[M4IF Technotes] Motion vector predictor

[Stathis Voukelatos]

Hi Howard,
If a neighbouring block belongs to an INTRA or not_coded macroblock
then its candidate predictor is set to zero.
It is only treated as not valid if the block is outside the VOP or video
packet boundaries.
Regards,
Stathis
Stathis Voukelatos, PhD      
Software Engineer       
IndigoVision Ltd     
The Edinburgh Technopole 
Bush Loan, Edinburgh 
Scotland, UK 
EH26 0PJ 
+44 (0)131 4757345      
+44 (0)131 4757201 (Fax)  
http:// <http:///> www.indigovision.com 
-----Original Message-----
From: Hao-Chieh Chang [mailto:howardchang   avermedia.com.tw]
Sent: Wednesday, July 16, 2023 3:27 AM
To: M4IF
Cc: ICIP-RD-???; ICIP-RD-???
Subject: [M4IF Technotes] Motion vector predictor
Dear all,
Motion vector predictor is defined in sec. 7.6.5 of ISO/IEC 14496-2-2001(E)
as
Px = Median(MV1x, MV2x, MV3x), Py = Median(MV1y, MV2y, MV3y).
    If the neighbourhood macroblock type is inter, there is no problem.
However, 
if the neighbourhood macroblock type is intra or not_coded = 1, there is no
motion
vector in that macroblock.  How to decide its motion vector?  Can we set
this
candicate predictor as zero?  Or treat this macroblock not valid as
trasparent
block?  These two methods will conduce different results when calculate Px
and Py.
    I can not find the answer in standard.  Please tell me if you know the
correct
method.  Thank you very much.
Howard Chang
IC/IP Product Division
TEL: +886-2-2226-3630 Ext 513  
FAX: +886-2-2226-7241
Mailto: howardchang   avermedia.com.tw <mailto:howardchang   avermedia.com.tw> 
http://www.avermedia.com <http://www.avermedia.com> 
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