Offline processing of multiple audio files in batch  
============================================================================================================================================


**05-batch-processing.py**

This program demonstrates how to use pyo to do offline batch processing
given a folder of sounds.

.. code-block:: python

    import os
    from pyo import *
    
    # Initialize the Server in offline mode.
    s = Server(audio="offline")
    
    # Path to your sound folder (SNDS_PATH is a folder containing a few sounds installed with pyo,
    # you can change this path to try with your own sounds).
    folder_path = SNDS_PATH
    
    # Path to the processed sounds folder (user's home directory/pyo_batch_fx/).
    output_folder = os.path.join(os.path.expanduser("~"), "pyo_batch_fx")
    
    # create the folder if it does not exist.
    if not os.path.isdir(output_folder):
        os.mkdir(output_folder)
    
    # Get the list of audio files to process.
    sounds = [f for f in os.listdir(folder_path) if sndinfo(os.path.join(folder_path, f)) is not None]
    
    # Enter the batch processing loop.
    for sound in sounds:
        # Retrieve info about the sound from its header.
        path = os.path.join(folder_path, sound)
        info = sndinfo(path)
        dur, sr, chnls = info[1], info[2], info[3]
        fformat = ["WAVE", "AIFF", "AU", "RAW", "SD2", "FLAC", "CAF", "OGG"].index(info[4])
        samptype = [
            "16 bit int",
            "24 bit int",
            "32 bit int",
            "32 bit float",
            "64 bits float",
            "U-Law encoded",
            "A-Law encoded",
        ].index(info[5])
    
        # Set server parameters according to the current sound info.
        s.setSamplingRate(sr)
        s.setNchnls(chnls)
        s.boot()
        s.recordOptions(
            dur=dur + 1,  # give some room for the reverb trail!
            filename=os.path.join(output_folder, sound),
            fileformat=fformat,
            sampletype=samptype,
        )
    
        # Simple processing applied to the sound.
        source = SfPlayer(path)
        bandpass = ButBP(source, 1000, 5)
        disto = Disto(bandpass, drive=0.9, slope=0.8)
        output = WGVerb(source + disto, feedback=0.8, cutoff=5000, bal=0.25, mul=0.5).out()
    
        # Start the rendering.
        s.start()
    
        # Cleanup for the next pass.
        s.shutdown()