Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_recodeevent”.

  FT_RECODEEVENT will recode the event structure, given the trial
  definition that was analyzed
  In FieldTrip, you always start with defining a "trl" field containing
  the samples in the raw datafile that you want to analyze. That "trl"
  is based on the events in the dataset. After artifact rejection, it may
  be the case that trials have been removed completely, or that trials
  have been cut into pieces. This complicates finding a match between the
  original events and the pieces of data that are analyzed. This functino
  restores that match.
  Use as
    [ev] = ft_recodeevent(cfg, data)
  where cfg is a structure with configuration settings and data contains the
  (nested) configuration that describes the original trial definition and
  event structure.
  Alternatively, you can also specify the event structure and trial definition
  yourself with
    [ev] = ft_recodeevent(cfg, event, trl)
  the configuration can contain
    cfg.eventtype   = empty, 'string' or cell-array with multiple strings
    cfg.eventvalue  = empty or a list of event values (can be numeric or string)
    cfg.searchrange = 'anywhere'      search anywhere for the event, (default)
                      'insidetrial'   only search inside
                      'outsidetrial'  only search outside
                      'beforetrial'   only search before the trial
                      'aftertrial'    only search after  the trial
                      'beforezero'    only search before time t=0 of each trial
                      'afterzero'     only search after  time t=0 of each trial
    cfg.nearestto   = 'trialzero'     compare with time t=0 for each trial (default)
                      'trialbegin'    compare with the begin of each trial
                      'trialend'      compare with the end of each trial
    cfg.match       = 'exact' or 'nearest'
    cfg.output      = 'event'             the event itself
                      'eventvalue'        the value of the event
                      'eventnumber'       the number of the event
                      'samplenumber'      the sample at which the event is located
                      'samplefromoffset'  number of samples from t=0 (c.f. response time)
                      'samplefrombegin'   number of samples from the begin of the trial
                      'samplefromend'     number of samples from the end   of the trial