EdfDecoder

_decodeData _decodeHeader constructor decode getOutput setInput

Edf

getNumberOfRecords getNumberOfSignals getPatientID getPhysicalSignal getPhysicalSignalConcatRecords getRawSignal getRecordDuration getRecordingID getRecordingStartDate getReservedField getSignalDigitalMax getSignalDigitalMin getSignalLabel getSignalNumberOfSamplesPerRecord getSignalPhysicalMax getSignalPhysicalMin getSignalPhysicalUnit getSignalPrefiltering getSignalSamplingFrequency getSignalTransducerType

EdfDecoder

An instance of EdfDecoder is used to decode an EDF file, or rather a buffer extracted from a EDF file. To specify the input, use the method .setInput(buf) , then launch the decoding with the method .decode() and finally get the content as an object with .getOutput(). If the output is null, then the parser was not able to decode the file.

_decodeData(byteOffset, header)

[PRIVATE] Decodes the data. Must be called after the header is decoded.

parameter type description
byteOffset Number

byte size of the header
header

_decodeHeader

[PRIVATE] Decodes the header or the file

constructor

Create a EdfDecoder.

decode

Decode the EDF file buffer set as input. This is done in two steps, first the header and then the data.

getOutput

Get the output as an object. The output contains the the header (Object), the raw (digital) signal as a Int16Array and the physical (scaled) signal as a Float32Array.

Returns

Object :

the output.

setInput(buff)

Set the buffer (most likey from a file) that contains some EDF data

parameter type description
buff ArrayBuffer

buffer from a file

Edf(header, rawSignals, physicalSignals)

An instance of Edf is usually given as output of an EdfDecoder. It provides an interface with a lot of helper function to query information that were extracted from en .edf file, such as header information, getting a signal at a given record or concatenating records of a given signal.

Keep in mind that the number of records in an edf file can be decoded by arbitrary measures, or it can be 1 second per records, etc.

parameter type description
header
rawSignals
physicalSignals

getNumberOfRecords

get the number of records per signal. Note: most of the time, records from the same signal are contiguous in time.

Returns

Number :

the number of records

getNumberOfSignals

get the number of signals. Note: a signal can have more than one record

Returns

Number :

the number of signals

getPatientID

Get the patien ID

Returns

String :

ID

getPhysicalSignal(index, record)

Get the physical (scaled) signal at a given index and record

parameter type description
index Number

index of the signal
record Number

index of the record

Returns

Float32Array :

the physical signal in Float32

getPhysicalSignalConcatRecords(index, recordStart, howMany)

Get concatenated contiguous records of a given signal, the index of the first record and the number of records to concat. Notice: this allocates a new buffer of an extented size.

parameter type description
index Number

index of the signal
recordStart Number

index of the record to start with
howMany Number

Number of records to concatenate

Returns

Float32Array :

the physical signal in Float32

getRawSignal(index, record)

Get the raw (digital) signal at a given index and record

parameter type description
index Number

index of the signal
record Number

index of the record

Returns

Int16Array :

the physical signal in Int16

getRecordDuration

Get the duration in second of a single record

Returns

Number :

duration

getRecordingID

Get the ID of the recording

Returns

String :

the ID

getRecordingStartDate

Get the date and the time at which the recording has started

Returns

Date :

the date

getReservedField(index)

Get the value of the reserved field, global (from header) or specific to a signal. Notice: reserved are rarely used.

parameter type description
index Number

if not specified, get the header's reserved field. If [0, nbSignals[ get the reserved field specific for the given signal

Returns

String :

the data of the reserved field.

getSignalDigitalMax(index)

Get the digital maximum for a given signal index

parameter type description
index Number

index of the signal

Returns

Number

getSignalDigitalMin(index)

Get the digital minimum for a given signal index

parameter type description
index Number

index of the signal

Returns

Number

getSignalLabel(index)

Get the label for a given signal index

parameter type description
index Number

index of the signal

Returns

String

getSignalNumberOfSamplesPerRecord(index)

Get the number of samples per record for a given signal index

parameter type description
index Number

index of the signal

Returns

Number

getSignalPhysicalMax(index)

Get the physical maximum for a given signal index

parameter type description
index Number

index of the signal

Returns

Number

getSignalPhysicalMin(index)

Get the physical minimum for a given signal index

parameter type description
index Number

index of the signal

Returns

Number

getSignalPhysicalUnit(index)

Get the unit (dimension label) used for a given signal index. E.g. this can be 'uV' when the signal is an EEG

parameter type description
index Number

index of the signal

Returns

String :

the unit name

getSignalPrefiltering(index)

Get the unit prefiltering info for a given signal index.

parameter type description
index Number

index of the signal

Returns

String :

the prefiltering info

getSignalSamplingFrequency(index)

Get the sampling frequency in Hz of a given signal

parameter type description
index Number

index of the signal

Returns

Number :

frequency in Hz

getSignalTransducerType(index)

Get the transducer type info for a given signal index.

parameter type description
index Number

index of the signal

Returns

String :

the transducer type info