Ok, I tried to understand the post on the French forum which explains how AIR works (according to a Devialet engineer). I used Google translate but as is often the case the output is not always perfect English 
so I made some changes. My French is certainly not perfect ...
"AIR transmits stored data and not a digital audio stream...
AIR transmits only the audio portion of digital audio files removing metadata, data length, and associated files. It sends only one format of file (presumably WAV - my comment). The computer decompresses compressed formats and transcodes as necessary.. The file is then transmitted in packets with a buffer at the start and the finish, speed controlled by the Devialet. AIR works only with bi-directional connections with flow control and the ability to re-issue a lost frame." For them (Devialet) 'bit exact' is to find all of the information stored in the audio file.
There's then a discussion about how if AIR is bit-perfect then no other way to transmit an audio file can be more bit-perfect. Hence philloouu's comment about no need for a Totaldac.
As I said before, I think the Totaldac is still very interesting if you want to use a steamer rather than a computer source and Guillaume and Rufus clearly preferred it using AES/EBU to AIR so I don't think we have the whole story yet
Philip
so I made some changes. My French is certainly not perfect ..."AIR transmits stored data and not a digital audio stream...
AIR transmits only the audio portion of digital audio files removing metadata, data length, and associated files. It sends only one format of file (presumably WAV - my comment). The computer decompresses compressed formats and transcodes as necessary.. The file is then transmitted in packets with a buffer at the start and the finish, speed controlled by the Devialet. AIR works only with bi-directional connections with flow control and the ability to re-issue a lost frame." For them (Devialet) 'bit exact' is to find all of the information stored in the audio file.
There's then a discussion about how if AIR is bit-perfect then no other way to transmit an audio file can be more bit-perfect. Hence philloouu's comment about no need for a Totaldac.
As I said before, I think the Totaldac is still very interesting if you want to use a steamer rather than a computer source and Guillaume and Rufus clearly preferred it using AES/EBU to AIR so I don't think we have the whole story yet
Philip
IMac macOS 10.15.3 (no link to Devialet 
) / MacBook Pro Retina OS X 10.14.4 / Linn LP12 / Devialet 200 / Wilson Benesch Discovery.
) / MacBook Pro Retina OS X 10.14.4 / Linn LP12 / Devialet 200 / Wilson Benesch Discovery. Qobuz Desktop Latest Version / Audirvana 3.2.18 / Audirvana Remote / iTunes 12.9 / AIR 3.0.4 / Wi-Fi / FW 8.1.0 / SAM 50%
Cambridge, UK (Updated 27th February, 2020)
