include audio language metadata in all streaming modes (#295)

* include audio language metadata in all streaming modes

* cleanup

ErsatzTV.Core/FFmpeg/FFmpegProcessBuilder.cs

@@ -230,14 +230,29 @@ namespace ErsatzTV.Core.FFmpeg
             return this;
         }
 
-        public FFmpegProcessBuilder WithMetadata(Channel channel)
+        public FFmpegProcessBuilder WithMetadata(Channel channel, Option<MediaStream> maybeAudioStream)
         {
+            if (channel.StreamingMode == StreamingMode.TransportStream)
+            {
+                _arguments.AddRange(new[] { "-map_metadata", "-1" });
+            }
+
+            foreach (MediaStream audioStream in maybeAudioStream)
+            {
+                if (!string.IsNullOrWhiteSpace(audioStream.Language))
+                {
+                    _arguments.AddRange(new[] { "-metadata:s:a:0", $"language={audioStream.Language}" });
+                }
+            }
+
             var arguments = new List<string>
             {
                 "-metadata", "service_provider=\"ErsatzTV\"",
                 "-metadata", $"service_name=\"{channel.Name}\""
             };
+
             _arguments.AddRange(arguments);
+
             return this;
         }
 
@@ -323,7 +338,6 @@ namespace ErsatzTV.Core.FFmpeg
                 new[]
                 {
                     "-c:a", playbackSettings.AudioCodec,
-                    "-map_metadata", "-1",
                     "-movflags", "+faststart",
                     "-muxdelay", "0",
                     "-muxpreload", "0"

ErsatzTV.Core/FFmpeg/FFmpegProcessService.cs

@@ -105,7 +105,7 @@ namespace ErsatzTV.Core.FFmpeg
                 });
 
             return builder.WithPlaybackArgs(playbackSettings)
-                .WithMetadata(channel)
+                .WithMetadata(channel, maybeAudioStream)
                 .WithFormat("mpegts")
                 .WithDuration(start + version.Duration - now)
                 .WithPipe()
@@ -130,7 +130,7 @@ namespace ErsatzTV.Core.FFmpeg
                 .WithErrorText(desiredResolution, errorMessage)
                 .WithPixfmt("yuv420p")
                 .WithPlaybackArgs(playbackSettings)
-                .WithMetadata(channel)
+                .WithMetadata(channel, None)
                 .WithFormat("mpegts");
 
             duration.IfSome(d => builder = builder.WithDuration(d));
@@ -149,7 +149,7 @@ namespace ErsatzTV.Core.FFmpeg
                 .WithRealtimeOutput(playbackSettings.RealtimeOutput)
                 .WithInfiniteLoop()
                 .WithConcat($"http://localhost:{Settings.ListenPort}/ffmpeg/concat/{channel.Number}")
-                .WithMetadata(channel)
+                .WithMetadata(channel, None)
                 .WithFormat("mpegts")
                 .WithPipe()
                 .Build();