[LAU] [LAD] How to change the USB bus sample rate ?

[Clemens Ladisch]

Adrien DANIEL wrote:
> On Tue, Aug 12, 2008 at 9:16 AM, Clemens Ladisch <cladisch at fastmail.net> wrote:
> > USB doesn't have a built-in sample rate; audio samples are transported
> > in packets.
>
> Yes. I am interested by the frequency at which these packets are send.
> [...]
> I read a post on another list that I could report here :
> --
> The reason is, the data bus of the USB is not all that fast - it's high
> bandwidth, but has a slow sample rate - default is only 125 Hz.
> This means you can only "deliver" a sound to begin roughly every 7.5 ms...

That post is wrong, audio data packets are always sent at 1000 Hz (every
1 ms), in both Windows and Linux (input devices use a different transfer
type).


Regards,
Clemens