update video audio encoding

MediaBrowser.Api/Playback/BaseStreamingService.cs

@@ -870,33 +870,47 @@ namespace MediaBrowser.Api.Playback
                 inputChannels = null;
             }
 
-            int? resultChannels = null;
+            int? transcoderChannelLimit = null;
             var codec = outputAudioCodec ?? string.Empty;
 
             if (codec.IndexOf("wma", StringComparison.OrdinalIgnoreCase) != -1)
             {
                 // wmav2 currently only supports two channel output
-                resultChannels = Math.Min(2, inputChannels ?? 2);
+                transcoderChannelLimit = 2;
             }
 
-            else if (request.MaxAudioChannels.HasValue)
+            else if (codec.IndexOf("mp3", StringComparison.OrdinalIgnoreCase) != -1)
+            {
+                // libmp3lame currently only supports two channel output
+                transcoderChannelLimit = 2;
+            }
+            else
             {
-                var channelLimit = codec.IndexOf("mp3", StringComparison.OrdinalIgnoreCase) != -1
-                   ? 2
-                   : 6;
+                // If we don't have any media info then limit it to 6 to prevent encoding errors due to asking for too many channels
+                transcoderChannelLimit = 6;
+            }
 
-                if (inputChannels.HasValue)
-                {
-                    channelLimit = Math.Min(channelLimit, inputChannels.Value);
-                }
+            var isTranscodingAudio = !string.Equals(codec, "copy", StringComparison.OrdinalIgnoreCase);
+
+            int? resultChannels = null;
+            if (isTranscodingAudio)
+            {
+                resultChannels = request.TranscodingMaxAudioChannels;
+            }
+            resultChannels = resultChannels ?? request.MaxAudioChannels ?? request.AudioChannels;
 
-                // If we don't have any media info then limit it to 5 to prevent encoding errors due to asking for too many channels
-                resultChannels = Math.Min(request.MaxAudioChannels.Value, channelLimit);
+            if (inputChannels.HasValue)
+            {
+                resultChannels = resultChannels.HasValue
+                    ? Math.Min(resultChannels.Value, inputChannels.Value)
+                    : inputChannels.Value;
             }
 
-            if (request.TranscodingMaxAudioChannels.HasValue && !string.Equals(codec, "copy", StringComparison.OrdinalIgnoreCase))
+            if (isTranscodingAudio && transcoderChannelLimit.HasValue)
             {
-                resultChannels = Math.Min(request.TranscodingMaxAudioChannels.Value, resultChannels ?? inputChannels ?? request.TranscodingMaxAudioChannels.Value);
+                resultChannels = resultChannels.HasValue
+                    ? Math.Min(resultChannels.Value, transcoderChannelLimit.Value)
+                    : transcoderChannelLimit.Value;
             }
 
             return resultChannels ?? request.AudioChannels;

MediaBrowser.Controller/MediaEncoding/EncodingJobOptions.cs

@@ -35,6 +35,7 @@ namespace MediaBrowser.Controller.MediaEncoding
 
         public string VideoCodec { get; set; }
 
+        public int? TranscodingMaxAudioChannels { get; set; }
         public int? VideoBitRate { get; set; }
         public int? AudioStreamIndex { get; set; }
         public int? VideoStreamIndex { get; set; }
@@ -86,6 +87,7 @@ namespace MediaBrowser.Controller.MediaEncoding
             MaxVideoBitDepth = info.MaxVideoBitDepth;
             SubtitleMethod = info.SubtitleDeliveryMethod;
             Context = info.Context;
+            TranscodingMaxAudioChannels = info.TranscodingMaxAudioChannels;
 
             if (info.SubtitleDeliveryMethod != SubtitleDeliveryMethod.External)
             {

MediaBrowser.MediaEncoding/Encoder/EncodingJobFactory.cs

@@ -370,30 +370,50 @@ namespace MediaBrowser.MediaEncoding.Encoder
                 inputChannels = null;
             }
 
+            int? transcoderChannelLimit = null;
             var codec = outputAudioCodec ?? string.Empty;
 
             if (codec.IndexOf("wma", StringComparison.OrdinalIgnoreCase) != -1)
             {
                 // wmav2 currently only supports two channel output
-                return Math.Min(2, inputChannels ?? 2);
+                transcoderChannelLimit = 2;
             }
 
-            if (request.MaxAudioChannels.HasValue)
+            else if (codec.IndexOf("mp3", StringComparison.OrdinalIgnoreCase) != -1)
             {
-                var channelLimit = codec.IndexOf("mp3", StringComparison.OrdinalIgnoreCase) != -1
-                   ? 2
-                   : 6;
+                // libmp3lame currently only supports two channel output
+                transcoderChannelLimit = 2;
+            }
+            else
+            {
+                // If we don't have any media info then limit it to 6 to prevent encoding errors due to asking for too many channels
+                transcoderChannelLimit = 6;
+            }
 
-                if (inputChannels.HasValue)
-                {
-                    channelLimit = Math.Min(channelLimit, inputChannels.Value);
-                }
+            var isTranscodingAudio = !string.Equals(codec, "copy", StringComparison.OrdinalIgnoreCase);
 
-                // If we don't have any media info then limit it to 5 to prevent encoding errors due to asking for too many channels
-                return Math.Min(request.MaxAudioChannels.Value, channelLimit);
+            int? resultChannels = null;
+            if (isTranscodingAudio)
+            {
+                resultChannels = request.TranscodingMaxAudioChannels;
+            }
+            resultChannels = resultChannels ?? request.MaxAudioChannels ?? request.AudioChannels;
+
+            if (inputChannels.HasValue)
+            {
+                resultChannels = resultChannels.HasValue
+                    ? Math.Min(resultChannels.Value, inputChannels.Value)
+                    : inputChannels.Value;
+            }
+
+            if (isTranscodingAudio && transcoderChannelLimit.HasValue)
+            {
+                resultChannels = resultChannels.HasValue
+                    ? Math.Min(resultChannels.Value, transcoderChannelLimit.Value)
+                    : transcoderChannelLimit.Value;
             }
 
-            return request.AudioChannels;
+            return resultChannels ?? request.AudioChannels;
         }
 
         private int? GetVideoBitrateParamValue(EncodingJobOptions request, MediaStream videoStream, string outputVideoCodec)