Client is: Plex for Android 8.11.0.22166-beta
Shield Pro 2019
PMS: 1.21.1.3842 on Ubuntu 18.04.4 LTS
Server Specs: i7 8700 hexacore, 128 GB RAM (hardware 4k transcoding incl tone mapping runs flawless!!!)
Bug report
When playing 4k Dolby Vision (e.g., dvhe.07.06) content (mkv) Plex suddenly starts buffering, after a while. There’s no particular point or time stamp in the file where it starts.
The movie resumes but buffering starts after some seconds, again.
Details
I’m certainly aware of current issues regarding DV support on Plex (beta). For example, correct triggering DV is a well described issue what is not new to me.
However, I noticed the described issue above only since some weeks or at most one month.
Yes, sometimes I have to re-start the movie until DV is triggered and then in most cases plex starts buffering after a while. Then, the movie resumes but buffering follows etc…
Before I noticed this issue, DV mkvs were played nicely
what I did up to now?
- Hardware definitely supports DV (SmartTV: Panasonic GZ-2000, Server: i7 8700 hexacore, 128 GB RAM). Premium HDMI 2.1 cables. Hardware (Shield Pro) is connected via ethernet.
- Network debugging: no issues were found regarding the gigabit switch or used ethernet cables. Disconnected all other devices.
- Plex log (see attached)
- playing different files varying in size and bitrate
- research on the internet
additional information
Here is the mediainfo of an example that started buffering.
General
Unique ID : xxx
Complete name : 4k-DV-movie.mkv
Format : Matroska
Format version : Version 4
File size : 112 GiB
Duration : 3 h 55 min
Overall bit rate mode : Variable
Overall bit rate : 68.3 Mb/s
Encoded date : UTC 2020-11-30 20:21:18
Writing application : mkvmerge v51.0.0 ('I Wish') 64-bit
Writing library : libebml v1.4.0 + libmatroska v1.6.2
Video
ID : 1
Format : HEVC
Format/Info : High Efficiency Video Coding
Format profile : Main 10@L5.1@High
HDR format : Dolby Vision, Version 1.0, dvhe.07.06, BL+EL+RPU, Blu-ray compatible / SMPTE ST 2086, HDR10 compatible
Codec ID : V_MPEGH/ISO/HEVC
Duration : 3 h 55 min
Bit rate : 62.2 Mb/s
Width : 3 840 pixels Height : 2 160 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 (24000/1001) FPS
Color space : YUV
Chroma subsampling : 4:2:0 (Type 2)
Bit depth : 10 bits
Bits/(Pixel*Frame) : 0.313
Stream size : 102 GiB (91%)
Default : Yes
Forced : No
Color range : Limited
Color primaries : BT.2020
Transfer characteristics : PQ
Matrix coefficients : BT.2020 non-constant
Mastering display color primaries : Display P3 Mastering display luminance : min: 0.0050 cd/m2, max: 4000 cd/m2
Maximum Content Light Level : 827 cd/m2
Maximum Frame-Average Light Level : 329 cd/m2
(Please forget about the file size… I know it is large… however, even smaller files starting buffering after a while)
You can find the log attached. For the present log, I had to re-start the file about 3 times until DV was triggered (this is not my problem!)… unfortunately, in this particular case there was no buffering. Maybe the devs can, however, see what may be the issue. If not, please let me know so that I can create a new log showing the buffering. log.txt (1.2 MB)
Does someone else also noticed this issue? Can someone please try to replicate the issue?
Interestingly, when I force Plex to transcode, the movie resumes flawless (even if it remains 1080p with HDR10 or tone mapping).
So it seems that my problem is caused by DV in combination with current Plex beta versions.
In the meantime I will successively downgrade until I find a Plex beta version with no problems
Thank you
