[MEncoder-users] Bug: floating point exception when converting to DV

[Corey Hickey]

Levente Novák wrote:
>> I can reproduce this bug. Sometime in the next day or two, I'll 
>> investigate it, and there's a change I'll be able to write a patch.
>>
>> If anybody else wants to fix it first, though, I wouldn't mind. :)
> 
> Thanks in advance! I would fix it myself if I had the necessary
> knowledge :(

Here's what I have so far. It's not finished, and it doesn't entirely
work. I don't really know what I'm doing and some of the patch's hunks
are probably unacceptable hacks. Finishing the patch and submitting it
for review (or asking for help) will have to come later; I won't be able
to proceed until around the middle of next week.


Presently, the visible problem is that lavf's dv muxer discards some
video frames. This leads to A-V desync and messages like:

[NULL @ 0xd7a200]Can't process DV frame #9837. Insufficient audio data
or severe sync problem.

I don't know how to fix that yet.

I am encoding with this command:
$ mencoder /tmp/dv/a.mpg -of lavf -lavfopts \
i_certify_that_my_video_stream_does_not_use_b_frames:format=dv \
-oac pcm -ovc lavc -lavcopts vcodec=dvvideo -o /tmp/dv/a.dv \
-vf scale=720:576 -af resample=48000

a.mpg is 30000/1001 fps.

-Corey
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