OpenBSD-4.6/share/man/man4/envy.4

.\" $OpenBSD: envy.4,v 1.6 2009/05/08 19:03:55 ratchov Exp $
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.\" Copyright (c) 2007 Alexandre Ratchov <alex@caoua.org>
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.Dd $Mdocdate: May 8 2009 $
.Dt ENVY 4
.Os
.Sh NAME
.Nm envy
.Nd VIA Envy24 audio device
.Sh SYNOPSIS
.Cd "envy* at pci?"
.Cd "audio* at envy?"
.Sh DESCRIPTION
The
.Nm
driver supports sound cards based on VIA Envy24 and Envy24HT PCI chips.
The following sound cards are currently supported:
.Pp
.Bl -bullet -compact -offset indent
.It
M-Audio Delta 1010, 1010LT, 66 and 44
.It
ESI Julia
.El
.Ss Mixer device
The chip features a digital mixer that routes and mixes the
streams below as follows:
.Bl -tag -width playback
.It Dv inputs
There are 8 streams corresponding to data received by the
device from the codecs.
They are labelled
.Va line0
\(en
.Va line7
in the
.Xr mixer 4
interface.
.It Dv outputs
There are 8 streams corresponding to data sent by the device to the codecs.
They are labelled
.Va line0
\(en
.Va line7 .
Each of them can be individually configured to use any of
the external inputs or its corresponding playback stream as source.
Additionally, outputs
.Va line0
and
.Va line1
can be configured to use
.Va mon0
or
.Va mon1
as sources.
.It Dv monitor
There are 2 streams that can be configured to contain any linear
superposition of any of the 10 playback and 10 external input streams.
They are labelled
.Va mon0
and
.Va mon1 .
From the mixer's point of view they are input streams,
so they can be used as sources of output streams.
This feature is specific to Envy24 based cards.
.It Dv playback
There are 10 streams corresponding to samples transferred
from the host to the device.
They are labelled
.Va play0
\(en
.Va play9 .
From the mixer's point of view they are input streams,
so they are usable as sources of output streams.
.It Dv record
There are 12 streams corresponding to samples transferred
from the device to the host.
They are not controllable by the mixer.
Streams 0 to 7 are hardwired to external inputs
.Va line0
\(en
.Va line7
and streams 10 and 11 are hardwired to
.Va mon0
and
.Va mon1 .
.El
.Ss Playback and record data formats
Both playback and record use linear encoding.
Samples are represented by 32-bit signed numbers in little endian order.
Only the first 24 most significant bits are used.
On Envy24-based cards, playback uses 10 channels and record uses 12 channels,
while on Envy24HT-based cards the number of streams depend on the
number of codecs physically present on the card.
.Sh SEE ALSO
.Xr audio 4 ,
.Xr intro 4 ,
.Xr pci 4
.Sh HISTORY
The
.Nm
driver first appeared in
.Ox 4.3 .
.Sh BUGS
MIDI and S/PDIF transmitter/receivers are not yet supported.
.Pp
The current
.Xr audio 4
driver doesn't allow playback and record blocks to have the same duration,
making the device hardly usable for block based I/O in full-duplex.
Playback and capture cannot be started atomically.
Ring buffer sizes are limited to 64kB,
which can be limiting at high sample rates.