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View Full Version : DivX 5.0.4 and Motion Vector Reuse


Gej
20th April 2003, 18:30
A quick official word about the MV files and DivX 5.0.4:
Due to some decision difference between 1st pass and nth pass (due to Psychovisual enhancements decision, different quantization decision or Interlace decision), the motion estimation may need to be different on some blocks, so MV file could not be used during the nth pass, enabling MV reuse during nth pass may cause strange artifacts. The Beta period help us to put light on this issue, the 5.0.4 Release carry a workaround: MV reuse is internally disabled; MV files are not wrote nor read. This may cause a little slowdown during nth pass, but will avoid any kind of visual artifacts.
We are working on fixing this issue, but the whole MV reuse concept suffers some major drawback in a mutli-pass environment where encoder can (and will) make different decision during each passes.

Acaila
20th April 2003, 18:56
Welcome to this forum Gej, and thank you for that explanation. I'll keep it a sticky until this issue gets resolved.

magomago
22nd April 2003, 23:31
Will this affect the quality of the Divxs? I'm not too converend with time but I'm owrired that strange artifacts will start appaering out of nowhere

Gej
22nd April 2003, 23:38
The fix actually prevent ANY MV files related artefact form showing up.

raistlin2k
27th April 2003, 16:08
How about old 2-pass-encoding (disabled profiles)?

Can I reuse Motion Vector there? Or is it also disabled for that?

Thanks
Raist

XiS
26th June 2003, 14:50
No you can't. The old 2 passes system was implemented to obtain a fixed file size (as XVID)

raistlin2k
26th June 2003, 18:35
Originally posted by XiS
No you can't. The old 2 passes system was implemented to obtain a fixed file size (as XVID)

This has nothing to do with MV-files, you know?!?:angry:

These files are only for saving time on the second go!!

Raist

P.S. Are you the guy behind XMPEG?

XiS
27th June 2003, 13:51
Old two pass system seems to use only the first pass log file. I've tested with and without and I've two identical files.

Eric

PS : Yes

Acaila
27th June 2003, 16:05
Old two pass system seems to use only the first pass log file. I've tested with and without and I've two identical files.That's why this thread exists in the first place. Motion Vector hintfiles have been disabled from DivX 5.04 and onward, so now only the log file will be used like you found out.

hakko504
22nd October 2003, 21:24
As this feature has changed again in DivX 5.1 this thread has been unstuck.