关于 Apple TV 4K 的格式输出疑问

[Lavventura]

电视是索尼的 x9500G，支持杜比视界和 HDR;

ATV 是刚入手的 2021 新款，线材是贝尔金的 8k 2.1 ；

这几天一直没搞明白，我输出的模式应该直接选择 [杜比视界 4k 60 帧] ，还是选择 [ 4k SDR 60 帧] ？ 有人说应该默认 SDR，开启自动兼容，会更好？

求有懂的大佬帮忙解答一下，万分感谢～

以下是经过我这几天的各种尝试，仅限我电视和线缆完全支持杜比标准的情况下，这样是最合适的：

1 、视频输出选择 4k 杜比视界
2 、关闭动态范围和帧速率的自动匹配

带来的效果是：

1 、杜比视界的界面显示效果无偏色，更明亮（但也有人喜欢 sdr 的界面色彩）；
2 、播放视频时，退出不会显示 2-3 秒的黑屏；

[geniussoft]

问题是，9500G 并不支持杜比视界 4k60 啊...

[wy315700]

@geniussoft 9500G 支持杜比视界 4k60 的

[wanguorui123]

杜比视界 4k60，开启自动匹配码率格式

[ytzong]

这种问题 google 一下就有

[levineet]

我在 Apple TV 设置里面直接选择 杜比视界 4K 60，相当于系统 UI 界面也是这个色彩格式

之前也看到有人说选 SDR 然后自动匹配，但是这样播放视频退出的时候会黑屏一下，选了杜比视界就不会这样了，另外感觉杜比视界去看系统 UI 界面也没什么问题...

另外我选 SDR 自动匹配，YouTube 的 HDR 没办法激活。选了杜比感觉就默认是 HDR 了

[Lavventura]

@levineet 好的，感谢～

[ShuaiMakMak]

请问假如我只是旧的 4K 电视，是不是开 4K SDR 60，然后关掉[符合内容]，就 ok 了？

[manfred4527]

KD9000F 使用杜比视界 感觉画面 UI 这些偏灰色，我使用 4K60 SDR 模式加 IPhone 调色

[pycq2002]

4k 60 SDR，打开匹配动态范围，动态分辨率要看你的电视支不支持检测 24p via 60 signal，下面是在 reddit 上看到的

TL;DR: It depends on your TV…leave Match Frame Rate off if your TV can do this[https://www.rtings.com/tv/tests/motion/24p].

Longwinded explanation: Most modern TVs refresh their screen 120 times per second (120Hz). The nice thing about this number is that both 24fps (for film) and 30fps (for video) map nicely (5Hz/frame and 4Hz/frame, respectively), so the TV can accurately display the source. Some TVs add "motion smoothing", and use their additional cycles to interpolate between the actual frames, and that leads to the Soap Opera Effect…that's a function of the TV, not the Apple TV, and you should disable it accordingly. ;)

Meanwhile, the Apple TV prefers to output a 60Hz signal. 30fps video is doubled (without smoothing), and then the TV doubles that again to match its 120Hz refresh rate (hopefully without smoothing), and you ultimately see 30fps.

You might have noticed that 24fps won't divide evenly into this 60Hz output signal, so the Apple TV has two options when it needs to display 24fps movies:

Use a 3:2 cadence, such that alternating frames are displayed for 3Hz or 2Hz. This is what happens when you leave Match Frame Rate off.

Switch its output signal to 24Hz, so there's a direct mapping of 1 frame to 1Hz. This is what happens when you turn Match Frame Rate on.

So…the option you choose depends on your TV.

Up until recently, 3:2 wasn't ideal, because (as you might imagine) displaying alternating frames for different lengths of time results in uneven playback (called "judder"). 24Hz was preferred, as this explicitly told the TV to display 24fps.

However, many modern TVs can detect the 3:2 cadence within the 60Hz signal, understand that it's 24fps in disguise, and adjust to properly display 24fps (with each frame getting 5Hz) on screen.

So: If your TV can do that, it's the best option…your TV won't need to switch modes as often (resulting in fewer black screens and greater stability), and the Apple TV can draw its UI at 60Hz (if it switches to 24Hz, everything is drawn 24 times per second, leading to chunky UI animations).

[haohahaha]

我推荐设置 4ksdr ，然后打开自动匹配帧速率和动态范围。
这样的好处是保证每个视频都已最合适的色彩播放，避免 sdr 在 hdr 下播放色彩失真的问题。同时因为 sdr 短内容比 hdr 多，也尽量减少了 sdr 和 hdr 切换时的黑屏次数

[haohahaha]

举个例子。YouTube 的广告都是 sdr 的，如果视频也是 sdr ，那从列表打开一个视频就完全不会黑屏，如果是 hdr 视频，也只黑屏一次。