% Documentations stolen and LaTeX'ed from comments in file. \section{\module{wave} --- Read and write WAV files} \declaremodule{standard}{wave} \sectionauthor{Moshe Zadka}{mzadka@geocities.com} \modulesynopsis{Provide an interface to the WAV sound format.} The \module{wave} module provides a convenient interface to the WAV sound format. It does not support compression/decompression, but it does support mono/stereo. The \module{wave} module defines the following function and exception: \begin{funcdesc}{open}{file\optional{, mode}} If \var{file} is a string, open the file by that name, other treat it as a seekable file-like object. \var{mode} can be any of \begin{description} \item[\code{'r'}, \code{'rb'}] Read only mode. \item[\code{'w'}, \code{'wb'}] Write only mode. \end{description} Note that it does not allow read/write WAV files. A \var{mode} of \code{'r'} or \code{'rb'} returns a \class{Wave_read} object, while a \var{mode} of \code{'w'} or \code{'wb'} returns a \class{Wave_write} object. If \var{mode} is omitted and a file-like object is passed as \var{file}, \code{\var{file}.mode} is used as the default value for \var{mode} (the \character{b} flag is still added if necessary). \end{funcdesc} \begin{funcdesc}{openfp}{file, mode} A synonym for \function{open()}, maintained for backwards compatibility. \end{funcdesc} \begin{excdesc}{Error} An error raised when something is impossible because it violates the WAV specification or hits an implementation deficiency. \end{excdesc} \subsection{Wave_read Objects \label{Wave-read-objects}} Wave_read objects, as returned by \function{open()}, have the following methods: \begin{methoddesc}[Wave_read]{close}{} Close the stream, and make the instance unusable. This is called automatically on object collection. \end{methoddesc} \begin{methoddesc}[Wave_read]{getnchannels}{} Returns number of audio channels (\code{1} for mono, \code{2} for stereo). \end{methoddesc} \begin{methoddesc}[Wave_read]{getsampwidth}{} Returns sample width in bytes. \end{methoddesc} \begin{methoddesc}[Wave_read]{getframerate}{} Returns sampling frequency. \end{methoddesc} \begin{methoddesc}[Wave_read]{getnframes}{} Returns number of audio frames. \end{methoddesc} \begin{methoddesc}[Wave_read]{getcomptype}{} Returns compression type (\code{'NONE'} is the only supported type). \end{methoddesc} \begin{methoddesc}[Wave_read]{getcompname}{} Human-readable version of \method{getcomptype()}. Usually \code{'not compressed'} parallels \code{'NONE'}. \end{methoddesc} \begin{methoddesc}[Wave_read]{getparams}{} Returns a tuple \code{(\var{nchannels}, \var{sampwidth}, \var{framerate}, \var{nframes}, \var{comptype}, \var{compname})}, equivalent to output of the \method{get*()} methods. \end{methoddesc} \begin{methoddesc}[Wave_read]{readframes}{n} Reads and returns at most \var{n} frames of audio, as a string of bytes. \end{methoddesc} \begin{methoddesc}[Wave_read]{rewind}{} Rewind the file pointer to the beginning of the audio stream. \end{methoddesc} The following two methods are defined for compatibility with the \refmodule{aifc} module, and don't do anything interesting. \begin{methoddesc}[Wave_read]{getmarkers}{} Returns \code{None}. \end{methoddesc} \begin{methoddesc}[Wave_read]{getmark}{id} Raise an error. \end{methoddesc} The following two methods define a term ``position'' which is compatible between them, and is otherwise implementation dependant. \begin{methoddesc}[Wave_read]{setpos}{pos} Set the file pointer to the specified position. \end{methoddesc} \begin{methoddesc}[Wave_read]{tell}{} Return current file pointer position. \end{methoddesc} \subsection{Wave_write Objects \label{Wave-write-objects}} Wave_write objects, as returned by \function{open()}, have the following methods: \begin{methoddesc}[Wave_write]{close}{} Make sure \var{nframes} is correct, and close the file. This method is called upon deletion. \end{methoddesc} \begin{methoddesc}[Wave_write]{setnchannels}{n} Set the number of channels. \end{methoddesc} \begin{methoddesc}[Wave_write]{setsampwidth}{n} Set the sample width to \var{n} bytes. \end{methoddesc} \begin{methoddesc}[Wave_write]{setframerate}{n} Set the frame rate to \var{n}. \end{methoddesc} \begin{methoddesc}[Wave_write]{setnframes}{n} Set the number of frames to \var{n}. This will be changed later if more frames are written. \end{methoddesc} \begin{methoddesc}[Wave_write]{setcomptype}{type, name} Set the compression type and description. \end{methoddesc} \begin{methoddesc}[Wave_write]{setparams}{tuple} The \var{tuple} should be \code{(\var{nchannels}, \var{sampwidth}, \var{framerate}, \var{nframes}, \var{comptype}, \var{compname})}, with values valid for the \method{set*()} methods. Sets all parameters. \end{methoddesc} \begin{methoddesc}[Wave_write]{tell}{} Return current position in the file, with the same disclaimer for the \method{Wave_read.tell()} and \method{Wave_read.setpos()} methods. \end{methoddesc} \begin{methoddesc}[Wave_write]{writeframesraw}{data} Write audio frames, without correcting \var{nframes}. \end{methoddesc} \begin{methoddesc}[Wave_write]{writeframes}{data} Write audio frames and make sure \var{nframes} is correct. \end{methoddesc} Note that it is invalid to set any parameters after calling \method{writeframes()} or \method{writeframesraw()}, and any attempt to do so will raise \exception{wave.Error}.