I have some EDF files in REC format. How can I open them in EDF browser or Matlab?
These files can be opened in Matlab with their standard format. For this to happen, you need Read Medical Data 3D class or edfRead which can be found on the Matlab Central website.
Along with the downloads, you also have instructions how to add these classes to Matlab so that you can open your files.
One possibility is this free viewer: