Subtitle hard-burn implementation.

FFMpegCore.Test/ArgumentBuilderTest.cs

@@ -317,6 +317,27 @@ public void Builder_BuildString_DrawtextFilter_Alt()
                 str);
         }
 
+        [TestMethod]
+        public void Builder_BuildString_SubtitleHardBurnFilter()
+        {
+            var str = FFMpegArguments
+                .FromFileInput("input.mp4")
+                .OutputToFile("output.mp4", false, opt => opt
+                    .WithVideoFilters(filterOptions => filterOptions
+                        .HardBurnSubtitle(SubtitleHardBurnOptions
+                            .Create(subtitlePath: "sample.srt")
+                            .SetCharacterEncoding("UTF-8")
+                            .SetOriginalSize(1366,768)
+                            .SetSubtitleIndex(0)
+                            .WithStyle(StyleOptions.Create()
+                                .WithParameter("FontName", "DejaVu Serif")
+                                .WithParameter("PrimaryColour", "&HAA00FF00")))))
+                .Arguments;
+
+            Assert.AreEqual("-i \"input.mp4\" -vf \"subtitles=sample.srt:charenc=UTF-8:original_size=1366x768:si=0:force_style='FontName=DejaVu Serif\\,PrimaryColour=&HAA00FF00'\" \"output.mp4\"",
+                str);
+        }
+
         [TestMethod]
         public void Builder_BuildString_StartNumber()
         {

FFMpegCore/Extend/KeyValuePairExtensions.cs

@@ -0,0 +1,15 @@
+using System.Collections.Generic;
+
+namespace FFMpegCore.Extend
+{
+    internal static class KeyValuePairExtensions
+    {
+        public static string FormatArgumentPair(this KeyValuePair<string, string> pair, bool enclose)
+        {
+            var key = pair.Key;
+            var value = enclose ? pair.Value.EncloseIfContainsSpace() : pair.Value;
+
+            return $"{key}={value}";
+        }
+    }
+}

FFMpegCore/Extend/StringExtensions.cs

@@ -0,0 +1,10 @@
+namespace FFMpegCore.Extend
+{
+    internal static class StringExtensions
+    {
+        public static string EncloseIfContainsSpace(this string input)
+        {
+            return input.Contains(" ") ? $"'{input}'" : input;
+        }
+    }
+}

FFMpegCore/FFMpeg/Arguments/SubtitleHardBurnArgument.cs

@@ -0,0 +1,89 @@
+using FFMpegCore.Extend;
+using System.Collections.Generic;
+using System.Drawing;
+using System.Linq;
+
+namespace FFMpegCore.Arguments
+{
+    public class SubtitleHardBurnArgument : IVideoFilterArgument
+    {
+        private readonly SubtitleHardBurnOptions _subtitleHardBurnOptions;
+
+        public SubtitleHardBurnArgument(SubtitleHardBurnOptions subtitleHardBurnOptions)
+        {
+            _subtitleHardBurnOptions = subtitleHardBurnOptions;
+        }
+
+        public string Key => "subtitles";
+
+        public string Value => _subtitleHardBurnOptions.TextInternal;
+    }
+
+    public class SubtitleHardBurnOptions
+    {
+        private readonly string _subtitle;
+
+        public readonly Dictionary<string, string> Parameters = new Dictionary<string, string>();
+
+        public static SubtitleHardBurnOptions Create(string subtitlePath)
+        {
+            return new SubtitleHardBurnOptions(subtitlePath);
+        }
+
+        private SubtitleHardBurnOptions(string subtitle)
+        {
+            _subtitle = subtitle;
+        }
+
+        public SubtitleHardBurnOptions SetOriginalSize(int width, int height)
+        {
+            return WithParameter("original_size", $"{width}x{height}");
+        }
+
+        public SubtitleHardBurnOptions SetOriginalSize(Size size)
+        {
+            return SetOriginalSize(size.Width, size.Height);
+        }
+
+        public SubtitleHardBurnOptions SetSubtitleIndex(int index)
+        {
+            return WithParameter("si", index.ToString());
+        }
+
+        public SubtitleHardBurnOptions SetCharacterEncoding(string encode)
+        {
+            return WithParameter("charenc", encode);
+        }
+
+        public SubtitleHardBurnOptions WithStyle(StyleOptions styleOptions)
+        {
+            return WithParameter("force_style", styleOptions.TextInternal);
+        }
+
+        public SubtitleHardBurnOptions WithParameter(string key, string value)
+        {
+            Parameters.Add(key, value);
+            return this;
+        }
+
+        internal string TextInternal => string.Join(":", new[] { _subtitle.EncloseIfContainsSpace() }.Concat(Parameters.Select(parameter => parameter.FormatArgumentPair(enclose: true))));
+    }
+
+    public class StyleOptions
+    {
+        public readonly Dictionary<string, string> Parameters = new Dictionary<string, string>();
+
+        public static StyleOptions Create()
+        {
+            return new StyleOptions();
+        }
+
+        public StyleOptions WithParameter(string key, string value)
+        {
+            Parameters.Add(key, value);
+            return this;
+        }
+
+        internal string TextInternal => string.Join(",", Parameters.Select(parameter => parameter.FormatArgumentPair(enclose: false)));
+    }
+}

FFMpegCore/FFMpeg/Arguments/VideoFiltersArgument.cs

@@ -50,6 +50,7 @@ public class VideoFilterOptions
         public VideoFilterOptions Transpose(Transposition transposition) => WithArgument(new TransposeArgument(transposition));
         public VideoFilterOptions Mirror(Mirroring mirroring) => WithArgument(new SetMirroringArgument(mirroring));
         public VideoFilterOptions DrawText(DrawTextOptions drawTextOptions) => WithArgument(new DrawTextArgument(drawTextOptions));
+        public VideoFilterOptions HardBurnSubtitle(SubtitleHardBurnOptions subtitleHardBurnOptions) => WithArgument(new SubtitleHardBurnArgument(subtitleHardBurnOptions));
 
         private VideoFilterOptions WithArgument(IVideoFilterArgument argument)
         {