From ec1b8a6b0757281825c4c9e869b698e8ada33206 Mon Sep 17 00:00:00 2001
From: Victor Horobchuk <Gorobchuk333@gmail.com>
Date: Wed, 17 Mar 2021 00:09:56 +0200
Subject: [PATCH] Add mirror and default ForceFormat for OutputPipeArgument

---
 FFMpegCore/FFMpeg/Arguments/SetMirrorVideo.cs | 11 +++++++++++
 FFMpegCore/FFMpeg/FFMpegArguments.cs          |  6 ++++++
 2 files changed, 17 insertions(+)
 create mode 100644 FFMpegCore/FFMpeg/Arguments/SetMirrorVideo.cs

diff --git a/FFMpegCore/FFMpeg/Arguments/SetMirrorVideo.cs b/FFMpegCore/FFMpeg/Arguments/SetMirrorVideo.cs
new file mode 100644
index 0000000..4c18cef
--- /dev/null
+++ b/FFMpegCore/FFMpeg/Arguments/SetMirrorVideo.cs
@@ -0,0 +1,11 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace FFMpegCore.Arguments
+{
+    public class SetMirrorVideo : IArgument
+    {
+        public string Text { get; set; } = "-vf \"hflip\"";
+    }
+}
diff --git a/FFMpegCore/FFMpeg/FFMpegArguments.cs b/FFMpegCore/FFMpeg/FFMpegArguments.cs
index 847e68c..5aa913d 100644
--- a/FFMpegCore/FFMpeg/FFMpegArguments.cs
+++ b/FFMpegCore/FFMpeg/FFMpegArguments.cs
@@ -57,6 +57,12 @@ private FFMpegArgumentProcessor ToProcessor(IOutputArgument argument, Action<FFM
         {
             var args = new FFMpegArgumentOptions();
             addArguments?.Invoke(args);
+
+            if (argument is OutputPipeArgument && !Arguments.Any(x => x is ForceFormatArgument))
+            {
+                args.ForceFormat("matroska");
+            }
+
             Arguments.AddRange(args.Arguments);
             Arguments.Add(argument);
             return new FFMpegArgumentProcessor(this);