Page 5 of 8

Re: Missing Shadow Detail, nothing below 2% black

Posted: 14 Feb 2018, 02:12
by davilla
As reported:

Code: Select all

- using the TV's native media player: 66 and up are visible (nominal),
- using Infuse on Apple TV 4K: 84 and up are visible,
- using MrMC on Apple TV 4K: 84 and up are visible,
- using the "Computers" app on Apple TV 4K (through iTunes homesharing): 72 and up are visible.
But zero info on what 1) really means as there is no 'native' media player at the tvOS app level. As far as APIs, there are three a) AVPlayer b) AVPlayerViewController and c) AVSampleBufferLayer. a) and b) are more or less identical. c is a lower level than a or b).

MrMC uses c). We will investigate further but this is low on our priority list.

Re: Missing Shadow Detail, nothing below 2% black

Posted: 14 Feb 2018, 04:02
by cosmoxl
davilla wrote:
14 Feb 2018, 02:12
As reported:

Code: Select all

- using the TV's native media player: 66 and up are visible (nominal),
- using Infuse on Apple TV 4K: 84 and up are visible,
- using MrMC on Apple TV 4K: 84 and up are visible,
- using the "Computers" app on Apple TV 4K (through iTunes homesharing): 72 and up are visible.
But zero info on what 1) really means as there is no 'native' media player at the tvOS app level. As far as APIs, there are three a) AVPlayer b) AVPlayerViewController and c) AVSampleBufferLayer. a) and b) are more or less identical. c is a lower level than a or b).

MrMC uses c). We will investigate further but this is low on our priority list.
I think "tv's native media player" meant the media player on their TV, not ATV4k.

Re: Missing Shadow Detail, nothing below 2% black

Posted: 14 Feb 2018, 20:59
by davilla
Anyone try VLC yet ? Their 3.0 version says it has HDR support.

Re: Missing Shadow Detail, nothing below 2% black

Posted: 14 Feb 2018, 21:20
by cosmoxl
davilla wrote:
14 Feb 2018, 20:59
Anyone try VLC yet ? Their 3.0 version says it has HDR support.
Whatever method VLC uses it's mapping HDR to SDR for me. MrMC used to do that but in 11.3 beta it doesn't.

Also, VLC is not matching frame rate of content for me.

I'm guessing that of the 3 API you mentioned earlier it uses one different from MrMC?

Re: Missing Shadow Detail, nothing below 2% black

Posted: 19 Feb 2018, 00:54
by wesk05
I tried one of the black level clips that was posted on the Infuse forum (https://firecore.com/comment/81963#comment-81963). It has been muxed to m4v container. When played via iTunes Home Sharing using the "Computers" app, it shows all the bars upto 66 (64 shouldn't be visible). You may have to increase the brightness on your TV to see bars 66 & 68. The same file when played in MrMC or Infuse only shows upto 84. It looks like there is definitely a difference in the rendering mechanism.

I tired VLC 3.0.1. HDR didn't work for me. Frame rate matching also didn't work.

Re: Missing Shadow Detail, nothing below 2% black

Posted: 19 Feb 2018, 02:16
by davilla
wesk05 wrote:
19 Feb 2018, 00:54
I tried one of the black level clips that was posted on the Infuse forum (https://firecore.com/comment/81963#comment-81963). It has been muxed to m4v container. When played via iTunes Home Sharing using the "Computers" app, it shows all the bars upto 66 (64 shouldn't be visible). You may have to increase the brightness on your TV to see bars 66 & 68. The same file when played in MrMC or Infuse only shows upto 84. It looks like there is definitely a difference in the rendering mechanism.

I tired VLC 3.0.1. HDR didn't work for me. Frame rate matching also didn't work.
Good info wesk05, now that I can see the difference, I can start poking around as to why.

Re: Missing Shadow Detail, nothing below 2% black

Posted: 20 Feb 2018, 16:57
by davilla
Found it :) As it seems that other 3rd party apps have similar behavior, this looks like a bug on the tvOS but there does seem to be a workaround. Now at least matches
'- using the "Computers" app on Apple TV 4K (through iTunes homesharing): 72 and up are visible.
This is 03 black-level-v3.m4v with levels blown up to show details on browsers.

Image

Re: Missing Shadow Detail, nothing below 2% black

Posted: 20 Feb 2018, 18:03
by cosmoxl
davilla wrote:
20 Feb 2018, 16:57
Found it :) As it seems that other 3rd party apps have similar behavior, this looks like a bug on the tvOS but there does seem to be a workaround. Now at least matches
'- using the "Computers" app on Apple TV 4K (through iTunes homesharing): 72 and up are visible.
This is 03 black-level-v3.m4v with levels blown up to show details on browsers.

Image
So what's going to happen if/when apple fixes their bug? :)

Re: Missing Shadow Detail, nothing below 2% black

Posted: 20 Feb 2018, 18:13
by davilla
nothing :)

Re: Missing Shadow Detail, nothing below 2% black

Posted: 21 Feb 2018, 02:37
by davilla
new TestFlight pushed, please test and verify the fix.