Deinterlace .wav files: $ python2 wav-deinterlacer.py <filename.wav> <samplesize (in bytes)>

wav-deinterlacer.py

import os
import sys
import binascii
from itertools import chain, izip, repeat, islice
# this program is compatible with python 2.7.8

# interspace function
def intersperse(delimiter, seq):
    return islice(chain.from_iterable(izip(repeat(delimiter), seq)), 1, None)

# parse command line arguments
if len(sys.argv) != 3:
    print("Usage: python deinterlacer.py <\"filename\"> <samplesize_bytes>")
    exit()
else:
    # arguments are okay, check if file exists:
    found = False
    files = [f for f in os.listdir('.') if os.path.isfile(f)] # lists all files
    for f in files:
        if f == sys.argv[1]: # match
            # file found
            found = True

            # check sample size:
            '''
            1 byte = 4 bits
            2 bytes = 8 bits
            4 bytes = 16 bits
            8 bytes = 32 bits
            '''
            if sys.argv[2] == "1" or sys.argv[2] == "2" or sys.argv[2] == "4" or sys.argv[2] == "8":
                # valid sample size:
                print("File found")
                
                # open input file, read it into memory:
                fin = sys.argv[1]
                with open(fin, 'rb') as f:
                    content = f.read()
                f.close()

                # separate hex header from hex data
                xcontent = binascii.hexlify(content)
                xdatadelim = "64617461"
                delim = xcontent.find(xdatadelim)
                xdata = xcontent[delim+len(xdatadelim)+8:]
                header = xcontent[0:144+len(xdatadelim)+8]

                # print first 30 hex for both header and data
                print("header: "+header[0:30])
                print("data:   "+xdata[0:30])
                
                chunksize = int(sys.argv[2])

                # group data according to argument passed
                hexes = []
                for index, item in enumerate(xdata):
                    if index % chunksize == 0:
                        concat = xdata[index:index+chunksize]
                        hexes.append(concat)
                
                '''
                print(hexes[0])
                print(hexes[1])
                print(hexes[2])
                print(hexes[3])
                print('')
                '''
                
                # clear clear one of the channels
                leftdata = hexes[0::2]
                '''
                in mono, commenting out the previous inline slows
                down the song by repeating the frequencies lol
                adding: # hexes = hexes[::3] will speed up song
                might need to be adjusted for stereo
                '''

                # shift and clear the channel
                rightdata = hexes[1::] # snip first element
                rightdata = rightdata[0::2] # get every other element

                '''
                print("raw left speaker data")
                print(leftdata[0])
                print(leftdata[1])
                print(leftdata[2])
                print(leftdata[3])

                print("raw right speaker data")
                print(rightdata[0])
                print(rightdata[1])
                print(rightdata[2])
                print(rightdata[3])
                ''' 

                # now that we have raw audio data, we intersperse it
                # with 0s in order to silence the other speaker                
                ''' slow (unusable solution when interspersing python lists)
                for index, item in enumerate(hexes):
                    if index % 2 == 0:
                        hexes.insert(index-1, '00000000')
                '''

                # we intersperse with the correct amount of 0s:
                silence = "00000000" # max is 8 bytes of hex data
                silence = silence[0:chunksize]

                # badass solution to intersperse python lists:
                leftspeaker = list(intersperse(silence, leftdata))
                rightspeaker = list(intersperse(silence, rightdata)) # intersperse with silence
                rightspeaker = [silence] + rightspeaker # append silence to head which was previously removed

                print("left speaker deinterlaced data:")
                print(leftspeaker[0])
                print(leftspeaker[1])
                print(leftspeaker[2])
                print(leftspeaker[3])

                print("right speaker deinterlaced data:")
                print(rightspeaker[0])
                print(rightspeaker[1])
                print(rightspeaker[2])
                print(rightspeaker[3])
                
                foutr = "right.wav"
                foutl = "left.wav" 

                # write right speaker file:
                with open(foutr, 'wb') as fout:
                    # write header:
                    fout.write(binascii.unhexlify(header))

                    # write data for right speaker on right speaker file:
                    for index, item in enumerate(rightspeaker):
                        fout.write(binascii.unhexlify(item))
                    
                fout.close()
                print("right speaker file written")

                # write left speaker file:
                with open(foutl, 'wb') as fout:
                    # write header:
                    fout.write(binascii.unhexlify(header))

                    # write data for left speaker on left speaker file:
                    for index, item in enumerate(leftspeaker):
                        fout.write(binascii.unhexlify(item))

                fout.close()
                print("left speaker file written")

            else:
                print("Sample size must be in bytes.\nSupported sample "+
                "sizes: 1, 2, 4, or 8 bytes")
                exit()

    if(found == False):
        print("File requested not available in directory.")
        exit()