range limited required?

[benwaggoner]

Originally Posted by FranceBB

Well, since we're talking about annoying things from the past, what about overscan/safe area?
To this very day, in 2021, some TVs still crop the image... and for what? Only 'cause back in the days timecodes and teletex subtitles were not muxed but rather displayed in the inactive lines of the screen which were not meant to be displayed to the user... Nowadays, in 2021, everything is muxed, it would be madness to put the timecode or subtitles there when you can easily just mux them in the container, but TVs still crop all around the screen, getting rid of what is actually a part of the image that should be displayed and they do that "just to play safe"...

Overscan can definitely die now. In the Filmmaker Mode spec from the UHDA, we mandated that there be no overscan.

The only content that even nominally benefits from overscan is legacy standard def stuff. And the solution there is simply cropping to 704x480 or 704x576 as appropriate. The eight left/right pixels aren't supposed to be displayed per SMPTE spec, and there's definitely no reason to encode them if they contain non-image content.

[kolak]

Originally Posted by FranceBB

- Overshooting
Some light overshoots are still allowed, though. The reason is that, even though you might get the waveform perfectly fine in Avisynth, once you encode with a lossy codec, the approximations that are gonna occur might lead to overshooting, so slightly out of range values. This was very much true for MPEG-2, but way less pronounced for H.264 and H.265, but it still occurs, which is why nobody is gonna tell you anything if you get some light compression overshooting every now and then.

Not only heavy compression overshoots, but intermediate codecs as well (ProRes, DNxHR etc). Quite often it's good few levels (of course on high contrast areas).
Not a big deal in current digital world. Broadcast freaks out about it for no real reason (it was a real problem in analog era, but not now).

Good that EBU R103 got updated. Key point is in line 2:

"The EBU, considering that,
• video levels have traditionally been measured with devices that display a trace, such as a traditional waveform monitor,
• that readings in mV no longer give relevant information in digital signal infrastructures,
• television systems now include high dynamic range and wide colour space images as well as
standard dynamic range and colour space images in the same digital container,
• that a certain tolerance can be allowed in digital signal levels,"

mV should be gone. They serve no role anymore. It should be either % of signal or simply levels per given bit depths.

[Balling]

Facepalm! Ffmpeg default to limited BT.601 matrix. Okay. If you are using swscale that is, if you are using zscale it defaults to source range.

Oh, and also, ffmpeg still does not support limited RGB. So... It should now only ever tag full.

[Balling]

"To this very day, in 2021, some TVs still crop the image... and for what? "

It is very hard to not crop the image for HW SD image. Google VITC, for example. LG CX started doing that though.

[FranceBB]

Originally Posted by Balling

It is very hard to not crop the image for HW SD image.

For SD sure, but the problem is that this still happens for FULL HD. You have no idea how many people use their TVs by default and watch FULL HD 25i channels and they expect the safe area / overscan to be respected 'cause otherwise it crops.
Sure, they can disable overscan in their TV settings if they want to, but by default TVs still crop and that's insanity but it's one of the reasons why we have to respect safe area / overscan for HD/FULL HD contents as well.

See the bottom blue line with no thicker on it (right below the white option on the right with the green button to get into the interactive menu)?



Well, that thing is there to respect the safe area / overscan.
Users at home who don't disable safe area / overscan in their newly purchased Samsung TV only see this:



As you can see this is just right 'cause we can't take a risk and therefore we make sure everyone (even those who don't disable overscan) see it correctly.
I would very much like to see TV manufacturers shipping TVs with the default option of NOT Cropping anything above SD resolutions...

[Balling]

Well, what happens on ads? I guess it will not account for it, just checked with my channels. Usually those UIs are very old.

[Balling]

BTW, D-1 has nothing to do with 16-235, 16-240 designation. See: https://tech.ebu.ch/docs/techreview/...ec601_wood.pdf

It was actually different originally, changed last moment. If we believe the doc, original was 72-252 for chroma, dunno for luma.