Re: [ecasound] Re: ecasound & full duplex (fwd)

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Subject: Re: [ecasound] Re: ecasound & full duplex (fwd)
From: Jeremy Hall (jhall@UU.NET )
Date: Thu Jan 20 2000 - 14:41:13 EET

On these shadow devices, shouldn't you read from dsp0 and write to
dsp1?? in this way, you are recording on dsp0 and playing to dsp1

_J

In the new year, Kai Vehmanen wrote:
> Here's another very common question:
>
> ---------- Forwarded message ----------
> > Is it, or will it be, possible to record using full duplex. Currently
> > (RH Linux 6.0; ecasound 1.6.9r9), I tried the following:
> [...]
> > ecasound -d:10 -a:1 -i Fly1.wav -o /dev/dsp -a:2 -i /dev/dsp -o
> > Mix.wav
>
> It has been since ecasound's first public version. ;) What ecasound
> doesn't support, is opening soundcard devices in read-write mode. In
> other words, ecasound treats each input and output as a separate
> device. Because of this, read-write is impossible. But there are better
> ways to do this:
>
> 1. multi-open
>
> Some soundcard drivers support so called 'multi-open', meaning device
> can be opened twice - once for playback, once for recording. This
> doesn't seem to work with your card.
>
> 2. shadow devices
>
> The other solution is shadow devices. If you use OSS/commercial, you
> probably have these. Check your /dev/sndstat. For instance, I have:
>
> -- cut from /proc/sndstat --
> Audio devices:
> 0: GUS MAX (CS4231) (DUPLEX)
> 1: Shadow of audio device #0 (DUPLEX)
> 2: Ultrasound (DUPLEX)
> 3: Creative SB AWE64 Gold (4.16) (DUPLEX)
> 4: SB secondary device (DUPLEX)
> --cut--
>
> In other words, I have two soundcards, but I can still use five
> separate devices, /dev/dsp0, /dev/dsp1 ... /dev/dsp4 ... let's
> modify your example:
>
> ecasound -d:10 -b:128 -a:1 -i Fly1.wav -o /dev/dsp0 -a:2 -i /dev/dsp1 -o Mix.wav
>
> 3. ALSA drivers
>
> ALSA is an alternative to OSS drivers. They offer OSS-compatibility,
> full-duplex, many advanced features like pcm-loopback, multichannel
> devices, etc etc... You'll find their home page at
> http://www.alsa-project.org
>
> I hope this helps.
>
> --
> Kai Vehmanen <kaiv@wakkanet.fi> -------- CS, University of Turku, Finland
> . http://www.wakkanet.fi/ecasound/ - linux multitrack audio processing
> . http://www.wakkanet.fi/sculpscape/ - ambient-idm-rock-... mp3/ra/wav
>
>

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