[MEncoder-users] Want a sample command to convert files to FLV

howard chen howachen at gmail.com
Sat Aug 12 04:57:23 CEST 2006

On 8/12/06, RC <rcooley at spamcop.net> wrote:
> On Fri, 11 Aug 2006 16:43:33 +0800
> "howard chen" <howachen at gmail.com> wrote:
> > I really want a sample command to convert files to FLV, that "preserve
> > 100% A/V sync".
> There's really no possible way to guarantee perfect sync with EVERY type
> of input.  They vary far too much.  Human intervention is sometimes
> going to be required.  (FLV has nothing to do with it)
> Look through the docs and mailing lists for tips on fixing A/V sync
> issues.

My source is WMV files with difference frame-rate. If I provided the
correct framerate as the "-ofps" during encoding, the A/V sync will be
correct. If I put "30" for all files, the A/V sync has little problem
(not serious as I added the "harddup", only a few ms audio/video
de-sync). I assume Mencoder will auto correct the sync for me by
dropping or duplicating frame? Maybe this caused the problem.

Another problem is I can't get the source frame rate data via
"-identify" command. I need to use windows media player to open the
file and get the frame rate. And use that frame rate to encode, but
too complicated, not suitable for batch processing.

If using FFmpeg, the problem of A/V sync is acceptable no matter what
the source frame-rate, but using Mencoder, the difference is bigger. I
assume they are using the same lavac codec? The command of FFmpeg is
more simple and I wonder if it is possible to get the same effect as
FFmpeg using Mencoder as Mencoder is better for processing WMV.

Thanks for any comment.

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