Hello.

I want to make a program to capture the frames from a security cam. I have the following hardware components:
- CCD security cam
- AV-RF modulator
- TV Tuner (Hauppauge HVR-900 hybrid TV stick - usb)
To make this program I used the capture.c example from video4linux2. The problem is that the captured image is a green/pink image. I don't know what settings should I apply in order to get the correct image. The pixelformat is:
where fmt is struct v4l2_format. The video standard is set to V4L2_STD_PAL_B.
I tried to change the CID values (hue, saturation, brightness, etc) but still no effect

I need to mention that everything is ok if use a player (like mplayer). The frames are displayed as they should be.

Any idea what can cause this?

Thank you

until you get a better reply why not pipe thru mplayer first into a capture device

mplayer or vlc may allow capture first off?

2) how do you know the cam is a v4l2 device and not just a v4l1 device?

there are capture apps called guvcview and luvcview that might provide terminal output that could assist?

Thanks for your answer.

The device is a v4l2 one. I think I'm going to solve the problem.
The frame I get into the buffer is YUYV format. I managed to convert it to RGB24 and imagemagik displays it correctly. What I was doing until now was to display a raw YUYV image with a wrong viewer.
Now I'm trying to convert the RGB stream to BMP format... hopefully with positive results this time. In the end I should have something like this:

(camera image) -> (v4l2 buffer YUYV raw) -> (my RGB24 buffer) -> (BMP file)

Thank you.

v4l-info

There's generally several input modes.

v4l-info:

video capture
VIDIOC_ENUM_FMT(0,VIDEO_CAPTURE)
index : 0
type : VIDEO_CAPTURE
flags : 0
description : "8 bpp, gray"
pixelformat : 0x59455247 [GREY]
VIDIOC_ENUM_FMT(1,VIDEO_CAPTURE)
index : 1
type : VIDEO_CAPTURE
flags : 0
description : "15 bpp RGB, le"
pixelformat : 0x4f424752 [RGBO]
VIDIOC_ENUM_FMT(2,VIDEO_CAPTURE)
index : 2
type : VIDEO_CAPTURE
flags : 0
description : "15 bpp RGB, be"
pixelformat : 0x51424752 [RGBQ]
VIDIOC_ENUM_FMT(3,VIDEO_CAPTURE)
index : 3
type : VIDEO_CAPTURE
flags : 0
description : "16 bpp RGB, le"
pixelformat : 0x50424752 [RGBP]
VIDIOC_ENUM_FMT(4,VIDEO_CAPTURE)
index : 4
type : VIDEO_CAPTURE
flags : 0
description : "16 bpp RGB, be"
pixelformat : 0x52424752 [RGBR]
VIDIOC_ENUM_FMT(5,VIDEO_CAPTURE)
index : 5
type : VIDEO_CAPTURE
flags : 0
description : "24 bpp RGB, le"
pixelformat : 0x33524742 [BGR3]
VIDIOC_ENUM_FMT(6,VIDEO_CAPTURE)
index : 6
type : VIDEO_CAPTURE
flags : 0
description : "32 bpp RGB, le"
pixelformat : 0x34524742 [BGR4]
VIDIOC_ENUM_FMT(7,VIDEO_CAPTURE)
index : 7
type : VIDEO_CAPTURE
flags : 0
description : "32 bpp RGB, be"
pixelformat : 0x34424752 [RGB4]
VIDIOC_ENUM_FMT(8,VIDEO_CAPTURE)
index : 8
type : VIDEO_CAPTURE
flags : 0
description : "4:2:2, packed, YUYV"
pixelformat : 0x56595559 [YUYV]
VIDIOC_ENUM_FMT(9,VIDEO_CAPTURE)
index : 9
type : VIDEO_CAPTURE
flags : 0
description : "4:2:2, packed, UYVY"
pixelformat : 0x59565955 [UYVY]
VIDIOC_G_FMT(VIDEO_CAPTURE)
type : VIDEO_CAPTURE
fmt.pix.width : 320
fmt.pix.height : 240
fmt.pix.pixelformat : 0x33524742 [BGR3]
fmt.pix.field : INTERLACED
fmt.pix.bytesperline : 960
fmt.pix.sizeimage : 230400
fmt.pix.colorspace : unknown
fmt.pix.priv : 0

-----

capture for me:

mencoder tv://3 -audio-delay 0.164 -aspect 4:3 -oac pcm -ovc lavc -lavcopts vcodec=mjpeg:autoaspect=1 -o tvcapture.avi

With some settings in /etc/mplayer/mencoder.conf

fps=60000/1001
ofps=30000/1001
oac=lavc=yes
ovc=lavc=yes
lavcopts=vcodec=mjpeg:acodec=pcm
tv=driver=v4l2:input=0utfmt=uyvy:chanlist=us-cable:norm=NTSC-M:width=720:height=480:brightness=8:contrast=4:amode=1:audiorate=48000:quality=100
vf=yadif,scale,eq2

note input= and outfmt=, which have a direct relationship to v4l-info specs.

Thanks Shadow 7.

I finally figured what was the problem.
The video standard was set to PAL_B and the frame had two colors only. I changed it to PAL and now I get the coloured frame.

Thank you.