103 lines
3.4 KiB
Python
103 lines
3.4 KiB
Python
# Copyright 2020 Mycroft AI Inc.
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
#
|
|
"""Data structures used by the speech client."""
|
|
|
|
|
|
class RollingMean:
|
|
"""Simple rolling mean calculation optimized for speed.
|
|
|
|
The optimization is made for cases where value retrieval is made at a
|
|
comparative rate to the sample additions.
|
|
|
|
Args:
|
|
mean_samples: Number of samples to use for mean value
|
|
"""
|
|
def __init__(self, mean_samples):
|
|
self.num_samples = mean_samples
|
|
self.samples = []
|
|
self.value = None # Leave unintialized
|
|
self.replace_pos = 0 # Position to replace
|
|
|
|
def append_sample(self, sample):
|
|
"""Add a sample to the buffer.
|
|
|
|
The sample will be appended if there is room in the buffer,
|
|
otherwise it will replace the oldest sample in the buffer.
|
|
"""
|
|
sample = float(sample)
|
|
current_len = len(self.samples)
|
|
if current_len < self.num_samples:
|
|
# build the mean
|
|
self.samples.append(sample)
|
|
if self.value is not None:
|
|
avgsum = self.value * current_len + sample
|
|
self.value = avgsum / (current_len + 1)
|
|
else: # If no samples are in the buffer set the sample as mean
|
|
self.value = sample
|
|
else:
|
|
# Remove the contribution of the old sample
|
|
replace_val = self.samples[self.replace_pos]
|
|
self.value -= replace_val / self.num_samples
|
|
|
|
# Replace it with the new sample and update the mean with it's
|
|
# contribution
|
|
self.value += sample / self.num_samples
|
|
self.samples[self.replace_pos] = sample
|
|
|
|
# Update replace position
|
|
self.replace_pos = (self.replace_pos + 1) % self.num_samples
|
|
|
|
|
|
class CyclicAudioBuffer:
|
|
"""A Cyclic audio buffer for storing binary data.
|
|
|
|
TODO: The class is still unoptimized and performance can probably be
|
|
enhanced.
|
|
|
|
Args:
|
|
size (int): size in bytes
|
|
initial_data (bytes): initial buffer data
|
|
"""
|
|
def __init__(self, size, initial_data):
|
|
self.size = size
|
|
# Get at most size bytes from the end of the initial data
|
|
self._buffer = initial_data[-size:]
|
|
|
|
def append(self, data):
|
|
"""Add new data to the buffer, and slide out data if the buffer is full
|
|
|
|
Args:
|
|
data (bytes): binary data to append to the buffer. If buffer size
|
|
is exceeded the oldest data will be dropped.
|
|
"""
|
|
buff = self._buffer + data
|
|
if len(buff) > self.size:
|
|
buff = buff[-self.size:]
|
|
self._buffer = buff
|
|
|
|
def get(self):
|
|
"""Get the binary data."""
|
|
return self._buffer
|
|
|
|
def get_last(self, size):
|
|
"""Get the last entries of the buffer."""
|
|
return self._buffer[-size:]
|
|
|
|
def __getitem__(self, key):
|
|
return self._buffer[key]
|
|
|
|
def __len__(self):
|
|
return len(self._buffer)
|