I was always a hardcore HTPC user, but I made the switch to streaming devices in hopes of simplifying things (big mistake). Now I’m back using my M2 as a client in the Home Theatre, and so glad you guys kept working on Plex HTPC because it’s working great on my Mac Mini M2!
However I would like clarity on a few issues and maybe a few tips from the devs @gbooker02
Remote Control support. I had the Apple TV remote connected via Bluetooth, but it doesn’t work for scrolling or any other gestures. Checking the input maps I didn’t see anything to suggest it SHOULDNT work. Any tips for how to get that working? Flinging from my iPhone works fine but it doesn’t let me scroll the library in the TV.
Audio Passthrough. Any limitations here? I have HDMI enabled and a A/V setup that supports TrueHD and all the HD codecs like DTS-HD etc. Everything seems to be passing through just fine for me but was wondering if because I’m on MacOS I would be getting a downgraded signal to PCM?
Clarification on HDR/Dolby Vision support. I know the M2 Mac Minis support HDR, however when I enable HDR from the system menus the app has extreme colors and looks washed out. The HDR tone mapping looks very very good without HDR enabled so this is not a big issue, however just curious what the future looks like for HDR and Dolby Vision for Plex HTPC on Mac?
Why doesn’t playback start right away when I press play? When I initially press play it pauses, and I have to press play 2 times more before playback will start. This happens with keyboard or when casting from my phone.
So glad that Plex HTPC for Mac keeps improving and thanks for all the hard work that’s been put into it
Dolby Vision will probably never be an option, as it is a closed-source technology and so on…
mpv however does support tone mapping some Dolby Vision profiles to SDR - due to license restrictions, Plex is not allowed to feature those code bits.
As far as I can tell it’s passing audio through. Should this not be the case? I’m on MacOS Ventura.
Under audio settings in Plex HTPC I have it set “HDMI” and all the codecs checked. I’ve played a bunch of 4K UHD rips and haven’t had any audio issues with TrueHD and DTS-HD. For example I just checked playback settings on Ambulance which I ripped from my 4K disk, and the Audio Codec shows:
Codec: truehd
Bitrate: 3.1 Mbps
Channels: 7.1
And thanks for the info regarding HDR and Dolby Vision. This is not too big an issue as I really like the SDR Tone Mapping in PlexHTPC and can set the HDR modes manually on my Sony X90J.
And I solved the remote issue. For those like me who have spare Apple TV remotes, I downloaded an app called “Remote Buddy 2” which works very well with Plex HTPC. Identical to how it would work on an actual Apple TV 4K.
The only other issue I cannot figure out is that when I hit play on a movie or tv show, it doesn’t start right away and stays at 0:00 until I pause and hit play again. Any idea what that could be? Thanks for the reply!
Where are you checking this? Is this the info you see in Plex or is this what you see on a device downstream on the HDMI? HTPC is capable of decoding these audio codecs into PCM so if passthrough fails you’d still get audio. Last I looked, the Mac couldn’t passthrough HD audio codecs but perhaps that has changed.
HDR really isn’t going to be acceptable on the Mac until MPV has a non-OpenGL rendering mechanism on the Mac. There is some promising work with MoltenVK so that’s likely the route that’ll bring it here. Now if Apple had just supported Vulkan themselves, we’d already have this.
I’m checking the audio/video in the HTPC app during playback. I’m not sure how to check my TV or home theatre system to be sure. What leads me to believe it’s passing through is that I had a soundbar system that didn’t support TrueHD previously and when I tried to play any TrueHD movies I got silent audio. Now with a system that supports TrueHD and all the various codecs everything plays fine. So idk
And cool what should I look for in the logs to see what’s going on? Should I just open the HTPC app and close after hitting play to see what the log generates? Or just let me know what I need to do and I’ll upload the logs for you to look at tonight. Thanks!
Easiest is likely to look at the debug overlay (cmd-shft-d). In the right column of text you’ll see info about the audio. You should see something like:
I turned on “show console log overlay” and I see “playback state changed to: playing” when I select a movie and try to start playback. I still have to hit “pause/play” twice to get playback to start (or rewind or fast forward).
However it’s only on TrueHD, DTS, EAC3 audio tracks that don’t start immediately. With AC3 5.1 and even Stereo DTS movies or shows start right away. Seems to be an issue with HD formats starting right away?
If you are using refresh rate matching, this could be a transitory failure in the audio device caused by the refresh rate switch. If so, try increasing the Refresh Rate Switching Delay.
I tried 0, then 1 second delay, then 3 second delay, then 5 seconds and still the same behavior unfortunately.
All 5.1 AC3 or stereo tracks start instantly as expected, it’s only the HD formats that require a pause/play or rewind/fast forward to start playback.
Also if I turn off my display/TV while PlexHTPC is launched on my Mac Mini, when I turn it back on PlexHTPC is completely black. I have to close the app and reopen for the interface to show back up.
These are the only 2 issues I haven’t found a fix for yet. Although they are minor annoyances I would still appreciate a solution!
Found a fix for the issue regarding playback not starting immediately, and also it seems MacOS is passing through DTS Surround and Dolby Digital AC3 cause when I hit display on my Sony X90J, it shows those audio codecs under display view when that kind of audio track is played.
To make the playback start immediately each time I had to uncheck TrueHD, EAC3 and DTS-HD from settings>audio. Seems having those checked didn’t allow playback to start immediately for whatever reason. So now I only have DTS (DCA) and Dolby Digital (AC3) checked and playback is starting as it should for all files.
I’m guessing for the other formats like TrueHD atmos it’s just sending out as 5.1 or 7.1 PCM? Not terrible but surely wish MacOS would allow full audio passthrough
MacOS does support passthrough of the non-HD codecs. So that means it supports DTS and Dolby Digital (also called AC3).
The having to pause/resume may indicate that it is failing to open the audio device for HD passthrough and falling back to a different mechanism. It’d likely indicate this in the logs.
Though the real question is, does the machine actually support passthrough of HD audio codecs? If not, you really shouldn’t enable these settings.
As gbooker02 already wrote passthrough is possible on macOS - however only limited to Ac3/DD and DTS. Nothing else, this is due to the Samplerate limit on the Apple Silicons HDMI port. A quick search showed it only supports 48khz. (I thought 96khz is the limit, maybe that was with the Intel-based Macs). With a maximum of 48khz, only passthrough of legacy codecs is possible. (for dd/dts audio is sent as 2ch@48khz, dd+/dts-hd hra as 2ch@192khz and truehd/dts-hd ma as 7.1@192khz)
On my Mac Mini M2 under audio devices when I select my Sony X90J TV, I’m getting 6 channel 24 bit audio output at 48khz not 2 channel.
I checked media info on several TrueHD Atmos audio tracks, and they are at that same exact sample rate (24 bit 48khz) so TrueHD Atmos should technically be possible? Maybe a software limitation rather than hardware?
It’s just so much misinformation regarding macs and audio passthrough online it’s hard to really know what’s possible. I see some talking about using USB dacs to get better audio quality, then some claiming it’s not necessary etc etc as the M1-M2 macs have a high quality DAC on board. Very confusing!
Dolby Digital or DTS stereo or 5.1 audio tracks are ALL sent as 2ch@48Khz bit-stream to the AVR
DD+/DTS-HD HRA no matter what channel configuration is always sent as 2ch@192Khz
TrueHD/DTS-HD MA - Again no matter what channel count or sample rate, it is always bit-streamed (not the same as PCM) at a fixed 7.1@192Khz stream.
So even though the atmos track shows only 7.1 48Khz and the Mac is also able to output 7.1@48Khz (=pcm), it cannot output the atmos track natively as it would need a 7.1 192Khz output mode, where the codec data could be capsulated.
It is confusing, indeed!
I also guess this is also an artificial limit made by Apple, the hardware should be more than capable of outputting audio at 7.1@192khz.
To clarify, the 48KHz and 192KHz sample rates mentioned above when bitstreaming audio data (passthrough) is really about bitrate and not about the sample rate of the decoded audio.
So, in trying to determine if you can actually passthrough HD audio codecs, you need to examine what the downstream HDMI device (AVR/TV) is receiving. Often these have info overlays which will tell you to varying decrees of detail (AVRs are generally much better about this).
Some of this is because of the little details. IIRC, with the Intel Macs, HD audio passthrough was not ever possible when running MacOS but at least some of these machines could perform HD audio passthrough when running Linux. I don’t know if this has changed with the ARM macs but I would tend to doubt it given Apple’s past behavior.
Thanks to both of you for the helpful information. Makes a bit more sense now!
I’ve read some Reddit post claiming that running boot camp and then installing windows on some M1 Mac Minis, they were able to get full audio passthrough that way. But I have the base M2 model so only 8GB ram and 256gb so not much room to experiment since it also runs my Plex media server.
I guess for now this setup will do as it is the most stable of all my different streaming devices and just works. Thanks again for the info and hopefully Apple opens up the OS to allow full audio passthrough in the future.
