[MEncoder-users] avi sync questions

[Erik Slagter]

Wes Morgan wrote:
>> 4) 712 is not a multiple of 16. It is generally wise to choose
>> dimensions that are multiple of 16.
> 
> To preserve as many lines of resolution as possible rather than cropping 
> them. I'm aware this effects compressibility. Would it be "better" to 
> scale it down to a multiple of 16 after cropping, then? Believe it or not, 
> I was actually noticing the missing vertical resolution on some DVDs. It 
> was a decision made during the encodefest as I examined output.

You'd best fiddle with resolution/dimensions as little as possible. 
Every time you change the resolution, the quality gets worse, scaling is 
a lossy process (if not scaled by exactly 2,4,1/2,1/4 etc.).

I'd recommend using the exact original DVD resolution, which also 
happens to be nice at 16-pixel boundaries. And yes, that really helps 
for encoding.

The only exception to this rule is if you have material that is 
hard-letterboxed (i.e. has black borders in the movie itself, evil!), 
I'd recommend to crop these off to a multiple of 16 pixels, and at 
playback have the player re-add the borders when necessary (i.e. playing 
on 4:3 equipment).