Add "GifPalettArgument" for outputting GIFs

FFMpegCore/FFMpeg/Arguments/GifPalettArgument.cs

@@ -0,0 +1,21 @@
+using System.Drawing;
+
+namespace FFMpegCore.Arguments
+{
+    public class GifPalettArgument : IArgument
+    {
+        private readonly int _fps;
+
+        private readonly Size? _size;
+
+        public GifPalettArgument(int fps, Size? size)
+        {
+            _fps = fps;
+            _size = size;
+        }
+
+        private string ScaleText => _size.HasValue ? $"scale=w={_size.Value.Width}:h={_size.Value.Height}," : string.Empty;
+
+        public string Text => $"-filter_complex \"[0:v] fps={_fps},{ScaleText}split [a][b];[a] palettegen=max_colors=32 [p];[b][p] paletteuse=dither=bayer\"";
+    }
+}