[Mp4-tech] RE: Deblocking at slice level

[LinCheng Wang]

Gomathi,
disable_deblocking_filter_idc, specified in slice_header(), decides the
behavior of deblocking filter.
When disable_deblocking_filter_idc is 0, the deblocking process filters on
MB edges, regardless of slice boundaries.
It supports Gary's statement.
Bit-perfect decoded pictures are not guaranteed, if you perform deblocking
at slice level, on any of the following conditions:
1. FMO,
2. ASO,
3. Redundant coded pictures.
Regards,
LinCheng
  _____  
From: mp4-tech-bounces lists.mpegif.org
[mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of Gary Sullivan
Sent: Friday, November 02, 2023 6:12 PM
To: Gomathi Ramamoorthy; mp4-tech lists.mpegif.org
Subject: [Mp4-tech] RE: Deblocking at slice level
Gomathi Ramamoorthy et al,
I believe the statement saying that "the standard clearly tells that no need
of deblocking at slice boundaries " is false.
(at least when speaking something being always true from the decoding
perspective)
Best Regards,
Gary  Sullivan
  _____  
From: mp4-tech-bounces lists.mpegif.org
[mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of Gomathi Ramamoorthy
Sent: Thursday, November 01, 2023 10:25 PM
To: mp4-tech lists.mpegif.org
Subject: [Mp4-tech] Deblocking at slice level
Dear all,
In the JM reference code deblocking is being done at frame level. I've
changed the code such that deblocking slice after decoding one slice . It
holds good and bit exact with the Jm software output for normal files. For
FMO files since I'm deblocking at slice level the output doen't match but
the picture doen't have any blocking artifacts.
Since  the standard clearly tells that no need of deblocking at slice
boundaries why the JM reference code depends on blocks from previous slice
to deblock ?
Is there any reason to do deblocking at frame level rather than slice level.
Thanks & Regards,
Gomathi Ramamoorthy| Senior Engineer | Mindtree Consulting Ltd | Global
Village , RVCE post , Mysore Road, Bangalore - 560059,India | Voice +91 80
26264000 Extn 66521 | Fax +91 80 26264100 | Mob +91 9901074757 | Email:
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