[mp4-tech][video]: Question about h.264 Inter Prediction

[David Wu]

Hi Experts,
There are some descriptions in H.264 (2005/03) Section 8.4 that confuse me; please see if you can help me 
clarify them. Thanks in advance.
Question 1: 
The statement below says "when chroma_format_idc is not equal to 0 (monochrome) two 8x8 arrays predCr and predCb ... ",
Is this true ? What about 4:2:2 and 4:4:4 formats, there ar emore than 64 cb/cr samples for 4:2:2 and 4:4:4.
"8.4 Inter prediction process
This process is invoked when decoding P and B macroblock types.
Outputs of this process are Inter prediction samples for the current macroblock that are a 16x16 array predL of luma
samples and when chroma_format_idc is not equal to 0 (monochrome) two 8x8 arrays predCr and predCb of chroma
samples, one for each of the chroma components Cb and Cr."
Question 2:  
How is Table 8-10 derived (see statement below)?
How come the same scenario does not apply to motion vector for luma component ? Shouldn't the vertical motion vector
behave the same for 4:2:2 and 4:4:4 where the ratio of the number of samples (vertical direction) is 1:1.
"- Otherwise (chroma_format_idc is equal to 1 and the current macroblock is a field macroblock), only the horizontal
component of the chroma motion vector mvCLX[ 0 ] is derived using Equation 8-218. The vertical component of
the chroma motion vector mvCLX[ 1 ] is dependent on the parity of the current field or the current macroblock and
the reference picture, which is referred by the reference index refIdxLX. mvCLX[ 1 ] is derived from mvLX[ 1 ]
according to Table 8-10.
Table 8-10 - Derivation of the vertical component of the chroma vector in field coding mode"
Regards,
David Wu
david_t_wu hotmail.com
Fremont CA USA
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