I’m running Ubuntu 18.04 on a i7-8700 which has a UHD Graphics 630. Some x265 10bit movies play fine (although the buffer is small) and others play for twenty seconds before plex shows the loading icon.
By going from (in this videos case) convert: 1080p high 3.2Mbps maximum to 1080p (12mbps)… the issue goes away. Still a small buffer.
So I’m going to assume plex is using less power on the 1080p 12mbps stream, even though its higher then the sources 3.2Mbps.
According to intel_gpu_top it’s nowhere near max capacity on maximum conversation, but still can’t maintain a buffer. This GPU should be able to convert 4k HEVC 10bit, so why is plex struggling?
We can only utilize the GPU for encoding the h264 video. We can’t use it to decode the hevc, so that is done by cpu. Your cpu should have no issues with a 3.2 Mbps hevc source, so there must be something else going on. Please recreate your issue and provide the log from PMS and the client.
I’ll do this in a bit, but it’s definitely the GPU as intel_gpu_top shows usage, top shows CPU at less then 20% of a single core on the transcoder and my E3-1245 V2 that I upgraded from was not able to play 10bit videos on hardware and I could definitely see the CPU usage on that (with this same video).
Doh. Sorry. I got the issue mixed up with someone else. Thought an NVidia graphics card was involved.
Since HW is being used, the issue could be from something else. @Paradox55, Please replay the video and provide me the log from PMS so we can see how the transcode is going. Also provide me the log from the client so we can see how it is handling the playback.
I would like to see DEBUG, not VERBOSE, logs (Settings - Server - General) of the playback session, captured as:
Have the server as quiescent as possible (nobody else streaming)
Begin playback and let stream until it buffers.
Stop Playback
Wait 30 seconds for PMS to terminate all activity
Settings - Server - Help - Download Logs to retrieve the logs
Attach the ZIP file it presents you
Also attach the XML for the item played (Hover over it, expose the ellipsis, click it, Get Info, View XML).
Edit: I request DEBUG-only logs (not VERBOSE) because VERBOSE only retains 2-3 minutes. DEBUG will retain more than 30 minutes when one person is streaming.
Although turning verbose off is a good idea, the logs actually do contain useful info. The transcoder is indeed using quick sync to do the work. It appears to be running properly.
The only thing I see is that the playback appears to be coming from outside your network. Is your internet able to handle an upload speed of 15 Mbps? Is the player location able to download at 15 Mbps?
Yes, I can play 1080p 18Mbps streams from this location and my connection maxes out at 75Mbps during buffer. This shouldn’t be a problem for a 3.2Mbps converted HEVC video.
When HEVC is converted to H264, we scale up the bitrate (x4) otherwise the quality would be horrible. I didn’t see anything in your PMS log to indicate why there is a buffer. Can you reproduce and provide a log from the client?
I generally don’t let plex transcode for me. I can stream 1080p 18Mbps bitrate mkv/x264 files just fine and can max my connection @ 70Mbps.
That being said, the server is far from my house. I’m seeing between 7Mbps-13Mbps transfer on transcoding which leads me to believe the way plex handles direct streaming is different and might be multithreaded to maximize my connection.
Changing this from the top setting to 20Mbps generally resolves the issue (although it still only streams between 7Mbps-13Mbps) with a small buffer. Setting it to 12Mbps gives me a large buffer.
Did you playback the same file as before? Your PMS log has a hevc video with ac3 audio. This one is hevc with flac audio and a subtitle track.
If you are going to play a different file, you need to provide a matching PMS log. What you provided doesn’t help now as you are running different scenarios. Please stick to using the same file. Please repeat the playback again and provide both the PMS and Web logs.
Edit - To review what I see in the log you did provide. I first see you playing a file and resuming from about 2 minutes into the file. It plays for about 30 seconds without issues, then you fast forwarded, that played fine for a little while then you hit stop. I did not see any buffering in this one.
Then you play a second video, but this one has subtitles, so your PMS has to burn them in. With this video, I see playback for about 34 seconds then it starts to buffer. Could be the subtitle affecting this, but I need to see the PMS logs to see what it’s doing. Some subtitles transcode really slow so it could be the problem.
Yes, it was a different file. Here is the old file I was playing. Playback started in half the movie (saved position). No skips forward, a couple of buffering moments before stopping.
The movie does have subtitles, but they are not enabled. I guess plex would have to burn them anyway though.
Ok, I see the buffering. Unfortunately, there isn’t information on why. The only thing I notice is that you are using a custom URL. Have you tried using the IP directly or using the hosted version of Web? Just wondering if it might be an issue with the redirect you have for your custom URL.
Same issue with the direct IP. Is there a difference in how plex streams transcoded content compared to direct stream? Does direct stream have better networking throughput/performance?
Transcoded content and direct streamed content are done the same. Bandwidth shouldn’t matter. Do you notice the same using other clients besides Web? If you have an Android device that also has this issue, a log from that would be helpful. Web doesn’t log too much info, but the Android app does and could reveal more info.
