我需要使用gstreamer传输视频。正确提供media-ctl命令后当我发出此命令LD_PRELOAD=/usr/lib/libv4l/v4l2convert.so mplayer tv:// -tv driver=v4l2:device=/dev/video6 -vo png -fps 1时，它成功捕获帧，但只有Gstreamer有问题。
Gstreamer管道：
root@overo:~# LD_PRELOAD=/usr/lib/libv4l/v4l2convert.so gst-launch-0.10 -v v4l2src device=/dev/video6 queue-size=8 ! video/x-raw-yuv,format=\(fourcc\)UYVY,width=720,height=480 ! ffmpegcolorspace ! tcpserversink host=192.168.1.104 port=5000
Setting pipeline to PAUSED ...
ERROR: Pipeline doesn't want to pause.
ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0: Failed to enumerate possible video formats device '/dev/video6' can work with
Additional debug info:
/home/siguser/yocto-28-11/build/tmp/work/armv7a-vfp-neon-poky-linux-gnueabi/gst-plugins-good/0.10.31-r8/gst-plugins-good-0.10.31/sys/v4l2/gstv4l2object.c(1122): gst_v4l2_object_fill_format_list (): /GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
Failed to get number 0 in pixelformat enumeration for /dev/video6. (25 - Inappropriate ioctl for device)
Setting pipeline to NULL ...
Freeing pipeline ...
更改分辨率后，我得到同样的错误：
root@overo:~# LD_PRELOAD=/usr/lib/libv4l/v4l2convert.so gst-launch-0.10 v4l2src --gst-debug=0 device=/dev/video6 ! video/x-raw-yuv,width=640,height=480,framerate=\(fraction\)2/1 ! ffmpegcolorspace ! smokeenc keyframe=8 qmax=40 ! udpsink host=192.168.1.104 port=5000
Setting pipeline to PAUSED ...
ERROR: Pipeline doesn't want to pause.
ERROR: from element /GstPipeline:pipeline0/GstV4l2Src:v4l2src0: Failed to enumerate possible video formats device '/dev/video6' can work with
Additional debug info:
/home/siguser/yocto-28-11/build/tmp/work/armv7a-vfp-neon-poky-linux-gnueabi/gst-plugins-good/0.10.31-r8/gst-plugins-good-0.10.31/sys/v4l2/gstv4l2object.c(1122): gst_v4l2_object_fill_format_list (): /GstPipeline:pipeline0/GstV4l2Src:v4l2src0:
Failed to get number 0 in pixelformat enumeration for /dev/video6. (25 - Inappropriate ioctl for device)
Setting pipeline to NULL ...
Freeing pipeline ...
root @ overo：〜＃LD_PRELOAD = / usr / lib / libv4l / v4l2convert.so v4l2-ctl -d 6 --list-formats
ioctl: VIDIOC_ENUM_FMT
Index : 0
Type : Video Capture
Pixel Format: 'RGB3' (emulated)
Name : RGB3
Index : 1
Type : Video Capture
Pixel Format: 'BGR3' (emulated)
Name : BGR3
Index : 2
Type : Video Capture
Pixel Format: 'YU12' (emulated)
Name : YU12
Index : 3
Type : Video Capture
Pixel Format: 'YV12' (emulated)
Name : YV12
我正在尝试让caspa相机在3.5.7 linux内核上使用yocto 1.4.2（dylan）。
答案 0 :(得分：0)
如果你也为gst创建了comp_ lib，那该怎么办？
LD_PRELOAD=/usr/lib/libv4l/v4l2convert.so gst-launch-0.10 v4l2src ...
还要考虑使用gstreamer-1.0。
答案 1 :(得分：0)
解决方案是关注gstreamer和overo isp
http://gumstix.8.x6.nabble.com/Overo-COM-Caspa-Camera-for-image-processing-td4965139.html#a4965265
答案 2 :(得分：0)
问题在于Gumstix目前使用的3.5.7内核版本中的omap ispvideo驱动程序代码。要使用我们自己的编解码器输出视频，驱动程序应该知道使用了哪种编解码器。将更改应用于位于
的ispvideo.c/home/yocto/build/work/.../drivers/media/video/omap3isp/ispvideo.c
From 2ea2a64d737236ed84f8aa481f4331eecbe6081f Mon Sep 17 00:00:00 2001
From:
Date: Thu, 9 Jan 2014 15:32:50 +0100
Subject: [PATCH] Adding missing ioctl's
---
drivers/media/video/omap3isp/ispvideo.c | 48 +++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)
diff --git a/drivers/media/video/omap3isp/ispvideo.c b/drivers/media/video/omap3isp/ispvideo.c
index b37379d..0bf5c5b 100644
--- a/drivers/media/video/omap3isp/ispvideo.c
+++ b/drivers/media/video/omap3isp/ispvideo.c
@@ -662,6 +662,39 @@ isp_video_querycap(struct file *file, void *fh, struct v4l2_capability *cap)
}
static int
+// My patch changes
+isp_video_enum_format(struct file *file, void *fh, struct v4l2_fmtdesc*fmtdesc)
+{
+ struct isp_video_fh *vfh = to_isp_video_fh(fh);
+ struct isp_video *video = video_drvdata(file);
+
+ if (fmtdesc->index)
+ {
+// printk(KERN_ERR "%s: invalid index (%d)\n",__func__,fmtdesc->index);
+ return -EINVAL;
+ }
+
+ if (fmtdesc->type != video->type)
+ {
+// printk(KERN_ERR "%s: invalid type (%d). Current type:%d\n",__func__, fmtdesc->type, video->type);
+ return -EINVAL;
+ }
+
+ // trying to produce direct output in VYVY format. Hardcoded.
+ fmtdesc->flags = 0;
+ fmtdesc->description[0] = 'U';
+ fmtdesc->description[1] = 'Y';
+ fmtdesc->description[2] = 'V';
+ fmtdesc->description[3] = 'Y';
+ fmtdesc->description[4] = '0';
+ fmtdesc->pixelformat = V4L2_PIX_FMT_UYVY;
+
+ return 0;
+}
+
+static int
+
+
isp_video_get_format(struct file *file, void *fh, struct v4l2_format *format)
{
struct isp_video_fh *vfh = to_isp_video_fh(fh);
@@ -678,6 +711,7 @@ isp_video_get_format(struct file *file, void *fh, struct v4l2_format *format)
}
static int
+
isp_video_set_format(struct file *file, void *fh, struct v4l2_format *format)
{
struct isp_video_fh *vfh = to_isp_video_fh(fh);
@@ -1189,8 +1223,21 @@ isp_video_s_input(struct file *file, void *fh, unsigned int input)
return input == 0 ? 0 : -EINVAL;
}
+static int
+isp_video_queryctrl(struct file *file, void *fh, struct v4l2_queryctrl*queryctrl)
+{
+// printk(KERN_ERR "%s: query id (%d)\n",__func__, queryctrl->id);
+// printk(KERN_ERR "%s: query type (%d)\n",__func__, queryctrl->type);
+
+ if (queryctrl->id < V4L2_CID_BASE)
+ return -EDOM;
+
+ return -EINVAL;
+}
+
static const struct v4l2_ioctl_ops isp_video_ioctl_ops = {
.vidioc_querycap = isp_video_querycap,
+ .vidioc_enum_fmt_vid_cap = isp_video_enum_format,
.vidioc_g_fmt_vid_cap = isp_video_get_format,
.vidioc_s_fmt_vid_cap = isp_video_set_format,
.vidioc_try_fmt_vid_cap = isp_video_try_format,
@@ -1211,6 +1258,7 @@ static const struct v4l2_ioctl_ops isp_video_ioctl_ops = {
.vidioc_enum_input = isp_video_enum_input,
.vidioc_g_input = isp_video_g_input,
.vidioc_s_input = isp_video_s_input,
+ .vidioc_queryctrl = isp_video_queryctrl,
};
/* -----------------------------------------------------------------------------
--
1.7.9.5
之后提交补丁更改。请按照本教程了解如何创建补丁。
该补丁取自here