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Old 9th September 2009, 04:05   #1  |  Link
Chengbin
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Does MBtree affect decoding?

Videos encoded with MBtree seems to have strange seeking. i.e. it would skip in large blocks. Therefore I almost always jump too far, even though I didn't hold the FF key for very long. Videos without MBtree seems to skip to every I frame. The seeking is smooth.
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Old 9th September 2009, 07:12   #2  |  Link
Sagekilla
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MBtree shouldn't affect decoding in any noticeable way.

Have you checked the distribution of I Frames? Are there fewer I's with MBtree on? If so, that could be the cause why.
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Old 9th September 2009, 13:05   #3  |  Link
Chengbin
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How do I check for the distribution of I frames?
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Old 9th September 2009, 13:32   #4  |  Link
juGGaKNot
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Yes, lately i noticed that on a 3 minutes sample i only get 4 i frames, before 28 i think
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Old 9th September 2009, 18:45   #5  |  Link
Sagekilla
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Quote:
Originally Posted by Chengbin View Post
How do I check for the distribution of I frames?
--stats "file.stats"

x264 also prints the number of I Frames that get encoded by default
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Old 13th September 2009, 22:48   #6  |  Link
benwaggoner
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Quote:
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Yes, lately i noticed that on a 3 minutes sample i only get 4 i frames, before 28 i think
If random access performance isn't good enough, a smaller max GOP duration is probably in order. The default of 250 is pretty darn long. I tend to use 4 second GOPs for most HD content, so 96 frames with 24p.
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