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Netflix / vmaf

Perceptual video quality assessment based on multi-method fusion.
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How does VMAF decides how many threads to use #1394

Open tarun-discovery opened 1 month ago

tarun-discovery commented 1 month ago

when we pass thread argument which lets say 32 value, I have noticed a 20min video run with 0.9x speed, however a 3hrs video runs with 0.25x speed, what are the factors that decide this speed

nilfm99 commented 1 month ago

@kylophone FYI, I remember a conversation a long time ago about the sublinear gains of threads.

@tarun-discovery I'd like to confirm a few things:

  1. Are you passing this to the vmaf standalone executable or to ffmpeg?
  2. What hardware are you running on?
tarun-discovery commented 1 month ago

I am passing it to ffmpeg, I am running it on k8 infra with 32vCPU

tarun-discovery commented 4 weeks ago

just to add, I tried another 3hr long video with same setup and for that video vmaf ran at 1x speed and completed in 3hrs. So that leads me to question what are those parameters in source video that affects ffmpeg vmaf speed