[Mp4-tech] [video][H.264] Regarding disable_deblocking_filter_idc

[Satendra]

Hi Smitha, Shen, et al.
I cant produce any better example, then FMO usage.
First of all, I want to tell you that Filtering can be implemented in
two ways in H264,
1)  Frame based filtering, in which you will first decode the whole
frame and then do the filteriing job, as a post processing job...but
on a frame basis.
2) MB based filtering.. here you decode a MB and filter out its edges,
here you need to take care of Intra coded MBs as Intra prediction
needs unfiltered MBs.
Now I want to talk about FMO.. Flexible MB Ordering. 
In case of FMO, you can only implement a Frame based filtering, why???
because you may not  have MBs previous to current MB in scan order..
i.e. neighbouring MBs.
To implement FMO with MB based filtering, you need to put constraints
on filtering, that is use disable_deblocking_filter_idc, to disable
filtering across slice edges. In this case you can filter the MBs and
leave the edges if they are slice edges.
I think my understanging is OK and will help you.
Correct me, if I am wrong.
Satendra
On Apr 6, 2024 3:32 PM, Smitha Joseph <smithajo gmail.com> wrote:
> Hi,
> 
> The H.264 standard specifies the parameter
> disable_deblocking_filter_idc in the slice header which specifies
> whether the deblocking filter is disabled for the
> macroblock/macroblock edges in that slice. The details of how the
> parameter disables filtering at the decoder side for the different
> values is clear from the standard. My doubt is how does the encoder
> decide whether to enable or disable filtering for each
> macroblock/macroblock edges in a slice?
> 
> Thanks,
> Smitha Joseph
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