How to optimize encoding for Vimeo?

S

Steve Ogden

Well-known member
Hi all,
I just made a postcard video for a local mountain biking event, uploaded it to Vimeo and see some things I want to fix but not sure what to do next.

First of all, it was shot on a GH5 @ 4k 60p 10 bit recorded externally to a Ninja Inferno using the DNX HQX codec and graded in premier. The adobe media encoder settings were at two-pass with a target of 80 Mbps/100 max. The maximum render quality checkbox was selected. I added neat noise reduction to any shot that had significant shadow/dark areas. The MP4 file I uploaded to Vimeo is beautiful - no issues whatsoever. My server just went down and it will be Friday before I can experiment further but thought I'd ask y'all for ideas where I should start when I can start editing again.

The places where the compression breaks down (that I noticed) are: :28, :38, 1:43, 2:02 with the worst at :38. I've thought about running the bit rate way higher & see if that helps but I'm asking for guidance on anything else where I can do a better job to prepare for the Vimeo surgery. . .


Thanks!
 
Steve Ogden said:
Hi all,
The adobe media encoder settings were at two-pass with a target of 80 Mbps/100 max.
Click to expand...
Two-pass encoding does not improve the quality of encoding.
Two-pass encoding only has a use if you want to encode the video for a given maximum file size (for instance if you want to put it on a blu-ray).

Steve Ogden said:
I added neat noise reduction to any shot that had significant shadow/dark areas.
Click to expand...
"Mushing" the blacks/shadows will give an encoder an opportunity to cut corners in the shadow/dark areas.

I love details in the shadows but I do not love raised blacks (those two things are not identical!), your video has raised blacks. Additionally the problem with raised blacks (blacks tend to have very little detail) is that the encoder sees an opportunity to cut corners there.

So in summary I would advice to try not to "mush" the blacks/shadows by applying noise reduction and not to raise the black levels.

You also might want to consider some steeper highlight rolloff, the overall image is rather bland, the raised blacks and conservative highlights makes the overall image a bit lifeless.
 
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Thanks for the replies. Yes, I've looked at the Vimeo guidelines and didn't find anything useful there - seemed their advice is "more bits faster & bigger files".

Cary, I appreciate the feedback. I'll get back into lumetri & see what I can figure out when Synology gets me a replacement disk station. This trial & error learning isn't very efficient.
 
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Steve Ogden said:
Thanks for the replies. Yes, I've looked at the Vimeo guidelines and didn't find anything useful there - seemed their advice is "more bits faster & bigger files".
Click to expand...

...But do you see a clean image when you view your Vimeo upload files locally ?

Because if it doesn't look good before you upload, there's no way in h*ll it will look any better after Vimeo has processed it another time.
 
Yes, it looks good (I think. . .) before uploading. None of the shimmering/blocking, etc. As for better coloring & blacks as Cary talked about, I'll see what I can do. But the original file that I upload to Vimeo looks clean & shows clean blacks and none of the artifacts - to my untrained eye. Here is a screen shot of Windows playing the upload file.

Capture.jpg
 
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I see the issues that you mentioned. As Cary recommended go with constant bitrate and see if that makes a difference. As a long time Vimeo user I can tell you that the "sweet spot" is very elusive.
 
Mark Williams said:
As Cary recommended go with constant bitrate and see if that makes a difference.
Click to expand...

I almost always upload my videos using a constant bitrate of 8,000 or 10,000kbps, depending on the length (read: file size in this case). Never had such an issue, even with videos with grain added in the picture (short films).
 
So I sent an inquiry to Vimeo's tech support. The first layer of support asked me to download the Vimeo encoded 4k file then view it in the same player I watch here on my own computer. If I saw the pixelation, to send them screen shots. They have sent it on to the engineers for further review.

Here is a screenshot from the downloaded 4k Vimeo file:
3vKPNBO.jpg


And here is a screenshot from the original file I uploaded:
MrAj5HK.jpg
 
The black levels on the first smaller frame are distinctly different from the second large frame.
Did you re-encode with lower black levels or was one of the images post-processed?
 
The first frame above is Vimeo compression. The second pic above is what came out of premier & uploaded to Vimeo. Only re-encoding is what the Vimeo compression did. As a test, Vimeo had me download the 4k file they encoded from the original then take screen shots at about the same place from the original/source file that I uploaded. They should be the same size, they are here. . .
 
Steve Ogden said:
The first frame above is Vimeo compression. The second pic above is what came out of premier & uploaded to Vimeo. Only re-encoding is what the Vimeo compression did. As a test, Vimeo had me download the 4k file they encoded from the original then take screen shots at about the same place from the original/source file that I uploaded. They should be the same size, they are here. . .
Click to expand...
I understand that but I am comparing the first little frame you posted a bunch of postings ago with the larger frame, the black levels are completely different. I was wondering what happened?

This frame you posted first:

attachment.php


And this is the second one you posted:

MrAj5HK.jpg


Observe that the back levels are different.
 
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My bad, I understand your question now. Yes to the change in post processing. After your initial comments I applied an S curve in Lumetri.
 
Out of curiosity did you record V-Log or Re.709?

The blue-grey area just looks so mushy (and is an open invitation for the encoder to compress this).

Could you dropbox a few seconds of unaltered out of camera frames?
 
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