Jun 28 14:23:32 <prunedtree>    T0B1A5, there are several ways of doing hierachical ME
Jun 28 14:24:34 <prunedtree>    and they do work. however hierarchical ME is interressing only because it has an indirect effect on MV coherence
Jun 28 14:24:51 <prunedtree>    imho it's much better to enforce that coherence by other means
Jun 28 14:27:11 <prunedtree>    the two main alternatives for hierachical ME are : 
Jun 28 14:27:20 <prunedtree>    - using coarse to fine block size. (no speed gain)
Jun 28 14:27:46 <prunedtree>    - using coarse to fine resolution. (ME searches on reduced resolution data aren't very usefull)
Jun 28 14:28:22 <prunedtree>    ME is very simple as soon as you understand that the problem is ill-posed
Jun 28 14:32:47 <T0B1A5>        ill-posed?
Jun 28 14:59:39 <prunedtree>    yes
Jun 28 14:59:47 <prunedtree>    it's an undercomplete problem
Jun 28 14:59:52 <prunedtree>    more unknows that constraints
Jun 28 15:01:01 <prunedtree>    so to improve results, we have to add constraints based on our expert domain knowledge
Jun 28 15:02:39 <prunedtree>    btw, i'm talking about natural (true) motion
Jun 28 15:03:10 <prunedtree>    block based ME in video codecs is used as a vector prediction
Jun 28 15:04:09 <prunedtree>    that's why stuff like RDO ME can make sense, as long as you have enough texture bits
Jun 28 15:04:32 <prunedtree>    if the texture bits are too low then i believe RDO ME is harmfull
Jun 28 15:06:54 <prunedtree>    (because keeping a high MV consistency will yield better visual results even if it has very high distortion)
Jun 28 15:14:33 <T0B1A5>        so realvideo actually does the right thing(tm)?
Jun 28 15:14:39 <T0B1A5>        for sub 100k video
Jun 28 16:05:12 <T0B1A5>        prunedtree: thanks for the answer about hierarchical ME
Jun 28 17:17:38 <prunedtree>    <T0B1A5> so realvideo actually does the right thing(tm)? << why are you saying that ?
Jun 28 17:17:57 <prunedtree>    they said they avoid rdo me for low bitrates ?
Jun 28 17:18:38 <prunedtree>    btw average bitrate is meaningless. you could find very low texture data on many frames even at 2+ mbps
Jun 28 17:19:54 <T0B1A5>        well, for low bitrates the image distorts a lot but mv field is homogeneous
Jun 28 17:44:56 <superdump>     maybe that's why bluesky sucks a bit in x264
Jun 28 17:45:02 <superdump>     i never checked the mvs