1 """utility routines to slice sound files at given timestamps"""
4 from aubio import source, sink
9 def slice_source_at_stamps(source_file, timestamps, timestamps_end=None,
10 output_dir=None, samplerate=0, hopsize=256,
12 """Slice a sound file at given timestamps.
14 This function reads `source_file` and creates slices, new smaller
15 files each starting at `t` in `timestamps`, a list of integer
16 corresponding to time locations in `source_file`, in samples.
18 If `timestamps_end` is unspecified, the slices will end at
19 `timestamps_end[n] = timestamps[n+1]-1`, or the end of file.
20 Otherwise, `timestamps_end` should be a list with the same length
21 as `timestamps` containing the locations of the end of each slice.
23 If `output_dir` is unspecified, the new slices will be written in
24 the current directory. If `output_dir` is a string, new slices
25 will be written in `output_dir`, after creating the directory if
28 The default `samplerate` is 0, meaning the original sampling rate
29 of `source_file` will be used. When using a sampling rate
30 different to the one of the original files, `timestamps` and
31 `timestamps_end` should be expressed in the re-sampled signal.
33 The `hopsize` parameter simply tells :class:`source` to use this
34 hopsize and does not change the output slices.
36 If `create_first` is True and `timestamps` does not start with `0`, the
37 first slice from `0` to `timestamps[0] - 1` will be automatically added.
42 path of the resource to slice
43 timestamps : :obj:`list` of :obj:`int`
44 time stamps at which to slice, in samples
45 timestamps_end : :obj:`list` of :obj:`int` (optional)
46 time stamps at which to end the slices
47 output_dir : str (optional)
48 output directory to write the slices to
49 samplerate : int (optional)
50 samplerate to read the file at
51 hopsize : int (optional)
52 number of samples read from source per iteration
53 create_first : bool (optional)
54 always create the slice at the start of the file
58 Create two slices: the first slice starts at the beginning of the
59 input file `loop.wav` and lasts exactly one second, starting at
60 sample `0` and ending at sample `44099`; the second slice starts
61 at sample `44100` and lasts until the end of the input file:
63 >>> aubio.slice_source_at_stamps('loop.wav', [0, 44100])
65 Create one slice, from 1 second to 2 seconds:
67 >>> aubio.slice_source_at_stamps('loop.wav', [44100], [44100 * 2 - 1])
71 Slices may be overlapping. If `timestamps_end` is `1` element
72 shorter than `timestamps`, the last slice will end at the end of
77 raise ValueError("no timestamps given")
79 if timestamps[0] != 0 and create_first:
80 timestamps = [0] + timestamps
81 if timestamps_end is not None:
82 timestamps_end = [timestamps[1] - 1] + timestamps_end
84 if timestamps_end is not None:
85 if len(timestamps_end) == len(timestamps) - 1:
86 timestamps_end = timestamps_end + [_max_timestamp]
87 elif len(timestamps_end) != len(timestamps):
88 raise ValueError("len(timestamps_end) != len(timestamps)")
90 timestamps_end = [t - 1 for t in timestamps[1:]] + [_max_timestamp]
92 regions = list(zip(timestamps, timestamps_end))
94 source_base_name, _ = os.path.splitext(os.path.basename(source_file))
95 if output_dir is not None:
96 if not os.path.isdir(output_dir):
97 os.makedirs(output_dir)
98 source_base_name = os.path.join(output_dir, source_base_name)
100 def _new_sink_name(source_base_name, timestamp, samplerate):
101 # create name based on a timestamp in samples, converted in seconds
102 timestamp_seconds = timestamp / float(samplerate)
103 return source_base_name + "_%011.6f" % timestamp_seconds + '.wav'
106 _source = source(source_file, samplerate, hopsize)
107 samplerate = _source.samplerate
113 # get hopsize new samples from source
114 vec, read = _source.do_multi()
115 # if the total number of frames read will exceed the next region start
116 while regions and total_frames + read >= regions[0][0]:
118 start_stamp, end_stamp = regions.pop(0)
119 # create a name for the sink
120 new_sink_path = _new_sink_name(source_base_name, start_stamp,
123 _sink = sink(new_sink_path, samplerate, _source.channels)
124 # create a dictionary containing all this
125 new_slice = {'start_stamp': start_stamp, 'end_stamp': end_stamp,
127 # append the dictionary to the current list of slices
128 slices.append(new_slice)
130 for current_slice in slices:
131 start_stamp = current_slice['start_stamp']
132 end_stamp = current_slice['end_stamp']
133 _sink = current_slice['sink']
134 # sample index to start writing from new source vector
135 start = max(start_stamp - total_frames, 0)
136 # number of samples yet to written be until end of region
137 remaining = end_stamp - total_frames + 1
138 # not enough frames remaining, time to split
140 if remaining > start:
141 # write remaining samples from current region
142 _sink.do_multi(vec[:, start:remaining], remaining - start)
146 # write all the samples
147 _sink.do_multi(vec[:, start:read], read - start)
150 slices = list(filter(lambda s: s['end_stamp'] > total_frames,