Don't start waiting for a segment which doesn't exist if transcoding is not running

MediaBrowser.Api/Playback/Hls/DynamicHlsService.cs

@@ -482,7 +482,9 @@ namespace MediaBrowser.Api.Playback.Hls
             }
 
             var nextSegmentPath = GetSegmentPath(state, playlistPath, segmentIndex + 1);
-            while (!cancellationToken.IsCancellationRequested && transcodingJob != null && !transcodingJob.HasExited)
+            if (transcodingJob != null)
+            {
+                while (!cancellationToken.IsCancellationRequested && !transcodingJob.HasExited)
                 {
                     // To be considered ready, the segment file has to exist AND
                     // either the transcoding job should be done or next segment should also exist
@@ -514,6 +516,12 @@ namespace MediaBrowser.Api.Playback.Hls
                 {
                     Logger.LogDebug("serving {0} as it's on disk and transcoding stopped", segmentPath);
                 }
+            }
+            else
+            {
+                Logger.LogWarning("cannot serve {0} as it doesn't exist and no transcode is running", segmentPath);
+            }
+
             return await GetSegmentResult(state, segmentPath, segmentIndex, transcodingJob).ConfigureAwait(false);
         }