[MPlayer-users] Scaling and expanding when encoding tv

Barton Bosch bartonbosch at SoftHome.net
Tue Dec 14 21:36:52 CET 2004

D Richard Felker III wrote:
>>Is this caused by the 29.97 frame rate?  How do you all deal with 
>>this?  Would it be better to set the tv card's capture rate to 25 or 
>>27 in the -tv options?  To set the fps to 25 or 27 in -lacvopts?  Or 
>>maybe dealing with it on playback with the general mplayer -fps option?
> Never set the framerate to anything other than the actual correct
> framerate, in this case 30000/1001 aka 29.97. Anything else will give
> horrible results.

Ok, so is it necessary to pass the frame rate to the tuner card or 
mencoder to get optimal results?  I've noticed that in the intial 
output, mencoder reports the frame rate as 29 fps and that in the 
status line (after it settles out) it reads 30 fps.

I assumed that the initial fluctuation in the status line was due to 
averaging as the buffers filled and that the difference between the 
two reported rates was semantic rather than actual.  Is this correct?

Maybe the jumpiness that I'm seeing is introduced during playback 
rather than encoding...  The file is recorded at high bit rates 
(640x480 video at 16000 kbps and 2 channels of mono raw pcm audio) 
and played in fullscreen at 1152x864 using software scaling w/ the 
x11 driver.  This last is down to not having the mga drivers 
available;  mplayer was installed from RPMs for simplicity's sake 
during testing.

Loren Merritt wrote:

Unless your movie is exactly the same resolution as your monitor, it 
will have to rescale during playback anyway. There is no additional 
penalty for correcting aspect ratio at the same time.

For that matter, 4:3 might not actually be the correct aspect ratio 
of your movie. The original broadcast was 4:3 (assuming they got it 
right). But if you crop it, mencoder/lavc's autoaspect should do the 
right thing without any additional overrides.

Yeah, ok that makes sense, thanks.


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