Add contrast, gamma and saturation

src/main/java/com/annimon/ffmpegbot/commands/ffmpeg/FFmpegCommandBuilder.java

@@ -18,12 +18,14 @@ public class FFmpegCommandBuilder implements Visitor<MediaSession> {
     private final List<String> videoCommands;
     private final List<String> audioFilters;
     private final List<String> videoFilters;
+    private final List<String> eq;
 
     public FFmpegCommandBuilder() {
         audioCommands = new ArrayList<>();
         videoCommands = new ArrayList<>();
         audioFilters = new ArrayList<>();
         videoFilters = new ArrayList<>();
+        eq = new ArrayList<>();
     }
 
     @Override
@@ -80,6 +82,27 @@ public class FFmpegCommandBuilder implements Visitor<MediaSession> {
         audioCommands.add("0:m:language:" + p.getValue());
     }
 
+    @Override
+    public void visit(Contrast p, MediaSession input) {
+        String value = p.getValue();
+        if (value.equals("1")) return;
+        eq.add("contrast=" + value);
+    }
+
+    @Override
+    public void visit(Gamma p, MediaSession input) {
+        String value = p.getValue();
+        if (value.equals("1")) return;
+        eq.add("gamma=" + value);
+    }
+
+    @Override
+    public void visit(Saturation p, MediaSession input) {
+        String value = p.getValue();
+        if (value.equals("1")) return;
+        eq.add("saturation=" + value);
+    }
+
     @Override
     public void visit(SpeedFactor p, MediaSession input) {
         if (p.getValue().equals("1")) return;
@@ -148,6 +171,9 @@ public class FFmpegCommandBuilder implements Visitor<MediaSession> {
         }
         if (FileTypes.canContainVideo(session.getFileType())) {
             commands.addAll(videoCommands);
+            if (!eq.isEmpty()) {
+                videoFilters.add("eq=" + String.join(":", eq));
+            }
             if (!videoFilters.isEmpty()) {
                 commands.add("-vf");
                 commands.add(String.join(",", videoFilters));

src/main/java/com/annimon/ffmpegbot/commands/ffmpeg/Visitor.java

@@ -9,6 +9,9 @@ public interface Visitor<I> {
     void visit(AudioPitch p, I input);
     void visit(AudioVolume p, I input);
     void visit(AudioStreamByLanguage p, I input);
+    void visit(Contrast p, I input);
+    void visit(Gamma p, I input);
+    void visit(Saturation p, I input);
     void visit(SpeedFactor p, I input);
     void visit(VideoBitrate p, I input);
     void visit(VideoScale p, I input);

src/main/java/com/annimon/ffmpegbot/parameters/Contrast.java

@@ -0,0 +1,26 @@
+package com.annimon.ffmpegbot.parameters;
+
+import com.annimon.ffmpegbot.commands.ffmpeg.Visitor;
+import java.util.List;
+
+public class Contrast extends StringParameter {
+    private static final List<String> VALUES = List.of(
+            "0.4", "0.6", "0.8",
+            "1", "1.2", "1.4", "1.6",
+            "1.8", "2"
+    );
+
+    public Contrast() {
+        super("contrast", "Contrast", VALUES, "1");
+    }
+
+    @Override
+    public int defaultColumnsCount() {
+        return 3;
+    }
+
+    @Override
+    public <I> void accept(Visitor<I> visitor, I input) {
+        visitor.visit(this, input);
+    }
+}

src/main/java/com/annimon/ffmpegbot/parameters/Gamma.java

@@ -0,0 +1,26 @@
+package com.annimon.ffmpegbot.parameters;
+
+import com.annimon.ffmpegbot.commands.ffmpeg.Visitor;
+import java.util.List;
+
+public class Gamma extends StringParameter {
+    private static final List<String> VALUES = List.of(
+            "0.2", "0.4", "0.6", "0.8",
+            "1", "1.2", "1.4", "1.6",
+            "1.8", "2", "2.2", "2.4"
+    );
+
+    public Gamma() {
+        super("gamma", "Gamma", VALUES, "1");
+    }
+
+    @Override
+    public int defaultColumnsCount() {
+        return 4;
+    }
+
+    @Override
+    public <I> void accept(Visitor<I> visitor, I input) {
+        visitor.visit(this, input);
+    }
+}

src/main/java/com/annimon/ffmpegbot/parameters/Saturation.java

@@ -0,0 +1,26 @@
+package com.annimon.ffmpegbot.parameters;
+
+import com.annimon.ffmpegbot.commands.ffmpeg.Visitor;
+import java.util.List;
+
+public class Saturation extends StringParameter {
+    private static final List<String> VALUES = List.of(
+            "0", "0.25", "0.5", "0.75",
+            "1", "1.25", "1.5", "1.75",
+            "2", "2.25", "2.5", "3"
+    );
+
+    public Saturation() {
+        super("saturation", "Saturation", VALUES, "1");
+    }
+
+    @Override
+    public int defaultColumnsCount() {
+        return 4;
+    }
+
+    @Override
+    public <I> void accept(Visitor<I> visitor, I input) {
+        visitor.visit(this, input);
+    }
+}

src/main/java/com/annimon/ffmpegbot/parameters/resolvers/VideoResolver.java

@@ -16,6 +16,9 @@ public class VideoResolver implements ParametersResolver {
 
         if (hasVideo) {
             parameters.addAll(List.of(
+                    new Contrast(),
+                    new Gamma(),
+                    new Saturation(),
                     new VideoBitrate(),
                     new VideoScale(),
                     new VideoFrameRate()