MPEG skipped block and motion vector?

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davyzhu

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Hi all,

I am reading Fogg's MPEG FAQ.
(**broken link removed**)
The FAQ have several diagrams about skipped block and motion vector.

How to determine the skipped block in B frame?
And what syntax in video stream describe it?

e.g. If I have a picture sequance I1 B2 B3 P4. The frame have frame prediction.
If B2 have same microblock as I1 or P4, is the mb in B3 skipped?
And any other situations?

Any suggestions will be appreciated!
Best regards,
Davy
 

Hi,
Skipped macroBLock occurs when ever there is no Block coefficients to be encoded in the block. This may occur when there is a perfect prediction from the reference frame or after quantisation there are no block coefficients.
They are skipped since they need not send any extra information regarding that block to reconstruct the block.

Hope this clears the doubt.

Regards,
KJN.
 

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    davyzhu

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