[MPlayer-dev-eng] Need help with A/V sync in new video filter

[Walter Belhaven]

--- Rich Felker <dalias at aerifal.cx> wrote:

> > (Softpulldown complains with lots of "Unexpected field flags" when
> > analyzing my 1080i source, and doesn't do what I want when it
> > encounters those 'unexpected' flags.)
> 
> I think you misunderstand the issues involved. 

That's entirely possible, if not probable. :)

> I may be mistaken but I'm pretty sure softpulldown allows any
> sequence as long as the sequence is valid.

When this check fails:

  if ((state == 0 && !(flags & MP_IMGFIELD_TOP_FIRST)) ||
      (state == 1 &&   flags & MP_IMGFIELD_TOP_FIRST))

as it does with this messed up 1080i source, softpulldown produces the
the "wrong" output -- it ends up discarding perfectly valid fields
that it stored previously.

> What you're trying to do does not look valid. Why are you trying to
> add/remove fields? The repetition pattern in the original stream
> should just be used as-is.

I'm just trying to expand fields/frames exactly as the flags suggest.
The reason I'm going through all of this is that I cannot find a
reliable way of transcoding 1080i "video" (not film!!) to (interlaced)
NSTC DVD.  One of two things happens:

1. Something tries to inverse telecine or deinterlace.
2. I get seemingly random field reversals.

Both of these look horrific, as you can imagine, in the final DVD.

If there's another solution to this general problem then I'd welcome
some suggestions.  I've tried just about every permutation of the
'phase' filter, 'top', and everything else I could find, but none of
them work on the 1080i source I have without one of those two problems
showing up.

> Yes, it will mess it up. I'm still completely confused about why you
> want to do this.. Just pass the original TFF/RFF flags to the
> encoder!

Because certain filters such as 'scale' eat the TFF/RFF flags, so the
encoder will never see them.  I put a hack in to dump the flags
before/after 'scale' (-vf scale=720:480:1), and regardless of the
input flags, 0x0 comes out every time.

So, my thought is to create a sequence of Frames that can withstand
this carnage. :) Of course, the right answer might be to "fix" all
such filters, but that could be a gargantuan undertaking.

I appreciate your help Rich.  Any further suggestions?

Cheers,
WB


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