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From: Andreas Weber <andy.weber.aw@gmail.com>
To: linux-media@vger.kernel.org
Cc: andy.weber.aw@gmail.com
Subject: How to tell libv4l2 which src_fmt should be prefered?
Date: Sat, 18 Jan 2014 11:43:06 +0100	[thread overview]
Message-ID: <52DA5ABA.7070003@gmail.com> (raw)

Dear maintainer and user,

Is there a way to tell libv4l2 which native source format it should
prefer to convert from? For example my uvcvideo webcam supports natively
YUYV and MJPG (see output below) and when I request V4L2_PIX_FMT_RGB24 I
see in the logs:

...
VIDIOC_S_FMT app requesting: RGB3
VIDIOC_S_FMT converting from: YUYV
request == VIDIOC_S_FMT
  pixelformat: RGB3 640x480
  field: 1 bytesperline: 1920 imagesize921600
  colorspace: 8, priv: 0
...

So it picks up YUYV as source format. I had a look at
v4lconvert_try_format but can see no way how to do this.

Regards, Andy

$ v4l2-ctl --list-formats
ioctl: VIDIOC_ENUM_FMT
	Index       : 0
	Type        : Video Capture
	Pixel Format: 'YUYV'
	Name        : YUV 4:2:2 (YUYV)

	Index       : 1
	Type        : Video Capture
	Pixel Format: 'MJPG' (compressed)
	Name        : MJPEG

$ v4l2-ctl -w -D
Driver Info (using libv4l2):
	Driver name   : uvcvideo
	Card type     : UVC Camera (046d:0825)
	Bus info      : usb-0000:00:16.2-2
	Driver version: 3.2.51
	Capabilities  : 0x05000001
		Video Capture
		Read/Write
		Streaming


             reply	other threads:[~2014-01-18 10:43 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-01-18 10:43 Andreas Weber [this message]
2014-01-18 22:34 ` How to tell libv4l2 which src_fmt should be prefered? Gregor Jasny

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