FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavformat/gif.c
Date: 2022-12-09 07:38:14
Exec Total Coverage
Lines: 72 89 80.9%
Functions: 5 5 100.0%
Branches: 33 62 53.2%

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 "libavutil/imgutils.h"
27 #include "libavutil/log.h"
28 #include "libavutil/opt.h"
29 #include "libavcodec/bytestream.h"
30 #include "libavcodec/gif.h"
31
32 typedef struct GIFContext {
33 AVClass *class;
34 int loop;
35 int last_delay;
36 int duration;
37 int64_t last_pos;
38 int have_end;
39 AVPacket *prev_pkt;
40 } GIFContext;
41
42 1 static int gif_write_header(AVFormatContext *s)
43 {
44
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1 if (s->nb_streams != 1 ||
45
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1 s->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_VIDEO ||
46
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1 s->streams[0]->codecpar->codec_id != AV_CODEC_ID_GIF) {
47 av_log(s, AV_LOG_ERROR,
48 "GIF muxer supports only a single video GIF stream.\n");
49 return AVERROR(EINVAL);
50 }
51
52 1 avpriv_set_pts_info(s->streams[0], 64, 1, 100);
53
54 1 return 0;
55 }
56
57 25 static int gif_parse_packet(AVFormatContext *s, const uint8_t *data, int size)
58 {
59 GetByteContext gb;
60 int x;
61
62 25 bytestream2_init(&gb, data, size);
63
64
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25 while (bytestream2_get_bytes_left(&gb) > 0) {
65 25 x = bytestream2_get_byte(&gb);
66
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25 if (x != GIF_EXTENSION_INTRODUCER)
67 return 0;
68
69 25 x = bytestream2_get_byte(&gb);
70
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25 while (x != GIF_GCE_EXT_LABEL && bytestream2_get_bytes_left(&gb) > 0) {
71 int block_size = bytestream2_get_byte(&gb);
72 if (!block_size)
73 break;
74 bytestream2_skip(&gb, block_size);
75 }
76
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25 if (x == GIF_GCE_EXT_LABEL)
78 25 return bytestream2_tell(&gb) + 2;
79 }
80
81 return 0;
82 }
83
84 25 static int gif_get_delay(GIFContext *gif, AVPacket *prev, AVPacket *new)
85 {
86
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25 if (new && new->pts != AV_NOPTS_VALUE)
87 24 gif->duration = av_clip_uint16(new->pts - prev->pts);
88
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1 else if (!new && gif->last_delay >= 0)
89 gif->duration = gif->last_delay;
90
91 25 return gif->duration;
92 }
93
94 26 static int gif_write_packet(AVFormatContext *s, AVPacket *new_pkt)
95 {
96 26 GIFContext *gif = s->priv_data;
97 26 AVIOContext *pb = s->pb;
98 26 AVPacket *pkt = gif->prev_pkt;
99
100
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26 if (!gif->prev_pkt) {
101 1 gif->prev_pkt = av_packet_alloc();
102
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1 if (!gif->prev_pkt)
103 return AVERROR(ENOMEM);
104 1 return av_packet_ref(gif->prev_pkt, new_pkt);
105 }
106
107 25 gif->last_pos = avio_tell(pb);
108
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25 if (pkt->size > 0)
109 25 gif->have_end = pkt->data[pkt->size - 1] == GIF_TRAILER;
110
111
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25 if (!gif->last_pos) {
112 int delay_pos;
113 1 int off = 13;
114
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1 if (pkt->size < 13)
116 return AVERROR(EINVAL);
117
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1 if (pkt->data[10] & 0x80)
119 1 off += 3 * (1 << ((pkt->data[10] & 0x07) + 1));
120
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1 if (pkt->size < off + 2)
122 return AVERROR(EINVAL);
123
124 1 avio_write(pb, pkt->data, off);
125
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1 if (pkt->data[off] == GIF_EXTENSION_INTRODUCER && pkt->data[off + 1] == 0xff)
127 off += 19;
128
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1 if (pkt->size <= off)
130 return AVERROR(EINVAL);
131
132 /* "NETSCAPE EXTENSION" for looped animation GIF */
133
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1 if (gif->loop >= 0) {
134 1 avio_w8(pb, GIF_EXTENSION_INTRODUCER); /* GIF Extension code */
135 1 avio_w8(pb, GIF_APP_EXT_LABEL); /* Application Extension Label */
136 1 avio_w8(pb, 0x0b); /* Length of Application Block */
137 1 avio_write(pb, "NETSCAPE2.0", sizeof("NETSCAPE2.0") - 1);
138 1 avio_w8(pb, 0x03); /* Length of Data Sub-Block */
139 1 avio_w8(pb, 0x01);
140 1 avio_wl16(pb, (uint16_t)gif->loop);
141 1 avio_w8(pb, 0x00); /* Data Sub-block Terminator */
142 }
143
144 1 delay_pos = gif_parse_packet(s, pkt->data + off, pkt->size - off);
145
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1 if (delay_pos > 0 && delay_pos < pkt->size - off - 2) {
146 1 avio_write(pb, pkt->data + off, delay_pos);
147 1 avio_wl16(pb, gif_get_delay(gif, pkt, new_pkt));
148 1 avio_write(pb, pkt->data + off + delay_pos + 2, pkt->size - off - delay_pos - 2);
149 } else {
150 avio_write(pb, pkt->data + off, pkt->size - off);
151 }
152 } else {
153 24 int delay_pos = gif_parse_packet(s, pkt->data, pkt->size);
154
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24 if (delay_pos > 0 && delay_pos < pkt->size - 2) {
156 24 avio_write(pb, pkt->data, delay_pos);
157 24 avio_wl16(pb, gif_get_delay(gif, pkt, new_pkt));
158 24 avio_write(pb, pkt->data + delay_pos + 2, pkt->size - delay_pos - 2);
159 } else {
160 avio_write(pb, pkt->data, pkt->size);
161 }
162 }
163
164 25 av_packet_unref(gif->prev_pkt);
165
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25 if (new_pkt)
166 24 return av_packet_ref(gif->prev_pkt, new_pkt);
167
168 1 return 0;
169 }
170
171 1 static int gif_write_trailer(AVFormatContext *s)
172 {
173 1 GIFContext *gif = s->priv_data;
174 1 AVIOContext *pb = s->pb;
175
176
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1 if (!gif->prev_pkt)
177 return AVERROR(EINVAL);
178
179 1 gif_write_packet(s, NULL);
180
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1 if (!gif->have_end)
182 1 avio_w8(pb, GIF_TRAILER);
183 1 av_packet_free(&gif->prev_pkt);
184
185 1 return 0;
186 }
187
188 #define OFFSET(x) offsetof(GIFContext, x)
189 #define ENC AV_OPT_FLAG_ENCODING_PARAM
190 static const AVOption options[] = {
191 { "loop", "Number of times to loop the output: -1 - no loop, 0 - infinite loop", OFFSET(loop),
192 AV_OPT_TYPE_INT, { .i64 = 0 }, -1, 65535, ENC },
193 { "final_delay", "Force delay (in centiseconds) after the last frame", OFFSET(last_delay),
194 AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 65535, ENC },
195 { NULL },
196 };
197
198 static const AVClass gif_muxer_class = {
199 .class_name = "GIF muxer",
200 .item_name = av_default_item_name,
201 .version = LIBAVUTIL_VERSION_INT,
202 .option = options,
203 };
204
205 const AVOutputFormat ff_gif_muxer = {
206 .name = "gif",
207 .long_name = NULL_IF_CONFIG_SMALL("CompuServe Graphics Interchange Format (GIF)"),
208 .mime_type = "image/gif",
209 .extensions = "gif",
210 .priv_data_size = sizeof(GIFContext),
211 .audio_codec = AV_CODEC_ID_NONE,
212 .video_codec = AV_CODEC_ID_GIF,
213 .write_header = gif_write_header,
214 .write_packet = gif_write_packet,
215 .write_trailer = gif_write_trailer,
216 .priv_class = &gif_muxer_class,
217 .flags = AVFMT_VARIABLE_FPS,
218 };
219