2 :mod:`al` --- Audio functions on the SGI
3 ========================================
7 :synopsis: Audio functions on the SGI.
10 This module provides access to the audio facilities of the SGI Indy and Indigo
11 workstations. See section 3A of the IRIX man pages for details. You'll need to
12 read those man pages to understand what these functions do! Some of the
13 functions are not available in IRIX releases before 4.0.5. Again, see the
14 manual to check whether a specific function is available on your platform.
16 All functions and methods defined in this module are equivalent to the C
17 functions with ``AL`` prefixed to their name.
21 Symbolic constants from the C header file ``<audio.h>`` are defined in the
22 standard module :mod:`AL`, see below.
26 The current version of the audio library may dump core when bad argument values
27 are passed rather than returning an error status. Unfortunately, since the
28 precise circumstances under which this may happen are undocumented and hard to
29 check, the Python interface can provide no protection against this kind of
30 problems. (One example is specifying an excessive queue size --- there is no
31 documented upper limit.)
33 The module defines the following functions:
36 .. function:: openport(name, direction[, config])
38 The name and direction arguments are strings. The optional *config* argument is
39 a configuration object as returned by :func:`newconfig`. The return value is an
40 :dfn:`audio port object`; methods of audio port objects are described below.
43 .. function:: newconfig()
45 The return value is a new :dfn:`audio configuration object`; methods of audio
46 configuration objects are described below.
49 .. function:: queryparams(device)
51 The device argument is an integer. The return value is a list of integers
52 containing the data returned by :cfunc:`ALqueryparams`.
55 .. function:: getparams(device, list)
57 The *device* argument is an integer. The list argument is a list such as
58 returned by :func:`queryparams`; it is modified in place (!).
61 .. function:: setparams(device, list)
63 The *device* argument is an integer. The *list* argument is a list such as
64 returned by :func:`queryparams`.
67 .. _al-config-objects:
72 Configuration objects returned by :func:`newconfig` have the following methods:
75 .. method:: audio configuration.getqueuesize()
77 Return the queue size.
80 .. method:: audio configuration.setqueuesize(size)
85 .. method:: audio configuration.getwidth()
90 .. method:: audio configuration.setwidth(width)
95 .. method:: audio configuration.getchannels()
97 Get the channel count.
100 .. method:: audio configuration.setchannels(nchannels)
102 Set the channel count.
105 .. method:: audio configuration.getsampfmt()
107 Get the sample format.
110 .. method:: audio configuration.setsampfmt(sampfmt)
112 Set the sample format.
115 .. method:: audio configuration.getfloatmax()
117 Get the maximum value for floating sample formats.
120 .. method:: audio configuration.setfloatmax(floatmax)
122 Set the maximum value for floating sample formats.
130 Port objects, as returned by :func:`openport`, have the following methods:
133 .. method:: audio port.closeport()
138 .. method:: audio port.getfd()
140 Return the file descriptor as an int.
143 .. method:: audio port.getfilled()
145 Return the number of filled samples.
148 .. method:: audio port.getfillable()
150 Return the number of fillable samples.
153 .. method:: audio port.readsamps(nsamples)
155 Read a number of samples from the queue, blocking if necessary. Return the data
156 as a string containing the raw data, (e.g., 2 bytes per sample in big-endian
157 byte order (high byte, low byte) if you have set the sample width to 2 bytes).
160 .. method:: audio port.writesamps(samples)
162 Write samples into the queue, blocking if necessary. The samples are encoded as
163 described for the :meth:`readsamps` return value.
166 .. method:: audio port.getfillpoint()
168 Return the 'fill point'.
171 .. method:: audio port.setfillpoint(fillpoint)
173 Set the 'fill point'.
176 .. method:: audio port.getconfig()
178 Return a configuration object containing the current configuration of the port.
181 .. method:: audio port.setconfig(config)
183 Set the configuration from the argument, a configuration object.
186 .. method:: audio port.getstatus(list)
188 Get status information on last error.
191 :mod:`AL` --- Constants used with the :mod:`al` module
192 ======================================================
196 :synopsis: Constants used with the al module.
199 This module defines symbolic constants needed to use the built-in module
200 :mod:`al` (see above); they are equivalent to those defined in the C header file
201 ``<audio.h>`` except that the name prefix ``AL_`` is omitted. Read the module
202 source for a complete list of the defined names. Suggested use::