(x) offsetof(GIFContext, x)
184 #define ENC AV_OPT_FLAG_ENCODING_PARAM
185 static const AVOption options[] = {
186 { "loop", "Number of times to loop the output: -1 - no loop, 0 - infinite loop", OFFSET(loop),
187 AV_OPT_TYPE_INT, { .i64 = 0 }, -1, 65535, ENC },
188 { "final_delay", "Force delay (in centiseconds) after the last frame", OFFSET(last_delay),
189 AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 65535, ENC },
190 { NULL },
191 };
192
193 static const AVClass gif_muxer_class = {
194 .class_name = "GIF muxer",
195 .item_name = av_default_item_name,
196 .version = LIBAVUTIL_VERSION_INT,
197 .option = options,
198 };
199
200 const FFOutputFormat ff_gif_muxer = {
201 .p.name = "gif",
202 .p.long_name = NULL_IF_CONFIG_SMALL("CompuServe Graphics Interchange Format (GIF)"),
203 .p.mime_type = "image/gif",
204 .p.extensions = "gif",
205 .priv_data_size = sizeof(GIFContext),
206 .p.audio_codec = AV_CODEC_ID_NONE,
207 .p.video_codec = AV_CODEC_ID_GIF,
208 .p.subtitle_codec = AV_CODEC_ID_NONE,
209 .flags_internal = FF_OFMT_FLAG_MAX_ONE_OF_EACH |
210 FF_OFMT_FLAG_ONLY_DEFAULT_CODECS,
211 .init = gif_init,
212 .write_packet = gif_write_packet,
213 .write_trailer = gif_write_trailer,
214 .p.priv_class = &gif_muxer_class,
215 .p.flags = AVFMT_VARIABLE_FPS,
216 };
217