Changes between Initial Version and Version 1 of Ticket #1114, comment 2


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Timestamp:
30 Jun 2020, 07:43:16 (4 years ago)
Author:
zhangkai
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  • Ticket #1114, comment 2

    initial v1  
    11There will be a mismatch between spec and SW for the RPR case though no issue for the non-RPR case, due to the 2x2 chroma subblock MC manner in the spec.
    2 rom eq.(935) and eq.(936), we can find that for the top-left position of each sub-block, we keep a precision of 14 bit + 5 bit = 19 bits (14 scaling window + 5 MV), as shown in (935).  But for other positions, the calculated precision is 10 bits. That's why we have  ( ( Sign( refxSbC ) * ( ( Abs( refxSbC ) + 256 )  >>  9 ) in eq. (936).
     2From eq.(935) and eq.(936), we can find that for the top-left position of each sub-block, we keep a precision of 14 bit + 5 bit = 19 bits (14 scaling window + 5 MV), as shown in (935).  But for other positions, the calculated precision is 10 bits. That's why we have  ( ( Sign( refxSbC ) * ( ( Abs( refxSbC ) + 256 )  >>  9 ) in eq. (936).
    33As a results of rounding, for a specific position, whether it is calculated as the top-left sample of a subblock, or it is calculated as an inner sample, the results may be different. Attached is an example to show such a difference.