source: python/demos/demo_timestretch_online.py @ a0a073f

feature/autosinkfeature/constantqfeature/pitchshiftfeature/pydocstringsfeature/timestretchsampleryinfft+
Last change on this file since a0a073f was a0a073f, checked in by Paul Brossier <piem@piem.org>, 3 years ago

python/demos/demo_timestretch_online.py: use 512, fix block counter

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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
9import sys
10from aubio import source, sink, pvoc, cvec
11from aubio import unwrap2pi, float_type
12import numpy as np
13
14win_s = 512
15hop_s = win_s // 8 # 87.5 % overlap
16
17warmup = win_s // hop_s - 1
18
19if 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
30source_filename = sys.argv[1]
31output_filename = sys.argv[2]
32rate = float(sys.argv[3])
33
34samplerate = 0 if len(sys.argv) < 5 else int(sys.argv[4])
35source_in = source(source_filename, samplerate, hop_s)
36samplerate = source_in.samplerate
37p = pvoc(win_s, hop_s)
38
39sink_out = sink(output_filename, samplerate)
40
41# excepted phase advance in each bin
42phi_advance = np.linspace(0, np.pi * hop_s, win_s / 2 + 1).astype (float_type)
43
44old_grain = cvec(win_s)
45new_grain = cvec(win_s)
46
47block_read = 0
48interp_read = 0
49interp_block = 0
50while 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    # until end of file
96    if read < hop_s: break
97    # increment block counter
98    block_read += 1
99
100for t in range(warmup + 2): # purge the last frames from the phase vocoder
101    new_grain.norm[:] = 0
102    new_grain.phas[:] = 0
103    samples = p.rdo(new_grain)
104    sink_out(samples, read if t == warmup + 1 else hop_s)
105
106# just to make sure
107source_in.close()
108sink_out.close()
109
110format_out = "read {:d} blocks from {:s} at {:d}Hz and rate {:f}, wrote {:d} blocks to {:s}"
111print (format_out.format(block_read, source_filename, samplerate, rate,
112    interp_block, output_filename))
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