[MEncoder-users] Accuracy of the -endpos option

[Josef Wolf]

On Mon, Jun 28, 2010 at 04:38:29PM +0200, belcampo wrote:
> Josef Wolf wrote:
> >Hello,
> >
> >I have troubles with the accuracy of the -endpos option. Most of the time,
> >I get about 40 to 50 frames too much. When I adjust the value to get the
> >correct end position, then audio ends about 2 seconds too early.
> With ffmpeg -vframes ### you can exactly say how many frames you want.
> The problem with -endpos or -t when using ffmpeg, it uses recording
> duration, NOT video- or audio-duration but the smallest of them.

Hmmm... Does mencoder have a counterpart to -vframes? I have gone a long way
to optimize the codec settings for mencoder and would like to avoid to start
from scratch when moving to ffmpeg...

> >The problem doesn't seem to be dependant on the source material or the
> >codec. I had the problem with ljpeg and DV source (which should both be
> >searchable on a frame-by-frame bassis). Using lavc instead of x264 don'
> >help either.
> Is DV source all-keyframes ??

At least, the -ss option is precise for both, ljpeg and DV. BTW: While I can
see reasons for -ss to position only on keyframes, I don't see why -endpos
would require such a restriction.