FFmpeg
v4l2enc.c
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1 /*
2  * Copyright (c) 2013 Clément Bœsch
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 #include "v4l2-common.h"
22 #include "avdevice.h"
23 
24 typedef struct {
25  AVClass *class;
26  int fd;
27 } V4L2Context;
28 
30 {
31  int res = 0, flags = O_RDWR;
32  struct v4l2_format fmt = {
33  .type = V4L2_BUF_TYPE_VIDEO_OUTPUT
34  };
35  V4L2Context *s = s1->priv_data;
36  AVCodecParameters *par;
37  uint32_t v4l2_pixfmt;
38 
39  if (s1->flags & AVFMT_FLAG_NONBLOCK)
40  flags |= O_NONBLOCK;
41 
42  s->fd = open(s1->url, flags);
43  if (s->fd < 0) {
44  res = AVERROR(errno);
45  av_log(s1, AV_LOG_ERROR, "Unable to open V4L2 device '%s'\n", s1->url);
46  return res;
47  }
48 
49  if (s1->nb_streams != 1 ||
52  av_log(s1, AV_LOG_ERROR,
53  "V4L2 output device supports only a single raw video stream\n");
54  return AVERROR(EINVAL);
55  }
56 
57  par = s1->streams[0]->codecpar;
58 
59  v4l2_pixfmt = ff_fmt_ff2v4l(par->format, AV_CODEC_ID_RAWVIDEO);
60  if (!v4l2_pixfmt) { // XXX: try to force them one by one?
61  av_log(s1, AV_LOG_ERROR, "Unknown V4L2 pixel format equivalent for %s\n",
63  return AVERROR(EINVAL);
64  }
65 
66  if (ioctl(s->fd, VIDIOC_G_FMT, &fmt) < 0) {
67  res = AVERROR(errno);
68  av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_FMT): %s\n", av_err2str(res));
69  return res;
70  }
71 
72  fmt.fmt.pix.width = par->width;
73  fmt.fmt.pix.height = par->height;
74  fmt.fmt.pix.pixelformat = v4l2_pixfmt;
75  fmt.fmt.pix.sizeimage = av_image_get_buffer_size(par->format, par->width, par->height, 1);
76 
77  if (ioctl(s->fd, VIDIOC_S_FMT, &fmt) < 0) {
78  res = AVERROR(errno);
79  av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_S_FMT): %s\n", av_err2str(res));
80  return res;
81  }
82 
83  return res;
84 }
85 
87 {
88  const V4L2Context *s = s1->priv_data;
89  if (write(s->fd, pkt->data, pkt->size) == -1)
90  return AVERROR(errno);
91  return 0;
92 }
93 
95 {
96  const V4L2Context *s = s1->priv_data;
97  close(s->fd);
98  return 0;
99 }
100 
101 static const AVClass v4l2_class = {
102  .class_name = "V4L2 outdev",
103  .item_name = av_default_item_name,
104  .version = LIBAVUTIL_VERSION_INT,
106 };
107 
109  .name = "video4linux2,v4l2",
110  .long_name = NULL_IF_CONFIG_SMALL("Video4Linux2 output device"),
111  .priv_data_size = sizeof(V4L2Context),
112  .audio_codec = AV_CODEC_ID_NONE,
113  .video_codec = AV_CODEC_ID_RAWVIDEO,
117  .flags = AVFMT_NOFILE,
118  .priv_class = &v4l2_class,
119 };
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
static const AVClass v4l2_class
Definition: v4l2enc.c:101
enum AVCodecID codec_id
Specific type of the encoded data (the codec used).
Definition: avcodec.h:3957
int size
Definition: avcodec.h:1478
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:191
uint32_t ff_fmt_ff2v4l(enum AVPixelFormat pix_fmt, enum AVCodecID codec_id)
Definition: v4l2-common.c:73
static AVPacket pkt
This struct describes the properties of an encoded stream.
Definition: avcodec.h:3949
Format I/O context.
Definition: avformat.h:1358
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
#define AVFMT_FLAG_NONBLOCK
Do not block when reading packets from input.
Definition: avformat.h:1492
#define av_cold
Definition: attributes.h:82
int width
Video only.
Definition: avcodec.h:4023
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1426
int flags
Flags modifying the (de)muxer behaviour.
Definition: avformat.h:1489
uint8_t * data
Definition: avcodec.h:1477
#define av_log(a,...)
static av_cold int write_header(AVFormatContext *s1)
Definition: v4l2enc.c:29
Main libavdevice API header.
int av_image_get_buffer_size(enum AVPixelFormat pix_fmt, int width, int height, int align)
Return the size in bytes of the amount of data required to store an image with the given parameters...
Definition: imgutils.c:431
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
char * url
input or output URL.
Definition: avformat.h:1454
enum AVMediaType codec_type
General type of the encoded data.
Definition: avcodec.h:3953
AVOutputFormat ff_v4l2_muxer
Definition: v4l2enc.c:108
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1414
static int write_trailer(AVFormatContext *s1)
Definition: v4l2enc.c:94
const char * name
Definition: avformat.h:505
#define av_err2str(errnum)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: error.h:119
#define s(width, name)
Definition: cbs_vp9.c:257
int fd
Definition: v4l2enc.c:26
Describe the class of an AVClass context structure.
Definition: log.h:67
#define s1
Definition: regdef.h:38
#define flags(name, subs,...)
Definition: cbs_av1.c:561
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:463
void * priv_data
Format private data.
Definition: avformat.h:1386
AVCodecParameters * codecpar
Codec parameters associated with this stream.
Definition: avformat.h:1028
const char * av_get_pix_fmt_name(enum AVPixelFormat pix_fmt)
Return the short name for a pixel format, NULL in case pix_fmt is unknown.
Definition: pixdesc.c:2438
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
This structure stores compressed data.
Definition: avcodec.h:1454
static int write_packet(AVFormatContext *s1, AVPacket *pkt)
Definition: v4l2enc.c:86