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89 lines
2.3 KiB
Python
Executable File
89 lines
2.3 KiB
Python
Executable File
#!/usr/bin/env python3
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#
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# Copyright 2024 Google LLC
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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import argparse
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import lc3
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import struct
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import sys
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import wave
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parser = argparse.ArgumentParser(description='LC3 Encoder')
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parser.add_argument(
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'wav_file', nargs='?',
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help='Input wave file, default is stdin',
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type=argparse.FileType('rb'), default=sys.stdin.buffer)
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parser.add_argument(
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'lc3_file', nargs='?',
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help='Output bitstream file, default is stdout',
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type=argparse.FileType('wb'), default=sys.stdout.buffer)
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parser.add_argument(
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'--bitrate', help='Bitrate in bps', type=int, required=True)
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parser.add_argument(
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'--frame_duration', help='Frame duration in ms', type=float, default=10)
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parser.add_argument(
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'--libpath', help='LC3 Library path')
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args = parser.parse_args()
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# --- WAV File input ---
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f_wav = args.wav_file
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wavfile = wave.open(f_wav, 'rb')
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samplerate = wavfile.getframerate()
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nchannels = wavfile.getnchannels()
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bitdepth = wavfile.getsampwidth() * 8
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stream_length = wavfile.getnframes()
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# --- Setup encoder ---
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enc = lc3.Encoder(
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args.frame_duration, samplerate, nchannels, libpath=args.libpath)
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frame_size = enc.get_frame_bytes(args.bitrate)
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frame_length = enc.get_frame_samples()
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bitrate = enc.resolve_bitrate(frame_size)
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# --- Setup output ---
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f_lc3 = args.lc3_file
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f_lc3.write(struct.pack(
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'=HHHHHHHI', 0xcc1c, 18,
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samplerate // 100, bitrate // 100, nchannels,
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int(args.frame_duration * 100), 0, stream_length))
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# --- Encoding loop ---
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for i in range(0, stream_length, frame_length):
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f_lc3.write(struct.pack('=H', frame_size))
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pcm = wavfile.readframes(frame_length)
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f_lc3.write(enc.encode(pcm, frame_size, bitdepth=bitdepth))
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# --- Cleanup ---
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wavfile.close()
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for f in (f_wav, f_lc3):
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if f is not sys.stdout.buffer:
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f.close()
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