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Old 17th September 2013, 09:48   #1  |  Link
dumdum23
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Motion Vector Prediction in H.264

Hi,
I have a couple of doubts regarding the Motion Vector Prediction in H264.
1) As per the algo, i the top-right neighbour is not present, we consider the Top-left neighbour. Why is the Top-right given priority over Top-left in the first place? Is there any specific reason for that
2) Also, can the Motion Estimation be a lossy process if the MV prediction is incorrect. Say, my MVP should have been +10 and it has been taken as +8 and the difference encoded and sent. What I can understand is if the MVP calculation at decode side is done and the MVP comes to be +10, then the decoded picture might not be the correct representation. Can there be any other cases?

Thanks in advance
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Old 17th September 2013, 14:19   #2  |  Link
raffriff42
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1) The choice is arbitrary, I think.
2) Errors in motion detection create larger post-motion-compensation difference data, which results in larger files / lower compression efficiency. There is no direct quality loss, but In constant bitrate mode, quality will be lower.
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Old 18th September 2013, 10:36   #3  |  Link
dumdum23
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1) Guess so, tried to look for information on this but couldn't find any
2) Thanks a lot, got it
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h.264/avc, h.264;mvc;decoder, motion vector, video codec

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