[MEncoder-users] Skipping frame! and duplicate frame(s)! problems

[Rich Felker]

On Fri, Jun 10, 2005 at 11:27:54PM -0700, Corey Hickey wrote:
> Jonathan wrote:
> >>>  While trying to encode some of my DVDs for portability purposes
> >>>I've run into problems with a lot of skipped and duplicated frames.
> >>
> >>
> >>I see that you've got a few duplicate frames, and skiped frames,
> >>but I don't see a problem.
> > 
> > 
> > In the areas where this happens the output is horribly 
> > interlaced/telecined and farther into the source it starts skipping 
> > frames every 5-10 frames and went on doing so for over 500 frames before 
> > I killed the encode.
> > 
>
> Try using filmdint. In my experience it does better than pullup (and
> ivtc) with regard to skipped frames in telecined video. If your video
> isn't telecined, though, the skipping is pretty much unavoidable.

"skipping frames" does NOT mean that pullup is failing. Rather, it's
lots of "duplicate frame" messages in a row that indicate a problem --
they indicate that pullup is throwing away lots of fields because it's
unable to match them. Normall "skipping frames" just means pullup
output 30p frames instead of 24p because there was no motion by which
to detect duplicate fields.

It's possible that filmdint will do better, but the "skipping frames"
message is not a metric by which to measure which does better.
filmdint tries to force a 5:4 input to output ratio, so it throws away
fields or interpolates (bobs) to make a paired field if the input is
not exactly standard telecine or not detected as such. pullup just
performs optimal field matching (optimal in terms of my metrics, which
are not necessarily correct for all content) without any regard to the
number of output frames.

> > Of course I feel rather stupid for not checking the effects on the 
> > actual playback before sending an email but I guess thats what I get for 
> > sending mail when tired :P  I still have not checked the effects on 
> > encoded material but thats partly a time issue, H.264 is *really* nice 
> > but a bit slow!
> 
> Just for fun, try out snow. On my tests, it retains considerably more
> detail than x264. Snow is not finished yet, but I like it already.

:))

Corey is right though -- it's "just for fun". Snow is experimental and
WILL change before the final version, so don't use it to encode
anything you want to keep!!

Rich