R/pipe.downsample.R

In tz-lom/Resonance-Rproj: Interface for Resonance project

pipe.downsample = function(input, dec){
  processor(
    input,
    prepare = function(env){
      SI.is.channels(input) || stop('Must be channels in input')
      
      env$count <- 0
      
      SI.channels(channels = SI(input)$channels, samplingRate = SI(input)$samplingRate/dec)
    },
    online = function(db){
      n <- nrow(db)
      if(n>0){
        take <- which((1:n - count) %% dec == 0)
        
        count <<- count+n
        
        ret <- db[take,, drop=FALSE]
        attr(ret, 'TS') <- attr(db,'TS')[take]
        ret
      } else {
        db
      }
    }
  )
}