Colour Spaces LE vs CE… HDR -> SDR mapping

#1

Hi everyone.

I’m still a bit confused about some issues which could be already solved. I just don’t know.

As far as I know CoreElec is based upon 3.14 Linux kernel and in OSMC forums I’ve read that 4.9 kernel is better for HDR->SDR tone mapping.

Does it mean that if the TV is SDR-only should I use Libreelec.?

I also read about some HDMI and colour space issues in 905/912. Dates are old but not really sure if it was fixed/solved for CoreElec or LibreElec is a more reliable regarding to those (old) problems due to newer kernel.

Sorry if questions sound a bit “stupid”. I’m just not very sure about which “flavour” will fit better to feed my old 1080p SDR TV set.

Thanks in advance.

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#2

In reality it is generally OK, working quite well. But lately I’ve got many movies too dark to be watchable. Probably a new bug?

I will not buy a useless 4K HDR TV, it’s useless for >3m distnace. Also when a movie is good handeled in HDR for SDR TVs (and it is in 99 %) you cannot see the difference also in 99 %. My 3D 1080p is far better experience than any just 4K TV without 3D. 4K+HDR brings literally nothing for 95 % of users.

So I’d appreciate a good coversion HDR->SDR because sometimes there is just 4K and <1080p quality available.

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#3

I can’t answer your question directly if kernel 3.14 with multiple patches is better/worse compared to 4.9 regarding HDR-> SDR tone-mapping, yet I can give you a clear answer regarding tone-mapping:

STAY AWAY FROM TONE-MAPPING

There are no reasons to watch 4k HDR content on a 1080p TV and tone-mapping is a word/method professional calibrators are having nightmares about! I can get it if the only available versions are 4K or 720p, yet there always most certainly is a 1080p version available as 1080p is the most used resolution nowadays. If you don’t care about buying a new 4K HDR TV you definitely should not care about 4K HDR content… And even if you want content to be played on multiple TVs/PCs, you should have multiple versions as tone-mapping is a terrible solution…

@msider, from a technical perspective an untouched 1080p file is way better than any HDR->SDR tone-mapping even if the source is 4K as you always will lose picture quality when tone-mapping (the exception is when you have a huge screen or sitting extremely close and the resolution is worth the loss in colour quality)… You are right regarding viewing distance and 4K, yet it depends on your TV size. I completely disagree with your regarding HDR which is a huge difference compared to SDR… However, it’s important to point that it’s subjective and if you can’t see a difference, then the option is not worth it for you :slight_smile:

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#4

It’s for a second TV. Since the main one is 4K-HDR I’m getting some of those files in the NAS and all I want is to see those “good enough” in the non-hdr TV. That’s why I’m asking about the tone mapping.

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