This is actually the same change I saw as well. I reported it as well to Moussa. My understanding, after talking to him, was that there was actually two underlying bugs causing problems. The last update should have helped with a majority of cases, but will not fix 100% of problems. (I actually do not know the exact specifics of the problems just that they were closely mingled together). Moussa is still looking at resolving the secondary issue.
This fix also led to another issue I was seeing and reported back to Moussa. And it deal with a remuxed video. I had a problem video that was mkv/hevc/truehd and a secondary ac3 track. I remuxed the file so that it was mkv/hevc/ac3 with truehd as the secondary track. This actually resulted in no change of playback for me which was odd. I tracked it down to the TrueHD still had the āforcedā tag and the server was still checking the TrueHD parameters even though I had a different track selected. Moussa was still looking into this trying to get a reproduction for testing.
To reiterate - I confirm described behavior, and this is not limited to truehd. The same is with DTS tracks. Allow me to speculate that either Plex server is looking for source audio track needed for AC3 extract, even for cases when AC3 extract is not needed, or Plex server supplies several audio tracks and Windows platform generally does not like that (sometimes throwing error, sometimes gracefully ignoring).
Second speculation can be easily detected by looking at the ffmpeg commandline (assuming that it is accurate in debug log).
After latest updates issue is still active and I noticed another problem:
When I try to reproduce issue with tracing, Plex Media Server may crash. I assume this depends on memory available on the client. This crash is not happening if you restart console. Scenario is following:
Launch game
Play for some time
Quit game
Launch Plex
Press and hold Xbox button
Select report problem and repro with a tace for media apps issues
Start watching 4K HEVC HDR movie - frame rate will be significantly downgraded. It is expected.
Then where previously stream was switching to transcoding, crash happens on the server. You need to start server again.
What server are you running dx? I missed during my first read through that you said the server was crashing at the end. While I can reproduce the HDR and bad transcoding decision I havenāt seen a server crash yet, but that might be because of the version I am on.
I can confirm that after latest update experience of 4K HDR is completely destroyed. 1080p HEVC is also broken. State is such that HEVC support degraded significantly.
Plex version: 2.15.2.70
OS version: 17733.2001 rs5 1810.180807-1920
Container MKV contains multiple audio tracks and 1 sub track.
Here is what happens with following selection 4K HEVC HDR + AC3 audio track - no subs:
In DirectPlay Mode instead of buffering message after 40sec now buffering occurs about 8 times/sec. Previously it was similar to DirectStream mode, which was logical, now it is different, not sure why. After 40sec connection to Plex Server is lost. Plex Server is still running.
In DirectStream mode buffering message appears after 40sec.
Note: 40sec is dependent on specific movie. On others problem may appear after 20sec.
Here is what happens on with 4K HEVC HDR + DTS audio track - no subs:
(DirectStream mode available only) buffering message appears after 40sec.
Scenario: Container MP4 contains 1 audio AC3 track. Work as intended. Playback without interruptions.
Other scenarios:
1080p HEVC SDR + DTS - broken. Buffering/stuttering issues. Previously worked fine.
1080p HEVC SDR + FLAC 5.1 - broken. Buffering/stuttering issues. Previously worked fine.
1080p SDR - works as intended.
I can confirm that after latest update 4K HDR is broken. There is no way to enjoy 4K HDR, even in MP4 container due to lost frames - it was possible before.
Plex version: 2.15.2.70
OS version: 17733.2001 rs5 1810.180808-2036
Scenario: container MKV contains multiple audio tracks and 1 sub track.
Here is what happens with following selection 4K HEVC HDR + AC3 audio track - no subs:
In DirectStream mode buffering message appears after 40sec.
Note: 40sec is dependent on specific movie. On others problem may appear after 20sec.
Here is what happens on with 4K HEVC HDR + DTS audio track - no subs:
Buffering message appears after 40sec.
Scenario: container MP4 contains 1 audio AC3 track. Loosing frames after random durations. No video buffering occurs.
Other scenarios:
1080p HEVC SDR + DTS - works as intended. No buffering, no audio issues, no subtitles issues.
1080p HEVC SDR + FLAC 5.1 - works as intended. No buffering, no audio issues, no subtitles issues.
1080p SDR - works as intended.
I have rechecked 4K HDR scenarios multiple times with allow DirectPlay and allow Display Mode Switching options enabled/disabled.
Are you in the skip ahead or alpha ring? We have had 1 other report of that update effectively breaking all 4K playback. I am not a part of either of those so I canāt test them at all. In either case I forwarded this onto Moussa because a future update completely breaking the app is not a good thing.
I am in alpha - 1, this is very similar to Skip Ahead. But I also can test even earlier releases, so you can be aware of whatās coming.
Not sure about other reports. I can see lost frames on other apps as well - some youtube videos, but I am not able to confirm that 100% as this depends on source material quality. If you see other reports make sure that:
Console was restarted after update.
Update status in Latest Update status contains no Update Pending or any errors
Main tests should be performed only after fresh restart of console. Plex and itās media framework tends to leave some memory occupied and you may get unexpected/inconsistent results
Sleep mode may have its implications as well, so restart before tests is needed.
Test same video source material as before to get consistent comparison.
For MP4 DirectPlay must be enabled.
For example before fresh restart I was getting lost audio for 1-2 seconds. Restarted console - rerun tests and audio is fine but lost frames persist. It is not like a lot of lost frame, but 1-2 frames, every 5-10 sec. Maybe it happens more often, but 1-2 frames is what my eyes are able to notice to make it distracting. I have reported lost frames on Pause and Fast forward - visually it is similar, but number of lost frames is much less than when pausing of ff.
Updated to: OS version: 17733.2001 rs5 1810.180810-1920
now lost frames issue minimized. still present (MP4 + 4K HDR HEVC + AC3 - nosubs) but in a form like 1 lost frame per 10-15 seconds - this is what is visible to my old eyes.
The v2.17.1 update should be now rolling out to users, which includes possible performance improvements for streaming 4K media. Please give it a try and let me know if it helps!
So far so good, I need to watch some videos all the way through but after watching a few mins of several the buffering seems to have stopped and HDR is intact. Iāll need to test more on Sunday but a promising start
@Moussa
The buffering now happens randomly instead of at certain fixed point. The behaviour also changed. Now when it shows buffering Plex wonāt actually drop back to transcoding but instead just stuck at buffering. If you exit and resume at previous time it will keep playing normally until the buffering shows up again.
Progress is very positive. I will present results tomorrow after thorough testing. There are still some things left related to the platform, but those problems apply to all apps, not only plex.
I can confirm that after latest update 4K HDR issue is partially present, though lost frames issue was introduced. I can also confirm that now NO TRANSCODING IS PERFORMED for video stream.
Plex version: 2.17.1.70
OS version: 17755.2000 rs5 1810.180905-1920
Scenario 1: MKV container contains multiple audio tracks and 1 sub track.
Single buffering message appears after 40sec. Movie continues to play after this single buffering message disappears without transcoding. Movie further plays in HDR with no buffering messages - about 15+mins tested. Lost frames are regular and distracting.
Selection: 4K HEVC HDR + AC3 audio track - no subs. Forced DirectStream via DirectPlay disabled:
DirectStream used for video and DirectStream used for audio. No buffering messages. Lost frames are regular and distracting.
DirectPlay mode is used. Minimal amount of lost of frame, though still visible and regular. Moving picture resolution is greatly improved - theory: because of less lost frames.
DirectPlay mode is used. Minimal amount of lost of frame, though still visible and regular.
Other scenarios:
1080p HEVC SDR + DTS - works as intended. No buffering, no audio issues, no subtitles issues.
1080p SDR + AC3 - works as intended.
1080p HEVC SDR + FLAC 5.1 selected from multiple audio tracks. FLAC 5.1 converted to AAC - bug.
So far MP4 + AC3 in DirectPlay mode is still the only way to watch 4K HDR. Lost frames is different issue but it still affects the scenario. When I looked at the MP4+AC3, first I though that something is wrong - picture became clearer, more details were visible. Checked multiple times everything. We do not see real time fps and this makes analysis harder.
And also unnecessary conversion in HEVC SDR + FLAC 5.1 on multiple audio tracks video file needs to be fixed. This and also this single buffering message problem needs to be fixed - then we can move onto lost frames issue.
