Re: [Linux-uvc-devel] how to get mencoder en mplayer working with uvc v4l2 webcams

[Jelle de J. <jel...@po...>]

Hi Paulo and thank you for the help,

Paulo Assis wrote:
> Mplayer works fine with the following command:
> �mplayer tv:// -tv
> driver=v4l2:device=/dev/video0:width=800:height=600:fps=25
> 
> see mplayer.log

It seems mplayer does not! work fine, see the resolution, it is unable to
render 800x600 it keep sticking at 640x480.

Could you or somebody else try this command and show the full report:
mplayer -identify -benchmark -v tv:// -tv
driver=v4l2:device=/dev/video0:width=800:height=600:fps=25

> but fails for the ones below.
> see mplayer_1.log
> 

Thank you, it seems mplayer dies on your system when trying to access the
sound of the webcam I will report this back to mplayer developers

> see mplayer_2.log
The command was not correctly formatted since you use /dev/video0 and not
/dev/video1. Could you or somebody else try the bellow command and show
the full report:

mplayer -identify -benchmark -v tv:// -tv
driver=v4l2:device=/dev/video0:adevice=/dev/dsp1:immediatemode=0:forceaudio:width=800:height=600

> see mencoder.log

could you please test ;-) and show the full report

mencoder tv:// -tv
driver=v4l2:device=/dev/video0:width=800:height=600:fps=25 -of rawvideo
-nosound -ovc lavc -lavcopts vcodec=mpeg4:threads=4 -of lavf -lavfopts
format=avi -o output0.avi

> I could only get 640x480, this limit seems to be hardcoded in mplayer.

The mplayer developer tell me it is not hardcoded and is looking up v4l2
stuff. I don't know what is exactly going on here ...

> Like I said live video mpeg encoding requires a lot of cpu power, you
> wont find many apps out there that can deliver this, with the quality
> you want.

My system is powerful enough to do live recordings with mpeg4 with only
20% cpu load with mencoder on the 640x480 15fps stream... thats why I
need mencoder and mplayer to be able to view the 800x600 at 25 fps
streams so I can record them with mencoder and have a more then powerful
engough system. mjpeg does not use treading and is very heavy for a dual
threaded designed/optimized atom cpu.

> these are vendor specif controls, they are defined in the uvc spec and
> the linux-uvc driver has support for them.
> Since they are vendor specific, they cannot be defined in the v4l2 API,
> so they need to be mapped into a valid control, but applications must be
> aware of them.
> 
> They are the ones I know.

Thanks for the info!

Best regards,

Jelle de Jong