Video buffering after few seconds (audio keeps going)

Plex Media Server NAS & Devices
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1

Server Version#: 1.40.2.8395 DS218+

This issue has been driving me crazy. Each year, me and the wife rewatch some vacation pictures from an old vacation (yes we’re sad don’t judge me). These are sorted in a photo library with each day being a folder with pictures + a few random videos from iphones, android phones, canon camera etc which sit in the same pictures folder and play as part of the picture slide show.

Each year, it seems to be a different issue popping up. This year, the videos are suddenly buffering after a few seconds. We’re talking anything from 4K drone shots to negligible 1080P footage. Any video longer than 10-15 seconds will all of a sudden start buffering after about 9 seconds even though the audio is still playing. It’s not network buffering because if i go into the folder and play them directly, they play just fine from the same player with the same network connection. But if I start in slide show mode and play a few pictures before the video, then that’s when the video will buffer. I’ve messed with Plex settings, from playing original quality, all the way down to 3Mbps 1080P. I’ve tried re-encoding with handbrake the MP4 & MOV to MKV. All to no avail. Some of these files are only 3 Mbps after converting to MKV. So can’t possibly be network issue on a 5GHz network 3 meters from the router with no walls in between when 4K videos can stream no problem (if i select them directly).

Video files play fine from a PC using explorer or with any of the below mentioned players if i play any video file directly from plex without doing a picture slideshow first.

Player Version#: 10.14.0.541 (4f9fb644) Fire TV first gen, hardwired.
buffered icon after about 10 seconds but audio keeps playing
Player Version#: 10.14.0.541 (4f9fb644) Chromecast, wifi 5GHz.
buffered icon after about 10 seconds but audio keeps playing
Player Version#: 5.81.1 Samsung 55" TV built in smart hub
No buffering but the portrait video is terribly stretched horizontally.
Player Version#: Version 1.91.0.129-1cd63c1d (Plex for Windows)
Here it works on a Windows 11 PC. But i don’t have a windows 11 PC by my living room TV.

Driving me crazy. Any ideas? Seems to affect primarily android players.

2

Need server DEBUG logs which capture the start of a playback which fails so we can see what it’s trying to do and then gauge.

Given you have a Syno server… Synology CPUs are terrible with transcoding in almost every way these days and anything with subtitles in it will just kill it.

3

Attached. I’m always a bit hesitant to upload logs as there seems to be a lot of files & information in them. But like i said, i’m desperate:)

I started the slide show right around 8:23pm Berlin time (UTC+2). The sample video causing the issues is called “2018_04_23_0756_Entrance 001” and starts around 8:25pm in case it helps. Starts buffering after 9 seconds into the video but audio keeps playing. Taken from iphone & reencoded as MKV in an attempt to solve the issue.

MODERATOR EDIT Logs removed

4

Looking at your logs,

  1. The J3355 CPU is a dual (2) core processor without HDR capability.
    It won’t be as ‘crisp’ as the majority quick are quad (4) core .

  2. In the logs you provided, I see PMS trying to ingest a bunch of 2018-04-03 photos.

  3. Then, I see a fair amount of activity which will jam up a dual core (serviving + database) pretty quickly;
    – The scanner is running (Dexter, Family Guy, etc etc)
    – Playback (transcoding) to the Google TV (HW transcoding)
    – Playback request for a C48x TV (the photos being rendered and sent to tv?)
    – Playback request for a 55" TV

I cannot see any of the video properties for “Entrance 001.mkv”

Can you show me the Media Info?

what I can see doesn’t look the best… Thare are elements of the video recording which don’t make belong in the individual frames.

You’ll also notice the ‘no picture’ errors. These are telling me that data was lost.

May 11, 2024 20:44:15.061 [139838461557560] DEBUG - [MI] Opening input file: "/volume1/Plex/Pictures/2018-04-23 Tokyo Disneyland/2018_04_23_0756_Entrance 001.mkv"
May 11, 2024 20:44:15.061 [139838461557560] DEBUG - [FFMPEG] - Opening '/volume1/Plex/Pictures/2018-04-23 Tokyo Disneyland/2018_04_23_0756_Entrance 001.mkv' for reading
May 11, 2024 20:44:15.061 [139838461557560] DEBUG - [FFMPEG] - Setting default whitelist 'file,crypto,data'
May 11, 2024 20:44:15.061 [139838461557560] DEBUG - [FFMPEG] - Format matroska,webm probed with size=2048 and score=100
May 11, 2024 20:44:15.061 [139838461557560] DEBUG - [FFMPEG] - st:0 removing common factor 1000000 from timebase
May 11, 2024 20:44:15.061 [139838461557560] DEBUG - [FFMPEG] - st:1 removing common factor 1000000 from timebase
May 11, 2024 20:44:15.061 [139838461557560] DEBUG - [FFMPEG] - Before avformat_find_stream_info() pos: 752 bytes read:32768 seeks:0 nb_streams:2
May 11, 2024 20:44:15.062 [139838461557560] DEBUG - [FFMPEG] - nal_unit_type: 7(SPS), nal_ref_idc: 3
May 11, 2024 20:44:15.062 [139838461557560] DEBUG - [FFMPEG] - nal_unit_type: 8(PPS), nal_ref_idc: 3
May 11, 2024 20:44:15.063 [139838461557560] DEBUG - [FFMPEG] - nal_unit_type: 7(SPS), nal_ref_idc: 3
May 11, 2024 20:44:15.063 [139838461557560] DEBUG - [FFMPEG] - nal_unit_type: 8(PPS), nal_ref_idc: 3
May 11, 2024 20:44:15.064 [139838461557560] DEBUG - [FFMPEG] - nal_unit_type: 6(SEI), nal_ref_idc: 0
May 11, 2024 20:44:15.064 [139838461557560] DEBUG - [FFMPEG] - nal_unit_type: 5(IDR), nal_ref_idc: 3
May 11, 2024 20:44:15.064 [139838461557560] DEBUG - [FFMPEG] - Format yuv420p chosen by get_format().
May 11, 2024 20:44:15.070 [139838461557560] DEBUG - [FFMPEG] - no picture 
May 11, 2024 20:44:15.100 [139838461557560] DEBUG - [FFMPEG] - nal_unit_type: 1(Coded slice of a non-IDR picture), nal_ref_idc: 2
May 11, 2024 20:44:15.103 [139838461557560] DEBUG - [FFMPEG] - no picture 
May 11, 2024 20:44:15.116 [139838461557560] DEBUG - [FFMPEG] - nal_unit_type: 1(Coded slice of a non-IDR picture), nal_ref_idc: 2
May 11, 2024 20:44:15.132 [139838461557560] DEBUG - [FFMPEG] - nal_unit_type: 1(Coded slice of a non-IDR picture), nal_ref_idc: 0
May 11, 2024 20:44:15.147 [139838461557560] DEBUG - [FFMPEG] - nal_unit_type: 1(Coded slice of a non-IDR picture), nal_ref_idc: 0
May 11, 2024 20:44:15.161 [139838461557560] DEBUG - [FFMPEG] - nal_unit_type: 1(Coded slice of a non-IDR picture), nal_ref_idc: 2
May 11, 2024 20:44:15.176 [139838461557560] DEBUG - [FFMPEG] - nal_unit_type: 1(Coded slice of a non-IDR picture), nal_ref_idc: 2
May 11, 2024 20:44:15.189 [139838461557560] DEBUG - [FFMPEG] - nal_unit_type: 1(Coded slice of a non-IDR picture), nal_ref_idc: 0
May 11, 2024 20:44:15.200 [139838461557560] DEBUG - [FFMPEG] - nal_unit_type: 1(Coded slice of a non-IDR picture), nal_ref_idc: 0
May 11, 2024 20:44:15.212 [139838461557560] DEBUG - [FFMPEG] - All info found
May 11, 2024 20:44:15.215 [139838461557560] DEBUG - [FFMPEG] - After avformat_find_stream_info() pos: 216433 bytes read:246100 seeks:0 frames:21
May 11, 2024 20:44:15.215 [139838461557560] DEBUG - [MI]  * 39dfb0886c971ebf011a68cdc2052e34a09059fa [mkv h264/aac] Duration: 25820ms, 1080x1920 (0.562500) 30.000fps, bitrate=2634kbps, audio channels=1, optimizedForStreaming=0 ("/volume1/Plex/Pictures/2018-04-23 Tokyo Disneyland/2018_04_23_0756_Entrance 001.mkv")

HandBrake or MKVToolNix might resolve this video

My comments here also look at the other things I see (as general info)

5

Thank you for taking the time to have a look. Let me try and digest one at a time.

  1. The J3355 CPU is a dual (2) core processor without HDR capability.
    It won’t be as ‘crisp’ as the majority quick are quad (4) core .

I don’t really care about the HDR feature. Unless you are saying it’s possible that I might have an HDR feature turned on that could be causing unexpected lag or load on the CPU. The NAS is a DS218+ that is years old. But it’s my old faithful. And i know from experience it can handle 4K streams. Has HW transcoding, and in general, serves plex up beautifully. And obviously, buying a new NAS & making the transfer is painful & expensive. And with 2 toddlers, i’m just lacking the time to be honest. So would prefer to stick with what i got for now.

  1. In the logs you provided, I see PMS trying to ingest a bunch of 2018-04-03 photos.

When I was recording the log, i was only playing the slide show of the 2018-04-23 folder. I also had Plex Dash open on my phone and there were no other concurrent users doing anything (it’s just me and the wife consuming from Plex). So if there was something going on with a 2018-04-03 folder, it would either be a bug or some kind of background job/scan. But the folder name is valid. I do have a folder by that name also with picture (i have hundreds of these folders in the same picture library)

Is this a setting i could/should turn off? Here are some related settings that i can think of
Settings → Library
On: Scan my library automatically
On: Run a partial scan when changes are detected
Off: Scan my library periodically
Settings → Scheduled Tasks
Tasks start at 2am and stop at 5am so i assume none of the tasks here could have been running since log was outside this time window.

  1. Then, I see a fair amount of activity which will jam up a dual core (serviving + database) pretty quickly;
    – The scanner is running (Dexter, Family Guy, etc etc)
    – Playback (transcoding) to the Google TV (HW transcoding)
    – Playback request for a C48x TV (the photos being rendered and sent to tv?)
    – Playback request for a 55" TV

Valid TV seasons but nobody was playing them. Scheduled tasks running outside their scheduled time? The google TV would have been my chromecast that i was playing on i assume. Not sure on the C48x. Don’t know what that is. Here is the play history for that time window. 55" Living R is the Alexa Fire TV. The Chromecast is the Google Chromecast. I was alternating using both for debugging purposes. But never at the same time.

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I cannot see any of the video properties for “Entrance 001.mkv”
Can you show me the Media Info?

Here

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Again, I have the feeling that it’s somehow related to how Plex serves up or ques multiple pictures & videos when they are part of a slide show. I say that because the same video plays correctly if i manually select it and play it from the same app on the same devices. Of course it could be also the stuff you mentioned instead. Or some combination. I’m unfortunately not smart enough to figure it out myself. Are there any other logs/debug modes i can turn on for extra info?

6

Your settings look good.

As FYI, which you can MOVE the drives directly from 218 without fuss.

Synology DiskStation DS918+ 4-Bay NAS w/3x 8TB Irn Wolf Drives | eBay?

Not endorsing this person but it’s an idea.

  1. DSM will keep everything you have and update the firmware
  2. you’ll have more slots to grow into (always what gets expensive in the long run)
  3. The 918+ is the J3455+, More slots --AND-- Quad Core --AND-- HDR capable.

I’m keenly aware of toddlers and expenses. It’s why I went to look for this type alternative for you. It’s a viable path forward for whatever you want to do with it.
It’s a lot quicker than the J3355

Another thing to consider (given the media / photos) is cleaning up the Plex database.

If you want to give that a shot, I’ll point you to the tool I wrote and the instructions I wrote for Synology (you can run it in Task Scheduler)

7

I prefer to go the cleanup route first. The reason i say that is because

  1. I can do dual 4K direct play streams at the same time, limited only by network/wifi.
  2. The videos only have an issue in slideshow mode. Suggesting that it’s something not performance related going on. Because otherwise, why would the same video play when i select it in plex directly? Somehow there is some bug in the buffering going on or something isn’t optimized with how it’s being fetched in slide show mode.

I noticed also that after a video is done playing, it takes 3-4 seconds for the next image to play. Which seems silly as it should be pre-fetched.

If you don’t mind, send me the tool. Are there any official methods i can use that might help also? Examples being the “Analyze” or “Empty Trash” or “Scan library files” options?

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Alternatively, is it worth trying to figure out if there are process or actions running in the log that should not be?

8

Bump. Would like to give this one more shot. I’m convinced that it’s something recently changed with the android based plex player app. Because I have 2 different devices (Google Chromecast, Alexa Fire TV that have the same issue with videos buffering. I say that because i recently moved my mini PC to the same location (same cables, same TV, same network cable) and it plays fine there on windows plex player. Again, it has to be something related to how plex player loads & buffers multiple pictures & videos in a slide show setting. Any ideas? Driving me crazy

Works fine on these
W10 Version 1.94.1.155-f1e7f457
W11 Version 1.91.0.129-1cd63c1d

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