edfrw.writer
Write data to files in European Data Format (EDF).
EdfWriter(filename, header, saving_period_s)
Bases: object
Open an EDF for writing.
Attributes:
| Name | Type | Description |
|---|---|---|
filename |
str
|
EDF file name. |
header |
object of `class::EdfHeader`
|
File header. |
saving_period_s |
int
|
How often to write data to the EDF file. |
closed |
bool
|
Whether the file has been closed. |
Create and open an EDF file for writing.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
filename |
str
|
EDF file name. |
required |
header |
instance of
|
The file header. |
required |
saving_period_s |
integer
|
How often (in seconds) will the data be saved to disk? This
value sets EDF header’s From the specification: “The duration of each data record is recommended to be a whole number of seconds and its size (number of bytes) is recommended not to exceed 61440. Only if a 1s data record exceeds this size limit, the duration is recommended to be smaller than 1s (e.g. 0.01).” |
required |
close()
Close the EDF file
update_number_of_records()
Update the number of data records in the file header.
Writes to the header the most recent value of ‘number_of_data_records’ (referred to as ‘nr’ in the EDF specification).
By definition, this value is 8-bits long and it starts at position 236 in the header.
write_data_record(buffer)
Write one data record.
Parameters:
| Name | Type | Description | Default |
|---|---|---|---|
buffer |
uint16
|
The data to be save to disk. It must be an unsigned 16-bit integer, two-complement values, as required by the EDF file format specification. |
required |
Notes
Signals are allowed to be acquired at different sampling rates.
The data are saved in data blocks (named ‘data records’ in the
specification). The total number of samples in the block is thus
determined by adding the sizes of the individual signals
(signal.number_of_samples_in_data_record).
Each data block holds all data acquired during a time interval
of header.duration_of_data_record seconds, and the total
number of data records in the file are
header.number_of_data_records.
Thus, to write a data block (data record), the data must be
the concatenation of samples acquired during the period of time
duration_of_data_record first all samples from signal 0, then
signal 1, etc:
signal_0.samples[sig_0_number_of_samples_in_data_record] signal_1.samples[sig_1_number_of_samples_in_data_record]
write_header()
Write the EDF header to the current file.
Packs the header record attributes in the format required by EDF and writes these values at the beginning of the current file.