[openbeosmediakit] Re: device driver

  • From: "Marcus Overhagen" <dos4gw@xxxxxx>
  • To: openbeosmediakit@xxxxxxxxxxxxx
  • Date: Mon, 20 May 2002 14:50:35 +0200

Andrea Anzani <oxygenum@xxxxxxxxxx> wrote:
>Hi all, this is my first post :)
>I'm not signed to any part of the project, yet.
>I'm not a very expert programmer, but i would like to ask something:
>I'm looking at the current code of the media_kit.
>I'm interesting in undestand how the media_addon_server and the media_server
>speak to the kernel.. ok they use the ioctl calls.. Can I ask the kernel to 
>tell me witch drivers are loaded and working for audio? How can I undestand 
>if the stream from the driver is littlendian/bigendian?

The kernel loads every existing driver during system startup.
Those drivers that find audio hardware then publish entries in /dev/audio
When the media_server gets started, it starts the media_addon_server
The media_addon_server loads all dormant media nodes from 
and from /boot/home/config/add-ons/media
multi_audio.media_addon and legacy.media_addon search for published entried in 
for each soundcard input, they publish a BMediaNode that is a BBufferProducer, 
for each soundcard output, they publish a BMediaNode that is a BBufferConsumer.
Application can then connect to these BMediaNodes using the BMediaRoster.
They can request a specific format, and are told during connection which format 
used, including the edianess.

Check also out the Cortex application from www.BeBits.com which provides a GUI 
interface for media nodes.

What exactly do you want to know and do?


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