You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
87 lines
3.1 KiB
87 lines
3.1 KiB
# Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
|
|
#
|
|
# 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.
|
|
|
|
|
|
class Frame(object):
|
|
"""Represents a "frame" of audio data."""
|
|
|
|
def __init__(self, bytes, timestamp, duration):
|
|
self.bytes = bytes
|
|
self.timestamp = timestamp
|
|
self.duration = duration
|
|
|
|
|
|
class ChunkBuffer(object):
|
|
def __init__(self,
|
|
window_n=7,
|
|
shift_n=4,
|
|
window_ms=20,
|
|
shift_ms=10,
|
|
sample_rate=16000,
|
|
sample_width=2):
|
|
"""audio sample data point buffer
|
|
|
|
Args:
|
|
window_n (int, optional): decode window frame length. Defaults to 7 frame.
|
|
shift_n (int, optional): decode shift frame length. Defaults to 4 frame.
|
|
window_ms (int, optional): frame length, ms. Defaults to 20 ms.
|
|
shift_ms (int, optional): shift length, ms. Defaults to 10 ms.
|
|
sample_rate (int, optional): audio sample rate. Defaults to 16000.
|
|
sample_width (int, optional): sample point bytes. Defaults to 2 bytes.
|
|
"""
|
|
self.window_n = window_n
|
|
self.shift_n = shift_n
|
|
self.window_ms = window_ms
|
|
self.shift_ms = shift_ms
|
|
self.sample_rate = sample_rate
|
|
self.sample_width = sample_width # int16 = 2; float32 = 4
|
|
|
|
self.window_sec = float((self.window_n - 1) * self.shift_ms +
|
|
self.window_ms) / 1000.0
|
|
self.shift_sec = float(self.shift_n * self.shift_ms / 1000.0)
|
|
|
|
self.window_bytes = int(self.window_sec * self.sample_rate *
|
|
self.sample_width)
|
|
self.shift_bytes = int(self.shift_sec * self.sample_rate *
|
|
self.sample_width)
|
|
|
|
self.remained_audio = b''
|
|
# abs timestamp from `start` or latest `reset`
|
|
self.timestamp = 0.0
|
|
|
|
def reset(self):
|
|
"""
|
|
reset buffer state.
|
|
"""
|
|
self.timestamp = 0.0
|
|
self.remained_audio = b''
|
|
|
|
def frame_generator(self, audio):
|
|
"""Generates audio frames from PCM audio data.
|
|
Takes the desired frame duration in milliseconds, the PCM data, and
|
|
the sample rate.
|
|
Yields Frames of the requested duration.
|
|
"""
|
|
audio = self.remained_audio + audio
|
|
self.remained_audio = b''
|
|
|
|
offset = 0
|
|
while offset + self.window_bytes <= len(audio):
|
|
yield Frame(audio[offset:offset + self.window_bytes],
|
|
self.timestamp, self.window_sec)
|
|
self.timestamp += self.shift_sec
|
|
offset += self.shift_bytes
|
|
|
|
self.remained_audio += audio[offset:]
|