Help please - rendering problem - video goes blocky halfway through

jayessar wrote on 1/14/2019, 12:00 PM

Hi, new to Vegas but have experience with Movie Edit Pro. I made a 6 minute tutorial in Vegas Pro 15 (build 416) with text and images layered upon the base video. When I render to mp4, the video looks fine up to a point about halfway through. From then to the end the video suddenly changes - it appears very blocky, with lots of shadows, really poor quality and the text becomes almost unreadable. I have tried rendering it several times with the same problem.

It always changes at the same point in the video, but I cannot see anything on the timeline which would result in this.

I'm hoping someone may be able to shed some light on this please.

Thank you.

Jon

 

PS It looks fine in the viewer when played.

Screenshot of early in the video:

Screenshot of later:

Screenshot of Vegas at the same point:

Comments

Grazie wrote on 1/14/2019, 1:10 PM

@jayessar : Welcome to the Forum. Waaaaay beyond my pay-grade, however it appears as if yo may have a variable Bitrate going on...

Kinvermark wrote on 1/14/2019, 1:28 PM

+1. Looks like a media capture issue. OBS? Going to need your details: https://www.vegascreativesoftware.info/us/forum/important-information-required-to-help-you--110457/

 

Musicvid wrote on 1/14/2019, 2:30 PM

Looks like they were captured or grabbed at different resolutions.

It does not look encoder-related.

jayessar wrote on 1/14/2019, 4:41 PM

@Grazie, @Kinvermark, @Musicvid - Thank you so much for your replies, and for your warm welcome!

 

.....you may have a variable Bitrate going on......

Ah, that seems to make sense - I captured the screen with ShareX but I'm a newbie to variable bitrates, so I will look into it, and find out what settings it was captured at. I was trying to render to a HEVC (Mp4) at 25fps (12Mbps) - is that the best option?

Any tips on how I can check the bitrate of clips, and/or how to manage them in Vegas would be helpul as well, thanks!

 

john_dennis wrote on 1/14/2019, 6:33 PM

Mediainfo Start here.

Musicvid wrote on 1/14/2019, 8:06 PM

jayessar wrote on 1/14/2019, 3:41 PM

@Grazie, @Kinvermark, @Musicvid - Thank you so much for your replies, and for your warm welcome!

We warmly welcome those without extra baggage..

Welcome!

NickHope wrote on 1/14/2019, 11:04 PM
We warmly welcome those without extra baggage..

...but only if they don't ignore requests for info 😉

@jayessar What are you doing with the rendered file? If it's for YouTube etc. then AVC is less likely to be troublesome than HEVC.

You may also find that OBS with these settings will be more Vegas-friendly capture method than ShareX.

Musicvid wrote on 1/14/2019, 11:21 PM

but only if they don't ignore requests for info 😉

Well taken, Nick.

jayessar wrote on 1/15/2019, 5:22 AM

Going to need your details: We warmly welcome those without extra baggage..

...but only if they don't ignore requests for info 😉

OK, I'm getting the hang of it! You need more details!! Thank you. Details below. I come as a friend...!!!!

I looked in detail at the point at which the render turns blocky - it's right where I added a JPG screenshot ("frame 015") to the timeline, after the clip "tutorial 02". "Tutorial 02" seems to render fine. See screenshot below. The cursor is at the point the render goes AWOL.

 

 

VEGAS Version & Build:
Version 15.0 (Build 261) [EDIT: 416, not 261. My error, apologies..]

Windows Edition & Version:
Windows 10 version 1803 (OS build 17134.523).

Possible problematic clip:
jpg screenshot - name "frame015"

Properties screenshot of "frame 015":


Mediainfo of "frame 015":

General
Format                                   : JPEG
File size                                : 284 KiB
Image format                                   : JPEG
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Color space                           : YUV
Chroma subsampling              : 4:2:0
Bit depth                                : 8 bits
Compression mode                         : Lossy
Stream size                              : 284 KiB (100%)

 

Vegas Project properties:

I also searched this erstwhile forum late last night for "variable bitrate". Thank you. And Googled it, and watched a youtube video on it. I picked up that it may be a good idea to check "disable resampling". Would this help?

 

What are you doing with the rendered file? If it's for YouTube etc. then AVC is less likely to be troublesome than HEVC.

You may also find that OBS with these settings will be more Vegas-friendly capture method than ShareX.

Thank you. I tried OBS about a year ago but kept getting a black screen when trying to capture. Windows 10. I'll give it another go with your settings. Thanks!

Any help would be gratefully received!

vkmast wrote on 1/15/2019, 5:38 AM

VEGAS [Pro] Version & Build:
Version 15.0 (Build 261) 

That was Update 1. The last one is Update 8.

jayessar wrote on 1/15/2019, 6:07 AM

Oops, that should be build 416. Sorry, my mistake ...

jayessar wrote on 1/15/2019, 7:21 AM

DEVELOPMENT - I think it's working now.

I didn't have time to do it all systematically, but I changed three things:

1) I checked "disable resample" in Project Properties;

2) I changed the frame rate to "25" in Project properties (to match the rendering setting I chose);

3) I re-made the screenshot ("frame 015") and re-imported it into Vegas.

I then rendered a small loop region which straddled the previous "good" output and the "bad" output -

and so far, it works - woo hoo!

Pity I can't be sure which one of the three things above got it to work. Could it be option 1 (disable resample?)

When I walk the dog later, I'll set it rendering the whole project (takes 30 minutes) and see if it works OK. I'll report back.

Thanks for your help guys. Also, thanks to @NickHope I have set up OBS again and got it to work OK.

I

jayessar wrote on 1/15/2019, 9:55 AM

OK, dog has been walked ... I set my video rendering as an MP4 (AVC), as suggested by @NickHope and it worked beautifully!

 

Not entirely sure which one of 3 options (see last post) worked, but I'm marking it as solved.

Thanks to all!! 👍👍😄😄

Grazie wrote on 1/15/2019, 11:50 AM

Your Dog worked it out. They always do 😉.

Last changed by Grazie on 1/15/2019, 11:51 AM, changed a total of 1 times.

Grazie

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jayessar wrote on 1/15/2019, 2:21 PM

😃😃😃😄

jayessar wrote on 1/16/2019, 9:55 AM

For the benefit of others, I came across this excellent tutorial explaining about using clips with varying frame-rates, and I thought I'd share it here.