The dreaded Gamma shift showing on Vimeo

Great question, Jan. I thought the root of the problem was that some players made assumptions about the tagging being 1-1-1 but I have since lost the plot, lol.

About all these videos don’t get into real issue, just say things around real problem. Not very good.

Solution is plain simple. Want video on YT/Vimeo look good on Mac export it with Rec.709-A gamma ( you can grade to any other gamma, but change export setting before rendering). That’s it.
For Windows do the same, but export as sRGB or 2.2 gamma. Best setting for both OS is probably sRGB gamma on export.
You can’t have fairly accurate preview on both systems which is industry biggest failure and requires actions from standardisation bodies like ITU ( and also Apple/MS down to BM/ Adobe).

Stop watching those videos as they’re useless and basically never give correct explanation/solution ( as single one doesn’t exist).
If you need to watch video this is the closest to proper explanation( although title is misleading as it’s not QT issue at all):

Whole issue is now understood and confirmed by people from companies which have required knowledge (eg. FSI, Baselight) as well as individuals who wasted days trying to get into root of the problem.

Andrew, sRGB isn't "exactly" the same as Rec709 gamma 2,2?

sRGB and pure 2.2 gamma are not exactly the same, but what is more important is that out of those 2, only sRGB flagging is recognised by Apple color engine.
There is no way to pass reliably info about 2.2 or 2.4 gamma even if about all content is graded to one or another.
sRGB would work, but both Vimeo and YT overwrite tag to 1–1-1, so problem is back.
Tried to convince Vimeo to pass sRGB tag if source is based on it, but unsuccessfully.

Hi everyone, thanks for the posts above - i have a slightly different gamma shift issue.
The 1080 file uploaded to YT has a gamma shift compared to 2160 file.

I am using v18.1 on an iMac and set the project to Color managed, sdr rec709, separate output colour space and selected 709a

When exporting under advance colour space tag - same as project and Gamma tag Rec.709A

When i view the exported files bith the 1080 and 2160 as exactly what i see in Davinci.

When i upload the 1080 to YT, it looks correct.
BUT when i upload a 2160 file is has a gamma shift and is darker, even the 1080 quality setting is darker.

I have tried this with several options and versions - same result.
https://snipboard.io/0KchuA.jpg

I really hope someone can help point me in the rght direction.

Q

It will be YT reading UHD file differently. Don't you have gamut issues as well - file look desaturated?

Download your UHD file encode by YT and post media info grab from it.

You can needlessly send yourself insane worrying about this as it's likely a playback issue and beyond your control.

Have you tried downloading the encoded file (not original) from Vimeo and dropping it back into Resolve? How does it look? Run a test by exporting some colour bars from resolve, use video levels, upload to Vimeo and test on multiple devices.

All browsers seem to respond to system colour management differently, things also change with software updates over time. Last week my android mobile was showing Vimeo playback with raised black levels, but this week it seems to be working fine.

As someone that delivers HD SDR ads and web content all the time at a post facility, all we do is grade at Gamma 2.4, export our masters as ProRes at Video levels, no gamma tags are set. Then we encode with Media Encoder and upload to whichever platform is requested. If what comes out of Resolve also looks right when it's brought back in, then there's nothing else to worry about that's within your control.

2.4 for web is not the best choice.
2.2 or sRGB is better one.
YT should look the same (regardless if correct or not) if you upload HD or UHD (same export setting)- this problem is strange.

2.4 for web is not the best choice.
2.2 or sRGB is better one.
YT should look the same (regardless if correct or not) if you upload HD or UHD (same export setting)- this problem is strange.

Unless you have a VERY noisier image with colored noise (like a blue floor from underexposed film): the smaller frame will blend pixels together and potentially introduce a slight chroma shift.

It will be YT reading UHD file differently. Don't you have gamut issues as well - file look desaturated?

Download your UHD file encode by YT and post media info grab from it.

Thanks Andrew, i am new to this level of technicality and coming from a stills background it is a very steep learning curve which i am struggling with.

I downloaded the files fro you tube and they are 1280 x720, not sure if there is a way to download the 4k version?
Uploaded file on left, downloaded from YT on right.



Both were uploaded as quicktime .mov, but the YT version is an .mp4
Uploaded is AAC, HEVC and downloaded AAC, H.264

Hopefully this helps, please let me know if there is anything else i can try.

Thank you.

You can needlessly send yourself insane worrying about this as it's likely a playback issue and beyond your control.

Have you tried downloading the encoded file (not original) from Vimeo and dropping it back into Resolve? How does it look? Run a test by exporting some colour bars from resolve, use video levels, upload to Vimeo and test on multiple devices.

All browsers seem to respond to system colour management differently, things also change with software updates over time. Last week my android mobile was showing Vimeo playback with raised black levels, but this week it seems to be working fine.

As someone that delivers HD SDR ads and web content all the time at a post facility, all we do is grade at Gamma 2.4, export our masters as ProRes at Video levels, no gamma tags are set. Then we encode with Media Encoder and upload to whichever platform is requested. If what comes out of Resolve also looks right when it's brought back in, then there's nothing else to worry about that's within your control.

Thanks Paul.

The thing is i want the file i have created to look the same as how it was edited in Da Vinci.
Looks good in DV, looks the same exported, but darker on YT in Chrome, FF, but correct in Safari.
That bit darker is not what i want as this in most cases will be the final product for client.

2.4 for web is not the best choice.
2.2 or sRGB is better one.
YT should look the same (regardless if correct or not) if you upload HD or UHD (same export setting)- this problem is strange.

Thanks Andrew, i appreciate your efforts to help me with this.

So if i shot the footage in c-log, and the final product will almost certainly be used on the web at this stage of my career, what settings would you recommend i use?

DR preferences:


Project settings


Export panel


The result on YT.

It will look different on PC.
I thought your issue is different end result if you upload HD vs UHD ( from the same project with same settings)?

There is no way to get same look on PC and Mac and across all browsers.
If you want to be somewhere in the middle then use 2.2 or sRGB export gamma ( tag can be Rec. 709-A). That’s about best you can do.

It will look different on PC.
I thought your issue is different end result if you upload HD vs UHD ( from the same project with same settings)?

There is no way to get same look on PC and Mac and across all browsers.
If you want to be somewhere in the middle then use 2.2 or sRGB export gamma ( tag can be Rec. 709-A). That’s about best you can do.

Hi, I am on an iMac and the issue is a different end result if I upload 1080 + 2160.
Both look the same as what i see in Davinci.
1080 looks the same when uploaded
2160 is darker when uploaded.

Not sure where the PC part came in, sorry if i caused the confusion.

Ok, so this is a strange bit as it should not look differently. There is no real, obvious reason for it. This is new for me although never done such a comparison test. It must be related to how YT interprets those source files.

I don't understand at all. I could be doing something wrong and not even know.
Is there another way i can test - possibly using settings you suggest or are the settings above right?

Thank you.

There is noting wrong with your settings.
Are you sure that in both exports levels are set to Auto?

First compare Resolve export in QTX for HD and UHD- should look the same.
Then download both HD and UHD YT encodes made from corresponding sources and import them to Resolve and compare to your timeline. Make sure both are set to Rec.709-A in Resolve.

There is noting wrong with your settings.
Are you sure that in both exports levels are set to Auto?

First compare Resolve export in QTX for HD and UHD- should look the same.
Then download both HD and UHD YT encodes made from corresponding sources and import them to Resolve and compare to your timeline. Make sure both are set to Rec.709-A in Resolve.

Hi.
In clip attributes they are set to auto and the export levels are set to video.

When i download and import & set the input colour space to Rec.709-A - they look exactly the same as the original.
When opened as mp4 files they also look exactly the same as what i see in DaVinci.

Hmm...so all seems to be fine, yet...
This is very strange then- browser issue? Safari preview should look the same as QT X, so no idea what is going on.

When you compare do you press pause? There use to be a thing when YT would darken video when it was paused.

In safari the 2160 file looks the same as the 1080 and what i see in Da Vinci.

When i pause there is no darkening, i know because i am uploading both files and only the 1080 upload is the same as the exported file.

When i check the file info of the files exported - Colour profile is HD(1-1-1) for both.

But not when it goes through YT?

And you can't download 4K from YT? There are download 'websites'.
They may be flagging it differently and this will be the issue.

I have done so many tests now, but i have just uploaded a 1080 & 2160 series with auto, video and full levels - Quicktime h.264
All have the same result - 1080 is correct, 2160 is darker.

When i download the video & full levels 1080 and 2160 - they are all .mp4, 1280 × 720 and HD (1-1-1).

Try using one of the website which let you download YT links.

Sorry, i don't understand?

There are website where by pasting YT link it allows you to download actual video (different versions).

Does Vimeo look at color space / gamma tags or does it assume Rec709 Gamma 2.4 (or 2.2)? Just curious.

After many tests, I can confidently say—no, Vimeo does NOT honor gamma tags.


Sent from my iPhone using Tapatalk

There are website where by pasting YT link it allows you to download actual video (different versions).

I used 4k video downloader, but both times it only downloaded a 1080p file.

Both the 1080 version bd the 2160 version has the following stats when downloaded:
1920 × 1080, AAC, H.264, HD (1-1-1)

Jim Robinson in a Davinci group on FB thought it might be youTube conversion (compression). The 1080 is using h.264 and the larger one is using V9 ( vp09).

These are the stats for nerds and it shows exactly that.

Current / Optimal Res 3840x2160@25 / 3840x2160@25
Volume / Normalized 100% / 100% (content loudness -9986.0dB)
Codecs vp09.00.51.08.01.01.01.01.00 (313) / opus (251)
Color bt709 / bt709
Current / Optimal Res 1920x1080@25 / 1920x1080@25
Volume / Normalized 100% / 100% (content loudness -9986.0dB)
Codecs avc1.640028 (137) / opus (251)


So how do i solve this situation?
When i view the edit in DR and export the file on my machine i see one thing, but when i upload to YT it is darker.
I mean i can just do 1080, but that is not really a solution.
Thanks for your time so far.

How can you solve it if just sending higher resolution gives wrong results?
What you send is correct and YT never really adjusts it- just re-transcodes staying within YUV, so there is no room for any issues.
It can be related to the use of different codec. Maybe flagging is no 1-1-1 on VP9, so OSX color sync processes it differently. Don't see other place for an error.

YT24.net offers 4K.

Does Vimeo look at color space / gamma tags or does it assume Rec709 Gamma 2.4 (or 2.2)? Just curious.

After many tests, I can confidently say—no, Vimeo does NOT honor gamma tags.


Sent from my iPhone using Tapatalk

Vimeo takes source and always writes 1-1-1 after transcode (except HDR). Eg. send sRGB graded and tagged file to Vimeo and all what they will do is transcode to their profiles without touching it. You won't get sRGB tag anymore though, but Rec.709 (1-1-1). How this can give people correct preview I talked to their support, but after 3 moths it went nowhere.

I tried this and it works pretty well for me on Vimeo :

Color Management :

Timeline color space P3-D65
Output color space Same as Timeline

Deliver / Advanced Settings :

Color Space Tag P3-DCI
Gamma Tag SRGB

No idea why would you tag P3-D65 graded file as P3-DCI?
You basically tell Apple color sync to perform bad math.

There are probably a lot of ways to get around this but I'll share my Vimeo workflow. I edit and grade in Davinci Resolve now, so apologies for anyone still in Premiere.

I typically work in Davinci WG, Rec. 709 2.4 for my primary edit, but you can work in whatever color space you want for this to work. When I'm ready to export my project to Vimeo for client review, I create a duplicate timeline and change the output color space to Rec. 709-A. In my case, coming from Rec. 709 2.4, this makes everything look super washed out. Then I add a timeline correction node and adjust the curves until I have everything looking identical to my original grade. I've created a powergrade that I reuse for this step since the curve is always the same – you could probably use a color space transform or a conversion LUT for this as well. This is just the way I enjoy doing it.

Then I export the video making sure the Color Space and Gamma Tag options are both set to 'Same as Project' since I want Rec. 709-A.

When I upload the video to Vimeo, I see no discernible color or gamma shift. Aside from the obvious compression that Vimeo applies, it appear mostly identical. If you want to skip a step you could always grade in Rec. 709-A from the start.

Hope this is helpful.

I want to add to this since I struggled a lot to figure out the right means of getting the color to Vimeo from DaVinci

Here's what I did:

I already had my project graded before I had to transform the color space.

I shot on an Arri Alexa Mini and used the Maxon Magic Bullet looks to grade.

In the color management window I set the below

Color Space Timeline to Rec 709 - Gamma 2.4
Output Color Space - Rec 709-A

Then in every shot at the end of my node tree I added a Color space transform node and kept the input and color space as "Same as Timeline" but for the Output Color Space and Gamma as Rec 709 for Color Space and Rec 709-A for the Gamma. This properly set the color as I had it before but now with the 1-1-1 proper 1.96 gamma shift that works for Vimeo. It looks the same on QuickTime, on Vimeo and anywhere else I play it. I even tested on Vimeo and the color is still the same.

Once you set the Color Space Transform node I just duplicated that node onto every shot and the film and voila, all worked out properly.

When Exporting, in the Delivery Window be sure to set the Tags for Color Space Tag to Rec 709 and Gamma Tag to Rec 709-A.

Was very difficult to figure out.

See the screenshots below for my settings

You may also look at this explanation.

Most of it is correct (just not presented very clearly) except:
- all footage is still (and should be) encoded with 1.96 gamma and what is changing is "decoding/viewing" gamma, which can be 2.2, 2.4 etc. and defines final look,
- he did not mention at all Apple reference modes which are actually a fix to this problem. Unfortunately it's only a partial fix as works only on newer Macs. Still it would be nice (as mentioned) for Apple to apply 2.2, decoding by default on all Macs.

It's nothing new- he just confirmed what we knew for months now (some bits for years).