Possibility to input start time in formats HH:MM:SS, H:MM:SS, MM:SS, …

Helper.cs

@@ -178,6 +178,23 @@ public static bool checkFFmpegFontConfig()
             }
         }
 
+        /// <summary>
+        /// Converts input to HH:MM:SS format.
+        ///        1   -> 00:00:01
+        ///       11   -> 00:00:11
+        ///     1:11   -> 00:01:11
+        ///    11:11   -> 00:11:11
+        ///  1:11:11   -> 01:11:11
+        /// 11:11:11   -> 11:11:11
+        /// </summary>
+        /// <param name="timeInput">input text</param>
+        /// <returns></returns>
+        public static string fillMissingZeroes(string timeInput)
+        {
+            string zeroes = "00:00:00";
+            return zeroes.Substring(0, zeroes.Length - timeInput.Length) + timeInput;
+        }
+
         /// <summary>
         /// Verifies the version of the program.
         /// It will prompt the user if the program is

formMain.cs

@@ -17,7 +17,7 @@ public partial class formMain : Form
         private String runningDirectory = AppDomain.CurrentDomain.BaseDirectory;    // Obtains the root directory
 
         Regex verifyLength = new Regex(@"^\d{1,3}");                                // Regex to verify if txtLength is properly typed in
-        Regex verifyTimeStart = new Regex(@"^[0-6]\d:[0-6]\d:[0-6]\d");             // Regex to verify if txtStartTime is properly typed in
+        Regex verifyTimeStart = new Regex(@"^(([0-6]?\d\D+)?[0-6]?\d\D+)?[0-6]?\d");// Regex to verify if txtStartTime is properly typed in 
         Regex verifyWidth = new Regex(@"^\d{1,4}");                                 // Regex to verify if txtWidth is properly typed in
         Regex verifyMaxSize = new Regex(@"^\d{1,4}");                               // Regex to verify if txtMaxSize is properly typed in
         Regex verifyCrop = new Regex(@"^\d{1,4}:\d{1,4}:\d{1,4}:\d{1,4}");          // Regex to verify if txtCrop is properly typed in
@@ -95,6 +95,13 @@ private void btnConvert_Click(object sender, EventArgs e)
             }
             else
             {
+                if (txtTimeStart.Text.Length < 8)
+                {
+                    // Input is valid against regex, but maybe we have to add missing zeroes
+                    string correctedTimeInput = Helper.fillMissingZeroes(txtTimeStart.Text);
+                    txtTimeStart.Text = correctedTimeInput;
+                }
+
                 // Calculates the seconds from the time-code
                 double seconds = Helper.convertToSeconds(txtTimeStart.Text);