• MAG79
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Re: Issues related to "Processing Threads" when set to "Auto"

travolter
less frames ahead = less cpu usage?
No. Less threads = Less cpu usage.

less quality too?
No. Identical quality for any threads amount.

what are the pros and cons about use higher number or lower number of frames ahead?
higher is bad because it can cause audio desyncrhro.
lower is bad because it can lead to leak of source frames to calculate and to dropped frames effect.

52 Reply by mark007 (edited by mark007 28-03-2013 18:33:34)

  • Thanks: 4

Re: Issues related to "Processing Threads" when set to "Auto"

MAG79 wrote:

mark007
SetMTMode(3,16)
It is mean that Avisynth does calculating in 16 threads simultaneously. First thread need current frame and one next frame to calculate motion vectors. Second thread need calculate motion vectors between next two frames. So 16 threads need buffer 16 frames ahead. It is if in two words.

Audio sync problem was only is case 1:1 smoothing coefficient and was resolved in SVP 3.1.3.

What your case? Tell us more details about audio sync problem please.

I'm interpolating for example 23.976 to 59.94 ( 5/2 ). Even if I select 1 frame ahead in avisynth, smoothness is perfect, absolutely perfect! Even in really obvious scenes like the panning scene Death.and.Life.of.Bobby.Z.mkv its so perfectly smooth panning no jumps or glitches at all. How can this be so perfectly smooth if SVP really does need more than 1 frame ahead? Does SVP have its own way of still waiting for the correct frame to be available in this case?

With 1 frame ahead I get perfect smoothness but very bad audio desync. This baffles me. I'm just afraid even 16 frames ahead might still have a problem with audio desync, but that its just not so noticible.

This post seems to indicate the buffer ahead is only a workaround in avisynth for filters that don't support being asked for a particular frame?
http://ffdshow-tryout.sourceforge.net/w … back_ahead

"To work around this somewhat, the ffdshow AviSynth filter allows the user to specify a number of frames to buffer ahead and a number of frames to keep in a back-history. "

Maybe my setup of mpc-hc + lav filters actually supports this request for a particular frame and so I don't need the buffer ahead at all to keep smoothness. Even with buffers completely unticked I get perfectly smooth playback so I assume this setup doesn't require the avisynth buffer workaround at all. If thats the case the audio desync is still an issue. Is there any chance you can try to reproduce the lack of need for buffers with mpc-hc + lav filters and see can you reproduce the audio desync in that case?

FYI I have "Add ffdshow video source" disabled also during these tests. I use the code below to get the frames.

SetMTMode(3,16)
LoadPlugin("C:\Program Files (x86)\MPC-BE\SVP\svpflow1.dll")
LoadPlugin("C:\Program Files (x86)\MPC-BE\SVP\svpflow2.dll")
Input=ffdshow_source()
SetMTMode(2)

53 Reply by mark007 (edited by mark007 06-04-2013 12:07:43)

  • Thanks: 4

Re: Issues related to "Processing Threads" when set to "Auto"

Just posted a quick question about this on the avisynth usage area of the doom9 forums to see if anyone there has experience with not needing the ffdshow buffers, and the audio sync differences between various settings. (enabled vs disabled, vs enabled with different values)

http://forum.doom9.org/showthread.php?p … ost1622878

EDIT: Guys, looks like fdshow osd is saying no buffered frames are being requested at all by avisynth. I can't explain that. Still getting audio desync with it buffers being disabled. OSD says none being requested.

  • Thanks: 8

Re: Issues related to "Processing Threads" when set to "Auto"

@mark007

If I disable the ffdshow buffers checkbox the image becomes freezed. How do you disable it? I need to tweak some SVP file for that?

  • Thanks: 4

Re: Issues related to "Processing Threads" when set to "Auto"

Hi travolter. I'm using InterFrame scripts, slightly modified for my own system. For these I have this as my initial setup of the svp dlls and loading of ffdshow_source.

SetMTMode(3,16)
LoadPlugin("C:\Program Files (x86)\MPC-BE\SVP\svpflow1.dll")
LoadPlugin("C:\Program Files (x86)\MPC-BE\SVP\svpflow2.dll")
Input=ffdshow_source()
SetMTMode(2)

In ffdshow avisynth settings I therefore have "Add ffdshow video source" disabled also. At the end of the script I have this. Not sure if all of this matters.

smooth_video = SVSmoothFps(Input, Super, Vectors, SmoothString, url="www.svp-team.com", mt=Cores)
smooth_video
SetMTMode(1)
GetMTMode(false) > 0 ? distributor() : last

I hope someone can reproduce the audio sync differences to nail it down to something.

  • Thanks: 4

Re: Issues related to "Processing Threads" when set to "Auto"

Anyone interested in trying to reproduce audio sync problems with different buffer sizes, even though buffer sizes doesn't effect smoothness anymore (when using LAV at least). Hope this can be figured out and explained as it seems to indicate an issue in there somewhere.