lavd: add v4l2 outdev.

Changelog

@@ -51,6 +51,7 @@ version <next>:
 - Apple Intermediate Codec decoder
 - Escape 130 video decoder
 - FTP protocol support
+- V4L2 output device
 
 
 version 1.2:

configure

@@ -2079,6 +2079,7 @@ sndio_indev_deps="sndio_h"
 sndio_outdev_deps="sndio_h"
 v4l_indev_deps="linux_videodev_h"
 v4l2_indev_deps_any="linux_videodev2_h sys_videoio_h"
+v4l2_outdev_deps_any="linux_videodev2_h sys_videoio_h"
 vfwcap_indev_deps="capCreateCaptureWindow vfwcap_defines"
 vfwcap_indev_extralibs="-lavicap32"
 x11grab_indev_deps="x11grab"

doc/general.texi

@@ -1000,7 +1000,7 @@ performance on systems without hardware floating point support).
 @item OSS               @tab X      @tab X
 @item Pulseaudio        @tab X      @tab
 @item SDL               @tab        @tab X
-@item Video4Linux2      @tab X      @tab
+@item Video4Linux2      @tab X      @tab X
 @item VfW capture       @tab X      @tab
 @item X11 grabbing      @tab X      @tab
 @end multitable

libavdevice/Makefile

@@ -33,6 +33,7 @@ OBJS-$(CONFIG_SDL_OUTDEV)                += sdl.o
 OBJS-$(CONFIG_SNDIO_INDEV)               += sndio_common.o sndio_dec.o
 OBJS-$(CONFIG_SNDIO_OUTDEV)              += sndio_common.o sndio_enc.o
 OBJS-$(CONFIG_V4L2_INDEV)                += v4l2.o v4l2-common.o timefilter.o
+OBJS-$(CONFIG_V4L2_OUTDEV)               += v4l2enc.o v4l2-common.o
 OBJS-$(CONFIG_V4L_INDEV)                 += v4l.o
 OBJS-$(CONFIG_VFWCAP_INDEV)              += vfwcap.o
 OBJS-$(CONFIG_X11GRAB_INDEV)             += x11grab.o

libavdevice/alldevices.c

@@ -60,7 +60,7 @@ void avdevice_register_all(void)
     REGISTER_INDEV   (PULSE,            pulse);
     REGISTER_OUTDEV  (SDL,              sdl);
     REGISTER_INOUTDEV(SNDIO,            sndio);
-    REGISTER_INDEV   (V4L2,             v4l2);
+    REGISTER_INOUTDEV(V4L2,             v4l2);
 //    REGISTER_INDEV   (V4L,              v4l
     REGISTER_INDEV   (VFWCAP,           vfwcap);
     REGISTER_INDEV   (X11GRAB,          x11grab);

libavdevice/v4l2enc.c

@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2013 Clément Bœsch
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "v4l2-common.h"
+#include "avdevice.h"
+
+typedef struct {
+    int fd;
+} V4L2Context;
+
+static av_cold int write_header(AVFormatContext *s1)
+{
+    int res = 0, flags = O_RDWR;
+    struct v4l2_format fmt = {
+        .type = V4L2_BUF_TYPE_VIDEO_OUTPUT
+    };
+    V4L2Context *s = s1->priv_data;
+    AVCodecContext *enc_ctx;
+    uint32_t v4l2_pixfmt;
+
+    if (s1->flags & AVFMT_FLAG_NONBLOCK)
+        flags |= O_NONBLOCK;
+
+    s->fd = open(s1->filename, flags);
+    if (s->fd < 0) {
+        res = AVERROR(errno);
+        av_log(s1, AV_LOG_ERROR, "Unable to open V4L2 device '%s'\n", s1->filename);
+        return res;
+    }
+
+    if (s1->nb_streams != 1 ||
+        s1->streams[0]->codec->codec_type != AVMEDIA_TYPE_VIDEO ||
+        s1->streams[0]->codec->codec_id   != AV_CODEC_ID_RAWVIDEO) {
+        av_log(s1, AV_LOG_ERROR,
+               "V4L2 output device supports only a single raw video stream\n");
+        return AVERROR(EINVAL);
+    }
+
+    enc_ctx = s1->streams[0]->codec;
+
+    v4l2_pixfmt = avpriv_fmt_ff2v4l(enc_ctx->pix_fmt, AV_CODEC_ID_RAWVIDEO);
+    if (!v4l2_pixfmt) { // XXX: try to force them one by one?
+        av_log(s1, AV_LOG_ERROR, "Unknown V4L2 pixel format equivalent for %s\n",
+               av_get_pix_fmt_name(enc_ctx->pix_fmt));
+        return AVERROR(EINVAL);
+    }
+
+    if (ioctl(s->fd, VIDIOC_G_FMT, &fmt) < 0) {
+        res = AVERROR(errno);
+        av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_G_FMT): %s\n", av_err2str(res));
+        return res;
+    }
+
+    fmt.fmt.pix.width       = enc_ctx->width;
+    fmt.fmt.pix.height      = enc_ctx->height;
+    fmt.fmt.pix.pixelformat = v4l2_pixfmt;
+    fmt.fmt.pix.sizeimage   = av_image_get_buffer_size(enc_ctx->pix_fmt, enc_ctx->width, enc_ctx->height, 1);
+
+    if (ioctl(s->fd, VIDIOC_S_FMT, &fmt) < 0) {
+        res = AVERROR(errno);
+        av_log(s1, AV_LOG_ERROR, "ioctl(VIDIOC_S_FMT): %s\n", av_err2str(res));
+        return res;
+    }
+
+    return res;
+}
+
+static int write_packet(AVFormatContext *s1, AVPacket *pkt)
+{
+    const V4L2Context *s = s1->priv_data;
+    write(s->fd, pkt->data, pkt->size);
+    return 0;
+}
+
+static int write_trailer(AVFormatContext *s1)
+{
+    const V4L2Context *s = s1->priv_data;
+    close(s->fd);
+    return 0;
+}
+
+AVOutputFormat ff_v4l2_muxer = {
+    .name           = "v4l2",
+    .long_name      = NULL_IF_CONFIG_SMALL("Video4Linux2 output device"),
+    .priv_data_size = sizeof(V4L2Context),
+    .audio_codec    = AV_CODEC_ID_NONE,
+    .video_codec    = AV_CODEC_ID_RAWVIDEO,
+    .write_header   = write_header,
+    .write_packet   = write_packet,
+    .write_trailer  = write_trailer,
+    .flags          = AVFMT_NOFILE,
+};

libavdevice/version.h

@@ -28,7 +28,7 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVDEVICE_VERSION_MAJOR  55
-#define LIBAVDEVICE_VERSION_MINOR   0
+#define LIBAVDEVICE_VERSION_MINOR   1
 #define LIBAVDEVICE_VERSION_MICRO 100
 
 #define LIBAVDEVICE_VERSION_INT AV_VERSION_INT(LIBAVDEVICE_VERSION_MAJOR, \