[MPlayer-users] Re: [-] TV-recording with mencoder, "video-buffer full"

[Matthias Wieser]

Am Sonntag, 27. Februar 2005 20:18 schrieb The Eye:
> Hi list.
>
> I searched through the list-archives and also googled through the docs
> and didn't find this anywhere so I hope it is OK asking here.
>
> I often record stuff from my saa7134-based TV-card with a command like:

I own a saa7134 card, too.

> mencoder tv:// \
>  -tv driver=v4l2:width=768:height=576:amode=1:adevice=/dev/dsp1 -oac \
>  mp3lame -lameopts cbr:br=96 -ovc lavc -lavcopts \
>  vcodec=mpeg4:vbitrate=2000 -vf crop=698:558:12:2,scale=640:480,pp=lb /
>  -endpos 1:00:00 -o somefile.avi
>
>
> btw if anything about this is stupid, please tell me.

As Richard already said, don't scale befor deinterlacing.
Additionally, my card supports 720x576 which should give the same quality
at less work for the CPU. Maybe your card also supports 720x576.

You could try pp=fd instead of pp=lb. The former should give a
sharper image quality.

I have found that scaling a bit more down but using higher MPEG4 compression
quality gives a better overall quality. My skript (Athlon 1,75GHz):

mencoder tv:// -tv driver=v4l2:width=720:height=576:brightness=0:contrast=0:saturation=10:volume=35 \
-ovc lavc -lavcopts vcodec=mpeg4:vbitrate=2200:vratetol=32000:mbd=2:psnr:aspect=4/3 \
-oac mp3lame -lameopts abr:br=128 \
-vf crop=672:528:24:24,pp=fd,scale=576:432,denoise3d=7:5:9 \
-sws 6 -o Video-`date +%d.%m.-%H%MUhr`.avi -endpos $1

I use "vratetol=32000" to give the encoder a bit more freedom to nicely
compress momentary high-bitrate scenes.
"-lameopts abr:br=128": abr generally results in better quality than cbr.
"denoise3d=7:5:9" is good for my noisy terrestrical TV.
"-sws 6" is faster than "-sws 2" (default).
"aspect=4/3" tells the movie player that the video has an aspect ratio of
4/3. (you need to tell mplayer you monitor aspect ratio with
"-monitoraspect=xy", otherwise it just assumes a 4/3 monitor which is often
wrong).
"mbd=2": better encoding quality.


> Anyway, 9 times out of 10, this works just perfectly. But once in a
> while, I get lots of errors like
> Video-buffer full, dropping frame

You should take care that the cpu utilisation normally does not go above
85 to 90 %.

Hope that helps,
  Matthias