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SF #814606: merge from release23-maint branch: clarify/cleanup 

mixer docs; trim \platform{}, add \versionadded{}.
This commit is contained in:
Greg Ward 2004-05-05 01:36:16 +00:00
parent e9c2ecfb96
commit 4fe97ca4ce
1 changed files with 27 additions and 25 deletions
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50
Doc/lib/libossaudiodev.tex
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@ -2,9 +2,11 @@
Access to OSS-compatible audio devices}
\declaremodule{builtin}{ossaudiodev}
\platform{Linux, FreeBSD, maybe other Unix-like systems}
\platform{Linux, FreeBSD}
\modulesynopsis{Access to OSS-compatible audio devices.}
\versionadded{2.3}
This module allows you to access the OSS (Open Sound System) audio
interface. OSS is available for a wide range of open-source and
commercial Unices, and is the standard audio interface for Linux and
@ -289,7 +291,7 @@ buffer to be played without blocking.
\subsection{Mixer Device Objects \label{mixer-device-objects}}
File-like interface
The mixer object provides two file-like methods:
\begin{methoddesc}[mixer device]{close}{}
This method closes the open mixer device file. Any further attempts to
@ -300,38 +302,38 @@ use the mixer after this file is closed will raise an IOError.
Returns the file handle number of the open mixer device file.
\end{methoddesc}
Mixer interface
The remaining methods are specific to audio mixing:
\begin{methoddesc}[mixer device]{controls}{}
This method returns a bitmask specifying the available mixer controls
(``Control'' being a specific mixable ``channel'', such as
\constant{SOUND_MIXER_PCM} or \constant{SOUND_MIXER_SYNTH}). This
bitmask indicates a subset of all available mixer channels---the
bitmask indicates a subset of all available mixer controls---the
\constant{SOUND_MIXER_*} constants defined at module level. To determine if,
for example, the current mixer object supports a PCM mixer, use the
following Python code:
\begin{verbatim}
mixer=ossaudiodev.openmixer()
if mixer.channels() & (1 << ossaudiodev.SOUND_MIXER_PCM):
if mixer.controls() & (1 << ossaudiodev.SOUND_MIXER_PCM):
# PCM is supported
<code>
... code ...
\end{verbatim}
For most purposes, the \constant{SOUND_MIXER_VOLUME} (Master volume) and
\constant{SOUND_MIXER_PCM} channels should suffice---but code that uses the
mixer should be flexible when it comes to choosing sound channels. On
For most purposes, the \constant{SOUND_MIXER_VOLUME} (master volume) and
\constant{SOUND_MIXER_PCM} controls should suffice---but code that uses the
mixer should be flexible when it comes to choosing mixer controls. On
the Gravis Ultrasound, for example, \constant{SOUND_MIXER_VOLUME} does not
exist.
\end{methoddesc}
\begin{methoddesc}[mixer device]{stereocontrols}{}
Returns a bitmask indicating stereo mixer channels. If a bit is set,
the corresponding channel is stereo; if it is unset, the channel is
Returns a bitmask indicating stereo mixer controls. If a bit is set,
the corresponding control is stereo; if it is unset, the control is
either monophonic or not supported by the mixer (use in combination with
\method{channels()} to determine which).
\method{controls()} to determine which).
See the code example for the \method{channels()} function for an example
See the code example for the \method{controls()} function for an example
of getting data from a bitmask.
\end{methoddesc}
@ -341,30 +343,30 @@ record. See the code example for \method{controls()} for an example of
reading from a bitmask.
\end{methoddesc}
\begin{methoddesc}[mixer device]{get}{channel}
Returns the volume of a given mixer channel. The returned volume is a
\begin{methoddesc}[mixer device]{get}{control}
Returns the volume of a given mixer control. The returned volume is a
2-tuple \code{(left_volume,right_volume)}. Volumes are specified as
numbers from 0 (silent) to 100 (full volume). If the channel is
monophonic, a 2-tuple is still returned, but both channel volumes are
numbers from 0 (silent) to 100 (full volume). If the control is
monophonic, a 2-tuple is still returned, but both volumes are
the same.
If an unknown channel is specified, \exception{error} is raised.
Raises \exception{OSSAudioError} if an invalid control was is specified,
or \exception{IOError} if an unsupported control is specified.
\end{methoddesc}
\begin{methoddesc}[mixer device]{set}{channel, (left, right)}
Sets the volume for a given mixer channel to \code{(left,right)}.
\begin{methoddesc}[mixer device]{set}{control, (left, right)}
Sets the volume for a given mixer control to \code{(left,right)}.
\code{left} and \code{right} must be ints and between 0 (silent) and 100
(full volume). On success, the new volume is returned as a 2-tuple.
Note that this may not be exactly the same as the volume specified,
because of the limited resolution of some soundcard's mixers.
Raises \exception{IOError} if an invalid mixer channel was specified;
\exception{TypeError} if the argument format was incorrect, and
\exception{error} if the specified volumes were out-of-range.
Raises \exception{OSSAudioError} if an invalid mixer control was
specified, or if the specified volumes were out-of-range.
\end{methoddesc}
\begin{methoddesc}[mixer device]{get_recsrc}{}
This method returns a bitmask indicating which channel or channels are
This method returns a bitmask indicating which control(s) are
currently being used as a recording source.
\end{methoddesc}