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| 1 | #! /usr/bin/env python | ||
| 2 | |||
| 3 | # Implementation of the timescale algorithm according to Dan Ellis, *A Phase | ||
| 4 | # Vocoder in Matlab*. http://www.ee.columbia.edu/~dpwe/resources/matlab/pvoc/ | ||
| 5 | |||
| 6 | # This file performs both analysis and synthesis in a single pass. See also | ||
| 7 | # `demo_timestretch.py` for a version following the original implementation. | ||
| 8 | |||
| 9 | import sys | ||
| 10 | from aubio import source, sink, pvoc, mfcc, cvec | ||
| 11 | from aubio import unwrap2pi, float_type | ||
| 12 | import numpy as np | ||
| 13 | |||
| 14 | win_s = 1024 | ||
| 15 | hop_s = win_s / 8 # 87.5 % overlap | ||
| 16 | |||
| 17 | warmup = win_s // hop_s - 1 | ||
| 18 | |||
| 19 | if len(sys.argv) < 3: | ||
| 20 | print("Usage: %s <source_filename> <output_filename> <rate> [samplerate]".format(sys.argv[0])) | ||
| 21 | print("""Examples: | ||
| 22 | # twice faster | ||
| 23 | {0} track_01.mp3 track_01_faster.wav 2.0 | ||
| 24 | # twice slower | ||
| 25 | {0} track_02.flac track_02_slower.wav 0.5 | ||
| 26 | # one and a half time faster, resampling first the input to 22050 | ||
| 27 | {0} track_02.flac track_02_slower.wav 1.5 22050""".format(sys.argv[0])) | ||
| 28 | sys.exit(1) | ||
| 29 | |||
| 30 | source_filename = sys.argv[1] | ||
| 31 | output_filename = sys.argv[2] | ||
| 32 | rate = float(sys.argv[3]) | ||
| 33 | |||
| 34 | samplerate = 0 if len(sys.argv) < 5 else int(sys.argv[4]) | ||
| 35 | source_in = source(source_filename, samplerate, hop_s) | ||
| 36 | samplerate = source_in.samplerate | ||
| 37 | p = pvoc(win_s, hop_s) | ||
| 38 | |||
| 39 | sink_out = sink(output_filename, samplerate) | ||
| 40 | |||
| 41 | # excepted phase advance in each bin | ||
| 42 | phi_advance = np.linspace(0, np.pi * hop_s, win_s / 2 + 1).astype (float_type) | ||
| 43 | |||
| 44 | old_grain = cvec(win_s) | ||
| 45 | new_grain = cvec(win_s) | ||
| 46 | |||
| 47 | block_read = 0 | ||
| 48 | interp_read = 0 | ||
| 49 | interp_block = 0 | ||
| 50 | while True: | ||
| 51 | |||
| 52 | samples, read = source_in() | ||
| 53 | cur_grain = p(samples) | ||
| 54 | |||
| 55 | if block_read == 1: | ||
| 56 | phas_acc = old_grain.phas | ||
| 57 | |||
| 58 | #print "block_read", block_read | ||
| 59 | while True and (block_read > 0): | ||
| 60 | if interp_read >= block_read: | ||
| 61 | break | ||
| 62 | #print "`--- interp_block:", interp_block, | ||
| 63 | #print 'at orig_block', interp_read, '<- from', block_read - 1, block_read, | ||
| 64 | #print 'old_grain', old_grain, 'cur_grain', cur_grain | ||
| 65 | # time to compute interp grain | ||
| 66 | frac = 1. - np.mod(interp_read, 1.0) | ||
| 67 | |||
| 68 | # compute interpolated frame | ||
| 69 | new_grain.norm = frac * old_grain.norm + (1. - frac) * cur_grain.norm | ||
| 70 | new_grain.phas = phas_acc | ||
| 71 | |||
| 72 | # psola | ||
| 73 | samples = p.rdo(new_grain) | ||
| 74 | if interp_read > warmup: # skip the first frames to warm up phase vocoder | ||
| 75 | # write to sink | ||
| 76 | sink_out(samples, hop_s) | ||
| 77 | |||
| 78 | # calculate phase advance | ||
| 79 | dphas = cur_grain.phas - old_grain.phas - phi_advance | ||
| 80 | # unwrap angle to [-pi; pi] | ||
| 81 | dphas = unwrap2pi(dphas) | ||
| 82 | # cumulate phase, to be used for next frame | ||
| 83 | phas_acc += phi_advance + dphas | ||
| 84 | |||
| 85 | # prepare for next interp block | ||
| 86 | interp_block += 1 | ||
| 87 | interp_read = interp_block * rate | ||
| 88 | if interp_read >= block_read: | ||
| 89 | break | ||
| 90 | |||
| 91 | # copy cur_grain to old_grain | ||
| 92 | old_grain.norm = np.copy(cur_grain.norm) | ||
| 93 | old_grain.phas = np.copy(cur_grain.phas) | ||
| 94 | |||
| 95 | block_read += 1 | ||
| 96 | if read < hop_s: break | ||
| 97 | |||
| 98 | for t in range(warmup + 2): # purge the last frames from the phase vocoder | ||
| 99 | new_grain.norm[:] = 0 | ||
| 100 | new_grain.phas[:] = 0 | ||
| 101 | samples = p.rdo(new_grain) | ||
| 102 | sink_out(samples, read if t == warmup + 1 else hop_s) | ||
| 103 | |||
| 104 | # just to make sure | ||
| 105 | source_in.close() | ||
| 106 | sink_out.close() | ||
| 107 | |||
| 108 | format_out = "read {:d} blocks from {:s} at {:d}Hz and rate {:f}, wrote {:d} blocks to {:s}" | ||
| 109 | print (format_out.format(block_read, source_filename, samplerate, rate, | ||
| 110 | interp_block, output_filename)) | ||