[alsa-devel] EMU 0404USB: Odd sample rate shown during playback.
Hi there.
The EMU 0404 is running in async USB mode as you know. When looking at the stream parameters during playback the sample rate shown is always slightly below 44100 -- something like 44098 is shown.
As you write in the driver, the 0404 is returning number of samples per packet instead of the number of samples per microframes. Has this something to do with it?
Question: Are we looking at a wrong output or is the samplerate really lower than 44100?
THX Klaus
Klaus Schulz wrote:
The EMU 0404 is running in async USB mode as you know. When looking at the stream parameters during playback the sample rate shown is always slightly below 44100 -- something like 44098 is shown.
This is what "asynchronous" means: The computer's clock and the device's clock run independently from each other, so they can have slightly different speeds.
Best regards, Clemens
Hi Clemens.
THX for dropping in.
On my M-Audio Transit though it remains 44.1 even though it says "async" at 16/44.1 in the stream0 file.
Cheers \Klaus
On Jun 8, 2009 9:24am, Clemens Ladisch clemens@ladisch.de wrote:
Klaus Schulz wrote:
The EMU 0404 is running in async USB mode as you know. When looking at
the
stream parameters during playback the sample rate shown is always
slightly
below 44100 -- something like 44098 is shown.
This is what "asynchronous" means: The computer's clock and the device's
clock run independently from each other, so they can have slightly
different speeds.
Best regards,
Clemens
kls.schlz@googlemail.com wrote:
On my M-Audio Transit though it remains 44.1 even though it says "async" at 16/44.1 in the stream0 file.
It could have a clock that happens to run at the same speed as your computer's. Or it could be that it runs the ADC synchronously to the computer but says "async" so that it can deliver recorded SPDIF data at the source's speed.
Best regards, Clemens
Hi Clemens.
Reading you answer below. Does this mean the Transit is necessarily not running in async mode during playback of 44.1 material even though it says so in the stream0 file?
As far as I know I can slave the Transit to an external SPDIF clock. This would mean that in this case the Transit would slave the PC, thus working async.
The open question is still if even without external clock the Tranist works in async as the log is saying.
How can I find that out?
Cheers
On Mon, Jun 8, 2009 at 1:39 PM, Clemens Ladisch clemens@ladisch.de wrote:
kls.schlz@googlemail.com wrote:
On my M-Audio Transit though it remains 44.1 even though it says "async"
at
16/44.1 in the stream0 file.
It could have a clock that happens to run at the same speed as your computer's. Or it could be that it runs the ADC synchronously to the computer but says "async" so that it can deliver recorded SPDIF data at the source's speed.
Best regards, Clemens
participants (3)
-
Clemens Ladisch -
Klaus Schulz -
kls.schlz＠googlemail.com