libavdevice/v4l2enc.c

   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 "libavutil/imgutils.h"
  22 #include "libavutil/pixdesc.h"
  23 #include "libavformat/avformat.h"
  24 #include "libavformat/mux.h"
  25 #include "v4l2-common.h"
  26
  27 typedef struct {
  28     AVClass *class;
  29     int fd;
  30 } V4L2Context;
  31
  32 static av_cold int write_header(AVFormatContext *s1)
  33 {
  34     int res = 0, flags = O_RDWR;
  35     struct v4l2_format fmt = {
  36         .type = V4L2_BUF_TYPE_VIDEO_OUTPUT
  37     };
  38     V4L2Context *s = s1->priv_data;
  39     AVCodecParameters *par;
  40     uint32_t v4l2_pixfmt;
  41
  42     if (s1->flags & AVFMT_FLAG_NONBLOCK)
  43         flags |= O_NONBLOCK;
  44
  45     s->fd = open(s1->url, flags);
  46     if (s->fd < 0) {
  47         res = AVERROR(errno);
  48         av_log(s1, AV_LOG_ERROR, "Unable to open V4L2 device '%s'\n", s1->url);
  49         return res;
  50     }
  51
  52     if (s1->nb_streams != 1 ||
  53         s1->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_VIDEO) {
  54         av_log(s1, AV_LOG_ERROR,
  55                "V4L2 output device supports only a single raw video stream\n");
  56         return AVERROR(EINVAL);
  57     }
  58
  59     par = s1->streams[0]->codecpar;
  60
  61     if(par->codec_id == AV_CODEC_ID_RAWVIDEO) {
  62         v4l2_pixfmt = ff_fmt_ff2v4l(par->format, AV_CODEC_ID_RAWVIDEO);
  63     } else {
  64         v4l2_pixfmt = ff_fmt_ff2v4l(AV_PIX_FMT_NONE, par->codec_id);
  65     }
  66
  67     if (!v4l2_pixfmt) { // XXX: try to force them one by one?
  68         av_log(s1, AV_LOG_ERROR, "Unknown V4L2 pixel format equivalent for %s\n",
  69                av_get_pix_fmt_name(par->format));
  70         return AVERROR(EINVAL);
  71     }
  72
  73     if (ioctl(s->fd, VIDIOC_G_FMT, &fmt) < 0) {
  74         res = AVERROR(errno);
  75         av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_FMT): %s\n", av_err2str(res));
  76         return res;
  77     }
  78
  79     fmt.fmt.pix.width       = par->width;
  80     fmt.fmt.pix.height      = par->height;
  81     fmt.fmt.pix.pixelformat = v4l2_pixfmt;
  82     fmt.fmt.pix.sizeimage   = av_image_get_buffer_size(par->format, par->width, par->height, 1);
  83
  84     if (ioctl(s->fd, VIDIOC_S_FMT, &fmt) < 0) {
  85         res = AVERROR(errno);
  86         av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_S_FMT): %s\n", av_err2str(res));
  87         return res;
  88     }
  89
  90     return res;
  91 }
  92
  93 static int write_packet(AVFormatContext *s1, AVPacket *pkt)
  94 {
  95     const V4L2Context *s = s1->priv_data;
  96     if (write(s->fd, pkt->data, pkt->size) == -1)
  97         return AVERROR(errno);
  98     return 0;
  99 }
 100
 101 static int write_trailer(AVFormatContext *s1)
 102 {
 103     const V4L2Context *s = s1->priv_data;
 104     close(s->fd);
 105     return 0;
 106 }
 107
 108 static const AVClass v4l2_class = {
 109     .class_name = "V4L2 outdev",
 110     .item_name  = av_default_item_name,
 111     .version    = LIBAVUTIL_VERSION_INT,
 112     .category   = AV_CLASS_CATEGORY_DEVICE_VIDEO_OUTPUT,
 113 };
 114
 115 const FFOutputFormat ff_v4l2_muxer = {
 116     .p.name         = "video4linux2,v4l2",
 117     .p.long_name    = NULL_IF_CONFIG_SMALL("Video4Linux2 output device"),
 118     .priv_data_size = sizeof(V4L2Context),
 119     .p.audio_codec  = AV_CODEC_ID_NONE,
 120     .p.video_codec  = AV_CODEC_ID_RAWVIDEO,
 121     .write_header   = write_header,
 122     .write_packet   = write_packet,
 123     .write_trailer  = write_trailer,
 124     .p.flags        = AVFMT_NOFILE,
 125     .p.priv_class   = &v4l2_class,
 126 };