uaudio patch, capabilities

Kazuhito HONDA kazuhito at
Sat Mar 12 10:14:28 PST 2005

From: Mathew Kanner <mat at>
Subject: uaudio patch, capabilities
Date: Fri, 11 Mar 2005 20:02:48 -0500

> 	Please find attached my work in progress to add probing the
> min/max rate for the uaudio device.  


Thank you very much for your coding.  
But it had one problem when I tried it.

My USB audio device, SB Live! 24-bit External, 
has three fixed sampling rate, 44100, 48000, and 96000 Hz.
So min/max speeds of playback caps came to be 44100 Hz and 96000 Hz.
In this case, sound source of 44100 Hz and 48000 Hz could be played exactly,
and sound sources whose sampling rate was under 44100 Hz could be played
with converted, but sound sources whose sampling sate was between 44100 Hz 
and 48000 Hz couldn't be played.

I expected that only one sampling rate (when discrete) or 
one sampling rate range (when continuous) must be set in caps.

I guess that there are two solutions.
1) use only one sampling rate or rage, neglect others.
2) select one rate along a speed of a sound source 
         when the channel is initialized.

When I challenged it slightly, I aimed at 2).
It had no problem that I changed the caps at ua_chan_init() in uaudio_pcm.c.

Kazuhito HONDA 

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