cd.doc

reduced python source for embedded apps

Introduction.

A number of programs have been written which access the Silicon
Graphics CD-ROM player.  These programs all use the interface defined
in readcd.py (see readcd.doc for documentation).

Specifying music stretches.

The programs that are capable of reading music CD's all use the same
syntax to describe which part of the CD is to be read.  The syntax
closely corresponds to the available methods in readcd.py.

The music to be read is divided into stretches of music.  Each stretch
must be specified as a separate argument on the command line.  A
stretch can be a whole CD track, specified as a single number; or it
can be a start time and a end time.  The start and end times must be
specified as a tuple, thus: ``(starttime, endtime)''.  Don't forget to
quote the parenthesis to the shell.  Both starttime and endtime can be
``None'', a simple number which refers to a CD track, or a tuple
consisting of either 3 or 4 elements.  A starttime of ``None'' refers
to the start of the CD, an endtime of ``None'' refers to the end of
the CD.  A tuple of 3 elements is an absolute time on the CD.  The
three elements are (minutes, seconds, frames).  A tuple of 4 elements
is a track-relative time.  The four elements are (track, minutes,
seconds, frames).

When one stretch ends at the end of a track and the following stretch
starts at the next track, there is the option of either playing or not
playing the pause between the two tracks.  When either the end time of
the first stretch or the start time of the second stretch is specified
using absolute or track-relative times, the pause will not be played.
When both times are specified as simple track numbers, the pause will
be played.

If no stretches are specified, the whole CD will be played.

The programs.

Currently, the following programs exist.
playcd [ stretch specification ]
	Play (part of) a CD through the system loadspeaker or
	headphone set.
cdaiff [ file [ stretch specification ] ]
	Copy (part of) a CD to a file.  The file will be written in
	AIFF format.  If no file is specified, cdaiff will write to
	the file ``@'' in the current directory.