[Zodduska]

I was messing around the other night searching for the best sounding audio codec to play on my Zune since at the moment it does not support any lossless format.

I converted Tool's 10,000 days to 440 kbps, 2 channel 24 bit 2pass VBR with dbpoweramp using WMA 10 pro codec and decided to see if the Zune would play it. To my surprise the Zune software transfered it with no conversion to the player.. I gave it a listen and it is playing fine, however my untrained ears can not confirm that it is not somehow dithering it down to 16bit in playback and discarding some of the data defeating the point.

Does anyone know about DACs and 24 bit audio playback? Could it be the case that it is playing with dithering, or if 24bit were not supported would it not play at all?

here is some info on the Zune's DACs:
# ^ WM8978 - CODEC with speaker driver. Wolfson Microelectronics.: (WM8978G)
# ^ MC13783 : Power Management and Audio Component. Freescale.: Freescale MC13783

the Wolfson is a 24bit DAC, however the Freescale is not.

 

[Filburt]

I don't see how it would give any benefit to begin with. Your source material is 16 bits, 44.1KHz. dbpoweramp is not going to divine additional data out of it, and it's doubtful the output stage of the Zune would even take particular advantage of a 24 bit source quantitatively (I doubt it would matter either way, qualitatively). On top of that, you're using a lossy codec that I'm fairly certain is applying a threshold in quiet curve in addition to masking thresholds for reduction of data, most likely annihilating whatever could have been the gain from encoding in such a fashion (I still doubt there was any).

Basically, you're not gaining anything unless there is some sort of aspect of the Zune design that causes it to playback a 24 bit file better than a 16 bit file even if the depth of information does not differ.

 

[Zodduska]

Thank you for the enlightening response, I admit that I am lacking a lot of knowledge about the inner workings of digital audio and compression formats. I was reading someplace (which I cant seem to find now) that converting an uncompressed 16bit pcm would benefit by 24bit because it would somehow resample for higher accuracy, I may have misunderstood it though. That didnt seem right to me either, the bit accuracy is either there to begin with or it is not.

anyway, I guess the point of this regardless of the file I used is that it seems possible for the Zune to playback in 24 bit. Which would be worth it if there was a true 24 bit source to use unless like you say, the output stage might eliminate any quantitative and qualitative improvement.

 

[lan]

MP3 and other lossy files when encoded no longer have a bit depth associated with them. They are better off decoded into 24bit.

I'm not sure if the Zune hardware supports 24bit throughout the whole chain though.

I would do whatever sounds best to you.

--lan