def set_format(self, sample_rate, channels, channel_mask, bits_per_sample):
"""sets the output stream to the given format
if the stream hasn't been initialized, this method initializes it
if the stream has been initialized to a different format,
this method closes and reopens the stream to the new format
if the stream has been initialized to the same format,
this method does nothing"""
if (self.__coreaudio__ is None):
# output hasn't been initialized
from audiotools.output import CoreAudio
AudioOutput.set_format(self, sample_rate, channels, channel_mask,
bits_per_sample)
self.__coreaudio__ = CoreAudio(sample_rate, channels, channel_mask,
bits_per_sample)
elif (not self.compatible(sample_rate=sample_rate,
channels=channels,
channel_mask=channel_mask,
bits_per_sample=bits_per_sample)):
# output has been initialized in a different format
self.close()
self.set_format(sample_rate=sample_rate,
channels=channels,
channel_mask=channel_mask,
bits_per_sample=bits_per_sample)
