"Ad_Scan" 50-60% of 16/32 cpu...I had no idea this was so cpu heavy!

jmc

Active member
I don't really use Ad Scan but I've got a couple hundred hours of video to segment out.
So I thought that it would really save time to find the black areas.

Very surprised at the results...(4 hour 1080p.mp4, 2.9Mbps, h264)
3950x cpu
3.5 Ghz, 40s%, ----6m 10s
4.2 Ghz, 50s-60%, 5m 22s

20% speed boost, 13% faster(SSD), going to test a faster storage device...Ram Drive was no faster.

All the cores and threads were being used at the same level in task manager.(W10)

So looks like I will be Ad_Scaning one file while editing another in two VRDs. Hope it goes smoothly!

----------------EDIT----------
Everything works fine. Two Ad_Scans uses 80+ % but cpu is 69C. (Normal is 63C) LOW for anything using 80%.
Guess there are "loads" and then there are "LOADS". Not just a % of cpu use.
Two x.264 encodes can get 80s% but the temps are a "NOPE".

I put OBS at a "high" cpu priority when recording and any other normal computer use is still fine.


""@musicvid""
I've thankfully never had anything even vaguely normal" bog down my cpu.
Now testing to push the limits, yes...Several HEVC 4K/30Mbps/Slowest Preset, at less then 1 fps...ouch!

Thanks.
 
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jmc

Active member
You can always reduce thread priority if you want a less efficient scan pass...
Do you mean faster? I am only looking for sizable black areas (several seconds each).
Faster would be real nice...wish the file were .MPGs.
 

Dan203

Senior Developer
Staff member
Ad Scan is basically just decoding the file as quickly as possible and then recording statistics about each frame. Then at the very end, for a few seconds, it analyzes the data and decides where to add the scene markers.
 

Danr

Administrator
Staff member
Remember there are 2 adscan modes, interactive and non-interactive. The fastest mode is interactive with "enable fast search" checked.

In non-interactive mode, all video AND audio frames are decoded.

In interactive mode, all video frames are decoded, audio frames are ignored.

In interactive with "enable fast search" only video frames marked as reference are decoded. For MPEG2 files this typically means that 2 our of every 3 frames are skipped. For H264 and HEVC the calculation is more complex since some files have few reference frames (i.e. about 1 of every 3) and others have near 100% reference frames.

BTW, I'm now running on a 3950x system myself (LOVE IT!), and except for H264 encoding find it hard to peg the CPUs. For decoding especially, there are limits to the amount of parallelism that can be accomplished.
 

jmc

Active member
Remember there are 2 adscan modes, interactive and non-interactive. The fastest mode is interactive with "enable fast search" checked.
In non-interactive mode, all video AND audio frames are decoded.
In interactive mode, all video frames are decoded, audio frames are ignored.

In interactive with "enable fast search" only video frames marked as reference are decoded. For MPEG2 files this typically means that 2 our of every 3 frames are skipped. For H264 and HEVC the calculation is more complex since some files have few reference frames (i.e. about 1 of every 3) and others have near 100% reference frames.

BTW, I'm now running on a 3950x system myself (LOVE IT!), and except for H264 encoding find it hard to peg the CPUs. For decoding especially, there are limits to the amount of parallelism that can be accomplished.

Ok, I did have "interactive" and "enable fast search" ON. "Disable Display Update" seemed to drop my cpu use a tiny bit.
So that's probably as fast as it gets.

There is one thing that I may be misunderstanding...

"Minimum Seconds Between Marks"...I set that to 900 seconds, thinking that when it made a mark it would know that it could not make another mark for 15 minutes of video and would jump ahead. (that would be a real speed up)

Now that did not happen but the scan also put two marks 5 minutes apart...
So it's not functioning properly or I don't understand what that setting is supposed to actually do...?

------------

3950x... I had to turn off (bios) the "Core(or Cpu) performance boost" setting. That is the single core 4.7Ghz/1.5 volts boosting that get me 90+C temps.

If I'm encoding X264 I use Ryzen Master to set 4.2 Ghz(all core)@1.2375 Volts and it encodes faster then STOCK.
And so much cooler, low 70s C. And there is also the minimizing of VRD then it is even faster FPS and even cooler running.

So unless you need single thread speeds...I love the setting_off.

"For decoding especially, there are limits to the amount of parallelism that can be accomplished"
Would love to see where it stops. Seeing all 32 cores/threads being used on my cpu made me go WOW!

Thanks,
jmc
 
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Danr

Administrator
Staff member
The "minimum seconds between marks" is part of the logic that sets the scene markers, generally you want to set them around 5-10 seconds, maybe as high as 30 secs. If smaller then the scene markers can appear on the time line on top of one another. While scene markers are used to find adverts there is other logic that can override it. So, setting a high value for this field won't speed things up.

I'm running air-cooled on a B550 board, all stock. Temps never get hot even when doing full encoding. In fact, I've stopped looking at Ryzen master as it never went over 80c.
 

jmc

Active member
The "minimum seconds between marks" is part of the logic that sets the scene markers, generally you want to set them around 5-10 seconds, maybe as high as 30 secs. If smaller then the scene markers can appear on the time line on top of one another. While scene markers are used to find adverts there is other logic that can override it. So, setting a high value for this field won't speed things up.

I'm running air-cooled on a B550 board, all stock. Temps never get hot even when doing full encoding. In fact, I've stopped looking at Ryzen master as it never went over 80c.
Good to know, Had gotten my hopes up there.

Your 3950x is how I had hoped mine would be..."just run it stock" and all is good.
Maybe it is my 2017 X370 motherboard. I've thought of buying a 5XX series motherboard just to see if it helps.

But plan on upgrading this spring when (I hope) they finally bring out the new gen threadrippers, (last of the DDR4) I can still transfer my 64GB of ram over.
Be fun to play with and see what "Ad Scan" does here. (And that it will run stock and be happy like yours!)

Thanks,
jmc
 
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