Charles Chen wrote:
Hi, Roger,
I tried your code, and it works very well. I estimated that the speed
was about 2ms per irp(200bytes) and good enough for the standard audio
sampling rate of 44.1k.
Good, but you should be able to get close to 1000 irp/s, but it could be
according to the device specs that it only sends an irp for every 2
possible timeslots.
There is one thing I am not clear. I send irp with 200 bytes, but each
time I just get 192 bytes (actual length) back. I guess that is normal?
Again, could also be according to the device specs. To me and possible
other octet fanatics, 192 is a more "nice round number" than 200 ;-). Do
you know how it behaves in windows? (also applies to the previous question).
Other thing bothering me is, when I record a pure sine wave sound
signal, the data I captured show some periodic jitters (non-smooth
points) on the sine curve. Have any idea where should I look to solve
this problem?
Have not seen this with my program, but then of course it would not show
up as easely with video as with sound. Do you know where the jitter
occurs? Does it happen within an irp, between irps, or only between the
two group of irps that we are using? The implementation today does not
actually pass one irp from the kernel for each ms, instead it passes 20
irp's every 20ms, and it could be that we then manage to miss one irp (I
thought that should be taken care of by always having a fresh group of
irps submitted). If you interpolate and add an extra irp where you have
the jitter, would the signal be smooth then? If yes, then perhaps you
should have the JVM log the GC activity and see if that correlates to
the jitter.
//Roger Lindsjö
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