FFmpeg  4.4
webpenc.c
Go to the documentation of this file.
1 /*
2  * webp muxer
3  * Copyright (c) 2014 Michael Niedermayer
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "libavutil/intreadwrite.h"
23 #include "libavutil/opt.h"
24 #include "avformat.h"
25 #include "internal.h"
26 
27 typedef struct WebpContext{
28  AVClass *class;
31  int loop;
34 } WebpContext;
35 
37 {
38  AVStream *st;
39 
40  if (s->nb_streams != 1) {
41  av_log(s, AV_LOG_ERROR, "Only exactly 1 stream is supported\n");
42  return AVERROR(EINVAL);
43  }
44  st = s->streams[0];
45  if (st->codecpar->codec_id != AV_CODEC_ID_WEBP) {
46  av_log(s, AV_LOG_ERROR, "Only WebP is supported\n");
47  return AVERROR(EINVAL);
48  }
49  avpriv_set_pts_info(st, 24, 1, 1000);
50 
51  return 0;
52 }
53 
55 {
56  int skip = 0;
57  unsigned flags = 0;
58 
59  if (pkt->size < 4)
60  return AVERROR_INVALIDDATA;
61  if (AV_RL32(pkt->data) == AV_RL32("RIFF"))
62  skip = 12;
63  // Safe to do this as a valid WebP bitstream is >=30 bytes.
64  if (pkt->size < skip + 4)
65  return AVERROR_INVALIDDATA;
66  if (AV_RL32(pkt->data + skip) == AV_RL32("VP8X")) {
67  flags |= pkt->data[skip + 4 + 4];
68  }
69 
70  if (flags & 2) // ANIMATION_FLAG is on
71  return 1;
72  return 0;
73 }
74 
75 static int flush(AVFormatContext *s, int trailer, int64_t pts)
76 {
77  WebpContext *w = s->priv_data;
78  AVStream *st = s->streams[0];
79 
80  if (w->last_pkt.size) {
81  int skip = 0;
82  unsigned flags = 0;
83  int vp8x = 0;
84 
85  if (AV_RL32(w->last_pkt.data) == AV_RL32("RIFF"))
86  skip = 12;
87 
88  if (AV_RL32(w->last_pkt.data + skip) == AV_RL32("VP8X")) {
89  flags |= w->last_pkt.data[skip + 4 + 4];
90  vp8x = 1;
91  skip += AV_RL32(w->last_pkt.data + skip + 4) + 8;
92  }
93 
94  if (!w->wrote_webp_header) {
95  avio_write(s->pb, "RIFF\0\0\0\0WEBP", 12);
96  w->wrote_webp_header = 1;
97  if (w->frame_count > 1) // first non-empty packet
98  w->frame_count = 1; // so we don't count previous empty packets.
99  }
100 
101  if (w->frame_count == 1) {
102  if (!trailer) {
103  vp8x = 1;
104  flags |= 2 + 16;
105  }
106 
107  if (vp8x) {
108  avio_write(s->pb, "VP8X", 4);
109  avio_wl32(s->pb, 10);
110  avio_w8(s->pb, flags);
111  avio_wl24(s->pb, 0);
112  avio_wl24(s->pb, st->codecpar->width - 1);
113  avio_wl24(s->pb, st->codecpar->height - 1);
114  }
115  if (!trailer) {
116  avio_write(s->pb, "ANIM", 4);
117  avio_wl32(s->pb, 6);
118  avio_wl32(s->pb, 0xFFFFFFFF);
119  avio_wl16(s->pb, w->loop);
120  }
121  }
122 
123  if (w->frame_count > trailer) {
124  avio_write(s->pb, "ANMF", 4);
125  avio_wl32(s->pb, 16 + w->last_pkt.size - skip);
126  avio_wl24(s->pb, 0);
127  avio_wl24(s->pb, 0);
128  avio_wl24(s->pb, st->codecpar->width - 1);
129  avio_wl24(s->pb, st->codecpar->height - 1);
130  if (w->last_pkt.pts != AV_NOPTS_VALUE && pts != AV_NOPTS_VALUE) {
131  avio_wl24(s->pb, pts - w->last_pkt.pts);
132  } else
133  avio_wl24(s->pb, w->last_pkt.duration);
134  avio_w8(s->pb, 0);
135  }
136  avio_write(s->pb, w->last_pkt.data + skip, w->last_pkt.size - skip);
137  av_packet_unref(&w->last_pkt);
138  }
139 
140  return 0;
141 }
142 
144 {
145  WebpContext *w = s->priv_data;
146  int ret;
147 
148  if (!pkt->size)
149  return 0;
151  if (ret < 0)
152  return ret;
153  w->using_webp_anim_encoder |= ret;
154 
155  if (w->using_webp_anim_encoder) {
156  avio_write(s->pb, pkt->data, pkt->size);
157  w->wrote_webp_header = 1; // for good measure
158  } else {
159  int ret;
160  if ((ret = flush(s, 0, pkt->pts)) < 0)
161  return ret;
162  av_packet_ref(&w->last_pkt, pkt);
163  }
164  ++w->frame_count;
165 
166  return 0;
167 }
168 
170 {
171  unsigned filesize;
172  WebpContext *w = s->priv_data;
173 
174  if (w->using_webp_anim_encoder) {
175  if ((w->frame_count > 1) && w->loop) { // Write loop count.
176  avio_seek(s->pb, 42, SEEK_SET);
177  avio_wl16(s->pb, w->loop);
178  }
179  } else {
180  int ret;
181  if ((ret = flush(s, 1, AV_NOPTS_VALUE)) < 0)
182  return ret;
183 
184  filesize = avio_tell(s->pb);
185  avio_seek(s->pb, 4, SEEK_SET);
186  avio_wl32(s->pb, filesize - 8);
187  // Note: without the following, avio only writes 8 bytes to the file.
188  avio_seek(s->pb, filesize, SEEK_SET);
189  }
190 
191  return 0;
192 }
193 
195 {
196  WebpContext *w = s->priv_data;
197 
198  av_packet_unref(&w->last_pkt);
199 }
200 
201 #define OFFSET(x) offsetof(WebpContext, x)
202 #define ENC AV_OPT_FLAG_ENCODING_PARAM
203 static const AVOption options[] = {
204  { "loop", "Number of times to loop the output: 0 - infinite loop", OFFSET(loop),
205  AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 65535, ENC },
206  { NULL },
207 };
208 
209 static const AVClass webp_muxer_class = {
210  .class_name = "WebP muxer",
211  .item_name = av_default_item_name,
212  .version = LIBAVUTIL_VERSION_INT,
213  .option = options,
214 };
216  .name = "webp",
217  .long_name = NULL_IF_CONFIG_SMALL("WebP"),
218  .extensions = "webp",
219  .priv_data_size = sizeof(WebpContext),
220  .video_codec = AV_CODEC_ID_WEBP,
224  .deinit = webp_deinit,
225  .priv_class = &webp_muxer_class,
227 };
Main libavformat public API header.
#define AVFMT_VARIABLE_FPS
Format allows variable fps.
Definition: avformat.h:465
int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
fseek() equivalent for AVIOContext.
Definition: aviobuf.c:253
void avio_wl32(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:375
void avio_wl16(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:455
void avio_w8(AVIOContext *s, int b)
Definition: aviobuf.c:203
static av_always_inline int64_t avio_tell(AVIOContext *s)
ftell() equivalent for AVIOContext.
Definition: avio.h:557
void avio_wl24(AVIOContext *s, unsigned int val)
Definition: aviobuf.c:467
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:225
#define AV_RL32
Definition: intreadwrite.h:146
#define flags(name, subs,...)
Definition: cbs_av1.c:561
#define s(width, name)
Definition: cbs_vp9.c:257
#define NULL
Definition: coverity.c:32
static void write_packet(OutputFile *of, AVPacket *pkt, OutputStream *ost, int unqueue)
Definition: ffmpeg.c:729
static int loop
Definition: ffplay.c:341
static void write_header(FFV1Context *f)
Definition: ffv1enc.c:346
@ AV_OPT_TYPE_INT
Definition: opt.h:225
@ AV_CODEC_ID_WEBP
Definition: codec_id.h:221
void av_packet_unref(AVPacket *pkt)
Wipe the packet.
Definition: avpacket.c:634
int av_packet_ref(AVPacket *dst, const AVPacket *src)
Setup a new reference to the data described by a given packet.
Definition: avpacket.c:641
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:59
#define AVERROR(e)
Definition: error.h:43
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:194
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
#define AV_NOPTS_VALUE
Undefined timestamp value.
Definition: avutil.h:248
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
void avpriv_set_pts_info(AVStream *s, int pts_wrap_bits, unsigned int pts_num, unsigned int pts_den)
Set the time base and wrapping info for a given stream.
Definition: utils.c:4941
common internal API header
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
uint8_t w
Definition: llviddspenc.c:39
AVOptions.
Describe the class of an AVClass context structure.
Definition: log.h:67
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
int width
Video only.
Definition: codec_par.h:126
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: codec_par.h:60
Format I/O context.
Definition: avformat.h:1232
AVOption.
Definition: opt.h:248
const char * name
Definition: avformat.h:491
This structure stores compressed data.
Definition: packet.h:346
int size
Definition: packet.h:370
int64_t pts
Presentation timestamp in AVStream->time_base units; the time at which the decompressed packet will b...
Definition: packet.h:362
uint8_t * data
Definition: packet.h:369
Stream structure.
Definition: avformat.h:873
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1038
int loop
Definition: webpenc.c:31
int frame_count
Definition: webpenc.c:29
int using_webp_anim_encoder
Definition: webpenc.c:33
AVPacket last_pkt
Definition: webpenc.c:30
int wrote_webp_header
Definition: webpenc.c:32
#define av_log(a,...)
AVPacket * pkt
Definition: movenc.c:59
static int64_t pts
static int write_trailer(AVFormatContext *s1)
Definition: v4l2enc.c:98
static const AVOption options[]
Definition: webpenc.c:203
static void webp_deinit(AVFormatContext *s)
Definition: webpenc.c:194
static int webp_write_trailer(AVFormatContext *s)
Definition: webpenc.c:169
#define ENC
Definition: webpenc.c:202
AVOutputFormat ff_webp_muxer
Definition: webpenc.c:215
static int webp_write_header(AVFormatContext *s)
Definition: webpenc.c:36
static const AVClass webp_muxer_class
Definition: webpenc.c:209
#define OFFSET(x)
Definition: webpenc.c:201
static int is_animated_webp_packet(AVPacket *pkt)
Definition: webpenc.c:54
static int flush(AVFormatContext *s, int trailer, int64_t pts)
Definition: webpenc.c:75
static int webp_write_packet(AVFormatContext *s, AVPacket *pkt)
Definition: webpenc.c:143