[MPlayer-users] RFC: docs update for "how to create a high quality DVD rip"

Jack lt at speakeasy.net
Wed Jun 9 00:00:32 CEST 2004


D Richard Felker III wrote:

>>On Sun, 2004-06-06 at 19:46 -0400, D Richard Felker III wrote:
>>    
>>
>>>It doesn't work with inverse telecine or other filters that drop
>>>frames (or add them), it doesn't work with field-coded DVDs (and it's
>>>difficult to tell in advance which ones are field-coded), and it
>>>causes A/V desync. Also it has no useful purpose.
>>>      
>>>
>Nope, the first (frameno) pass does the a/v sync (choosing which
>frames to drop or duplicate) which can't be done correctly without
>decoding and filtering them. And it doesn't decode them. So it's
>broken.
>
>  
>
Odd... I've never had any A/V desync problems using 3-pass encoding and 
inverse telecine, even though I've seen this mentioned here many times 
before.  Nearly all of my encoding is done this way, and the only sync 
problems I ever see are there with or without 3-pass.  For instance, I 
almost always see that the audio is off by 1 or 2 frames for the whole 
video, but going to 2-pass doesn't fix it.

What kind of dvd would make frameno freak out?

>If you want to do the same sort of thing correctly, you should encode
>the audio separately with lame, then mux it with -oac copy and
>-audiofile during the normal 2 passes. This is actually the best way
>since bugs in mencoder cause slight a/v desync with modern versions of
>lame due to lack of buffer measurement.
>  
>
... Is this why I see that 1 or 2 frame offset?  I thought I was just 
going crazy over here.

-lt




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