Edf File parser
Package to parse/process edf file as detailed on the specification
Important: This is not and edf+ parser
Terminology
Below some terminology found in the source code that will help understanding the implementation faster:
DataBlock: The raw byte-encoded data samples as found in the file.
Record: The decoded samples found on a data block.
SignalProcessor: Interface for objects that can process/translate a raw set of bytes, representing the digital values,into the real physical values of a signal.
RecordProcessor: Interface for objects that can process/translate and entire datablock into its record.
Sample
if there is no time for to much reading file sample/sample.js provides a quick usage intro.
Some Implementation details
edf.DataBlock, implementing the stream.Transform interface, should be pipe into a stream reading the edf raw content, it will parse the header, signals headers, triggering the events header and signals respectivily containing the models, right after it will begin streaming each datarecord as a block
edf.RecordsStream, also implementing the stream.Transform interface, is design to take as input each datablock and translate it into a record, which gets push out the pipe (using object mode)for extra processing. the RecordStream does the transformation with the help of an object implementing the edf.RecordProcessor
edf.RecordProcessor object is a composition of multiple edf.SignalProcessor, and each signal processor is in charge of processing/decoding the data of the signal it represents. The responsability of a RecordProcessor is simply coordinating between each signal processor and keeping a time log to determine the start time of each data record.
The idea behind the composition is that different implementations of the SignalProcessor can be combine together.As sample i see the to-be-implemented DiscardSignal processor which basically discards all signal data from the record (usefull if only a subset of the signals needs to be use) or the logarithmic transformation described here.
the edf.utils namespace contains utility functions that facilitates the interconnection of the different parts of the parser.