[x264-devel] Re: Deblocking filter between frame and field MBs

[Loïc Le Loarer]

Le Thursday 16 November 2006 à 16:17:14 +0100, Bastien a écrit:
> Hi,
>
> I'm currently working on the deblocking filter of H264 and MBAFF mode
> is a problem for me. Using MB PAIRs (because MBAFF is set), if my
> current MB PAIR is a frame MB and my upper MB PAIR is a field MB, what
> will be the pixels used in filtering of the top MB edge?... if we keep
> MB field structure in state, then I will use the bottom field of the
> upper MB pair to filter my current MB top edge. It is troubling. I
> guess I have maybe missed something in the deblocking filter process.
> From my point of view, the most probable way to do this filtering is
> to deinterlace the MB Field pair. Is it the case ? Is it specified in
> the H264 standard or is it something that developers, in x264 for
> example, do from their own decision?
>
> So, in other words, is it specified that, after inverse transform, MB
> fields are deinterlaced when we are in MBAFF mode ? (and maybe also in
> pure interlaced mode, please precise it if it's the case).

This is completely specified in the H264 norms, the top field MB is not
deinterlaced, it is enough to use the pixels which are spatialy
colocated. Read the chapter "6.4.7 Derivation process for neighbouring
macroblock addresses and their availability in MBAFF frames", it is
quited difficulty to completely understand, you have to draw pictures to
understand, but the key to understand this chapter it is remember that
it is always spatialy driven.

Regards.

-- 
Loïc

"heaven is not a place, it's a feeling"
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