Skip empty subtitle elements when transcoding subtitle files

source/net/filebot/subtitle/SubtitleElement.java

@@ -1,7 +1,6 @@
 
 package net.filebot.subtitle;
 
-
 public class SubtitleElement {
 
 	private final long start;
@@ -9,28 +8,27 @@ public class SubtitleElement {
 
 	private final String text;
 
-
 	public SubtitleElement(long start, long end, String text) {
 		this.start = start;
 		this.end = end;
 		this.text = text;
 	}
 
-
 	public long getStart() {
 		return start;
 	}
 
-
 	public long getEnd() {
 		return end;
 	}
 
-
 	public String getText() {
 		return text;
 	}
 
+	public boolean isEmpty() {
+		return start >= end || text.isEmpty();
+	}
 
 	@Override
 	public String toString() {

source/net/filebot/subtitle/SubtitleUtilities.java

@@ -353,9 +353,16 @@ public final class SubtitleUtilities {
 			// convert to target format and target encoding
 			try (SubRipWriter out = new SubRipWriter(writer)) {
 				for (SubtitleElement it : decodeSubtitles(file)) {
+					if (it.isEmpty()) {
+						debug.warning(message("Subtitle element is empty", it));
+						continue;
+					}
+
+					// adjust offset if necessary
 					if (outputTimingOffset != 0) {
 						it = new SubtitleElement(Math.max(0, it.getStart() + outputTimingOffset), Math.max(0, it.getEnd() + outputTimingOffset), it.getText());
 					}
+
 					out.write(it);
 				}
 			}