MP 1,1-5,1 Disable HDMI audio

[stockholm80]

I have a Mac Pro 5,1 with a RX570 graphics card. Due to some issues with HDMI audio I would like to disable it completely so that the system doesn't recognize my TV and only sees my RME audio interface instead.

Is there a way to do this through patching the AppleHDA.kext or similar?

 

[MarciaFunebre]

HDMI - annoyingly - is designed to always see both video and sound.
I once spoke to an Apple technician and they explained that it is not possible to disable either audio or video separately from each other on a HDMI connection.

It has bugged me too a lot because I have a processor/pre amp connected to my Mac Pro and the only way to have encoded surround sound is to use HDMI. But at the same time MacOS sees the processor/pre amp also as an additional screen which creates a huge mess with my existing multi-screen setup (Two 4K screens and a Cintiq). Even SwitchResX can't really contain the chaos completely. Each reboot therefore is a PITA.

I wish too that there was some hidden Terminal command that would allow to just kill all video and/or sound output on selected ports.

 

[konqerror]

HDMI - annoyingly - is designed to always see both video and sound.
I once spoke to an Apple technician and they explained that it is not possible to disable either audio or video separately from each other on a HDMI connection.

That's not technically correct in both directions. HDMI cannot be sound only, that is true. Some devices that want to only output sound, like SACD players, will put in a blank 640x480 video signal. I do not believe any computer will do this.

However, HDMI can and is routinely sent without a sound signal. This includes legacy DVI devices, HDMI graphics cards that are too old to support sound, and even a common AV receiver which strips the sound out as to avoid having the TV play simultaneously.

Under Windows, you'd just disable the graphic card's audio device, but Apple has no official way of doing this.

 

[ProfDrLuigi]

That´s easy ... simply remove:

/System/Library/Extensions/AppleGFXHDA.kext

Et voila. HDMI Audio Device gone. Don´t forget to refresh Kextcache after deleting the kext.

 

[Rumblefi$h]

That´s easy ... simply remove:

/System/Library/Extensions/AppleGFXHDA.kext

Et voila. HDMI Audio Device gone. Don´t forget to refresh Kextcache after deleting the kext.

Excuse me for asking noob questions but how can I remove a file from System/Library/Extensions?
Seems impossible even with SIP turned off.
Looks like this file is there after fresh MacOs install. Is it ok to just do without?
And how do I refresh Kextcache in Mojave?

Thanks in advance