[MEncoder-users] ffvhuff: encoded frame too large

[Loren Merritt]

On Fri, 13 Apr 2007, infernix wrote:

> I'm encoding to a large resolution ffvhuff file (source is 1920x1040) and am 
> occasionally getting this message from mencoder:
>
> [ffvhuff @ 0x8847980]encoded frame too large
>
> I am using:
>
> mencoder -oac pcm -nosound -o $OUTFILE.huffyuv.avi -ovc lavc -lavcopts 
> vcodec=ffvhuff:vstrict=-1:pred=2:context=1 $INFILE
>
> I've watched the huffyuv output file closely and couldn't really detect any 
> problems with it at first glance.

The visible symptom is that the extra large frames will be truncated, so 
they'll display garbage at the bottom of the screen.

> Does anyone know what happens to a frame when this error occurs? Does it get 
> discarded? Is it because I'm encoding to avi?
>
> And if it is a problem (e.g. it gets discarded), what would be a proper 
> solution? A different container perhaps?

MEncoder allocates a constant buffer size of 2MB to hold a compressed 
frame. 1080p is 3MB uncompressed, and huffyuv (or any lossless codec) 
can't always compress a 3MB frame into less than 2MB.
Solution: increase the buffer size, and/or make it dynamic.

--Loren Merritt