Install-Package ZstdNet

byte[] sourceData = GetData(); //for example : File.ReadAllBytes(filePath);
byte[] compressedData;
using (var compressor = new Compressor())
{
    compressedData = compressor.Wrap(sourceData);
}  

var compressor = new Compressor(new CompressionOptions(compressionLevel: 5))

using (var decompressor = new Decompressor())
{
    byte[] sourceData = decompressor.Unwrap(compressedData);
}  

public static class ZstdCompression
{
    public static (decimal savedPercent, long savedSizeKB) Compress(string filePath, string savePath, int compressionLevel = 5)
    {
        var sourceData = File.ReadAllBytes(filePath);
        byte[] compressedData;

        using (var compressor = new Compressor(new CompressionOptions(compressionLevel)))
            compressedData = compressor.Wrap(sourceData);

        File.WriteAllBytes(savePath, compressedData);

        var diff = sourceData.LongLength - compressedData.LongLength;
        var savedpercent = (decimal)diff * 100 / sourceData.LongLength;
        var savedSizeKB = diff / 1024;

        return (savedpercent, savedSizeKB);
    }

    public static void Decompress(string filePath, string savePath)
    {
        var compressedData = File.ReadAllBytes(filePath);
        byte[] decompressedData;

        using (var decompressor = new Decompressor())
            decompressedData = decompressor.Unwrap(compressedData);

        File.WriteAllBytes(savePath, decompressedData);
    }
}  

var compressInfo = ZstdCompression.Compress(@"c:\video.mp4", @"c:\compressedFile");
Console.Write($"Saved : {compressInfo.savedPercent}% ({compressInfo.savedSizeKB} KB)");
//Output => Saved : 57% (7530 KB)