Add configurable FFmpeg log level

- Add FfmpegLogLevel property to EncodingOptions (default: 'error')
- Use configuration value in GetInputModifier instead of hardcoded value
- Allows changing log verbosity without rebuild via encoding.xml
- Possible values: quiet, panic, fatal, error, warning, info, verbose, debug, trace

MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs

@@ -7105,7 +7105,14 @@ namespace MediaBrowser.Controller.MediaEncoding
 
         public string GetInputModifier(EncodingJobInfo state, EncodingOptions encodingOptions, string segmentContainer)
         {
-            var inputModifier = "-loglevel error";
+            var inputModifier = string.Empty;
+
+            // Apply FFmpeg log level from configuration
+            if (!string.IsNullOrEmpty(encodingOptions.FfmpegLogLevel))
+            {
+                inputModifier = $"-loglevel {encodingOptions.FfmpegLogLevel}";
+            }
+
             var analyzeDurationArgument = string.Empty;
 
             // Apply -analyzeduration as per the environment variable,