Default video format keeps changing randomly since 14.5 update

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Level 1

9 points

Default video format keeps changing randomly since 14.5 update

I have two Apple TV 4K boxes. One has been updated to tvOS 14.5, while the other is still on 14.4 (intentionally). Since updating, the 14.5 box will switch the default video format to 4K HDR 4:2:0 at random with zero user input. This never happened with tvOS 14.4 and still doesn't on my other box that I've yet to update.

I have both Range & Frame Rate content matching enabled and keep the default format set to 4K SDR 4:4:4 as it is optimal for SDR content such as YouTube TV. SDR content tone-mapped to HDR 4:2:0 looks terrible to me, with text fringing and raised black levels so I'm constantly having to switch back to my preferred format since the update.

I've tried running an HDMI Connection Check to see if perhaps something was changed related to display detection but it did not resolve the issue. Content matching still works correctly, i.e. Playing a 24Hz Dolby Vision formatted movie will switch my LG CX to the correct mode. This doesn't really help the situation though, since SDR content isn't range matched rather, tone-mapped which again is sub-optimal.

Constantly having to change video format is a very poor user experience and a fix is needed quickly.

Apple TV 4K, tvOS 14

Posted on Apr 29, 2021 2:49 AM

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Answer 1

Urquhart1244

Level 10

149,322 points

Apr 29, 2021 3:59 AM in response to TheWahoo

As all streaming video content is 4:2:0 chroma, it makes no sense to set your HDMI connection for 4:4:4 chroma, which is not compatible with 4K HDR 60Hz for HDMI 2.0 connections anyway. It is fine to set SDR as default and Match Dynamic Range, but keep it at 4:2:0.

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Answer 2

TheWahoo Author

Level 1

9 points

Apr 29, 2021 5:27 AM in response to Urquhart1244

I'm aware that video content is typically mastered at 4:2:0 chroma but UI elements, such as the YouTube TV guide screen are not. At 4:2:0, guide text exhibits fringing, thus clarity suffers. Moreover, leaving it at 4:2:0 doesn't address the issue of tone-mapping SDR content to HDR, which again is sub-optimal.

If the A-TV did a better job tone-mapping, I might just set it to D-Vision, deal with the loss of text clarity and be done with it. As it stands, paper-white is eye-searingly bright when viewing SDR content tone-mapped to HDR/D-Vision and the only way I have to correct it is by lowering the OLED light setting on my TV. Again sub-optimal because doing so adversely effects actual HDR/D-Vision content that is mastered for a higher peak nit output. The only other option is to use an alternate picture mode on my TV and switch back and forth depending upon the format of what I'm watching. Oh joy!

As I stated, the default format will not persist as SDR, switching to HDR at (seemingly) random regardless of chroma setting. The entire point of range matching as I see it, is to avoid tone-mapping. Since the A-TV doesn't range match down to SDR when the default is set to HDR/D-Vision, it's usefulness is called into question when HDR or D-Vision is the default.

Regardless of any difference of opinion related to my personal preferences, the fact remains that version14.5 has changed the video format behavior, intentionally or otherwise. I don't think it's unreasonable to expect a setting that a device allows me to specify, persist indefinitely rather than be modified without my participation.

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Default video format keeps changing randomly since 14.5 update

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