1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
|
/*
* webp muxer
* Copyright (c) 2014 Michael Niedermayer
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "libavutil/intreadwrite.h"
#include "libavutil/opt.h"
#include "avformat.h"
#include "internal.h"
typedef struct WebpContext{
AVClass *class;
int frame_count;
AVPacket last_pkt;
int loop;
int wrote_webp_header;
int using_webp_anim_encoder;
} WebpContext;
static int webp_init(AVFormatContext *s)
{
AVStream *st;
if (s->nb_streams != 1) {
av_log(s, AV_LOG_ERROR, "Only exactly 1 stream is supported\n");
return AVERROR(EINVAL);
}
st = s->streams[0];
if (st->codecpar->codec_id != AV_CODEC_ID_WEBP) {
av_log(s, AV_LOG_ERROR, "Only WebP is supported\n");
return AVERROR(EINVAL);
}
avpriv_set_pts_info(st, 24, 1, 1000);
return 0;
}
static int is_animated_webp_packet(AVPacket *pkt)
{
int skip = 0;
unsigned flags = 0;
if (pkt->size < 4)
return AVERROR_INVALIDDATA;
if (AV_RL32(pkt->data) == AV_RL32("RIFF"))
skip = 12;
// Safe to do this as a valid WebP bitstream is >=30 bytes.
if (pkt->size < skip + 4)
return AVERROR_INVALIDDATA;
if (AV_RL32(pkt->data + skip) == AV_RL32("VP8X")) {
flags |= pkt->data[skip + 4 + 4];
}
if (flags & 2) // ANIMATION_FLAG is on
return 1;
return 0;
}
static int flush(AVFormatContext *s, int trailer, int64_t pts)
{
WebpContext *w = s->priv_data;
AVStream *st = s->streams[0];
if (w->last_pkt.size) {
int skip = 0;
unsigned flags = 0;
int vp8x = 0;
if (AV_RL32(w->last_pkt.data) == AV_RL32("RIFF"))
skip = 12;
if (AV_RL32(w->last_pkt.data + skip) == AV_RL32("VP8X")) {
flags |= w->last_pkt.data[skip + 4 + 4];
vp8x = 1;
skip += AV_RL32(w->last_pkt.data + skip + 4) + 8;
}
if (!w->wrote_webp_header) {
avio_write(s->pb, "RIFF\0\0\0\0WEBP", 12);
w->wrote_webp_header = 1;
if (w->frame_count > 1) // first non-empty packet
w->frame_count = 1; // so we don't count previous empty packets.
}
if (w->frame_count == 1) {
if (!trailer) {
vp8x = 1;
flags |= 2 + 16;
}
if (vp8x) {
avio_write(s->pb, "VP8X", 4);
avio_wl32(s->pb, 10);
avio_w8(s->pb, flags);
avio_wl24(s->pb, 0);
avio_wl24(s->pb, st->codecpar->width - 1);
avio_wl24(s->pb, st->codecpar->height - 1);
}
if (!trailer) {
avio_write(s->pb, "ANIM", 4);
avio_wl32(s->pb, 6);
avio_wl32(s->pb, 0xFFFFFFFF);
avio_wl16(s->pb, w->loop);
}
}
if (w->frame_count > trailer) {
avio_write(s->pb, "ANMF", 4);
avio_wl32(s->pb, 16 + w->last_pkt.size - skip);
avio_wl24(s->pb, 0);
avio_wl24(s->pb, 0);
avio_wl24(s->pb, st->codecpar->width - 1);
avio_wl24(s->pb, st->codecpar->height - 1);
if (w->last_pkt.pts != AV_NOPTS_VALUE && pts != AV_NOPTS_VALUE) {
avio_wl24(s->pb, pts - w->last_pkt.pts);
} else
avio_wl24(s->pb, w->last_pkt.duration);
avio_w8(s->pb, 0);
}
avio_write(s->pb, w->last_pkt.data + skip, w->last_pkt.size - skip);
av_packet_unref(&w->last_pkt);
}
return 0;
}
static int webp_write_packet(AVFormatContext *s, AVPacket *pkt)
{
WebpContext *w = s->priv_data;
int ret;
if (!pkt->size)
return 0;
ret = is_animated_webp_packet(pkt);
if (ret < 0)
return ret;
w->using_webp_anim_encoder |= ret;
if (w->using_webp_anim_encoder) {
avio_write(s->pb, pkt->data, pkt->size);
w->wrote_webp_header = 1; // for good measure
} else {
int ret;
if ((ret = flush(s, 0, pkt->pts)) < 0)
return ret;
av_packet_ref(&w->last_pkt, pkt);
}
++w->frame_count;
return 0;
}
static int webp_write_trailer(AVFormatContext *s)
{
unsigned filesize;
WebpContext *w = s->priv_data;
if (w->using_webp_anim_encoder) {
if ((w->frame_count > 1) && w->loop) { // Write loop count.
avio_seek(s->pb, 42, SEEK_SET);
avio_wl16(s->pb, w->loop);
}
} else {
int ret;
if ((ret = flush(s, 1, AV_NOPTS_VALUE)) < 0)
return ret;
filesize = avio_tell(s->pb);
avio_seek(s->pb, 4, SEEK_SET);
avio_wl32(s->pb, filesize - 8);
// Note: without the following, avio only writes 8 bytes to the file.
avio_seek(s->pb, filesize, SEEK_SET);
}
return 0;
}
static void webp_deinit(AVFormatContext *s)
{
WebpContext *w = s->priv_data;
av_packet_unref(&w->last_pkt);
}
#define OFFSET(x) offsetof(WebpContext, x)
#define ENC AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
{ "loop", "Number of times to loop the output: 0 - infinite loop", OFFSET(loop),
AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 65535, ENC },
{ NULL },
};
static const AVClass webp_muxer_class = {
.class_name = "WebP muxer",
.item_name = av_default_item_name,
.version = LIBAVUTIL_VERSION_INT,
.option = options,
};
AVOutputFormat ff_webp_muxer = {
.name = "webp",
.long_name = NULL_IF_CONFIG_SMALL("WebP"),
.extensions = "webp",
.priv_data_size = sizeof(WebpContext),
.video_codec = AV_CODEC_ID_WEBP,
.init = webp_init,
.write_packet = webp_write_packet,
.write_trailer = webp_write_trailer,
.deinit = webp_deinit,
.priv_class = &webp_muxer_class,
.flags = AVFMT_VARIABLE_FPS,
};
|
