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PaddleSpeech/paddlespeech/server/utils/buffer.py

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2.9 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.remained_audio = b''
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)
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
timestamp = 0.0
while offset + self.window_bytes <= len(audio):
yield Frame(audio[offset:offset + self.window_bytes], timestamp,
self.window_sec)
timestamp += self.shift_sec
offset += self.shift_bytes
self.remained_audio += audio[offset:]