Created CoreAudioSettings

Author: dholl

sounddevice.py

@@ -232,6 +232,33 @@
 PaError Pa_GetSampleSize( PaSampleFormat format );
 void Pa_Sleep( long msec );
 
+/* pa_mac_core.h */
+
+typedef int32_t SInt32;
+typedef struct
+{
+    unsigned long size;
+    PaHostApiTypeId hostApiType;
+    unsigned long version;
+    unsigned long flags;
+    SInt32 const * channelMap;
+    unsigned long channelMapSize;
+} PaMacCoreStreamInfo;
+void PaMacCore_SetupStreamInfo( PaMacCoreStreamInfo *data, unsigned long flags );
+void PaMacCore_SetupChannelMap( PaMacCoreStreamInfo *data, const SInt32 * const channelMap, unsigned long channelMapSize );
+const char *PaMacCore_GetChannelName( int device, int channelIndex, bool input );
+#define paMacCoreChangeDeviceParameters 0x01
+#define paMacCoreFailIfConversionRequired 0x02
+#define paMacCoreConversionQualityMin    0x0100
+#define paMacCoreConversionQualityMedium 0x0200
+#define paMacCoreConversionQualityLow    0x0300
+#define paMacCoreConversionQualityHigh   0x0400
+#define paMacCoreConversionQualityMax    0x0000
+#define paMacCorePlayNice                    0x00
+#define paMacCorePro                         0x01
+#define paMacCoreMinimizeCPUButPlayNice      0x0100
+#define paMacCoreMinimizeCPU                 0x0101
+
 /* pa_win_waveformat.h */
 
 typedef unsigned long PaWinWaveFormatChannelMask;
@@ -2182,7 +2209,7 @@ class default(object):
 
     See Also
     --------
-    AsioSettings, WasapiSettings
+    AsioSettings, CoreAudioSettings, WasapiSettings
 
     """
     samplerate = None
@@ -2349,6 +2376,98 @@ def __init__(self, channel_selectors):
             channelSelectors=self._selectors))
 
 
+class CoreAudioSettings(object):
+
+    def __init__(self, channel_map=None, change_device_parameters=False,
+                 fail_if_conversion_required=False, conversion_quality='max'):
+        """Mac Core Audio-specific input/output settings.
+
+        Objects of this class can be used as *extra_settings* argument
+        to `Stream()` (and variants) or as `default.extra_settings`.
+
+        Parameters
+        ----------
+        channel_map : sequence of int, optional
+            Support for opening only specific channels of a Core Audio
+            device.  Note that *channel_map* is treated differently
+            between input and output channels.
+
+            For input devices, *channel_map* is a list of integers
+            specifying the (zero-based) channel numbers to use.
+
+            For output devices, *channel_map* must have the same length
+            as the number of output channels of the device.  Specify
+            unused channels with -1, and a 0-based index for any desired
+            channels.
+
+            See the example below.  For additional information, see the
+            `PortAudio documentation`__.
+
+            __ https://app.assembla.com/spaces/portaudio/git/source/
+               master/src/hostapi/coreaudio/notes.txt
+        change_device_parameters : bool, optional
+            If ``True``, allows PortAudio to change things like the
+            device's frame size, which allows for much lower latency,
+            but might disrupt the device if other programs are using it,
+            even when you are just querying the device.  ``False`` is
+            the default.
+        fail_if_conversion_required : bool, optional
+            In combination with the above flag, ``True`` causes the
+            stream opening to fail, unless the exact sample rates are
+            supported by the device.
+        conversion_quality : {'min', 'low', 'medium', 'high', 'max'}, optional
+            This sets Core Audio's sample rate conversion quality.
+            ``'max'`` is the default.
+
+        Example
+        -------
+        This example assumes a device having 6 input and 6 output
+        channels.  Input is from the second and fourth channels, and
+        output is to the device's third and fifth channels:
+
+        >>> import sounddevice as sd
+        >>> ca_in = sd.CoreAudioSettings(channel_map=[1, 3])
+        >>> ca_out = sd.CoreAudioSettings(channel_map=[-1, -1, 0, -1, 1, -1])
+        >>> sd.playrec(..., channels=2, extra_settings=(ca_in, ca_out))
+
+        """
+        conversion_dict = {
+            'min':    _lib.paMacCoreConversionQualityMin,
+            'low':    _lib.paMacCoreConversionQualityLow,
+            'medium': _lib.paMacCoreConversionQualityMedium,
+            'high':   _lib.paMacCoreConversionQualityHigh,
+            'max':    _lib.paMacCoreConversionQualityMax,
+        }
+
+        # Minimal checking on channel_map to catch errors that might
+        # otherwise go unnoticed:
+        if isinstance(channel_map, int):
+            raise TypeError('channel_map must be a list or tuple')
+
+        try:
+            self._flags = conversion_dict[conversion_quality.lower()]
+        except (KeyError, AttributeError):
+            raise ValueError('conversion_quality must be one of ' +
+                             repr(list(conversion_dict)))
+        if change_device_parameters:
+            self._flags |= _lib.paMacCoreChangeDeviceParameters
+        if fail_if_conversion_required:
+            self._flags |= _lib.paMacCoreFailIfConversionRequired
+
+        # this struct must be kept alive!
+        self._streaminfo = _ffi.new('PaMacCoreStreamInfo*')
+        _lib.PaMacCore_SetupStreamInfo(self._streaminfo, self._flags)
+
+        if channel_map is not None:
+            # this array must be kept alive!
+            self._channel_map = _ffi.new('SInt32[]', channel_map)
+            if len(self._channel_map) == 0:
+                raise TypeError('channel_map must not be empty')
+            _lib.PaMacCore_SetupChannelMap(self._streaminfo,
+                                           self._channel_map,
+                                           len(self._channel_map))
+
+
 class WasapiSettings(object):
 
     def __init__(self, exclusive=False):