[XviD-devel] b-frames motion estimation commited

[Christoph Lampert]

> 
> an extension field for in-development options seems like a good idea to me.
> I also think that a BbetweenP option with 0 as default value is more
> reasonable than num_bframes = -1. In all other respects I agree with pete...

Yes, but we would have to add an "low_delay" flag then somewhere. 

For bframes there are 3 different modes:

a) "Simple Profile": no bframes, low_delay flag is set, so decoding can
start instantly
b) no bframes, but no low_delay flag => decoding is delayed by one frame.
c) bframes: no low_delay => decoding is delayed by one frame

All three should still be possible, currently it's   

max_bframes==-1 =>a),    ==0 => b),    >0 => c)

a new field should have   ==0   => a), because that "old" behaviour. 
But b) and c) should still be possible. (yes, including b), too!)

So either we need something like "distance between P-frames" which
is "max-bframes + 1", so values are 

0 (special case) => a)    1 => b)   >1 => c) 

or we still use "BbetweenP" (like "max_bframes"), with 

0 => a)   >0  => c)   and need a special flag for b)

I'd prefer the "Pframes-distance" (which is needed internally anyway). 
Of course, the GUI might call it differenly, so people don't get confused,
but it seems like the cleanest alternative to me.

Christoph



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