[gst-devel] v4l2src & glupload at only 12 FPS?

[Filippo Argiolas]

On Wed, Mar 3, 2010 at 2:39 PM, Alexandre Quessy <alexandre at quessy.net> wrote:
> Hello everyone,
>
> It seems like the mesured framerate is consistently pretty slow. I get
> an average of 12 FPS on a Dual 2.2 GHz with the latest Ubuntu and a
> decent Nvidia graphic card. I obtained 30 FPS on a faster machine with
> a better V4L2-supported video capture card.

So, you are comparing two different v4l2 devices in two different
setups... I'm not sure how that could mean anything.
Did you try putting a videorate after the source capsfilter? Most
webcams I've seen, e.g., don't output frames at the framerate you set
in the caps: there are a lot of things that limit the actual
framerate, e.g. autoexposure, usb speed, etc...
Setting 30/1 in the caps I usually never get more than 15 frames per
second with decent lighting conditions.
If you put a videorate it will duplicate frames to reach the actual
framerate you want. Then you would be able to tell anything about gl
plugins causing any slow down. You have first to be sure that the
actual framerate entering glupload is the one you expect.

> Does someone have suggestions on how I could overcome this ? I would
> also prefer to have a framerate that's faster than the capture card's.
> 29.97 FPS is what NTSC gives me, whereas most projectors and monitors
> can do up to 60 FPS. I have tried to set the "sync" property of the
> fakesink element to FALSE, or TRUE, without success. Any other hint ?

Not sure how that could be useful but you can set 60/1 after the
videorate and it will duplicate frames to reach the requested rate.

Hope this helps,
Best Regards

Filippo