srecord FrequencyImageFromURL(S url) {

  // all broken?!

  //S url = "https://gaz.ai/dl/audiostreams/gigsauntppvwjyrq.ogg";

  //S url = "https://gaz.ai/dl/audiostreams/zgmyptzpqlvafoyz.ogg";

  //S url = "https://gaz.ai/dl/audiostreams/jlokvemsxqhuaups.ogg";

  *() { url = "https://gaz.ai/dl/audiostreams/bjfxzzpdtuhxewdx.ogg"; }

  BWImage image;

  run {

    temp var opus = new DecodeOpusStream(url);

    opus.minBytesPreloaded = 65536*2;

    temp var samples = opus!;

    opus.machine.init();

    opus.machine.opusDecoder.printResets = true;

    var querySound = SampleIteratorToQuerySound(1, samples);

    new PianoSampler2 sampler;

    //sampler.debug = true;

    sampler.frequencies = intersperseHalfTones(sampler.frequencies);

    sampler.loadSound(querySound, 1);

    sampler.fixedFactor = 5e-4;

    var windowSeconds = .05;

    var windowSamples = windowSeconds*sampler.sampleRate;

    printVars(+windowSeconds, +windowSamples);

    var relativeWindowSpeed = .5;

    int peekSize = iceil(max(windowSamples, sampler.minWindowSizeForBase())*2);

    var totalSeconds = 5;

    var startAtSeconds = 0;

    var endAtSample = (startAtSeconds+totalSeconds)*sampler.sampleRate;

    var seconds = doubleRangeWithLength(startAtSeconds, windowSeconds);

    DoubleRange sampleRange = scaleDoubleRange(seconds, sampler.sampleRate);

    // make initial window

    print(+peekSize);

    sampler.makeWindowAround(sampleRange.start, peekSize);

    printVars(+seconds, +sampleRange, bounds := sampler.bounds());

    new L<MakesBufferedImage> images;

    int safety = 0;

    while ping (sampleRange.end <= endAtSample && safety++ <= 1000) {

      //print(+sampleRange);

      images.add(sampler.imageColumn(sampler.measureWindow(sampleRange)));

      sampleRange = shiftDoubleRange(sampleRange, windowSamples*relativeWindowSpeed);

    }

    image = mergeBWImagesHorizontally(map toBWImage(images), spacing := 0);

    print(nSamples := opus.samplesSeen());

    print(sampler.stats());

  }

  void showImage { 

    dm_showPixelatedImage(image);

  }

}