[gst-devel] simultaneous OSS playback/record

Wilson, Diego dwilson at ti.com
Thu Jun 15 16:37:32 CEST 2006


Number 1 (getting a /dev/dsp device which can be opened twice) is
looking unlikely.

Your suggestion of creating a device-fd seems reasonable. I'll keep you
posted on the progress if you're interested.


Diego Wilson

-----Original Message-----
From: Edgard Lima [mailto:edgard.lima at indt.org.br] 
Sent: Wednesday, June 14, 2006 3:34 PM
To: Wilson, Diego
Cc: Thomas Vander Stichele; gstreamer-devel at lists.sourceforge.net
Subject: Re: [gst-devel] simultaneous OSS playback/record

I think 1. is good (may be better)

...if it is no possible

You could do 2. - Create a new property named "device-fd" (file 
descriptor of an open device) so you could open your device out of 
Gstremaer and then set this property in both osssrc and osssink.

Thomas, what do you think?


ext Wilson, Diego wrote:

>Here's my problem. I am very aware my OSS driver does not allow two
>opens. What's more I even know the person who wrote this OSS driver.
>I contacted him regarding the "full duplex" issue. 
>The driver writer (say that three times fast) is arguing you should not
>open a /dev/dsp device twice using OSS to begin with. And the "Open
>Sound System Programmer's Guide" supports his argument. The guide says
>you should open the device once, turn on a full duplex mode and then
>read and write like there was no tomorrow. The guide *is* the golden
>standard for OSS Audio isn't it? Cuz maybe I'm looking in the wrong
>Now IMHO there's only two possible solutions to my problem:
>1. Convince the writer of the OSS driver that you *should* be able to
>open the /dev/dsp device twice.
>2. Find a way of doing OSS full duplex in GStreamer by opening the
>/dev/dsp device once.
>For now, I'm making a plea to the GStreamer gods for an answer. C'mon,
>know your watching.
>Diego Wilson
>-----Original Message-----
>From: Thomas Vander Stichele [mailto:thomas at apestaart.org] 
>Sent: Wednesday, June 14, 2006 4:11 AM
>To: Wilson, Diego
>Cc: Edgard Lima; gstreamer-devel at lists.sourceforge.net
>Subject: Re: [gst-devel] simultaneous OSS playback/record
>On Tue, 2006-06-13 at 13:20 -0500, Wilson, Diego wrote:
>>None of them work. I'm getting the following error on all of them:
>>ERROR: from element /pipeline0/osssrc0: Unable to open device /dev/dsp
>>for recording: Device or resource busy
>Well, then your oss driver really *does not* allow two opens, even from
>the same process.
>I have the same for my ac97 intel sound card.  alsasrc ! alsasink works
>fine on it, so it's not the hardware's fault.
>gstreamer-devel mailing list
>gstreamer-devel at lists.sourceforge.net

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