WPP synchronization in x265

RARY · 4th June 2024, 20:42

How does synchronization happen when Wavefront parallel processing(WPP) is enabled and what's the exact mechanism in x265 and specifically in the processRowEncoder function which handles encoding part of each row in a frame as wavefronts?

Also,(if you can help)what are the functions and flags involved in it??

rwill · 4th June 2024, 20:49

Haha, the second assignment question within one week.

benwaggoner · 5th June 2024, 20:36

You can find everything you need to know here:
https://x265.readthedocs.io/en/maste...lel-processing
https://forum.doom9.org/showthread.php?t=167081

And in the code here:

https://bitbucket.org/multicoreware/...it/src/master/

RARY · 6th June 2024, 07:13

Can you help me more on how dependencies for a row/ CTU are checked when WPP is enabled ??
is that m_internalDependencyBitmap, and m_externalDependencyBitmap bitmaps used for it ?

I couldn't figure out clearly
And the doc just briefs on the concept.

4th June 2024, 20:42	#1 \| Link
RARY Registered User Join Date: Apr 2024 Posts: 2	WPP synchronization in x265 How does synchronization happen when Wavefront parallel processing(WPP) is enabled and what's the exact mechanism in x265 and specifically in the processRowEncoder function which handles encoding part of each row in a frame as wavefronts? Also,(if you can help)what are the functions and flags involved in it?? Last edited by RARY; 4th June 2024 at 20:44.

4th June 2024, 20:49	#2 \| Link
rwill Registered User Join Date: Dec 2013 Location: Berlin, Germany Posts: 396	Haha, the second assignment question within one week. __________________ My github...

5th June 2024, 20:36	#3 \| Link
benwaggoner Moderator Join Date: Jan 2006 Location: Portland, OR Posts: 4,876	You can find everything you need to know here: https://x265.readthedocs.io/en/maste...lel-processing https://forum.doom9.org/showthread.php?t=167081 And in the code here: https://bitbucket.org/multicoreware/...it/src/master/ __________________ Ben Waggoner Principal Video Specialist, Amazon Prime Video My Compression Book

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6th June 2024, 07:13	#4 \| Link
RARY Registered User Join Date: Apr 2024 Posts: 2	Can you help me more on how dependencies for a row/ CTU are checked when WPP is enabled ?? is that m_internalDependencyBitmap, and m_externalDependencyBitmap bitmaps used for it ? I couldn't figure out clearly And the doc just briefs on the concept.