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Diffstat (limited to 'Doc/lib/libossaudiodev.tex')
-rw-r--r-- | Doc/lib/libossaudiodev.tex | 46 |
1 files changed, 33 insertions, 13 deletions
diff --git a/Doc/lib/libossaudiodev.tex b/Doc/lib/libossaudiodev.tex index 201561d..1b679fd 100644 --- a/Doc/lib/libossaudiodev.tex +++ b/Doc/lib/libossaudiodev.tex @@ -49,14 +49,17 @@ recent versions of FreeBSD. \module{ossaudiodev} defines the following variables and functions: -\begin{excdesc}{error} +\begin{excdesc}{OSSAudioError} This exception is raised on certain errors. The argument is a string describing what went wrong. (If \module{ossaudiodev} receives an error from a system call such as \cfunction{open()}, \cfunction{write()}, or \cfunction{ioctl()}, it raises \exception{IOError}. Errors detected directly by -\module{ossaudiodev} result in \exception{ossaudiodev.error}.) +\module{ossaudiodev} result in \exception{OSSAudioError}.) + +(For backwards compatibility, the exception class is also available as +\code{ossaudiodev.error}.) \end{excdesc} \begin{funcdesc}{open}{\optional{device, }mode} @@ -201,8 +204,8 @@ of \constant{AFMT_QUERY}. \end{methoddesc} -\begin{methoddesc}[audio device]{channels}{num_channels} -Set the number of output channels to \var{num_channels}. A value of 1 +\begin{methoddesc}[audio device]{channels}{nchannels} +Set the number of output channels to \var{nchannels}. A value of 1 indicates monophonic sound, 2 stereophonic. Some devices may have more than 2 channels, and some high-end devices may not support mono. Returns the number of channels the device was set to. @@ -241,16 +244,33 @@ might use this after playing a spot sound effect, before waiting for user input, or before doing disk I/O. \end{methoddesc} -Convenience methods +The following convenience methods combine several ioctls, or one ioctl +and some simple calculations. + +\begin{methoddesc}[audio device]{setparameters} + {format, nchannels, samplerate \optional{, strict=False}} -\begin{methoddesc}[audio device]{setparameters}{samplerate,num_channels,format,emulate} -Initialise the sound device in one method. \var{samplerate}, -\var{channels} and \var{format} should be as specified in the -\method{speed()}, \method{channels()} and \method{setfmt()} -methods. If \var{emulate} is true, attempt to find the closest matching -format instead, otherwise raise ValueError if the device does not -support the format. The default is to raise ValueError on unsupported -formats. +Set the key audio sampling parameters---sample format, number of +channels, and sampling rate---in one method call. \var{format}, +\var{nchannels}, and \var{samplerate} should be as specified in the +\method{setfmt()}, \method{channels()}, and \method{speed()} +methods. If \var{strict} is true, \method{setparameters()} checks to +see if each parameter was actually set to the requested value, and +raises \exception{OSSAudioError} if not. Returns a tuple (\var{format}, +\var{nchannels}, \var{samplerate}) indicating the parameter values that +were actually set by the device driver (i.e., the same as the return +valus of \method{setfmt()}, \method{channels()}, and \method{speed()}). + +For example, +\begin{verbatim} + (fmt, channels, rate) = dsp.setparameters(fmt, channels, rate) +\end{verbatim} +is equivalent to +\begin{verbatim} + fmt = dsp.setfmt(fmt) + channels = dsp.channels(channels) + rate = dsp.rate(channels) +\end{verbatim} \end{methoddesc} \begin{methoddesc}[audio device]{bufsize}{} |