[BUG] VP17 Event Pan/Crop scaling and anti-aliasing methods

AnotherOne wrote on 10/4/2019, 3:14 PM

I'm also seeing the same. The rendered edges from VP17 are too soft. From VP13 they are much crisper.

Quite the opposite results on my side. Nice and soft-looking edges in VP13 and way too sharp and unpleasant edges in VP17.

It seems to only affect video rendering. If I use "Save snapshot to video file..." to grab PNGs from your projects (in VP13 & VP17 respectively), I don't really see a difference.

I'm getting the same result with both render and snapshot.

VP13, zoomed

VP17, zoomed

Sylk wrote on 10/4/2019, 10:29 PM

Encoder and render settings?

My test, VP17, AVI uncompressed output, png saved from MPC-HC:

Zoomed:

Just looks perfect (even better than your VP13)

And png snapshot from Vegas:

No difference.

AnotherOne wrote on 10/5/2019, 4:59 AM

@Sylk

Encoder and render settings?

Sylk wrote on 10/5/2019, 5:13 AM

NickHope wrote on 10/5/2019, 12:11 PM

Please ignore my previous tests, which I messed up.

I've done a load of more testing and this is what I've found. You need to click on the zoomed-in screengrabs below to see them full size (no anti-aliasing was added in the zoom). Best vs OK is a bit subjective. My GPU is an AMD Radeon HD6970:

1. Best Result (smooth but a bit soft perhaps)

VP13 with any setting
VP14-17 with GPU acceleration ON

2. Debatable Result (less smooth but sharper)

VP14-VP17 with GPU acceleration OFF (except #3 below)

3. Worst Result (too steppy)

VP17 Snapshot from the downscaled PNG (not rendered) with GPU acceleration OFF and deinterlace method none

A very brief test indicates that 8-bit project behaves same as 32-bit.

So basically it appears:

a) The anti-aliasing behaviour (CPU-only) got sharper/less smooth in VP14

b) Something has changed in VP17 to give the poor result from the combination in #3. Old advice to always set a deinterlacing method, is still good advice. Mine is always set to "interpolate".

I probably need to check all this, and further testing needed to see if it affects downscaled video and other image formats as well as PNGs.

altarvic wrote on 10/5/2019, 4:01 PM

I see that there is also no anti-aliasing with effects. Below is PiP effect (VP17, CPU only):

Here I magnified a little bit:

NickHope wrote on 10/7/2019, 1:25 PM

I see that there is also no anti-aliasing with effects. Below is PiP effect (VP17, CPU only):

And how about other effects / pre-14 versions of Vegas / GPU on?

I've done some more testing of the original issue. Anti-aliasing from a downscaled 3840x2160 uncompressed AVI file and from a 3840x2160 JPEG is like the "Best Result" in my comment above. i.e. no issue

So from my limited testing I would define the issue thus:

[VP14+] Anti-aliasing of downscaled PNG images is insufficiently smooth when GPU acceleration is OFF.

But this issue could really do with more verification, if anyone cares to test.

@AnotherOne Is your GPU acceleration OFF, and if so, do you see any improvement by turning it ON? Also, you mention Event Pan/Crop but the example project is just a straightforward downscale from 2160p to 720p. Do you see the issue in either case?

NickHope wrote on 10/12/2019, 1:51 AM

I would like to report this to the developers, as I think it's quite important, but could really do with some results from VP17 with NVIDIA GPUs or more recent AMD GPUs before I do.

It's not difficult:

Open vegas17-project-example.veg from the zip file in the first post 👆
Save snapshot to file
Do that 👆 with GPU acceleration of video processing both ON and OFF (restarting VEGAS between)
Upload the screengrabs somewhere that doesn't downscale them. e.g. Dropbox, Google Drive, OneDrive, mega.nz, wetransfer.com or mediafire.com. Not this forum.

Be careful zooming and examining the screengrabs in software that does its own anti-aliasing when zoomed. Photoshop doesn't, for example, but many do.

Sylk wrote on 10/12/2019, 4:27 AM

Can confirm result.

Smoother with Hardware Acceleration

Sharper without Hardware Acceleration

https://1drv.ms/u/s!AhcQ9Fj5Z-QwhjWbFxzkmoEYm80d?e=VWwMss

NickHope wrote on 10/12/2019, 4:39 AM

Can confirm result.

Smoother with Hardware Acceleration

Sharper without Hardware Acceleration

@Sylk What GPU/driver?

Sylk wrote on 10/12/2019, 4:45 AM

@Sylk What GPU/driver?

Same as my Signature. Post updated; link to image files added.

NickHope wrote on 10/12/2019, 4:53 AM

Thank you @Sylk. Exactly the same result with your NVIDIA GTX1080 as my AMD HD6970. Smoother (but softer) with GPU acceleration ON.

Sylk wrote on 10/12/2019, 5:02 AM

[VP14+] Anti-aliasing of downscaled PNG images is insufficiently smooth when GPU acceleration is OFF.

@NickHope And why not also suggest to allow us to define AA level?

Exactly the same result with your NVIDIA GTX1080 as my AMD HD6970.

Probably their only common point in Vegas 🙃

AnotherOne wrote on 10/19/2019, 3:01 AM

@NickHope

Is your GPU acceleration OFF

Yes, it is OFF.

and if so, do you see any improvement by turning it ON?

Yeah, I see almost identical results between VP13 GPUaccel OFF and VP17 GPUaccel ON.
But I guess almost every experienced Vegas user knows about GPU-related issues/crashes etc, so I personally don't use it that much (at least for a final rendering) unfortunately.

Also, you mention Event Pan/Crop but the example project is just a straightforward downscale from 2160p to 720p. Do you see the issue in either case?

I did some more research recently and I see it whenever an event (PNG/uncompressed AVI/nested Vegas project) with Alpha-transparency (important!) is present and some form of Event Pan/Crop transformation (resizing, rotation) is involved. It's just more noticable with a high-resolution source files, but the issue is still there with any other source file resolution.

Also, it doesn't seem to affect regular PNG24 files without Alpha-transparency (or any other non-Alpha files I guess). At least when there is no rotation in Pan/Crop window.

Interestingly, same transformations (resizing, rotation) but with a Track Motion for some reason looks much better than Pan/Crop and almost the same like in VP13.

Some examples (GPUaccel OFF):

VP13, PNG24+Alpha, Pan/Crop resize

VP17, PNG24+Alpha, Pan/Crop resize

VP17, PNG24 nonAlpha + whiteBG, Pan/Crop resize

VP13, PNG24+Alpha, Pan/Crop resize+rotate

VP17, PNG24+Alpha, Pan/Crop resize+rotate

VP17, PNG24+Alpha, TrackMotion resize

You can download .veg project files + sources with the complete set of rendering results (32 pics) here:
https://files.catbox.moe/i49yhl.zip (5,1 Mb)

Sylk wrote on 10/19/2019, 8:05 AM

But I guess almost every experienced Vegas user knows about GPU-related issues/crashes etc, so I personally don't use it that much (at least for a final rendering) unfortunately.

Did you personally encounter issues with GPU acceleration ON to make choice to deprive you of it??

Personally, that solves more problems than it causes.

NickHope wrote on 10/20/2019, 2:48 AM

@AnotherOne Thank you very much for your thorough testing and explanation and for providing projects and media that perfectly illustrate the problem. Please leave that zip file online so that developers can download it.

Further testing here shows that it's possible to get the "poor" anti-aliasing result even with media that does not have an alpha channel (e.g. JPEG), by setting its Alpha channel mode to Straight (unmatted), Premultiplied, or Premultiplied (dirty). It's the alpha mode that seems to be key, rather than simply the presence of an alpha channel.

So I've added this to the known issues post:

[VP14+] Anti-aliasing of downscaled media is insufficiently smooth when its alpha channel information is set to Straight (unmatted), Premultiplied, or Premultiplied (dirty) and GPU acceleration is OFF.

Please let me know if anyone disagrees with that.