source: python/aubio/task/cut.py @ a300cef

from task import task
from aubio.aubioclass import *

class taskcut(task):
        def __init__(self,input,slicetimes,params=None,output=None):
                """ open the input file and initialize arguments 
                parameters should be set *before* calling this method.
                """
                from os.path import basename,splitext
                task.__init__(self,input,output=None,params=params)
                self.soundoutbase, self.soundoutext = splitext(basename(self.input))
                self.newname   = "%s%s%09.5f%s%s" % (self.soundoutbase,".",
                                        self.frameread*self.params.step,".",self.soundoutext)
                self.fileo      = sndfile(self.newname,model=self.filei)
                self.myvec      = fvec(self.params.hopsize,self.channels)
                self.mycopy     = fvec(self.params.hopsize,self.channels)
                self.slicetimes = slicetimes 

        def __call__(self):
                task.__call__(self)
                # write to current file
                if len(self.slicetimes) and self.frameread >= self.slicetimes[0][0]:
                        self.slicetimes.pop(0)
                        # write up to 1st zero crossing
                        zerocross = 0
                        while ( abs( self.myvec.get(zerocross,0) ) > self.params.zerothres ):
                                zerocross += 1
                        writesize = self.fileo.write(zerocross,self.myvec)
                        fromcross = 0
                        while (zerocross < self.readsize):
                                for i in range(self.channels):
                                        self.mycopy.set(self.myvec.get(zerocross,i),fromcross,i)
                                        fromcross += 1
                                        zerocross += 1
                        del self.fileo
                        self.fileo = sndfile("%s%s%09.5f%s%s" % (self.soundoutbase,".",
                                self.frameread*self.params.step,".",self.soundoutext),model=self.filei)
                        writesize = self.fileo.write(fromcross,self.mycopy)
                else:
                        writesize = self.fileo.write(self.readsize,self.myvec)