Why don't slo-mo methods look as good as the Video Preview window?

stevefoobar2 wrote on 11/5/2023, 8:59 PM

This is something that I've been meaning to ask for a long time. Why doesn't any slo-mo method in Vegas Pro 19 look as good as the Video Preview does when I simply change the Normal Rate playback speed to less than 1.0? Even when I change the playback speed to as low as 0.20 (20%) the slo-mo in the Video Preview windows looks dramatically better than any rendered video using any of the commonly known slo-mo methods. Why can't Vegas render this video using the Normal Rate setting so the slo-mo rendered looks as good as the video preview?

In this particular project, I'm using 30 fps video that I want to slow down substantially. I know all the common slo-mo methods in Vegas and they all look bad compared to the video preview window and Normal Rate set to 20%. l realize I should shoot at a high frame rate for slo-mo, but that's not the question I'm asking or the point of this post.

Thanks!

Comments

Howard-Vigorita wrote on 11/5/2023, 9:17 PM

Can't provide reasons why but there's one commonly known method that should work if you like the preview: screen capture. Try previewing full screen and capturing with your video card manufacturer's facility if you can't get Vegas capture to work. Amd Relive works great for me on machines with Amd video. Otherwise I use OBS Studio.

stevefoobar2 wrote on 11/5/2023, 10:47 PM

I actually tried this with Microsoft Game Bar, but I felt the video quality was degraded. I do have an AMD video card, so I'll give Radeon ReLive a try. Thanks for the suggestion.

Robert Johnston wrote on 11/6/2023, 1:31 AM

@stevefoobar2  Are you comparing what you see in a small video preview window with a full-screen video player? There can be a big difference depending on which slow-motion method you used and what you have selected for resample mode in Project Properties. Do you have Optical Flow chosen for the resample mode in Project Properties? That gives the best slow-motion but takes a long time to render compared to "disable resample" or "frame blend." If you use the velocity envelope or playback rate in media properties to adjust speed, then choice of resample mode can make a difference when comparing a smaller resolution preview compared to playing back the rendered version full screen in a video player. If you use the Slow Motion Effect, then the resample mode doesn't seem to make a difference. You set the quality in the Slow Motion Effect, with "Fine" being almost the same as optical flow.

Intel Core i7 10700K CPU @ 3.80GHz (to 4.65GHz), NVIDIA GeForce RTX 2060 SUPER 8GBytes. Memory 32 GBytes DDR4. Also Intel UHD Graphics 630. Mainboard: Dell Inc. PCI-Express 3.0 (8.0 GT/s) Comet Lake. Bench CPU Multi Thread: 5500.5 per CPU-Z.

Vegas Pro 21.0 (Build 108) with Mocha Vegas

Windows 11 not pro

3POINT wrote on 11/6/2023, 3:33 AM

Why doesn't any slo-mo method in Vegas Pro 19 look as good as the Video Preview does when I simply change the Normal Rate playback speed to less than 1.0? Even when I change the playback speed to as low as 0.20 (20%) the slo-mo in the Video Preview windows looks dramatically better than any rendered video using any of the commonly known slo-mo methods. Why can't Vegas render this video using the Normal Rate setting so the slo-mo rendered looks as good as the video preview?

Depending on the preview quality settings, you will even not see the result of the resample method used for slomo. Only in preview mode good and best you will see the same result as the render result. In mode draft and preview, the chosen resample method is not applied to the preview, which looks at the first glance better and sharper (but with no fluent motion).

Howard-Vigorita wrote on 11/6/2023, 8:00 AM

@stevefoobar2 I should also mention that screen capture resolution will be limited by that of your monitor... it can really be quite good capturing off a 4k monitor if Vegas can preview your project smoothly at best-full.

mark-y wrote on 11/6/2023, 10:03 AM

Used correctly, Optical Flow resampling will eliminate the need for your question.

stevefoobar2 wrote on 11/6/2023, 1:14 PM

@stevefoobar2 I should also mention that screen capture resolution will be limited by that of your monitor... it can really be quite good capturing off a 4k monitor if Vegas can preview your project smoothly at best-full.

Howard, I tried using AMD Radeon's video screen recorder (note that ReLive was renamed to Record & Stream) and it starts recording the screen fine showing Vegas and me clicking on the "Video preview using external monitor" button (of course, I first set the quality to Best-Full), but once I click the "Video preview using external monitor" it records only a black screen. How did you get around this problem? Oh, and BTW I do have a 4K monitor. I'm using an older but still very capable Radeon 570 series card.

stevefoobar2 wrote on 11/6/2023, 1:40 PM

Why doesn't any slo-mo method in Vegas Pro 19 look as good as the Video Preview does when I simply change the Normal Rate playback speed to less than 1.0? Even when I change the playback speed to as low as 0.20 (20%) the slo-mo in the Video Preview windows looks dramatically better than any rendered video using any of the commonly known slo-mo methods. Why can't Vegas render this video using the Normal Rate setting so the slo-mo rendered looks as good as the video preview?

Depending on the preview quality settings, you will even not see the result of the resample method used for slomo. Only in preview mode good and best you will see the same result as the render result. In mode draft and preview, the chosen resample method is not applied to the preview, which looks at the first glance better and sharper (but with no fluent motion).

I already have the video preview quality set to "Best - Full", which is why the preview looks so good and the slo-mo is so smooth. I just don't understand why Vegas can't render what I'm seeing in the preview.

3POINT wrote on 11/6/2023, 3:30 PM

@stevefoobar2 Do your rendersettings match your project settings? I did today a 4k50 slomo with optical flow and the result was as good as seen in the preview (including the artifacts due to optical flow). Only disadvantage it took "ages" to render with optical flow set for resampling.

stevefoobar2 wrote on 11/7/2023, 11:50 AM

Why doesn't any slo-mo method in Vegas Pro 19 look as good as the Video Preview does when I simply change the Normal Rate playback speed to less than 1.0? Even when I change the playback speed to as low as 0.20 (20%) the slo-mo in the Video Preview windows looks dramatically better than any rendered video using any of the commonly known slo-mo methods. Why can't Vegas render this video using the Normal Rate setting so the slo-mo rendered looks as good as the video preview?

Depending on the preview quality settings, you will even not see the result of the resample method used for slomo. Only in preview mode good and best you will see the same result as the render result. In mode draft and preview, the chosen resample method is not applied to the preview, which looks at the first glance better and sharper (but with no fluent motion).

I already have the video preview quality set to "Best - Full", which is why the preview looks so good and the slo-mo is so smooth. I just don't understand why Vegas can't render what I'm seeing in the preview.

mark-y wrote on 11/7/2023, 12:11 PM

I haven't noticed the discrepancy, but I am not using legacy slomo methods.

Howard-Vigorita wrote on 11/7/2023, 5:06 PM
Howard, I tried using AMD Radeon's video screen recorder (note that ReLive was renamed to Record & Stream) and it starts recording the screen fine showing Vegas and me clicking on the "Video preview using external monitor" button (of course, I first set the quality to Best-Full), but once I click the "Video preview using external monitor" it records only a black screen. How did you get around this problem? Oh, and BTW I do have a 4K monitor. I'm using an older but still very capable Radeon 570 series card.

@stevefoobar2 I've never experienced that with a 6900xt... always been able to capture what I see on screen. But it's been a while. I suppose as a workaround you could just resize the preview screen as much as possible after unchecking showing Toolbar, Status Bar, and Transport Bar then crop it later.

stevefoobar2 wrote on 11/7/2023, 5:51 PM

RESPONSE AND SOLUTION AFTER SOME TRIAL AND ERROR

First, let me thank everyone for your input. They have all been great. As it turns out, the best solution did indeed involve setting the Project Resample Mode to Optical Flow as was suggested by a couple of people. Let me explain the complexities of the project and what I ended up doing to get the result I wanted.

First, I didn't go into details in the original post, but this was a 1080p 30 fps video that I wanted a "Locked on Stabilization" effect with. You've probably seen those videos where the subject is consistently centered in the frame but the background jumps around wildly. I found an excellent YouTube tutorial for this and it worked flawlessly.

But that meant that there was a LOT of keyframes (pretty much one per frame) in the short video clip and several other effects to achieve what I was looking for. Whenever I applied any slow motion effect such as clip edge Ctrl-dragging or inserting a velocity curve, two problems occurred:

  1. The slow motion video looked horrible because by default in new projects I have the Resample Mode set to Disable Resample.
  2. The keyframed effects got all screwed up and out of sync with the video frames.

Thanks to you folks, problem #1 was solved by changing the Resample Mode to Optical Flow as was mentioned by a couple of you.

Problem #2 was solved by using something I didn't even know Vegas Pro had--Nested Projects. I'm very happy I discovered this feature. By pulling my first project with all the keyframed effects as the .veg file directly onto the timeline in a brand new Vegas project, then applying the velocity curve to the clip on the timeline (which is really the entire previous Vegas project), I completely resolved this issue! This nesting is extremely powerful and I don't know how I missed it as a feature all this time.

Thanks again everyone for the great help!

mark-y wrote on 11/7/2023, 6:11 PM

...this was a 1080p 30 fps video that I wanted a "Locked on Stabilization" effect 

There is a built in Boris effect in the newest version of Vegas. Will do that and quite a bit more. As a Boris wannabe, I can promise there is a steep learning curve, not for the easily discouraged.

stevefoobar2 wrote on 11/8/2023, 11:17 AM

I haven't upgraded yet, however the link I put in my solution post on doing this "manually" is very straight forward--just more steps perhaps.