Nothing is ever bitstreamed on Apple TV hardware.
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So I have some questions about when Apple TV converts TrueHD to PCM. While there will be some compromises such as discarding the Atmos metadata, we are still get other benefits, right?
For example:
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Are we still getting a lossless audio quality, or is it something else? PCM is uncompressed so it should theoretically not downgrade the audio quality, right? There has to be a difference compared to something like a Dolby Digital Plus lossy source.
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If the original track was TrueHD Atmos 7.1, is it converted to PCM with a 7.1 multi-channel metadata, or is that lost with the Atmos metadata too? PCM supports up to 8 channels, right?
So the conclusion I am trying to get at is that we just lose the Atmos benefits, which mainly has to do with better surround techniques, but we still get the 8 channel setup and amazing audio quality that is more or less same to original TrueHD source, right?
Correct.
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In principle what you’re saying is correct. But, there is another caveat to consider: bandwidth.
Dolby Atmos and DTS-HD MA are lossless compressed format, and the receiver will have the role of decompressing them while PCM is raw lossless. The decompression is handle at the Infuse level. Now, HDMI has a fixed amount of bandwidth reserved for audio, so streaming a compressed format may result in higher bitrate while the raw version, it will consume more space and therefore, it may have a lower quality.
In practice we still talk about super high quality lossless, so the difference may not be that noticeable.
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The bandwidth of HDMI 2.0/2.1 is enough to transmit the unpacked sound without trimming the bitrate. Therefore, today it does not matter who exactly is engaged in unpacking these audio tracks.
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Apple TV 4K 2022 does not support Dolby Atmos Lossless and DTSX
Is there a solution for films with Atmos Lossless audio track to be played in Atmos DD+ instead of PCM 7.1 (TrueHD) and for DTSX?
Or do Atmos Lossless and DTSX films have to be obligatorily played in Dolby TrueHD/DTS-HD?
Thanks
I just gave up and using ATV as a main media player. What’s also annoying is that Firecore is loading libraries every time and it’s slow. Now I use Nvidia Shield Pro and Plex as main video player. All audio formats play perfectly. Apple really messed up by removing Passthrough.
I guess that just depends on your priorities. NVIDIA Shield will result in inaccurate colors for anyone who has Dolby Vision files in their library whereas Infuse has accurate colors but can’t passthrough object metadata of Spatial Audio formats.
Also, Apple didn’t remove Audio Passthrough… it never existed in the first place.
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Early versions of tvOS had bitstream support. It was removed in the 12 or 13 version of tvOS.
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I feel like it only supported 5.1 and there were issues. PCM worked much better.
There was. Long time ago when I used to use Apple tv for Kodi, there was working passthrough. I think it was TV OS 10. or 11. Can’t remember now. Shortly after that I switched to Coreelec media box because of that. And then Nvidia Shield Pro.
Not sure what do you mean about Dolby Vision on Shield but I have both Shield and Apple tv and both can play DV files fine. Apple tv DOES not display those better or worse. Just about the same.
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It’s not about bitstream or PCM. It’s just a matter of what your receiver supports. By itself, a bitstream is just a sound stream that can contain anything. what exactly is the receiver’s task. Apple TV 4K and Infuse have nothing to do with it. And since you had only 5.1 channel audio in the bitstream format many years ago, it only means that at that time you had a 5.1 channel audio system, nothing more.
No, I’ve had a 7.1 system long before Apple TV 4K even existed and have enjoyed bitstream audio with my blu-ray player. Regardless, the Apple TV doesn’t support it and I use my player for Atmos, but infuse for everything else 
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The Shield’s Dolby Vision color accuracy is fundamentally broken and appears to be unfixable given NVIDIA has known about this issue for years. Here are images demonstrating this.
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Sorry but that some kind of joke. I use ATV and Shield Pro side by side since 2020, upgrading ATV with every new version and never ever saw any Dolby Vision problem on Shield Pro. Just for you, I shot video on my iPhone 13 Pro Max, showing Dolby Vision demo file playing first in Infuse ATV and then Switching to Plex on Shield Pro. As you can see, there is ZERO difference in picture quality.
Here’s download link:
It’s pretty well known issue with Profile 7 and Profile 8 content.
Profile 5 doesn’t have the issue.
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In fact, Nvidia Shield had a problem with colors. One of the owners of the Shield was able to prove this to Nvidia tech support and literally 4 months ago this problem was solved.
That’s not the same issue with Dolby Vision Profile 7 and Profile 8 content.
This issue is still an outstanding issue that likely will never be fixed.
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AFAIK the only outstanding bug is slightly elevated reds in some DV content.
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