Unnecessary transcoding during 1080p video playback? (1813+)

[PinchOfSalt 0]

I have been running into playback issues trying to view blu-ray videos stored on my Synology 1813+ using Emby server running on the same box.  Playback comes in fits and spurts with buffering delays generously interspersed.  After many experiments using regular and blue neon Emby clients on my Roku 4, running the server software on a windows box instead of on the Synology platform, and even streaming directly from the Synology box to my new HDTV (which sees the Emby-on-Synology setup as a DLNA server), I have concluded that the issue is that the Emby/Synology implementation is transcoding when it does not have to.  (The same may be true of the Windows implementation, but being masked by the performance characteristics of my PC's hardware.)  Some key reasons why I believe this are:

 

- Playback is good (smooth, no buffering/loading issues) if I use the blue neon version of the Emby Roku app and force direct stream playback.  

- The playback problem is present if I use the vanilla Emby Roku app or do not force direct stream using the blue neon version.

- The playback problem is present if I stream directly from the Emby server to my HDTV.  (So, the problem is not particular to using the Emby Roku app.)

- At one point I experimented with Handbrake and made a 720P AAC3 audio version of a video.  It played back smoothly using the vanilla Emby Roku app while the original did not.

 

There should be no need to transcode.  My HDTV and the Roku player can deal with 1080P (and UHD and UHD/HDR) video.  The video files are ripped using MKV.  Plus, I keep on coming back to the fact that using direct stream playback works like a charm.

 

Perhaps there is some server configuration item that I have overlooked.  I have poked and prodded at the server dashboard and yes, read the wiki.  Maybe I have misunderstood something, or simply have overlooked some setting.  However it is also possible that the Emby server for Synology package is incorrectly determining that it needs to transcode when that simply isn't necessary.

 

Any suggestions or insights about this would be gratefully appreciated.

 

Thanks in advance!

- 

[Luke 37057]

Hi there @@PinchOfSalt, we're very sorry to hear about this. In order to best help you and explain this, please provide the information requested in how to report a media playback issue. Thanks !

[PinchOfSalt 0]

Emby-synology-transcoding-log-20161205.txt

 

Hi @@Luke, thanks for the quick response.  This is a log that captures what happened last night when I played a 1080p video via my Roku 4.  There were many pauses during which the "Loading, please wait" message was displayed.  Please let me know if you need any additional information or if you would like me to run a particular test.  As mentioned above, both the Roku and my HDTV support 1080p (and UHD and UHD/HDR), so there should be no need to transcode.  The server and the Roku are connected via a gigabit LAN, so there's plenty of very clean bandwidth.  The problem is 100 percent repeatable with any 1080p video, so it is not a matter of a damaged file.

Edited December 6, 2016 by PinchOfSalt

[Luke 37057]

Hi @@PinchOfSalt, it appears you've configured the Roku app with a max bitrate of around 6mbps, and the video you're trying to play is over 20mbps. That is the reason for the transcoding. So in essence, the app is doing what you asked it to do. Try going into app settings, then increase the max streaming bitrate to a higher value, as high as you think your Roku's network connection can handle. Let us know if this improves your playback. Thanks !

[PinchOfSalt 0]

@@Luke, thanks again!  Yes, as you indicate, the Emby Roku app was misconfigured.  Thank goodness the problem was as simple as that.

 

The good news is that fixing the max bitrate setting fixes the problem.  The bad news is that the max bitrate of the current official Emby Roku app is 30mps, which is not sufficient for at least some of my videos (for example, Fellowship of the Ring fails).  The good news is the blue neon variant does go to 50mps, and that seems to be working well for me.  So, a two-part suggestion for the ongoing work on the new Roku Emby app:

 

1. Increase the max supported bitrate to be at least 50mps.

2. Assuming the app can query the Roku unit to determine the model info, set the default for the max bitrate setting to be the maximum that can be supported by that device.  That should not be an issue for anyone running over a wired network or for people who use wifi "ac" or "n" networks.

 

For what it's worth, I would be happy to beta test the new Roku app when it gets to that stage of development.

[Luke 37057]

Ok yes the new app has both automatic bitrate detection as well as a higher bitrate ceiling in configuration.