Append and/or concatenate segments

Sometimes a recording can be split in several subparts, for instance a baseline and an intervention.

Similarly to NEO we define each subpart as a “segment”.

spikeinterface has tools to manipulate these segments. There are two ways:

1. append_recordings()/append_sortings()/append_events()

2. concatenate_recordings()/ concatenate_sortings()/ concatenate_events()

Here is the differemce. Imagine we have 2 recordings with 2 and 3 segments respectively:

1. In case 1. (append) we will end up with one recording with 5 segments.

2. In case 2. (concatenate) we will end up with one recording with 1 “big” segment that virtually concatenates all segments.

Here is a short example.

import matplotlib.pyplot as plt
import numpy as np


from spikeinterface import NumpyRecording, NumpySorting
from spikeinterface import append_recordings, concatenate_recordings

First let’s generate 2 recordings with 2 and 3 segments respectively:

sampling_frequency = 1000.

trace0 = np.zeros((150, 5), dtype='float32')
trace1 = np.zeros((100, 5), dtype='float32')
rec0 = NumpyRecording([trace0, trace1], sampling_frequency)
print(rec0)

trace2 = np.zeros((50, 5), dtype='float32')
trace3 = np.zeros((200, 5), dtype='float32')
trace4 = np.zeros((120, 5), dtype='float32')
rec1 = NumpyRecording([trace2, trace3, trace4], sampling_frequency)
print(rec1)

Out:

NumpyRecording: 5 channels - 2 segments - 1.0kHz - 0.250s
NumpyRecording: 5 channels - 3 segments - 1.0kHz - 0.370s

Let’s use the append_recordings():

recording_list = [rec0, rec1]
rec = append_recordings(recording_list)
print(rec)
for i in range(rec.get_num_segments()):
    s = rec.get_num_samples(segment_index=i)
    print(f'segment {i} num_samples {s}')

Out:

AppendSegmentRecording: 5 channels - 5 segments - 1.0kHz - 0.620s
segment 0 num_samples 150
segment 1 num_samples 100
segment 2 num_samples 50
segment 3 num_samples 200
segment 4 num_samples 120

Let’s use the concatenate_recordings():

recording_list = [rec0, rec1]
rec = concatenate_recordings(recording_list)
print(rec)
s = rec.get_num_samples(segment_index=0)
print(f'segment {0} num_samples {s}')

Out:

ConcatenateSegmentRecording: 5 channels - 1 segments - 1.0kHz - 0.620s
segment 0 num_samples 620