Shadow / Highlights

[DavidArango]

NOTE:
I know this feature has no direct correlation with the DENOISING process.. but it has great deal to do with the COLOR CORRECTION process, in wich NEAT VIDEO is INDISPENSABLE when shooting with DSLR's.

I Totally LOVE neat video, even if a scene is aparrently noise free, this tool gives me more latitude to color correct without fear of weird artifacts.

But there is one thing that has bothered me FOREVER with After Effects.

The Native shadow/highlights tool.

When color correcting S/H recovers detail in the shadows and highlights, and with Neat Video this tool becomes even more powerfull...

But in AE you cant render using multiple CPU's if you use this tool...

So all the power Neat Video has to offer, now with it's CUDA rendering engine, is worthless because the S/H effect is causing a bottleneck in the process.

I have 2GPU's and NV benchmark show 11FPS at full HD in GPU only mode.

But if S/H is enabled, I can only render 2,5 FPS... thats 1/4 of the potential speed!.

So If neat video could integrate this tool with its GPU rendering engine... MY GOD it would do wonders!.

Now, from a different view other than Color Correction... most NV users are using NV to remove noise from poorly lit scenes, so this addition would be useful for a wide variety of users.


I know some would say that levels/curves will have similar results.. but they dont offer nearly as much detailed control.


Anyway im eager to hear your feedback!

[NVTeam]

But in AE you cant render using multiple CPU's if you use this tool...

Neat Video would not be affected by that. Neat Video uses multiple CPUs and GPUs independently of any of AE filters and settings.

I have 2GPU's and NV benchmark show 11FPS at full HD in GPU only mode.

But if S/H is enabled, I can only render 2,5 FPS... thats 1/4 of the potential speed!.

These measurements seem to be related to different things so the comparison is not very useful. With S/H disabled, how fast is the render (not in Optimize but in actual render in AE)?

So If neat video could integrate this tool with its GPU rendering engine... MY GOD it would do wonders!.

Perhaps.. But again, perhaps the problem has a different cause and another solution as well.

One more thing. In AE, please make sure you place NV on top of the stack of effects. It is important for correct work of the filter specifically in AE.

Vlad

[DavidArango]

Indeed, NeatVideo isn't affected by AE´s global setting. NV will always use it's internal settings.

But...

A sequence in After Effects will render as fast as it's slowest/heaviest effect.

Here is the test I conducted:

An AVCHD secuence 324 frames long.
(NV 3.2 - CS6 - Win 7 x64 - i7 950 - 24GB RAM - GTX560GT Ti 2GB - GTX 460 1GB)
The following effects (in stack order):
1. Reduce Noise. (GPU only - Benchmark result = 14 fps)
2. Shadow and Highlights.
3. Unsharp Mask.
4. Hue/Saturation.
5. Curves.
6. Levels.

Here are the render time results:

1. ONLY Neat Video enabled with multiprocessing at 5 cores.
32 Seconds = 10.1 fps

2. ONLY Neat Video enabled with MP disabled.
33 Seconds = 9.8 fps

3. ALL the effects above EXCEPT Shadow and Highligths with MP enabled.
57 Seconds = 5.6 fps

4. ALL the effects above with MP disabled (automatically disabled because it doesnt support SH effect).
161 Seconds = 2 fps.


So as you see, Shadow/Highlights makes that the render time is nearly 3 times slower.
That means that in a composition 20 minutes long, it would take 4 hours to render, rather than just 1 hour and 20 minutes... And that's quite a difference!


I decided to make a second test, given that all the effects different than Neat Video's Reduce Noise and Shadow and Highlights could be summarized using Magic Bullet's Colorista.

I configured NV to only use 1 GPU (benchmark at 8 fps) and configured colorista to render using OpenGL.

This way I would take away any innecesary load from CPU.

1. NV and COLORISTA ONLY. MP enabled.
45 Seconds = 7,2 fps.

2. NV, COLORISTA and SH enabled. MP disabled.
138 Seconds = 2,3 fps.

This way, following the previous example, a 20 minute composition would take 3,4 hours with S/H and 1 hour 6 minutes without.


So using GPU rendering enables NV to reach its theoretical performance limit, while using CPU effects diminishes overall performance, but effects as Shadow and Higlights disables the possibility of rendering the whole composition using all available CPU's (even if NV is configured to do so..)
creating a noticeable bottleneck.

[NVTeam]

Our direct measurements show that Shadow and Highlights (alone) is slower than Neat Video. This seems to be the reason why using S/H is slowing the overall render so much. Neat Video does its part with the same speed using all available CPU cores, but the rest of the render process is slower because of S/H.

In my opinion, the correction solution to the problem would be to speed up S/H itself.

Vlad

[DavidArango]

Yes, it would be ideal, but this effect has been the same since the beguinning of AE... I have wrote adobe twice about this, but it doesnt seem to be on their TO DO list.
If this effect could be accelerated with your CUDA engine, that would be something.