MT newbie questions

[fvisagie]

Hi All,

I want to look into multi-threading for speeding up my processing. Unfortunately http://avisynth.org/mediawiki/Internal_functions/Multithreading_functions doesn't say much, only that this mode works faster but with fewer filters, that one uses more memory but works with more filters etc. Individual filter documentation often doesn't address multi-threaded use either.

Where can I see a list of which mode/s a particular filter is known to work with?

In the absence of such information for a particular filter, what is the typical minimum test case for checking stability in a particular mode? I don't relish the thought of say wading through {90 minutes of video} x {x filters} x {6 modes} each, looking for possible occasional glitches!

EDIT: I'm using 2.6.0 Alpha 4, BTW.

Thanks in advance,
Francois

[Selur]

a. normally you won't just get an occasional glitch but a crash or visual always obvious problems
b. did some small tests (https://docs.google.com/spreadsheet/ccc?key=0AvWxUS1XGCPAdERPR1Zwdi1ZYWwyNlZIaFBfdDY0RGc&usp=sharing) too see which filter I use gains how much from MT a while ago
-> most filters work fine with mode 2, gpu based filters normally all need mode 5

[osgZach]

I always Mode 5 source filters as well. Especially important if you do anything that requires linear frame access

[IanB]

For source filters mode 3 and mode 5 are the same. Including the ChangeFPS(Last, Last) hack with mode 5 will spoil the linear access.SetMTMode(3, N)
...Source(...)
ChangeFPS(Last, Last) # Access Linear
SetMTMode(2)
....

[fvisagie]

Thanks, guys, much appreciated.