4K H.265 + Dolby Atmos = "Not enough CPU for conversion of this item"

[dietchinator]

[duplicate of other issues, but was asked by Plex on Twitter to create a topic with logs attached]

Server Version#: 1.18.6.2350 (on a WD My Cloud Home)
Player Version#: 2.52.1.70

Output from ffmpeg -i:

Input #0, mpegts, from 'z:\Plex\Shared Movies\Trailers\Pufferfish.m2ts':
  Duration: 00:00:43.39, start: 11.650667, bitrate: 75907 kb/s
  Program 1
    Stream #0:0[0x1011]: Video: hevc (Main 10) (HDMV / 0x564D4448), yuv420p10le(tv, bt2020nc/bt2020/smpte2084), 3840x2160 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 90k tbn, 23.98 tbc
    Stream #0:1[0x1015]: Video: hevc (Main 10) (HDMV / 0x564D4448), yuv420p10le(tv, bt2020nc/bt2020/smpte2084), 1920x1080 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 90k tbn, 23.98 tbc
    Stream #0:2[0x1100]: Audio: truehd (AC-3 / 0x332D4341), 48000 Hz, 7.1, s32 (24 bit)
    Stream #0:3[0x1100]: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), fltp, 640 kb/s
    Stream #0:4[0x1101]: Audio: eac3 (AC-3 / 0x332D4341), 48000 Hz, 7.1, fltp, 1664 kb/s
    Stream #0:5[0x1102]: Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz, 5.1(side), fltp, 640 kb/s

Surprisingly, the files plays ok via DLNA from Plex server to Xbox One’s “Media Player” app seemingly without transcoding, but not on the Plex app. It seems Plex server would like to transcode it?

Logs after Plex app fails to play the file:
Plex Media Server Logs_2020-04-21_22-13-49.zip (956.2 KB)

Logs after Xbox’s Media Player surprisingly successfully plays the files via DLNA:
Plex Media Server Logs_2020-04-21_22-30-36.zip (979.7 KB)

Note: I also tried VLC as well, but it could play the audio only, but had black picture. My TV is only 1080p, so the Xbox is downscaling.

[TeknoJunky]

I suspect, that xbox native ‘media player’ has access to more capabilities than regular xbox apps/games.

The same thing happens on various smart tv, where a native media player may direct play something, but plex app (and other apps) cannot.

Basically, 3rd party apps are more locked down, and cannot/will not be able to do the same things the native (provided by os) can do.

[dietchinator]

Hmmm… not sure. I know there are native Dolby Atmos games, e.g. Forza Horizon 4, Shadow of the Tomb Raider, and Resident Evil 2, etc. And that the “Dolby Access” app itself can play the Leaf demo (although Dolby might have some arrangement perhaps and I’m not sure what file format the demo is in).

I was very surprised, as I had no expectations that the Media Player app would work - it was a long shot. LOL.

[TeknoJunky]

all those use dolby digital (or PCM) + atmos.

not truehd + atmos.

the only legitimate source of truehd + atmos is from bluray disk over hdmi.

other than nvidia shield, which is the only consumer streaming device that can pass through truehd+atmos, no one else wants to touch truehd, ostensibly because, they don’t want to support support ‘ripping’ of protected content.

yes I know the shield is expensive.
yes I know it is not perfect.

But we should all be thankful it exists, and if truehd/atmos is important to you (within plex), then it is your only real solution.

[dietchinator]

Interestingly, the Xbox VLC app can play the audio (Atmos/TrueHD), including height speakers, but no picture.

[TeknoJunky]

but does your receiver say TRUEHD or does it say PCM ?

[dietchinator]

The receiver is always going to show Dolby Atmos over LPCM, i.e. what’s known as “Dolby MAT”, and that’s even when playing native Dolby Atmos games, or Jack Ryan season 2 on Amazon Prime Video, etc. (Same as Apple TV I’ve heard).

The test is whether the correct sounds are coming out the height speakers, as MS have made it near impossible to tell otherwise.

[TeknoJunky]

that is xbox doing the lpcm.

if you have a bluray player direct to your receiver, or you play a bluray in you xbox, you should get the truehd indicator (not lcpm).

if/when your receiver has the truehd indicator up, that is when you are getting full pass through with no modification/processing.

[dietchinator]

That may been when playing BluRays. But otherwise it’s DAtmos over LPCM, which is a thing. Dolby MAT (Metadata-enhanced Audio Transport) is Dolby Atmos metadata with LPCM, and my receiver shows “DAtmos + LPCM”.

[TeknoJunky]

right, I think we are going in circles.

xbox always outputs pcm+atmos, except when playing a bluray disk.

truehd decoded to pcm is sonically the same (lossless), truehd is compressed lossless, while pcm is uncompressed lossless.

on something like nvidia shield, which will pass through the truehd directly to the receiver, the receiver will get truehd (not lpcm), then the receiver will decode the truehd to analog and send to the configured channels.

Here is my avr via shield

From Xbox

[dietchinator]

Right. But my point is, that both Media Player and VLC are outputting the right sounds to the height channels over Dolby MAT, like when playing native games.

[dietchinator]

Correction: I have noticed that the website where I downloaded the test files shows that the files have multiple audio streams: TrueHD/Atmos and DD+/Atmos. So it’s highly likely both Media Player and VLC are merely selecting the secondary Atmos stream. My apologies. Title has now been edited.

Update: I have confirmed by re-muxing just the 4K video and the Atmos/TrueHD stream into a new file. And the file won’t play now in Media Player.

So it seems Media Player can select the streams that are supported by the h/w, and ignore the ones not supported, whereas Plex doesn’t (in this case).