Created
November 6, 2021 09:16
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Convert TAP to WAV
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| #!/usr/bin/env python | |
| import argparse | |
| import struct | |
| import wave | |
| SECONDS_PAUSE = 1.5 | |
| SECONDS_PILOT_HEADER = 3 | |
| SECONDS_PILOT_DATA = 1.5 | |
| class StandardTimings: | |
| TSTATES_SYNC_1 = 667 | |
| TSTATES_SYNC_2 = 735 | |
| TSTATES_ZERO = 855 | |
| TSTATES_ONE = 1710 | |
| TSTATES_PILOT = 2168 | |
| class WeirdTimings: | |
| TSTATES_SYNC_1 = 667 * 0.85 | |
| TSTATES_SYNC_2 = 735 * 0.85 | |
| TSTATES_ZERO = 855 * 0.85 | |
| TSTATES_ONE = 1710 * 0.85 | |
| TSTATES_PILOT = 2168 * 0.85 | |
| class TapReader: | |
| def __init__(self, filename): | |
| self.filename = filename | |
| def blocks(self): | |
| with open(self.filename, 'rb') as f: | |
| while True: | |
| bs = f.read(2) | |
| if not bs: | |
| break | |
| block_size = struct.unpack('<H', bs)[0] | |
| block = f.read(block_size) | |
| yield block | |
| class WavWriter: | |
| def __init__(self, filename, timings=StandardTimings, rate=48000): | |
| self.timings = timings | |
| self.level = 0 | |
| self.rate = rate | |
| self.wav = wave.open(filename, 'wb') | |
| self.wav.setnchannels(1) | |
| self.wav.setsampwidth(1) | |
| self.wav.setframerate(self.rate) | |
| def close(self): | |
| self.wav.close() | |
| def bits(self, iterable): | |
| for byte in iterable: | |
| yield from ((byte >> (7 - i)) & 1 for i in range(8)) | |
| def tstates_to_samples(self, tstates): | |
| return int(round(self.rate * tstates / 3500000.0)) | |
| def emit_n_samples(self, count): | |
| self.wav.writeframesraw(bytes([self.level] * count)) | |
| self.level ^= 0xFF | |
| def emit_samples(self, tstates): | |
| count = self.tstates_to_samples(tstates) | |
| self.emit_n_samples(count) | |
| def emit_pause(self, seconds=SECONDS_PAUSE): | |
| count = int(self.rate * seconds) | |
| self.emit_n_samples(count) | |
| def emit_pulse(self, tstates): | |
| for _ in range(2): | |
| self.emit_samples(tstates) | |
| def emit_sync(self): | |
| self.emit_samples(self.timings.TSTATES_SYNC_1) | |
| self.emit_samples(self.timings.TSTATES_SYNC_2) | |
| def emit_pilot(self, seconds=SECONDS_PILOT_HEADER): | |
| count = int(self.rate * seconds / | |
| self.tstates_to_samples(self.timings.TSTATES_PILOT) / 2) | |
| for _ in range(count): | |
| self.emit_pulse(self.timings.TSTATES_PILOT) | |
| def emit_bit(self, bit): | |
| self.emit_pulse( | |
| self.timings.TSTATES_ONE if bit else self.timings.TSTATES_ZERO) | |
| def emit_block(self, block): | |
| is_header = block[0] == 0x00 | |
| self.emit_pilot( | |
| SECONDS_PILOT_HEADER if is_header else SECONDS_PILOT_DATA) | |
| self.emit_sync() | |
| for bit in self.bits(block): | |
| self.emit_bit(bit) | |
| self.emit_pause() | |
| class TapToWavConverter: | |
| def convert(self, tap, wav, timings=StandardTimings, rate=48000): | |
| tap_reader = TapReader(tap) | |
| wav_writer = WavWriter(wav, timings, rate) | |
| for block in tap_reader.blocks(): | |
| wav_writer.emit_block(block) | |
| wav_writer.close() | |
| if __name__ == '__main__': | |
| parser = argparse.ArgumentParser(description='Convert TAP to WAV') | |
| parser.add_argument('source', help='Source .tap file name') | |
| parser.add_argument('dest', help='Dest .wav file name', | |
| nargs='?', default=None) | |
| args = parser.parse_args() | |
| dest = args.dest or f'{args.source}.wav' | |
| print(f'{args.source} -> {dest}') | |
| converter = TapToWavConverter() | |
| converter.convert(args.source, dest, StandardTimings) |
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