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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  AVCodecContext *enc_ctx;
37  uint32_t v4l2_pixfmt;
38 
39  if (s1->flags & AVFMT_FLAG_NONBLOCK)
40  flags |= O_NONBLOCK;
41 
42  s->fd = open(s1->filename, 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->filename);
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  enc_ctx = s1->streams[0]->codec;
58 
59  v4l2_pixfmt = ff_fmt_ff2v4l(enc_ctx->pix_fmt, 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",
62  av_get_pix_fmt_name(enc_ctx->pix_fmt));
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 = enc_ctx->width;
73  fmt.fmt.pix.height = enc_ctx->height;
74  fmt.fmt.pix.pixelformat = v4l2_pixfmt;
75  fmt.fmt.pix.sizeimage = av_image_get_buffer_size(enc_ctx->pix_fmt, enc_ctx->width, enc_ctx->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 = "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 };
const char * s
Definition: avisynth_c.h:631
#define LIBAVUTIL_VERSION_INT
Definition: version.h:62
static const AVClass v4l2_class
Definition: v4l2enc.c:101
int size
Definition: avcodec.h:1423
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:1721
uint32_t ff_fmt_ff2v4l(enum AVPixelFormat pix_fmt, enum AVCodecID codec_id)
Definition: v4l2-common.c:64
static AVPacket pkt
Format I/O context.
Definition: avformat.h:1272
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:1386
#define av_cold
Definition: attributes.h:74
AVStream ** streams
A list of all streams in the file.
Definition: avformat.h:1340
int flags
Flags modifying the (de)muxer behaviour.
Definition: avformat.h:1383
uint8_t * data
Definition: avcodec.h:1422
#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:347
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
av_default_item_name
#define AVERROR(e)
Definition: error.h:43
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:175
AVOutputFormat ff_v4l2_muxer
Definition: v4l2enc.c:108
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:861
unsigned int nb_streams
Number of elements in AVFormatContext.streams.
Definition: avformat.h:1328
char filename[1024]
input or output filename
Definition: avformat.h:1348
int width
picture width / height.
Definition: avcodec.h:1680
static int write_trailer(AVFormatContext *s1)
Definition: v4l2enc.c:94
const char * name
Definition: avformat.h:513
#define av_err2str(errnum)
Convenience macro, the return value should be used only directly in function arguments but never stan...
Definition: error.h:119
int fd
Definition: v4l2enc.c:26
enum AVMediaType codec_type
Definition: avcodec.h:1509
enum AVCodecID codec_id
Definition: avcodec.h:1518
main external API structure.
Definition: avcodec.h:1501
Describe the class of an AVClass context structure.
Definition: log.h:67
#define s1
Definition: regdef.h:38
static int flags
Definition: cpu.c:47
#define AVFMT_NOFILE
Demuxer will use avio_open, no opened file should be provided by the caller.
Definition: avformat.h:465
void * priv_data
Format private data.
Definition: avformat.h:1300
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:2041
This structure stores compressed data.
Definition: avcodec.h:1399
static int write_packet(AVFormatContext *s1, AVPacket *pkt)
Definition: v4l2enc.c:86