/Doc/library/al.rst

  1
  2:mod:`al` --- Audio functions on the SGI
  3========================================
  4
  5.. module:: al
  6   :platform: IRIX
  7   :synopsis: Audio functions on the SGI.
  8   :deprecated:
  9
 10.. deprecated:: 2.6
 11    The :mod:`al` module has been deprecated for removal in Python 3.0.
 12
 13
 14This module provides access to the audio facilities of the SGI Indy and Indigo
 15workstations.  See section 3A of the IRIX man pages for details.  You'll need to
 16read those man pages to understand what these functions do!  Some of the
 17functions are not available in IRIX releases before 4.0.5.  Again, see the
 18manual to check whether a specific function is available on your platform.
 19
 20All functions and methods defined in this module are equivalent to the C
 21functions with ``AL`` prefixed to their name.
 22
 23.. index:: module: AL
 24
 25Symbolic constants from the C header file ``<audio.h>`` are defined in the
 26standard module :mod:`AL`, see below.
 27
 28.. warning::
 29
 30   The current version of the audio library may dump core when bad argument values
 31   are passed rather than returning an error status.  Unfortunately, since the
 32   precise circumstances under which this may happen are undocumented and hard to
 33   check, the Python interface can provide no protection against this kind of
 34   problems. (One example is specifying an excessive queue size --- there is no
 35   documented upper limit.)
 36
 37The module defines the following functions:
 38
 39
 40.. function:: openport(name, direction[, config])
 41
 42   The name and direction arguments are strings.  The optional *config* argument is
 43   a configuration object as returned by :func:`newconfig`.  The return value is an
 44   :dfn:`audio port object`; methods of audio port objects are described below.
 45
 46
 47.. function:: newconfig()
 48
 49   The return value is a new :dfn:`audio configuration object`; methods of audio
 50   configuration objects are described below.
 51
 52
 53.. function:: queryparams(device)
 54
 55   The device argument is an integer.  The return value is a list of integers
 56   containing the data returned by :cfunc:`ALqueryparams`.
 57
 58
 59.. function:: getparams(device, list)
 60
 61   The *device* argument is an integer.  The list argument is a list such as
 62   returned by :func:`queryparams`; it is modified in place (!).
 63
 64
 65.. function:: setparams(device, list)
 66
 67   The *device* argument is an integer.  The *list* argument is a list such as
 68   returned by :func:`queryparams`.
 69
 70
 71.. _al-config-objects:
 72
 73Configuration Objects
 74---------------------
 75
 76Configuration objects returned by :func:`newconfig` have the following methods:
 77
 78
 79.. method:: audio configuration.getqueuesize()
 80
 81   Return the queue size.
 82
 83
 84.. method:: audio configuration.setqueuesize(size)
 85
 86   Set the queue size.
 87
 88
 89.. method:: audio configuration.getwidth()
 90
 91   Get the sample width.
 92
 93
 94.. method:: audio configuration.setwidth(width)
 95
 96   Set the sample width.
 97
 98
 99.. method:: audio configuration.getchannels()
100
101   Get the channel count.
102
103
104.. method:: audio configuration.setchannels(nchannels)
105
106   Set the channel count.
107
108
109.. method:: audio configuration.getsampfmt()
110
111   Get the sample format.
112
113
114.. method:: audio configuration.setsampfmt(sampfmt)
115
116   Set the sample format.
117
118
119.. method:: audio configuration.getfloatmax()
120
121   Get the maximum value for floating sample formats.
122
123
124.. method:: audio configuration.setfloatmax(floatmax)
125
126   Set the maximum value for floating sample formats.
127
128
129.. _al-port-objects:
130
131Port Objects
132------------
133
134Port objects, as returned by :func:`openport`, have the following methods:
135
136
137.. method:: audio port.closeport()
138
139   Close the port.
140
141
142.. method:: audio port.getfd()
143
144   Return the file descriptor as an int.
145
146
147.. method:: audio port.getfilled()
148
149   Return the number of filled samples.
150
151
152.. method:: audio port.getfillable()
153
154   Return the number of fillable samples.
155
156
157.. method:: audio port.readsamps(nsamples)
158
159   Read a number of samples from the queue, blocking if necessary. Return the data
160   as a string containing the raw data, (e.g., 2 bytes per sample in big-endian
161   byte order (high byte, low byte) if you have set the sample width to 2 bytes).
162
163
164.. method:: audio port.writesamps(samples)
165
166   Write samples into the queue, blocking if necessary.  The samples are encoded as
167   described for the :meth:`readsamps` return value.
168
169
170.. method:: audio port.getfillpoint()
171
172   Return the 'fill point'.
173
174
175.. method:: audio port.setfillpoint(fillpoint)
176
177   Set the 'fill point'.
178
179
180.. method:: audio port.getconfig()
181
182   Return a configuration object containing the current configuration of the port.
183
184
185.. method:: audio port.setconfig(config)
186
187   Set the configuration from the argument, a configuration object.
188
189
190.. method:: audio port.getstatus(list)
191
192   Get status information on last error.
193
194
195:mod:`AL` --- Constants used with the :mod:`al` module
196======================================================
197
198.. module:: AL
199   :platform: IRIX
200   :synopsis: Constants used with the al module.
201   :deprecated:
202
203.. deprecated:: 2.6
204   The :mod:`AL` module has been deprecated for removal in Python 3.0.
205
206
207This module defines symbolic constants needed to use the built-in module
208:mod:`al` (see above); they are equivalent to those defined in the C header file
209``<audio.h>`` except that the name prefix ``AL_`` is omitted.  Read the module
210source for a complete list of the defined names.  Suggested use::
211
212   import al
213   from AL import *
214