[MPlayer-users] video buffer full

[Philip Walden]

James Lancaster wrote:

>[Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
>On Monday 06 October 2003 19:11, you wrote:
>  
>
>>[Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
>>I'd like to record a broadcast signal to a file. So I have been reading
>>and looking about and have come up with the following command line:
>>
>>mencoder -tv on:driver=v4l:width=640:height=480:norm=ntsc -ovc lavc
>>-lavcopts vcodec=mpeg4:vbitrate=350 -oac mp3lame -lameopts cbr:br=48
>>-sws 1 -o output.avi
>>
>>    
>>
>
>You are using an older mencoder, I would suggest upgrading it to main or the 
>new 1.0 beta
>
This I did as the athlon version was recently posted to the site. I now
have MEncoder 1.0pre2-RPM-3.1.

>
>then do (to get the exact same fuctionality):
>mencoder tv:// -tv driver=v4l:width=640:height=480:norm=ntsc -ovc lavc
> -lavcopts vcodec=mpeg4:vbitrate=350 -oac mp3lame -lameopts cbr:br=48
> -sws 1 -o output.avi
>
>
>
>  
>
>>This works great for about 40 seconds and then the following message
>>scrolls repeatedly up my screen.
>>
>>video buffer full - dropping frame
>>
>>    
>>
>
>This means your cpu is just not fast enough to do the 640x480 capture direct 
>to lavc mpeg4 (but oh so close). I have a similar problem (p3-800 dual w/2 
>tuners) What I do (and it won't playback corectly according to the docs with 
>anything other than mplayer) is use the aspect option, and encode 640x240 
>(NTSC is interlaced) (change height to 240, and add to lavcopts aspect=1.333) 
>mplayer will automatically scale this to the correct 640x480 on playing.
>
>OR you could add "-vf scale=640:480" to have mencoder scale the whole file. 
>This takes less time, and works on my p3-800s. 
>
>>At this point I interrupt the mencoder. The output file is about 2GB and
>>looks fine. I see that my disk activity is not very high during the
>>process, so I doubt it is my disk write rate that is the bottleneck. I
>>cannot do multiple passes as I am recording live TV broadcasts.
>>
>>    
>>
>2GB for 40sec?! with vbitrate=350 .... 
>something is wrong, using much higher (default, vbitrate=800) bitrates I have 
>somewhere around 400MB/hour.
>
oops. I meant 2MB.

>>So what can i do to up the frame/audio processing rate? Being a novice,
>>I am not sure what dials to tweak to reduce the load on my cpu and
>>eliminate the bottleneck. Lower quality is just fine. I just want to
>>recognize enough to get the storyline.
>>
>>I have a 800MHz athalon with 256MB ram (the max). I know this is not
>>much (these days) but that is all I have right now.
>>
>>    
>>
>
>cheat :) record at a lower resolution.
>
Well following your guidance I have stripped all the up front processing
to a minimum (I think). Reduced vertical to 240. No scaling.  Then do
the scaling during playback. This seems to work and the video quality is
better than I had expected. Almost there, except the sound has a lot os
"static" in it.

Any suggestion on improving audio quality? Here is my runstring:

mencoder tv:// -tv driver=v4l:width=640:height=240:norm=ntsc -ovc lavc
-lavcopts vcodec=mpeg4:vbitrate=350 -oac mp3lame -lameopts cbr:br=48 -o
output.avi


Thanks

Phil