[Mp4-tech] Deblocking at slice level

[D Soumya]

Dear Experts,
  I've got a small doubt in deblocking:
  How does deblocking take place for P_SKIP mb type?
  To be more precise, if Q and P denote two 4X4 blocks within an mb of type P_SKIP,  how are the values ref_p0,ref_q0, ref_p1,ref_q1 and also the corresponding list0 and list1motion vectors calculated in GetStrength function of JM encoder?
  Thanks in adv...
  Soumya
"Tourapis, Alexis" <alexis.tourapis dolby.com> wrote:
      v\:* {   BEHAVIOR: url(#default#VML)  }  o\:* {   BEHAVIOR: url(#default#VML)  }  w\:* {   BEHAVIOR: url(#default#VML)  }  ..shape {   BEHAVIOR: url(#default#VML)  }      st1\:* {   BEHAVIOR: url(#default#ieooui)  }      @font-face {   font-family: Tahoma;  }  @font-face {   font-family: Lucida Sans Unicode;  }  @font-face {   font-family: TimesNewRoman;  }  @page Section1 {size: 8.5in 11.0in; margin: 1.0in 1.25in 1.0in 1.25in; }  P.MsoNormal {   FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman"  }  LI.MsoNormal {   FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman"  }  DIV.MsoNormal {   FONT-SIZE: 12pt; MARGIN: 0in 0in 0pt; FONT-FAMILY: "Times New Roman"  }  A:link {   COLOR: blue; TEXT-DECORATION: underline  }  SPAN.MsoHyperlink {   COLOR: blue; TEXT-DECORATION: underline  }  A:visited {   COLOR: purple; TEXT-DECORATION: underline  }  SPAN.MsoHyperlinkFollowed {   COLOR: purple; TEXT-DECORATION: underline  }  P {   FONT-SIZE:
 12pt; MARGIN-LEFT: 0in; MARGIN-RIGHT: 0in; FONT-FAMILY: "Times New Roman"; mso-margin-top-alt: auto; mso-margin-bottom-alt: auto  }  SPAN.EmailStyle18 {   COLOR: windowtext; FONT-FAMILY: Arial; mso-style-type: personal  }  SPAN.EmailStyle19 {   COLOR: navy; FONT-FAMILY: Arial; mso-style-type: personal  }  SPAN.EmailStyle22 {   COLOR: navy; FONT-FAMILY: Arial; mso-style-type: personal-reply  }  DIV.Section1 {   page: Section1  }      You can do this by setting LoopFilterParametersFlag to 1 and LoopFilterDisable to 2. This is clearly stated within the reference software manual which is included in the JM package.
  Best regards,
  Alexis
---------------------------------
  From: mp4-tech-bounces lists.mpegif.org [mailto:mp4-tech-bounces lists.mpegif.org] On Behalf Of Gomathi Ramamoorthy
Sent: Monday, November 05, 2023 9:31 PM
To: LinCheng Wang
Cc: mp4-tech lists.mpegif.org
Subject: RE: [Mp4-tech] RE: Deblocking at slice level
    Dear LinCheng,
  Thanks for your reply.
  So if that is the case, can we set the disable_deblocking_filter_idc as 2 for all cases so that for all cases slices are independent and can avoid unnessecary deblocking at slice boundaries.
  If this is correct, then output of Jm decoder with disable_deblocking_filter_idc = 2 and the output of slice level deblocking should match right ?
  Thanks and regards
  Gomathi.
---------------------------------
  From: LinCheng Wang [mailto:lcw95129 sbcglobal.net] 
Sent: Tuesday, November 06, 2023 10:31 AM
To: Gomathi Ramamoorthy
Subject: RE: [Mp4-tech] RE: Deblocking at slice level
  Dear Gomathi,
  When disbale_deblocking_filter_idc is 2, deblocking filter process do not perform on MB edges on 2 MBs which are of different slices.
  In JM reference code, MbQ->mbAvailA is set to 0 if current MB Q and its left MB are not same slices.
  MbQ->mbAvailB is set to 0, if current MB Q and its top MB are not same slices.
  So filterLeftMbEdgeFlag is equal to MbQ->mbAvailA and filterTopMbEdgeFlag is equal to mbQ->mbAvailB.
  It is true only when disable_deblocking_filter_idc is 2.
  Do I answer your question? Or I misunderstand your quesiton?
  Regards,
  LinCheng
---------------------------------
  From: Gomathi Ramamoorthy [mailto:Gomathi_Ramamoorthy mindtree.com] 
Sent: Monday, November 05, 2023 8:06 PM
To: LinCheng Wang; mp4-tech lists.mpegif.org
Subject: RE: [Mp4-tech] RE: Deblocking at slice level
  Hi all,
  I got the below statement from the standard 
  “when disable_deblocking_filter_idc is equal to 2, macroblocks in different slices are considered not available during specified
  steps of the operation of the deblocking filter process”.
  Also in the JM reference code , when the disable_deblocking_filter_idc is equal to 2 and the top and left neighbouring macroblocks are not available, the flags 
  filterLeftMbEdgeFlag and filterTopMbEdgeFlag  are disabled.
  if (MbQ->LFDisableIdc==2)
               {
                          // don't filter at slice boundaries
                          filterLeftMbEdgeFlag = MbQ->mbAvailA;
                          // if this the bottom of a frame macroblock pair then always filter the top edge
                           filterTopMbEdgeFlag  = MbQ->mbAvailB;
               }
  So what is the significance of “disable_deblocking_filter_idc” being 2 then
  Thanks and Regards,
  Gomathi.
---------------------------------
  From: LinCheng Wang [mailto:lcw95129 sbcglobal.net] 
Sent: Sunday, November 04, 2023 6:10 AM
To: Gomathi Ramamoorthy; mp4-tech lists.mpegif.org
Subject: RE: [Mp4-tech] RE: Deblocking at slice level
  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: gomathi_ramamoorthy mindtree.com | www.mindtree.com|  
  DISCLAIMER:
This message (including attachment if any) is confidential and may be privileged. If you have received this message by mistake please notify the sender by return e-mail and delete this message from your system. Any unauthorized use or dissemination of this message in whole or in part is strictly prohibited.
  E-mail may contain viruses. Before opening attachments please check them for viruses and defects. While MindTree Consulting Limited (MindTree) has put in place checks to minimize the risks, MindTree will not be responsible for any viruses or defects or any forwarded attachments emanating either from within MindTree or outside.
  Please note that e-mails are susceptible to change and MindTree shall not be liable for any improper, untimely or incomplete transmission.
  MindTree reserves the right to monitor and review the content of all messages sent to or from MindTree e-mail address. Messages sent to or from this e-mail address may be stored on the MindTree e-mail system or else where.
  DISCLAIMER:
This message (including attachment if any) is confidential and may be privileged. If you have received this message by mistake please notify the sender by return e-mail and delete this message from your system. Any unauthorized use or dissemination of this message in whole or in part is strictly prohibited.
  E-mail may contain viruses. Before opening attachments please check them for viruses and defects. While MindTree Consulting Limited (MindTree) has put in place checks to minimize the risks, MindTree will not be responsible for any viruses or defects or any forwarded attachments emanating either from within MindTree or outside.
  Please note that e-mails are susceptible to change and MindTree shall not be liable for any improper, untimely or incomplete transmission.
  MindTree reserves the right to monitor and review the content of all messages sent to or from MindTree e-mail address. Messages sent to or from this e-mail address may be stored on the MindTree e-mail system or else where.
  DISCLAIMER:
This message (including attachment if any) is confidential and may be privileged. If you have received this message by mistake please notify the sender by return e-mail and delete this message from your system. Any unauthorized use or dissemination of this message in whole or in part is strictly prohibited.
  E-mail may contain viruses. Before opening attachments please check them for viruses and defects. While MindTree Consulting Limited (MindTree) has put in place checks to minimize the risks, MindTree will not be responsible for any viruses or defects or any forwarded attachments emanating either from within MindTree or outside.
  Please note that e-mails are susceptible to change and MindTree shall not be liable for any improper, untimely or incomplete transmission.
  MindTree reserves the right to monitor and review the content of all messages sent to or from MindTree e-mail address. Messages sent to or from this e-mail address may be stored on the MindTree e-mail system or else where.
_______________________________________________
NOTE: Please use clear subject lines for your posts. Include [audio, [video], [systems], [general] or another apppropriate identifier to indicate the type of question you have.
Note: Conduct on the mailing list is subject to the Antitrust guidelines found at http://www.mpegif.org/public/documents/vault/mp-out-30042-Antitrust.php
---------------------------------
 Why delete messages? Unlimited storage is just a click away.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: /pipermail/mp4-tech/attachments/20071113/4c2be848/attachment-0001.html