http://www.androidpolice.com/2016/01/06/qu...o-to-bluetooth/ (http://www.androidpolice.com/2016/01/06/qualcomms-new-aptx-hd-codec-brings-high-resolution-audio-to-bluetooth/)
(https://www.qualcomm.com/news/onq/2016/01/05/introducing-aptx-hd-meeting-need-hi-resolution-wireless-audio)
[/url]As well as accepting a 24-bit audio input, 24-bit audio resolution is maintained by using an extra two bits in each of the four sub-bands of processing. This results in lower signal-to-noise ratio (the signal strength signal strength relative to background noise) through the encode/decode cycle and less distortion, making aptX HD ideal for use as part of a high-resolution audio solution.
I'm guessing it's still not lossless, or else they would mention it, and given their playing coy in the past letting everyone in the tech world assume their original aptX was lossless without correcting anyone.
Personally, the improvements I'd like to see in BT audio is latency and lossless. The former is already available in theory with the aptX "Low Latency" format, but not many devices have it and it's not being promoted at all. Lossless just to avoid yet another recompression. For example, when you upload your music to Google Music it's likely to be recompressed to MP3 if it's not in that format (1), then when you stream it, it may not stream the original MP3 again (2), and then the bluetooth recompression (3). That's 4 lossy compressions in total.
If I recall correctly, BT audio is limited to like 352 kbps. I've seen mono signals with limited frequency range and all that jazz compress to ~320 kbps, but to do that consistently isn't likely to be possible.