What Are Correct White Levels 8-Bit Video / SD / Youtube?

In the parade / waveform / histogram, what is the proper level for white when editing 8-bit footage that will be used on youtube (and assumed for standard definition monitors)?

Do we need to use "broadcast safe" values when rendering for youtube???

In my footage, I notice that highlights are MUCH BRIGHTER than when I use the generator to generate a solid color white bar. Also, the highlights in my footage are much brighter than, say, white text in titles.

For example, if I use the generator for a solid white color and then look at the histogram, it shows a spike at 80. Likewise, the parade and the waveform indicate that it is around 800 (hard to tell exactly what it is).

However, clouds in the sky are regularly much higher (90 or higher in the histogram, and above the 896 level in the waveform and parade. Yet they don't look clipped. I can see detail in the clouds.

I am shooting mostly slog and using DaVinci Color Management. I have my monitor setting at 400 Nits (I don't know what my monitor actually displays).

Thanks in advance.

The values in the scopes are independent of what levels you select (video or data) in the Delivery page.

On the scopes, 0..1023 is the visible range, you should color correct in this range.


For export to YouTube, you should select video levels.

Hello,

From
https://support.google.com/youtube/answer/1722171?hl=en

Video codec: H.264

Progressive scan (no interlacing)
High Profile
2 consecutive B frames
Closed GOP. GOP of half the frame rate.
CABAC
Variable bitrate. No bitrate limit required, though we offer recommended bit rates below for reference
Chroma subsampling: 4:2:0

The values in the scopes are independent of what levels you select (video or data) in the Delivery page.

On the scopes, 0..1023 is the visible range, you should color correct in this range.


For export to YouTube, you should select video levels.

Thank you for the reply. I appreciate your input.

So in the preferences, so in the Project Settings -> Master Settings -> Video Monitoring I can have the Data levels set to Full (instead of set to Video), right?

And on the Deliver page, if I pick the YouTube 1080p preset, in the Advanced Settings -> Data Levels will it be ok to leave it at "Auto" where it is by default? Or do I specifically need to change it to "Video."

So in the preferences, so in the Project Settings -> Master Settings -> Video Monitoring I can have the Data levels set to Full (instead of set to Video), right?

That is not related to the above discussion. The levels in the scope are referring to the internal values, represented by floating point number where 0 is black and 1 is white. Resolve using 0-1023 is confusing many people, it would be better if Resolve would use 0..1. The scope values are independent of data or video levels, data or video level only matters during the delivery also some CODECs can take floating point data completely avoiding the video and data levels dichotomy.

With respect to the monitoring signal, typically you would want to send video levels.
Do a test: create a new HD project, use a SMPTE (ARIB) Color chart generator and make it into a compound clip.



If the -2% (sub-black) bar is visible you incorrectly send video levels while the monitor reads data levels. If the 2% and 4% dark bars are not distinguishable you incorrectly send data levels to a monitor configured for video levels. Of course, this is not a replacement for proper monitor calibration and a miscalibrated monitor may not even show those subtle differences.

And on the Deliver page, if I pick the YouTube 1080p preset, in the Advanced Settings -> Data Levels will it be ok to leave it at "Auto" where it is by default? Or do I specifically need to change it to "Video."

That depends on the codec. H.264 will default to video levels.

For example, if I use the generator for a solid white color and then look at the histogram, it shows a spike at 80. Likewise, the parade and the waveform indicate that it is around 800 (hard to tell exactly what it is).

it's this bug again:

viewtopic.php?f=21&t=73386

and until it gets fixed, you will have to grade in RCM, export it and then apply your generators in YRGB before mastering.

Or else use the Color Space Transform node instead of RCM and keep everything in DaVinci YRGB.

For example, if I use the generator for a solid white color and then look at the histogram, it shows a spike at 80. Likewise, the parade and the waveform indicate that it is around 800 (hard to tell exactly what it is).

it's this bug again:

viewtopic.php?f=21&t=73386

and until it gets fixed, you will have to grade in RCM, export it and then apply your generators in YRGB before mastering.

Or else use the Color Space Transform node instead of RCM and keep everything in DaVinci YRGB.

Thanks for the info and the link.

Ok, quick and dirty fix was to turn the solid color generator into a compound clip, and then grade it by bringing up the offset in the color wheels, so now it is around 95 or so on the histogram, which is close enough for me.

With respect to the monitoring signal, typically you would want to send video levels.
Do a test: create a new HD project, use a SMPTE (ARIB) Color chart generator and make it into a compound clip.

i also think, this kind of SMTPE color bars and especally the included "Y-ramp" are the most useful tools to verify correct levels in a reliable manner.

but i would add a few other hints:

1.) use a ffmpeg based player (e.g. mpv) for you tests, because that's closer to the software solutions, which are utilized by youtube etc. for the transcoding. it doesn't help, if you use any more expensive commercial software solution for your local tests, which interprets file formats in a different way.

2.) most ffmpeg based players also provide capabilities to use of lavfi-videofilters. this feature can be used to place waveform-view measurements on top of the actual played video. the required commands may look a little bit frightening at first sight, but in fact you just have copy and past them, once you figured out a working solution for your preferred player. in my case it looks like this:

Code: Select all

mpv -vf 'lavfi=[split=2[a][b];[b]waveform=components=7:graticule=green:display=overlay:bgopacity=.7,format=yuva444p[bb];[a][bb]overlay]' YOUR_VIDEO_FILE


(note: everthing should be on one line. the line breaks are only caused by the forum software.)

and the player will show the SMPTE testclip like this:


the diagonal white line (representing the Y-signal), should give you a rather reliable feedback about the actual video levels resp. possible misinterpretation of the file format.

3.) one of the nice advantages of this particular approach has to be see in the fact, that it doesn't only work for local video files, but you can place an URL pointing to the youtube video page instead of the local filename as well. it will work just the same!

e.g.:

Code: Select all

mpv -vf 'lavfi=[split=2[a][b];[b]waveform=components=7:graticule=green:display=overlay:bgopacity=.7,format=yuva444p[bb];[a][bb]overlay]' https://www.youtube.com/watch?v=56-PMaVvHmA

In the parade / waveform / histogram, what is the proper level for white when editing 8-bit footage that will be used on youtube (and assumed for standard definition monitors)?

Don't overthink this. When you export whatever you're working on in normal Rec709 HD, if you're rendering an H.264 8-bit file, everything will automatically be transformed from 0-1023 to 0-255 code values.

You should think of the scale as old-school values, in terms of percentages: 0-100. What you're doing will still relatively have values that relate to 0-100.

I would worry more about making sure peak levels don't exceed 100, and the chroma levels are reasonable and don't get into illegal gamut territory. Do some tests with short bits of material and see how they translate on YouTube. Be aware that things will look different on different browsers and different OS's. I find Vimeo Pro to look better than standard YouTube, but that's me.

I find Vimeo Pro to look better than standard YouTube, but that's me.

this may be caused by the fact, that you are using mac os and youtube will just just the same codec (h.264) as vimeo for delivery to this kind of devices and its applications, but for the large majority of the audience, youtube is using VP9 for delivery, which definitely looks noticeable better at the same bandwidth constraints.