Does there exist a HDMI endpoint ?
Most AVRs take HDMI in
Yes, I agreed any up-sampling will disrupt the necessary info for the renderer to work (de-blurring with leaky MQA filter at the DAC side). Don’t forget, there’s also ‘de-blurring’ done after the ADC at the mastering level.
The limitation for software decoding is it needs the profiling of different DACs; which are rather complex but not impossible to implement in the software level. So in the case of Audirvana, users can do any form of up-sampling and use their built-in digital filters to cater the sound they like without the full ‘de-blurring’ effect at the DACs side.
Roon has a comprehensive DSP and Room correction which can be used after the first decoding are a big advantage here. My speculation for Roon to implement a generic software renderer that will work with most DACs is something that will differentiate from the others (If they found a way to do it right).
There’s nothing unknown here; once you do a down-sampled you will lose information. It is technically a lossy compression system designed to save bandwidth. Of course the trade-off are the effective resolution is down and bandwidth is restricted with some lossy contents above the 22kHz. Which ‘they’ claim one is not able tell the difference…