Getting Max Amplitude For An Audio File Per Second

I know there are some similar questions here, but most of them are concerning generating waveform images, which is not what I want. My goal is to generate a waveform visualization

Solution 1:

If you allow gstreamer, here is a little script that could do the trick. It accept any audio file that gstreamer can handle.

• Construct a gstreamer pipeline, use audioconvert to reduce the channels to 1, and use level module to get peaks
• Run the pipeline until EOS is hit
• Normalize the peaks from the min/max found.

Snippet:

import os, sys, pygst
pygst.require('0.10')
import gst, gobject
gobject.threads_init()

defget_peaks(filename):
    global do_run

    pipeline_txt = (
        'filesrc location="%s" ! decodebin ! audioconvert ! ''audio/x-raw-int,channels=1,rate=44100,endianness=1234,''width=32,depth=32,signed=(bool)True !''level name=level interval=1000000000 !''fakesink' % filename)
    pipeline = gst.parse_launch(pipeline_txt)

    level = pipeline.get_by_name('level')
    bus = pipeline.get_bus()
    bus.add_signal_watch()

    peaks = []
    do_run = Truedefshow_peak(bus, message):
        global do_run
        if message.type == gst.MESSAGE_EOS:
            pipeline.set_state(gst.STATE_NULL)
            do_run = Falsereturn# filter only on level messagesif message.src isnot level or \
           not message.structure.has_key('peak'):
            return
        peaks.append(message.structure['peak'][0])

    # connect the callback
    bus.connect('message', show_peak)

    # run the pipeline until we got eos
    pipeline.set_state(gst.STATE_PLAYING)
    ctx = gobject.gobject.main_context_default()
    while ctx and do_run:
        ctx.iteration()

    return peaks

defnormalize(peaks):
    _min = min(peaks)
    _max = max(peaks)
    d = _max - _minreturn [(x - _min) / d for x in peaks]

if __name__ == '__main__':
    filename = os.path.realpath(sys.argv[1])
    peaks = get_peaks(filename)

    print'Sample is %d seconds' % len(peaks)
    print'Minimum is', min(peaks)
    print'Maximum is', max(peaks)

    peaks = normalize(peaks)
    print peaks

And one output example:

$ python gstreamerpeak.py 01\ Tron\ Legacy\ Track\ 1.mp3 
Sample is182 seconds
Minimum is-349.999999922
Maximum is-2.10678956719
[0.0, 0.0, 0.9274581631597019, 0.9528318436488018, 0.9492396611762614,
0.9523404330322813, 0.9471685835966183, 0.9537281219301242, 0.9473486577135167,
0.9479292126411365, 0.9538221105563514, 0.9483845795252251, 0.9536790832823281,
0.9477264933378022, 0.9480077366961968, ...