Author Topic: A/V SYNC Problem isolated(maybe)  (Read 2881 times)

September 05, 2009, 02:35:27 AM
Read 2881 times

Trac

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I believe I have isolated the audio/video sync problem to VFR(Variable Frame Rate)
HandBrake by default uses "Same as source" which = VFR
Detelecin and Decomb exacerbate this even more.

I tested this out with a video that was way out of sync by changing it to CBR at 29.97.  This was the stated framerate of the DVD according to MediaInfo.  It played fine with a very slight sync issue.  Then I unchecked Detelecine and Decomb, and the A/V was spot on.

The VOB was 29.97 however, the final MKV was 23.976 when encoded "Same as source">Detelecine>Decomb.

I was using v1.02.08.  When I flashed to v1.02.03, both VFR and CFR played flawlessly.

If WD can find out why VFR was compatible in v1.02.03 and earlier, maybe they can fix it in the next firmware.

From HandBrake:
http://trac.handbrake.fr/wiki/Telecine
NTSC Film runs at a speed of 24fps.
NTSC Video runs at a speed of 30fps.
So for every 4 frames, you've got to make an extra frame.
This is called telecining(or interlacing): transfering cinema to television.

The solution is to use Variable Frame Rate detelecine.

http://trac.handbrake.fr/wiki/VariableFrameRate
Variable frame rate is when one movie runs at different speeds in different parts.
This will happen when you mix progressive and interlaced content, or when film is converted to video (telecining).
To handle all those different kinds of content at once, enable variable frame rate encoding.
It will be faster than deinterlacing the whole thing, the picture will be higher quality, and everything should move with more fluidity.

October 04, 2009, 08:17:22 AM
Reply #1

greiland

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I just upgraded to version 1.02.11 and one of my files that was having serious sync problems with version 1.02.10 now plays perfectly.  Looks like they may have fixed the "variable frame rate" problem.  My file was encoded with Handbrake using "same as source".

Trac (or anyone else for that matter), do you have some Variable Frame Rate encodes that you can test out to see if they now work with version .11?

October 13, 2009, 09:36:40 AM
Reply #2

Trac

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I just upgraded to version 1.02.11 and one of my files that was having serious sync problems with version 1.02.10 now plays perfectly.  Looks like they may have fixed the "variable frame rate" problem.  My file was encoded with Handbrake using "same as source".

Trac (or anyone else for that matter), do you have some Variable Frame Rate encodes that you can test out to see if they now work with version .11?
I would love to, but I returned the wdtv.  All of my encodes are VFR and I'm sure v11 fixed it, however I recently purchased the ACRyan Play!On and it has far exceeded my expectations.
http://www.mpcclub.com/forum/links/reviews-2009-9/acryan-playonhd-128/
http://www.avsforum.com/avs-vb/showthread.php?p=17221885#post17221885