[FFmpeg-user] Grabbing quality from TV card

Carl Eugen Hoyos cehoyos at ag.or.at
Wed Mar 14 19:37:53 CET 2012

tovis <mailer.tovis <at> freemail.hu> writes:

> 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].

Note that it is possible to encode progressive material 
interlaced and interlaced material progressive, afaik only 
the visual inspection of the material is relevant.
(You only need a deinterlacer if the input material is 
really interlaced, no matter how it was encoded.)

> 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 :(

-qscale means "constant quality" (and variable bitrate as 
opposed to constant or adaptive bitrate), "2" is very high 
quality, it is normally only used for testing 
(or high quality lossy backup).
Try -vf yadif=0 and -vf yadif=1 - 1 doubles the framerate 
of the output file.

Please try to avoid top-posting, it is considered rude here.

Carl Eugen

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