def src_callback_new(callback, converter_type, channels):
"""Initialisation for the callback based API.
Parameters
----------
callback : function
Called whenever new frames are to be read. Must return a NumPy array
of shape (num_frames, channels).
converter_type : int
Converter to be used.
channels : int
Number of channels.
Returns
-------
state
An anonymous pointer to the internal state of the converter.
handle
A CFFI handle to the callback data.
error : int
Error code.
"""
cb_data = {'callback': callback, 'channels': channels}
handle = ffi.new_handle(cb_data)
error = ffi.new('int*')
state = _lib.src_callback_new(_src_input_callback, converter_type,
channels, error, handle)
if state == ffi.NULL:
return None, handle, error[0]
return state, handle, error[0]
def src_process(state, input_data, output_data, ratio, end_of_input=0):
"""Standard processing function.
Returns non zero on error.
"""
input_frames, _ = _check_data(input_data)
output_frames, _ = _check_data(output_data)
data = ffi.new('SRC_DATA*')
data.input_frames = input_frames
data.output_frames = output_frames
data.src_ratio = ratio
data.data_in = ffi.cast('float*', ffi.from_buffer(input_data))
data.data_out = ffi.cast('float*', ffi.from_buffer(output_data))
data.end_of_input = end_of_input
error = _lib.src_process(state, data)
return error, data.input_frames_used, data.output_frames_gen
def src_simple(input_data, output_data, ratio, converter_type, channels):
"""Perform a single conversion from an input buffer to an output buffer.
Simple interface for performing a single conversion from input buffer to
output buffer at a fixed conversion ratio. Simple interface does not require
initialisation as it can only operate on a single buffer worth of audio.
"""
input_frames, _ = _check_data(input_data)
output_frames, _ = _check_data(output_data)
data = ffi.new('SRC_DATA*')
data.input_frames = input_frames
data.output_frames = output_frames
data.src_ratio = ratio
data.data_in = ffi.cast('float*', ffi.from_buffer(input_data))
data.data_out = ffi.cast('float*', ffi.from_buffer(output_data))
error = _lib.src_simple(data, converter_type, channels)
return error, data.input_frames_used, data.output_frames_gen
def src_new(converter_type, channels):
"""Initialise a new sample rate converter.
Parameters
----------
converter_type : int
Converter to be used.
channels : int
Number of channels.
Returns
-------
state
An anonymous pointer to the internal state of the converter.
error : int
Error code.
"""
error = ffi.new('int*')
state = _lib.src_new(converter_type, channels, error)
return state, error[0]
def src_get_version(cls):
return ffi.new('char[]', 'libsamplerate-0.1.9 (c) ...')