In Reply to: Bluesound BlueOS supports MQA first two unfolds into non MQA DACs posted by bullethead on April 13, 2018 at 19:18:17:
To the best of my knowledge assuming a 24 bit / 96 kHz recording.
This recording is folded into a 24 bit/ 48 kHz pcm format
The frequency range between 24 and 48 kHz is compressed en stored below bit 17.
That is the reason why it is a lossy format.
The other reason is that a water mark is added in the bits 1-16.
To play this, the format has to be decoded to plain PCM
Hence the part below bit 17 is expanded to reconstruct the frequency's above 24 kHz and the sample rate is doubled.
This is the first unfolding.
The second unfolding is only allowed on a certified DAC.
If this DAC discovers the watermark, it will apply a specific filter bank and upsamples if needed.
To the best of my knowledge, this 2nd unfolding is only allowed in hardware hence a MQA certified DAC is needed.
I have never heard of a third unfolding.
The Well Tempered Computer
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- RE: Bluesound BlueOS supports MQA first two unfolds into non MQA DACs - Roseval 04/14/1806:41:25 04/14/18 (9)
- here you go - bullethead 21:45:06 04/14/18 (8)
- Thicker smoke, and mirrors ? - AbeCollins 08:21:12 04/15/18 (7)
- remember three blue lights in the USB demo unit? - bullethead 15:05:32 04/15/18 (5)
- But only two of those lights were MQA, as I recall. - AbeCollins 20:39:19 04/15/18 (4)
- You haven't listened to high res MQA then - bullethead 20:43:01 04/15/18 (3)
- I have, with the Tidal App w/o Roon in the picture - AbeCollins 06:33:41 04/16/18 (2)
- RE: I have, with the Tidal App w/o Roon in the picture - PAR 01:49:03 04/18/18 (0)
- RE: I have, with the Tidal App w/o Roon in the picture - bullethead 18:35:24 04/17/18 (0)
- RE: Thicker smoke, and mirrors ? - Roseval 08:54:17 04/15/18 (0)