Converting to Stereo in tvOS vs. in AVR

Is there a difference between having the Apple TV output stereo (e.g. converting 5.1. dolby into 2.0 PCM), and doing the same conversion in an AVR?

Please assume that the same DAC / amplification is applied to the resulting 2.0 stream. I am only interested in the decoding / mixing down of dolby surround, as well as potential differences in resulting bitrates (down/upsampling in either approach).

Has someone with AVR tested this? :slight_smile:

The reason for the question is that I am currently doing the translation to stereo in the ATV, then splitting the audio from the HDMI to a DAC, and feeding that to an AMP. I wonder whether to upgrade my DAC or to get an AVR, and therefore whether an AVR is beneficial to the processing of surround streams when compared to in-software conversion.

The short answer is no, with a few caveats.

The decoding/downmixng process is pretty standardized, and will not vary between certified implementations on various devices. However, this can be affected by enabling the ‘Reduce Loud Sounds’ option on the Apple TV, as this will affect the overall dynamic range of multi-channel output as well as stereo. Additionally, since tvOS handles the 2ch downmixing, we can’t be 100% sure of the exact process they are using, but we have no reason to believe they’re doing anything non-standard.

Of course, hardware differences can come into play when using different DACs and amps, though all of these occur well after the audio has left Infuse and the Apple TV.

Hope this helps. :wink: