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