FFMpegCore/FFMpegCore/FFMpeg/Arguments/DynamicNormalizerArgument.cs

using System.Globalization;

namespace FFMpegCore.Arguments;

public class DynamicNormalizerArgument : IAudioFilterArgument
{
    private readonly Dictionary<string, string> _arguments = new();

    /// <summary>
    ///     Dynamic Audio Normalizer. <see href="https://ffmpeg.org/ffmpeg-filters.html#dynaudnorm" />
    /// </summary>
    /// <param name="frameLength">Set the frame length in milliseconds. Must be between 10 to 8000. The default value is 500</param>
    /// <param name="filterWindow">Set the Gaussian filter window size. In range from 3 to 301, must be odd number. The default value is 31</param>
    /// <param name="targetPeak">Set the target peak value. The default value is 0.95</param>
    /// <param name="gainFactor">Set the maximum gain factor. In range from 1.0 to 100.0. Default is 10.0.</param>
    /// <param name="targetRms">Set the target RMS. In range from 0.0 to 1.0. Default to 0.0 (disabled)</param>
    /// <param name="channelCoupling">Enable channels coupling. By default is enabled.</param>
    /// <param name="enableDcBiasCorrection">Enable DC bias correction. By default is disabled.</param>
    /// <param name="enableAlternativeBoundary">Enable alternative boundary mode. By default is disabled.</param>
    /// <param name="compressorFactor">Set the compress factor. In range from 0.0 to 30.0. Default is 0.0 (disabled).</param>
    public DynamicNormalizerArgument(int frameLength = 500, int filterWindow = 31, double targetPeak = 0.95, double gainFactor = 10.0, double targetRms = 0.0,
        bool channelCoupling = true, bool enableDcBiasCorrection = false, bool enableAlternativeBoundary = false, double compressorFactor = 0.0)
    {
        if (frameLength < 10 || frameLength > 8000)
        {
            throw new ArgumentOutOfRangeException(nameof(frameLength), "Frame length must be between 10 to 8000");
        }

        if (filterWindow < 3 || filterWindow > 31)
        {
            throw new ArgumentOutOfRangeException(nameof(filterWindow), "Gaussian filter window size must be between 3 to 31");
        }

        if (filterWindow % 2 == 0)
        {
            throw new ArgumentOutOfRangeException(nameof(filterWindow), "Gaussian filter window size must be an odd number");
        }

        if (targetPeak <= 0 || targetPeak > 1)
        {
            throw new ArgumentOutOfRangeException(nameof(targetPeak));
        }

        if (gainFactor < 1 || gainFactor > 100)
        {
            throw new ArgumentOutOfRangeException(nameof(gainFactor), "Gain factor must be between 1.0 to 100.0");
        }

        if (targetRms < 0 || targetRms > 1)
        {
            throw new ArgumentOutOfRangeException(nameof(targetRms), "Target RMS must be between 0.0 and 1.0");
        }

        if (compressorFactor < 0 || compressorFactor > 30)
        {
            throw new ArgumentOutOfRangeException(nameof(compressorFactor), "Compressor factor must be between 0.0 and 30.0");
        }

        _arguments.Add("f", frameLength.ToString());
        _arguments.Add("g", filterWindow.ToString());
        _arguments.Add("p", targetPeak.ToString("0.00", CultureInfo.InvariantCulture));
        _arguments.Add("m", gainFactor.ToString("0.0", CultureInfo.InvariantCulture));
        _arguments.Add("r", targetRms.ToString("0.0", CultureInfo.InvariantCulture));
        _arguments.Add("n", (channelCoupling ? 1 : 0).ToString());
        _arguments.Add("c", (enableDcBiasCorrection ? 1 : 0).ToString());
        _arguments.Add("b", (enableAlternativeBoundary ? 1 : 0).ToString());
        _arguments.Add("s", compressorFactor.ToString("0.0", CultureInfo.InvariantCulture));
    }

    public string Key { get; } = "dynaudnorm";

    public string Value => string.Join(":", _arguments.Select(pair => $"{pair.Key}={pair.Value}"));
}