Redukce ticha na začátku wav souboru

gistfile1.py

# -*- coding: utf-8 -*-
import wave, array

wi = wave.open('a.wav', 'rb')
wo = wave.open('a-reduced.wav', 'wb')

wo.setparams(wi.getparams())

def process_start(frms):
    delta, threshold = 50, 250
    
    for i in range(0, len(frms)):
        if abs(frms[i])>=threshold:
            mark = i-delta if i>delta else 0
            return frms[mark:]    
    return frms

def make(frms):
    arr = array.array("h")
    arr.fromstring(frms)
    return arr

def unmake(arr):
    return arr.tostring()
    

buffer_length = 1000001
firstbatch = True
while True:
    frms = wi.readframes(buffer_length)
    print "Read %d frames" % (len(frms))
    if firstbatch:
        frms2 = unmake(process_start(make(frms)))
        print "Processed %d -> %d" % (len(frms), len(frms2))
        frms = frms2
        firstbatch = False
        
    if len(frms)<buffer_length:
        wo.writeframes(frms)
        break
    else:
        wo.writeframesraw(frms)
    

wi.close()
wo.close()