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diff --git a/share/man/man4/pcm.4 b/share/man/man4/pcm.4
--- a/share/man/man4/pcm.4
+++ b/share/man/man4/pcm.4
@@ -167,16 +167,16 @@
Multichannel audio, popularly referred to as
.Dq surround sound
is supported and enabled by default.
-The FreeBSD multichannel matrix processor supports up to 18 interleaved
-channels, but the limit is currently set to 8 channels (as commonly used
-for 7.1 surround sound).
+The
+.Fx
+multichannel matrix processor supports up to 18 interleaved channels, but the
+limit is currently set to 8 channels (as commonly used for 7.1 surround sound).
The internal matrix mapping can handle reduction, expansion or
re-routing of channels.
This provides a base interface for related multichannel
.Fn ioctl
support.
-Multichannel audio works both with and without
-.Tn VCHANs .
+Multichannel audio works both with and without VCHANs.
.Pp
Most bridge device drivers are still missing multichannel matrixing
support, but in most cases this should be trivial to implement.
@@ -202,21 +202,18 @@
Each device can optionally support more playback and recording channels
than physical hardware provides by using
.Dq virtual channels
-or
-.Tn VCHANs .
-.Tn VCHAN
-options can be configured via the
+or VCHANs.
+VCHAN options can be configured via the
.Xr sysctl 8
interface but can only be manipulated while the device is inactive.
.Ss VPC
-FreeBSD supports independent and individual volume controls for each active
+.Fx
+supports independent and individual volume controls for each active
application, without touching the master
.Nm
volume.
This is sometimes referred to as Volume Per Channel (VPC).
-The
-.Tn VPC
-feature is enabled by default.
+The VPC feature is enabled by default.
.Ss Loader Tunables
The following loader tunables are used to set driver configuration at the
.Xr loader 8
@@ -238,12 +235,9 @@
This tunable is undefined by default.
Equalizing is disabled by default.
.It Va hint.pcm.%d.vpc
-Set to 1 or 0 to explicitly enable (1) or disable (0) the
-.Tn VPC
-feature.
+Set to 1 or 0 to explicitly enable (1) or disable (0) the VPC feature.
This tunable is undefined by default.
-.Tn VPC
-is however enabled by default.
+VPC is however enabled by default.
.El
.Ss Runtime Configuration
There are a number of
@@ -365,16 +359,12 @@
rate, especially during high workload.
The default value is 1, which is considered a moderate/safe latency profile.
.It Va hw.snd.maxautovchans
-Global
-.Tn VCHAN
-setting that only affects devices with at least one playback or recording channel available.
-The sound system will dynamically create up to this many
-.Tn VCHANs .
+Global VCHAN setting that only affects devices with at least one playback or
+recording channel available.
+The sound system will dynamically create up to this many VCHANs.
Set to
.Dq 0
-if no
-.Tn VCHANs
-are desired.
+if no VCHANs are desired.
Maximum value is 256.
.It Va hw.snd.report_soft_formats
Controls the internal format conversion if it is
@@ -419,13 +409,11 @@
Enabling this will preserve the volume, at the cost of possible confusion
when applications tries to re-open the same device.
.It Va hw.snd.vpc_mixer_bypass
-The recommended way to use the
-.Tn VPC
-feature is to teach applications to use
-the correct
+The recommended way to use the VPC feature is to teach applications to use the
+correct
.Fn ioctl :
-.Dv SNDCTL_DSP_GETPLAYVOL, SNDCTL_DSP_SETPLAYVOL,
-.Dv SNDCTL_DSP_SETRECVOL, SNDCTL_DSP_SETRECVOL.
+.Dv SNDCTL_DSP_GETPLAYVOL , SNDCTL_DSP_SETPLAYVOL ,
+.Dv SNDCTL_DSP_SETRECVOL , SNDCTL_DSP_SETRECVOL .
This is however not always possible.
Enable this to allow applications to use their own existing mixer logic
to control their own channel volume.
@@ -438,30 +426,19 @@
The pure
.Nm
stream will be fed directly to the hardware.
-If
-.Tn VCHANs
-are enabled, the bitperfect mode will use the
-.Tn VCHAN
-format/rate as the definitive format/rate target.
-The recommended way to use bitperfect mode is to disable
-.Tn VCHANs
-and enable this sysctl.
+If VCHANs are enabled, the bitperfect mode will use the VCHAN format/rate as
+the definitive format/rate target.
+The recommended way to use bitperfect mode is to disable VCHANs and enable this
+sysctl.
Default is disabled.
.It Va dev.pcm.%d.[play|rec].vchans
-The current number of
-.Tn VCHANs
-allocated per device.
-This can be set to preallocate a certain number of
-.Tn VCHANs .
+The current number of VCHANs allocated per device.
+This can be set to preallocate a certain number of VCHANs.
Setting this value to
.Dq 0
-will disable
-.Tn VCHANs
-for this device.
+will disable VCHANs for this device.
.It Va dev.pcm.%d.[play|rec].vchanformat
-Format for
-.Tn VCHAN
-mixing.
+Format for VCHAN mixing.
All playback paths will be converted to this format before the mixing
process begins.
By default only 2 channels are enabled.
@@ -491,8 +468,7 @@
8 channels (4.0 + center + LFE + left and right side).
.El
.It Va dev.pcm.%d.[play|rec].vchanmode
-.Tn VCHAN
-format/rate selection.
+VCHAN format/rate selection.
Available options include:
.Bl -tag -width 2n
.It fixed
@@ -527,9 +503,7 @@
cause annoying pops or clicks.
.El
.It Va dev.pcm.%d.[play|rec].vchanrate
-Sample rate speed for
-.Tn VCHAN
-mixing.
+Sample rate speed for VCHAN mixing.
All playback paths will be converted to this sample rate before the mixing
process begins.
.It Va dev.pcm.%d.polling
@@ -552,17 +526,12 @@
So with situations involving overruns and underruns, consider the output
while the errant application is open and running.
.Ss IOCTL Support
-The driver supports most of the
-.Tn OSS
+The driver supports most of the OSS
.Fn ioctl
functions, and most applications work unmodified.
A few differences exist, while memory mapped playback is
-supported natively and in
-.Tn Linux
-emulation, memory mapped recording is
-not due to
-.Tn VM
-system design.
+supported natively and in Linux emulation, memory mapped recording is not due
+to VM system design.
As a consequence, some applications may need to be recompiled
with a slightly modified audio module.
See

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