DVD Talk Forum - what does this mean (isochronous bandwidth)

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what does this mean (isochronous bandwidth)

This is in relation to my audio problem

Quote:

Some USB host controllers don't function within USB specification. Also Windows, in conjunction with other hardware in your system, may be consuming all the isochronous bandwidth of the USB bus. Both of these interfere with the data flowing to the AN1, causing distortion. The main instances where this occurs is if:

USB frame rates that are out of specification - isochronous data transfer (required for audio) is not possible via USB with a frame rate that is too fast or too slow.

Controllers don't enumerate devices correctly - some controllers don't send USB resets at the appropriate times or may enumerate one part of a composite device.

Corrupting audio data - some USB controllers introduce artifacts into sound data (i.e. CATC traces of USB data have shown non-zero vales in data that should be all zeros).

What does this mean? Their solutions in the FAQ are mostly geared towards win98 problems and VIA PC/USB problems, neither of which help me.

Sounds like someone mis-spelled the word and it should be asynchronous

maybe not :D

isochronous

In information technology, isochronous (from the Greek "equal" and "time"; pronounced "eye-SAH-krun-us") pertains to processes that require timing coordination to be successful, such as voice and digital video transmission. A sound or picture going from a peripheral computer device or across a network into a computer or television set needs to arrive at close to the same rate of data flow as the source. In feeding digital image data from a peripheral device (such as a video camera) to a display mechanism within a computer, isochronous data transfer ensures that data flows continously and at a steady rate in close timing with the ability of the display mechanism to receive and display the image data. (FireWire, the IEEE 1394 High Performance Serial Bus, includes an isochronous interface.)
Isochronous can be distinguished from asynchronous, which pertains to processes that proceed independently of each other until a dependent process has to "interrupt" the other process, and synchronous, which pertains to processes in which one process has to wait on the completion of an event in another process before continuing.