This
is requirements of my driver
:
I
need to capture the audio stream from the USB audio class compliant camcorder
at high speed (USB 2.0). Presently mac provides the USB audio class driver but
that work for usb 1.1 only not usb 2.0
.
I
have following specifications for my project :
1) USB
2.0
2)
USB audio class compliant camcorder
3)
Audio stream has following char : Single input, 1 channel,
PCM, 16bits/resolution ,32 KHz sample
rate
4)
I do not need to control volume and other parameters
5)
I just need to capture the audio stream
6)
I want to make device specific driver only, that need not work
with every application in mac x. But it should work with my
application.(minimal task)
I
have following questions
:
1)
Should I look into AudioUSB driver in Darwin and make my own kernel
driver for this purpose?
2) What else do I need to do apart from this ?
3) What should application use (APIs) to access the audio streams
from my driver ?
4) From where should I start writing the audio driver ?
5) Are phantom audio ,sampleaudio and samplePCIaudio driver codes
are good enough to start with
?
6) Pls suggest good documentation also
7) wher does core audio fit into my requirement?
8) What is the time estimate for completion of this very very
specific device driver? (I have already worked on USB user space drivers in
mac X )??
Can you pls help me in writing customized audio driver for my
camcorder which usb audio class compliant and works on high speed?
I have studied the PhantomAudioDriver ,SamplePCIDriver,
SampleAudioDriver codes that are there in /developer/examples/iokit. I am also
studying the AppleUSBAudio code .
Do
I need to just modify some parts of this code where the actual streaming
of isochronous frames is done ?
I
used kextstat to see the status of the audio driver with our camcorder . It
gets loaded but gives the following error in log file ..
255 = potentiolaAltInterface failed in
USBAudioObject.cpp at line
222
0=
sampleRates failed in USBAudioObject.cpp at line 346
what
does it mean?
Also
I can see our camcorder in Audio midi setup . It shows the right
parameter in input section but it says that output not supported ..
Can you pls give your interpretation of above messages ??
Pls
suggest me fastest way to do this task
Regards,