Sorry about the attachement. I have some more info. If I use some software to look at the USB traffic in Windows, I can see that media player tries to send an isochronous transfer. I get the following error. Does anyone know what would cause this error. I can only believe that the descriptor must have a problem.
URB Isoch Transfer failed
Device Object 87C1B3B8h
Driver Object hhdusbh32
URB Function URB_FUNCTION_ISOCH_TRANSFER
URB Status USBD_STATUS_INVALID_PARAMETER
Endpoint 02h 2 Out, Isochronous
Number of Packets 10
It still hasnt attached the file. I keep adding it but it doesnt appear in the thread.
Problem solved. As I am using high speed USB the value of bInterval has to be set to 4 to give 1ms.
2 ^ 4-1 = 8
8 x 125us = 1 ms