Next: AL (uppercase)
Prev: SGI IRIX ONLY
Up: SGI IRIX ONLY
Top: Top
9.1. Built-in Module al
This module provides access to the audio facilities of the Indigo and
4D/35 workstations, described in section 3A of the IRIX 4.0 man pages
(and also available as an option in IRIX 3.3). You'll need to read
those man pages to understand what these functions do!
Some of the functions are not available in releases below 4.0.5.
Again, see the manual to check whether a specific function is
available on your platform.
Symbolic constants from the C header file <audio.h> are defined
in the standard module AL, see below.
Warning: the current version of the audio library may dump core
when bad argument values are passed rather than returning an error
status. Unfortunately, since the precise circumstances under which
this may happen are undocumented and hard to check, the Python
interface can provide no protection against this kind of problems.
(One example is specifying an excessive queue size --- there is no
documented upper limit.)
Module al defines the following functions:
- openport (name, direction, config) -- function of module al
-
Equivalent to the C function ALopenport(). The name and direction
arguments are strings. The optional config argument is an opaque
configuration object as returned by
al.newconfig(). The return
value is an opaque port object; methods of port objects are described
below.
- newconfig () -- function of module al
-
Equivalent to the C function ALnewconfig(). The return value is a new
opaque configuration object; methods of configuration objects are
described below.
- queryparams (device) -- function of module al
-
Equivalent to the C function ALqueryparams(). The device argument is
an integer. The return value is a list of integers containing the
data returned by ALqueryparams().
- getparams (device, list) -- function of module al
-
Equivalent to the C function ALgetparams(). The device argument is an
integer. The list argument is a list such as returned by
queryparams; it is modified in place (!).
- setparams (device, list) -- function of module al
-
Equivalent to the C function ALsetparams(). The device argument is an
integer.The list argument is a list such as returned by
al.queryparams.
Configuration objects (returned by al.newconfig() have the
following methods:
- getqueuesize () -- Method on audio configuration object
-
Return the queue size; equivalent to the C function ALgetqueuesize().
- setqueuesize (size) -- Method on audio configuration object
-
Set the queue size; equivalent to the C function ALsetqueuesize().
- getwidth () -- Method on audio configuration object
-
Get the sample width; equivalent to the C function ALgetwidth().
- getwidth (width) -- Method on audio configuration object
-
Set the sample width; equivalent to the C function ALsetwidth().
- getchannels () -- Method on audio configuration object
-
Get the channel count; equivalent to the C function ALgetchannels().
- setchannels (nchannels) -- Method on audio configuration object
-
Set the channel count; equivalent to the C function ALsetchannels().
- getsampfmt () -- Method on audio configuration object
-
Get the sample format; equivalent to the C function ALgetsampfmt().
- setsampfmt (sampfmt) -- Method on audio configuration object
-
Set the sample format; equivalent to the C function ALsetsampfmt().
- getfloatmax () -- Method on audio configuration object
-
Get the maximum value for floating sample formats;
equivalent to the C function ALgetfloatmax().
- setfloatmax (floatmax) -- Method on audio configuration object
-
Set the maximum value for floating sample formats;
equivalent to the C function ALsetfloatmax().
Port objects (returned by al.openport() have the following
methods:
- closeport () -- Method on audio port object
-
Close the port; equivalent to the C function ALcloseport().
- getfd () -- Method on audio port object
-
Return the file descriptor as an int; equivalent to the C function
ALgetfd().
- getfilled () -- Method on audio port object
-
Return the number of filled samples; equivalent to the C function
ALgetfilled().
- getfillable () -- Method on audio port object
-
Return the number of fillable samples; equivalent to the C function
ALgetfillable().
- readsamps (nsamples) -- Method on audio port object
-
Read a number of samples from the queue, blocking if necessary;
equivalent to the C function ALreadsamples. The data is returned as a
string containing the raw data (e.g. 2 bytes per sample in big-endian
byte order (high byte, low byte) if you have set the sample width to 2
bytes.
- writesamps (samples) -- Method on audio port object
-
Write samples into the queue, blocking if necessary; equivalent to the
C function ALwritesamples. The samples are encoded as described for
the
readsamps return value.
- getfillpoint () -- Method on audio port object
-
Return the `fill point'; equivalent to the C function ALgetfillpoint().
- setfillpoint (fillpoint) -- Method on audio port object
-
Set the `fill point'; equivalent to the C function ALsetfillpoint().
- getconfig () -- Method on audio port object
-
Return a configuration object containing the current configuration of
the port; equivalent to the C function ALgetconfig().
- setconfig (config) -- Method on audio port object
-
Set the configuration from the argument, a configuration object;
equivalent to the C function ALsetconfig().
- getstatus (list) -- Method on audio port object
-
Get status information on last error
equivalent to C function ALgetstatus().