extract key frame info

MediaBrowser.MediaEncoding/Encoder/MediaEncoder.cs

@@ -238,8 +238,9 @@ namespace MediaBrowser.MediaEncoding.Encoder
 
                     if (extractKeyFrameInterval && mediaInfo.RunTimeTicks.HasValue)
                     {
-                        foreach (var stream in mediaInfo.MediaStreams.Where(i => i.Type == MediaStreamType.Video)
+                        foreach (var stream in mediaInfo.MediaStreams)
-                            .ToList())
+                        {
+                            if (stream.Type == MediaStreamType.Video && string.Equals(stream.Codec, "h264", StringComparison.OrdinalIgnoreCase))
                             {
                                 try
                                 {
@@ -256,6 +257,7 @@ namespace MediaBrowser.MediaEncoding.Encoder
                                 }
                             }
                         }
+                    }
 
                     return mediaInfo;
                 }