MrMC

Is there any audio processing going on besides decoding for instance dts hd to pcm 7.1. Maybe becouse of Siri. There are lots of posts arround the web with people saying audio on Apple tv 4/4k is not good and recomend other devices if audio quality is top priority. I have a DD 5.1 file that is much lower volume on the Apple tv in mrmc vs my pc that is also decoding and sending pcm. But i also have lots of dts hd files that sound Identical.

Does mrmc do the decoding og is it tvos or both? Maybe mrmc decodes and sends it along and one can hope tvos just lets it pass trough or how does it work?

Volume on Netflix also seems a bit lov

We don't do any intentional audio processing. If passthrough is enabled, DD 5.1 goes right to the audio receiver/amp for decode. The receiver/amp should indicate it is getting a DD 5.1 signal. Same for DTS 5.1.

Where things get complicated is for HD audio of 5.1 or 7.1 channels. I say HD audio as AC3 (DD 5.1) != EAC3 (DD+ 5.1). tvOS does not have an API to passthrough the encoded audio signals so we have to decode them internally to PCM, then send that out. Now if your PC is sending HD audio via passthrough, then your receiver/amp might be doing extra things to the HD audio after decoding.

All we do is properly decode HD audio and send it up as PCM.

Thx for this.

Do we know what happens after mrmc sends audio up properbly decoded as pcm. Does it go to the receiver untuched or does the Apple tv tamper with it or process it in any way?

Hd audio. Do you mean dts hd and Dolby true as well?

Also. Is there any hardware related issues as to why Apple dont support bitstreaming?

My pc is decoding and sending pcm. So same as mrmc. Receiver is set to not alter the signal

No sure but we do know that if ant setting in tvOS that modifies audio (such as reduce loud ...), then passthrough breaks. The only thing we can assume is that the PCM is untouched for HD Audio.

Yes.

No.

Then how it your PC doing the decode into PCM ? Who's decoder ?

I use lav filters