Video looses AV sync after encoding to mpg2/divx.

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Archived from groups: rec.video.desktop (More info?)

I capture live broadcast from LifeView tuner in PicVideo MJPEG
using VirtualVCR with "resample audio dynamically" option.
The duration on capture is 30-60min. Captured video playback with
perfect audio sync. When I trancode it to mpg2(TMpgEnc) or DIVx
(Dr.Divx) the audio is off by a couple of seconds. Any ideas?

 

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Archived from groups: rec.video.desktop (More info?)

On a sunny day (21 Feb 2005 19:45:56 -0800) it happened "Worrier"
<irnmdn@email.com> wrote in
<1109043956.172865.109630@o13g2000cwo.googlegroups.com>:

>I capture live broadcast from LifeView tuner in PicVideo MJPEG
>using VirtualVCR with "resample audio dynamically" option.
>The duration on capture is 30-60min. Captured video playback with
>perfect audio sync. When I trancode it to mpg2(TMpgEnc) or DIVx
>(Dr.Divx) the audio is off by a couple of seconds. Any ideas?
Is it not possible to select yuv mode and then DivX codec directly in
'LifeView"?
I can do this in my old Asus 7100 Combo.
That saves you transcoding, and may use less disk space.
Still frame drops, (due to speed issues), can cause the audio to go out of
sync, so can interruptions in the TV signal.
For an existing problem one would have to see where the audio goes out of sync,
does it GRADUALLY linear change? Then it could be clock freq, as mentioned.
Or are there specific places where it suddenly is of by a second?
That would indicate dropped frames or other interruptions.
I such a case you can demux the audio and insert or delete pieces of silence
at the right points, then remux again.

 

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Archived from groups: rec.video.desktop (More info?)

The change is gradual. I loaded the file in VDUb and changed frame
rate to make both streams of equal length, now mpg2 encoded by TMPEnc
has proper sync; but Dr.Divx encoded Divx is few seconds off.