[Mp4-tech] RE: [jvt-experts] gaps_in_frame_num_value_allowed_flag...???

Tue Apr 8 16:59:21 EDT 2008

One way to effectively detect reference picture loss when frame_num gap
is allowed is to use reference picture list reordering (RPLR) for each
coded picture. With RPLR you can derive which reference pictures are
used for a picture after parsing the RPLR commands in the first slice
header. If a used reference picture is not available in the decoded
picture buffer and marked as "used for reference", then you know that
that reference picture was lost. 
BR, YK 
>-----Original Message-----
>From: jvt-experts-bounces lists.rwth-aachen.de 
>[mailto:jvt-experts-bounces lists.rwth-aachen.de] On Behalf Of 
>ext Deepak Singh
>Sent: Tuesday, April 08, 2024 2:46 PM
>To: jvt-experts lists.rwth-aachen.de
>Cc: mp4-tech lists.mpegif.org
>Subject: Re: [jvt-experts] gaps_in_frame_num_value_allowed_flag...???
>
>Hi Expert,
>
>ya Gary there was error in my first example.Sorry for the mistake.
>Thanks for correcting me.
>
>My next query on this issue is .....based on your reply
>
>>  I think the sequence of frame_num values for the second 
>case would be:
>>
>>  0,1,2,3,4,4,4,5,6,7,0
>>
>>  So for the frames that actually "exist", the frame_num 
>values that you would observe is:
>>
>>  0,1,3,4,4,6,7,0.
>>
>Why the Non -existing frame are considered as "used for reference"
>when those frames are non- existing and why this is affecting 
>the "frame_num".
>Why not Non -existing frame are considered as "Not used for 
>reference" .
>
>Actually I am working over "Frame Loss Recovery"....
>For detecting the Frame Loss I am using "frame_num" to detect 
>the reference frame and if frame_num is not in order I am 
>considering it as unintentional loss of frame as for example...
>(gap =0)
>frame_num :  0,1,3,3,4,5,0 ...
>So there is loss of  frame having frame_num = 2.
>
>I am referring the IEEE paper  Saurav K. Bandyopadhyay and 
>Zhenyu Wu, Purvin Pandit, Jill M. Boyce "AN ERROR CONCEALMENT 
>SCHEME FOR ENTIRE FRAME LOSSES FOR H.264/AVC" Circuits and 
>Systems, 2006. ISCAS 2006.
>Proceedings. 2006 IEEE International Symposium on Publication Date:
>21-24 May 2006
>
>But if  gap =1.
>How to detect the loss of frames...????
>
>
>
>
>On Fri, Apr 4, 2024 at 9:48 PM, Gary Sullivan 
><garysull windows.microsoft.com> wrote:
>>
>>  I think there is an error in your first example (gaps = 0).
>>
>>  Rather than:
>>
>> 0,1,2,3,3,4,5,0
>>  I think the frame_num values will be:
>>  0,1,2,3,3,3,4,0
>>
>>  I think the sequence of frame_num values for the second 
>case would be:
>>
>>  0,1,2,3,4,4,4,5,6,7,0
>>
>>  So for the frames that actually "exist", the frame_num 
>values that you would observe is:
>>
>>  0,1,3,4,4,6,7,0.
>>
>>  Best Regards,
>>
>>  Gary Sullivan
>>
>>  +> -----Original Message-----
>>  +> From: jvt-experts-bounces lists.rwth-aachen.de
>>  +> [mailto:jvt-experts-bounces lists.rwth-aachen.de] On 
>Behalf  +> Of 
>> Deepak Singh  +> Sent: Friday, April 04, 2024 4:17 AM  +> To: 
>> jvt-experts lists.rwth-aachen.de; mp4-tech lists.mpegif.org  +> 
>> Subject: [jvt-experts] gaps_in_frame_num_value_allowed_flag...???
>>  +>
>>  +> Dear Experts,
>>
>>
>> +>
>>  +>   I have query related to
>>  +> gaps_in_frame_num_value_allowed_flag and frame_num.
>>  +>
>>  +>   As per my understanding of standard when
>>  +>   gaps_in_frame_num_value_allowed_flag is 0 then 
>frame_num will be in
>>  +>  non decreasing order and increases till next IDR frame.
>>  +>
>>  +> The value of frame_num  increase with plus 1 with respect to 
>> previous  +>  reference frame.
>>  +>
>>  +>   Let me put an example for it.
>>  +>
>>  +>   Lets assume B- frame is not used for reference.
>>  +>   In h.264 coded bitstream the frames are : (frame_num as per my
>>  +>   understanding it will be)
>>  +>   Note: gaps_in_frame_num_value_allowed_flag = 0
>>  +>
>>  +>   Coded Frame  :  IDR -> P-> P-> B->B-> P-> P->IDR->....
>>  +>   Frame_num    :  0         1    2     3    3    4    5     0
>>  +>
>>  +>   My question is for the same sequence if
>>  +>   gaps_in_frame_num_value_allowed_flag = 1 and non- 
>existing frame
>>  +>   exists as
>>  +>
>>  +>   Note: gaps_in_frame_num_value_allowed_flag = 1, NE = Non
>>  +> Existing Frame.
>>  +>   Coded Frame : IDR -> P-> NE->P-> B->B->NE->NE-> P-> 
>P->IDR->....
>>  +>   Frame_num   :  0       1     ?      ?     ?    ? ?     ?
>>  +>     ?     ?     0
>>  +>
>>  +>   How the frame_num value will behave for the above situation???
>>  +>
>>  +>
>>  +>   --
>>  +>   Regards,
>>  +>   Deepak Singh
>>  +>
>>  +>
>>  +>
>>  +>  --
>>  +>  Regards,
>>  +>  Deepak Singh
>>  +>
>>  +>  Visit my blog for cool stuff...
>>  +> http://www.thinknaturally.blogspot.com/
>>  +>
>>  +>
>>  +>
>>  +> *************************************************************
>>  +> *********************************
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>> second place  +>  in this world"
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>>  +>   With caresss.
>>  +>
>>  +>
>>  +>
>>  +> --
>>  +> Regards,
>>  +> Deepak Singh
>>  +>
>>  +> Visit my blog for cool stuff...
>>  +> http://www.thinknaturally.blogspot.com/
>>  +>
>>  +>
>>  +> *************************************************************
>>  +> *********************************
>>  +> "If u really aspire for the FIRST place ,then there is no  +> 
>> second place  +> in this world"
>>  +> *************************************************************
>>  +> ***********************************
>>  +> My phone:09341097500 Just DIL SE........
>>  +>  With caresss.
>>  +> _______________________________________________
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>
>
>
>-- 
>Regards,
>Deepak Singh
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