[FFmpeg-user] Grabbing quality from TV card

tovis mailer.tovis at freemail.hu
Wed Mar 14 17:08:51 CET 2012

Hi Rodney!
It is much better with "-qscale 2" even if I use 640x480 resolution :D I
steel have errors:
libv4l2: error dequeuing buf: Resource temporarily unavailable
> I don't know about the "Resource temporarily unavailable" errors -
perhaps Carl Eugen (or one of the other devs) may have an idea. I'd try
Carl's suggestion re yadif too - if you have an interlaced source you
probably want
> to run it through the deinterlace filter.
Definitely I have interlaced input. I have put v4l2-info's output into the
pastebin: http://pastebin.com/SWb1u94B
The VIDIOC_G_FMT(VIDEO_CAPTURE) shows that is it has resolution 320x240
and it is interlaced and pixelformat 0x33524742 [BGR3].
I'm not so much understand v4l2 interface, there is such an interface
video overlay which have resolution 768x576, also interlaced. ffmpeg can
not use this interface?
Also how deinterlace/filter command parameter should be look like? I know
I ask too much, but I do not realy understand "-qscale 2" parameter too :(
Also yadif and -qscale should be used together?

> Only what Carl Eugen suggested:
> "Since it is likely that the input is interlaced, please first try
-qscale 2 out0.avi to test if this improves quality, then use yadif."

More information about the ffmpeg-user mailing list