Mel-Spectrogram Image Generation Issues

Hi, I’m trying to troubleshoot an error with my mel-spectrogram image generation. The saved .png image looks like the following:

Here is the code I am using:

var sg = new SpectrogramGenerator(sampleRate, FftSize, StepSize, 0, MaxFreq);
sg.Add(audio);

var bitmap = sg.GetBitmapMel(MelBinCount, Intensity, SaveAsDb);
bitmap.Save(file + "MelSpec.png", ImageFormat.Png);

where: FFTSize = 2048 StepSize = 300 MaxFreq = 3000 Intensity = 5 MelBinCount = 200 SaveAsDb = false

Also, I am using the ReadWAV method as it is shown in the readme to read .wav audio inputs.

Any help would be appreciated.

[jwoodtke]

You were totally right @swharden! I think another problem was the buffer array was in bytes rather than floats.

However, now the mel-spectrograms seem to be missing the bass component. Here is a sample image:

Also, here is the new code for audio reads:

        private async Task<(double[] audio, int sampleRate, double length)> ReadWav(string file, double multiplier = 16000)
        {
            await using (var afr = new AudioFileReader(file))
            {
                int sampleRate = afr.WaveFormat.SampleRate;
                int sampleCount = (int) (afr.Length / afr.WaveFormat.BitsPerSample / 8);
                int channelCount = afr.WaveFormat.Channels;
                var audio = new List<double>(sampleCount);
                var buffer = new float[sampleRate * channelCount];
                var length = afr.TotalTime;
                int samplesRead = 0;
                while ((samplesRead = await PopulateBufferArray(afr, buffer)) > 0)
                {
                    await AddAudioRange(audio, buffer.Take(samplesRead).Select(x => x * multiplier));
                }
                return (audio.ToArray(), sampleRate, length.TotalSeconds);
            }
        }

        private async Task<int> PopulateBufferArray(AudioFileReader afr, float[] buffer)
        {
            return afr.Read(buffer, 0, buffer.Length);
        }
        private async Task AddAudioRange(List<double> audio, IEnumerable<double> samplesRead)
        {
            audio.AddRange(samplesRead);
        }

[jwoodtke]

Nevermind, I think the mel bin count I was using was too high. It’s all iterative adjustment form here on out, thanks again for the help!