Double the speed of LSDJ samples that are over 2.843 seconds, but less than double that for valid sample lengths with the LSD-Patcher for LSDJ.

LSDJprep.py

import wave
import os
import glob
import contextlib

Change_RATE = 2
EXPORT_DIR = './LSDJprep/'
VALID_RESPONSES = ('yes', 'y')

# the maximum length file LSDJ can have in a kit
# based off of Audacity's export of a WAV Microsoft signed 16-bit PCM .wav file
# tested with LSD-Patcher v.19
MAX_LENGTH = 2.84300453515

if not os.path.exists(os.path.dirname(EXPORT_DIR)):
    directoryResponse = raw_input('LSDJPrep export folder does not exist, create it? yes/no: ')

    if directoryResponse.lower() in VALID_RESPONSES:
        try:
            os.makedirs(os.path.dirname(EXPORT_DIR))
        except OSError as exc: # Guard against race condition
            if exc.errno != errno.EEXIST:
                raise
    else:
        raise ValueError('User did not allow creation of export folder, quit.')



for filepath in glob.glob('./*.wav'):
    filepathSplit = os.path.splitext(os.path.basename(filepath))[0]

    with contextlib.closing(wave.open(filepath,'rb')) as f:
        frames = f.getnframes()
        rate = f.getframerate()
        CHANNELS = f.getnchannels()
        swidth = f.getsampwidth()
        duration = frames / float(rate)
        signal = f.readframes(-1)

        if duration > MAX_LENGTH and duration <= MAX_LENGTH*2:

            if os.path.exists(filepath):
                overwriteResponse = raw_input('\n' + filepathSplit + '.wav already exists in export folder (' + EXPORT_DIR + '), overwrite? yes/(no): ')

                if overwriteResponse.lower() not in VALID_RESPONSES:
                    print('Not overwriting ' + filepathSplit + '.wav, continuing...')
                    continue

            print(filepathSplit + ' : ' + str(duration) +' : Creating new WAV at 2x speed')
            wf = wave.open(EXPORT_DIR + filepathSplit + '.wav', 'wb')
            wf.setnchannels(CHANNELS)
            wf.setsampwidth(swidth)
            wf.setframerate(rate * Change_RATE)
            wf.writeframes(signal)
            wf.close()

        elif duration > MAX_LENGTH*2:
            print(filepathSplit + ' : ' + str(duration) + ' : This is too long!')