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Re: Core audio driver

Title: Re: Core audio driver
Be careful in your terminology here.  There is NO USB Audio 2.0 Device specification (that’s released to the public).  There is only a USB Audio 1.0 Device specification.  There is of course USB 2.0, and you can put USB Audio 1.0 Device functionality on a device that connects to the host over USB 2.0 and runs at high speed, but that doesn’t make it a USB Audio 2.0 device, and you will find a couple of short comings in the USB Audio 1.0 Device specification that limit the device’s usefulness.

The problem that you are seeing is that there is a bug in the USB stack that prevents the USB Audio 1.0 driver from working correctly on the USB 2.0 stack.  Until that is fixed, there is nothing that the driver can do to talk to a USB 2.0 device.

You must run your device with at least two endpoints and therefore must run the video and data in parallel because the USB Audio 1.0 Device specification doesn’t allow for video to be interspersed within the audio stream.  You will need to synchronize the two streams internal to your device so that they arrive at the host at the same time (that the audio frame for the video frame arrives in the same USB frame as the video frame’s data).

Good luck,
Mark
--
Mark Cookson
M-Audio, a division of Avid
225 Locust St.
Hudson, WI 54016

On 2/17/05 2:55 AM, "selvaganesan" <email@hidden> wrote:

Existing audio class driver in MAC x doesn't support the USB 2.0 Audio device.
so,
1.can i get the support for USB 2.0  Audio device from existing audio class driver if i will change the frame transferring rate ?
 
 
2.is frame rate the only difference between the USB2.0 and USB 1.1? or any other entity influenced Between the 2.0&1.1.

 
 
3. is there any other options for getting USB 2.0 support from existing audio class driver?
 
 
4.can i write the sound component for getting Audio frames? is it better option?

 
5. This is USB 2.0 device. if i will make sound component for USB 1.1 driver, will my device supports that component?
6. Actually my device is having separate(audio and video) interface.
            
       Can i get the audio and video frames parallely? I thing USB connector is having one or two data lines.

is it possible to getting parallel data from  usb connector?
  
like
Video--->
------------------------------------------------------------------------ frames
Audio----->
----------------------------------------------------------------------frames
or  sequentially like
video.........audio..........video..............audio.......frames
 
 
7.If any one  involving in the core audio development, Suggest me what are the areas i will make changes in existing audio class driver to get the support of
USB 2.0  if it is possible.
 
 
 
 
Plz suggest me.

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References: 
 >Core audio driver (From: selvaganesan <email@hidden>)



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