Convert a bunch of file to a specified format

AudioConverter.cs

using System.Diagnostics;

Console.WriteLine("What input format do you want?");
string format = Console.ReadLine();

Console.WriteLine("Enter the location of the files");
string path = Console.ReadLine();

void ConvertFolder(string path)
{
    foreach (var f in Directory.GetFiles(path))
    {
        var fi = new FileInfo(f);
        var name = Path.GetFileNameWithoutExtension(fi.Name);
        Process.Start("ffmpeg", $"-i {f} {path}{Path.DirectorySeparatorChar}{name}.{format}");
    }

    foreach (var d in Directory.GetDirectories(path))
    {
        ConvertFolder(d);
    }
}
ConvertFolder(path);

Get-ChildItem -Recurse -Filter *.mp4 | ForEach-Object { ffmpeg -i $_ "$($_.DirectoryName)/$($_.BaseName).mkv" }