manaox2
Headphoneus Supremus
- Joined
- Jul 27, 2007
- Posts
- 2,754
- Likes
- 18
Quote:
I usually see asynchronous synchronization schemes touted as being better for digital audio transfer as it has data "cells" that are intended to reduce jitter for realtime audio transfer. Its claimed that this is ignored as speeds have become faster and jitter isn't as rampant. USB does theoretically get data at 480 mbps, but this is usually a burst speed as I understand it. I would prefer asynchronous transfer mode scheme used for USB, there description of isynchronous has a lot of flowery language with little to no explanation of why its used for audio. Isynchronous guarantees bandwidth for unidirectional transfer while asynchronous uses everything available as it needs. Kind of reminds me of how Windows keeps bulking up with the excuse that processor speed has increased so who cares if its slower. Isynchronous seems to be a waste of bandwidth that increases jitter in return for reliability of bandwidth available in the other direction. I'm sure there is more to this too that I don't know of.
Originally Posted by hybris /img/forum/go_quote.gif Synchronisation and reliable transfer of audio is also a basis for the USB spec: "An essential issue in audio is synchronization of the data streams. Indeed, the smallest artifacts are easily detected by the human ear. Therefore, a robust synchronization scheme on isochronous transfers has been developed and incorporated in the USB Specification. The Audio Device Class definition adheres to this synchronization scheme to transport audio data reliably over the bus" |
I usually see asynchronous synchronization schemes touted as being better for digital audio transfer as it has data "cells" that are intended to reduce jitter for realtime audio transfer. Its claimed that this is ignored as speeds have become faster and jitter isn't as rampant. USB does theoretically get data at 480 mbps, but this is usually a burst speed as I understand it. I would prefer asynchronous transfer mode scheme used for USB, there description of isynchronous has a lot of flowery language with little to no explanation of why its used for audio. Isynchronous guarantees bandwidth for unidirectional transfer while asynchronous uses everything available as it needs. Kind of reminds me of how Windows keeps bulking up with the excuse that processor speed has increased so who cares if its slower. Isynchronous seems to be a waste of bandwidth that increases jitter in return for reliability of bandwidth available in the other direction. I'm sure there is more to this too that I don't know of.