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Old 4th February 2024, 17:51   #1  |  Link
Rob105
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Motion vector estimation does not work for P frames in AVC?

I noticed using Zond 265 or StreamEye successful motion vector estimation for AVC codec only shows on B frames (green arrows), on P frames its always red arrows it this some specifics of AVC codec?

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Last edited by Rob105; 4th February 2024 at 19:18.
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Old 5th February 2024, 06:58   #2  |  Link
rwill
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Quote:
Originally Posted by Rob105 View Post
I noticed using Zond 265 or StreamEye successful motion vector estimation for AVC codec only shows on B frames (green arrows), on P frames its always red arrows it this some specifics of AVC codec?

.
Your screens are not working and it might take a while to get them approved.

In AVC P Slices there is one way to code a motion vector: With the help of the Motion Vector Predictor (MVP) which is the motion vector predicted from neighboring blocks. In addition to that some Delta is Coded. The Delta can be implicitly set to 0,0 by signalling P_SKIP Mode. Macroblocks in P Slices only have Motion Vectors that use the L0 reference picture list.

In AVC B Slices there are two ways to code a motion vector: With the help of the MVP or the so called Direct Mode. MVP works like before but without the SKIP Part. Direct Mode, which produces either Temporal or Spatial predicted motion vectors, codes no Delta and is somewhat similar to P_SKIP in P Slices. Macroblocks in B Slices can use the L0 or L1 reference list, or both at the same time.

Are you sure you are interpreting the colors correctly?
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