DVR Buffering

Plex Media Server NAS & Devices
, , ,
1

Server Version#: 1.16.6.1592
Player Version#: 1.16.6.1592 (Web), 6.3.14.5387 (Roku)

Within the last week or so playing back DVR recordings has started buffering around every 30 seconds. Looking at the dashboard I can that the video is being transcoded:
1080i (MPEG2VIDEO) (hw) -> 1080P (H264)—Transcode (hw)

PMS is running on my Synology DS918+. According to DSM the CPU and RAM are both hovering around 30% the entire time this is happening. Bandwidth is also no where near saturation.

I get the same behavior when playing from the Roku app or from my desktop using the web client.

Other media, such as movies, that play without transcoding don’t suffer from this problem. But hardware transcoding is definitely enabled, so I don’t understand why this is happening. And why it only just started in the last week. It was working fine for months before this.

The DVR recordings are being captured with the SiliconDust HDHR3-US if that matters. No changes have been made to this device though so I can’t see how that could be causing the problem.

Any help would be greatly appreciated. Thanks!

2

Here’s the logs and XML file info.

For this log I was watching the show using the web client. The buffering happened at 12:12:03 (lasting 14 seconds) and again at 12:12:47 (last 14 seconds).

Plex Media Server Logs_2019-09-23_12-14-05.zip (1.5 MB)

<?xml version="1.0" encoding="UTF-8"?>
<MediaContainer size="1" allowSync="1" identifier="com.plexapp.plugins.library" librarySectionID="1" librarySectionTitle="DVR" librarySectionUUID="2853eb45-94ff-406e-8465-90ec16d0e80b" mediaTagPrefix="/system/bundle/media/flags/" mediaTagVersion="1566947198">
<Video ratingKey="9242" key="/library/metadata/9242" skipParent="1" grandparentRatingKey="9240" guid="com.plexapp.agents.thetvdb://143421/11/10?lang=en" parentGuid="com.plexapp.agents.thetvdb://143421/11?lang=en" grandparentGuid="com.plexapp.agents.thetvdb://143421?lang=en" librarySectionTitle="DVR" librarySectionID="1" librarySectionKey="/library/sections/1" type="episode" title="Mortising Jig &amp; Box Assembly" grandparentKey="/library/metadata/9240" grandparentTitle="Woodsmith Shop" parentTitle="Season 11" summary="A mortising jig is a great option for the combination router table. Plus, the Woodsmith editors cover the details of making a mitered box." index="10" parentIndex="11" viewOffset="164000" viewCount="1" lastViewedAt="1569212976" year="2017" thumb="/library/metadata/9242/thumb/1569065658" art="/library/metadata/9240/art/1569065660" grandparentThumb="/library/metadata/9240/thumb/1569065660" grandparentArt="/library/metadata/9240/art/1569065660" duration="1600942" originallyAvailableAt="2017-11-21" addedAt="1569065635" updatedAt="1569065658">
<Media id="9539" duration="1600942" bitrate="15300" width="1920" height="1080" aspectRatio="1.78" audioChannels="2" audioCodec="ac3" videoCodec="mpeg2video" videoResolution="1080" container="mpegts" videoFrameRate="NTSC" channelIdentifier="2.1" mediaGrabBeginsAt="1569063600" mediaGrabDevice="device://tv.plex.grabbers.tunerservice/dvb%23hdhr%231037ECE8" mediaGrabOriginalDuration="1769686" mediaGrabPartialRecording="1" mediaGrabPostProcessed="1" mediaGrabStatus="complete" origin="dvr" videoProfile="main">
<Part accessible="1" exists="1" id="9546" key="/library/parts/9546/1569065633/file.ts" duration="1600942" file="/volume1/DVR/Woodsmith Shop (2019)/Season 11/Woodsmith Shop (2019) - S11E10 - Mortising Jig &amp; Box Assembly.ts" size="1718230324" container="mpegts" deepAnalysisVersion="4" packetLength="188" requiredBandwidths="8544,8175,7982,7982,7982,7982,7982,7982" videoProfile="main">
<Stream id="14738" streamType="1" codec="mpeg2video" index="0" bitrate="7394" bitDepth="8" chromaLocation="left" chromaSubsampling="4:2:0" closedCaptions="1" colorPrimaries="bt709" colorRange="tv" colorSpace="bt709" colorTrc="bt709" frameRate="29.970" height="1080" level="4" profile="main" refFrames="1" requiredBandwidths="8032,7663,7476,7476,7476,7476,7476,7476" scanType="interlaced" streamIdentifier="256" width="1920" displayTitle="1080i (MPEG2VIDEO)"/>
<Stream id="14740" streamType="2" codec="ac3" index="1" channels="2" bitrate="128" language="Español" languageCode="spa" audioChannelLayout="stereo" requiredBandwidths="128,128,128,128,128,128,128,128" samplingRate="48000" streamIdentifier="257" displayTitle="Español (AC3 Stereo)"/>
<Stream id="14741" streamType="2" selected="1" codec="ac3" index="2" channels="2" bitrate="384" language="English" languageCode="eng" audioChannelLayout="stereo" requiredBandwidths="383,383,383,383,383,383,383,383" samplingRate="48000" streamIdentifier="258" displayTitle="English (AC3 Stereo)"/>
<Stream id="14739" streamType="3" codec="eia_608" index="0" bitrate="7394" embeddedInVideo="1" requiredBandwidths="8032,7663,7476,7476,7476,7476,7476,7476" streamIdentifier="256" displayTitle="Unknown (EIA_608)"/>
</Part>
</Media>
<Extras size="0">
</Extras>
</Video>
</MediaContainer>
4

Thanks @trumpy81!

I’ve enabled debug logging, cleared the logs, and updated to PMS 1.17.0.1709.

But after doing those things, the behavior has now changed. Previously video playback would stop and buffer. Now about 2-3 seconds after starting the video it gets very pixelated, but continues playing. Audio continues just fine. This lasts for about 40 seconds (9:39:40 - 9:40:18) and then the video clears up and things continue to play normally.

I’ve included the updated logs. I was testing with the same DVR recording, so I won’t post the info XML again.

Plex Media Server Logs_2019-09-24_21-42-02.zip (66.9 KB)

5

I’ve just realized that this behavior now applies to all video files, even movies that up until tonight weren’t having any problems playing at all.

7

Thanks for looking through the logs.

It’s definitely not signal break up in the DVR recording because if I stop playing and restart it again, I get the same 40 second fuzziness just in a different spot.

And re-encoding DVR shows is quite impractical as they are continually showing up.

I just don’t understand what changed to make this suddenly start happening a week ago when everything had been playing fine since the beginning of the year.

9

I’ll look into the Plex Optimize if we can’t get this resolved.

I uninstalled 1.17.0.1709 and installed the Synology provided version 1.16.5.1552 as you suggested. This brought back the buffering behavior with the DVR recordings that I described in my first post to this thread. I’ve followed the same steps as before and captured new logs. Buffering happened at 8:35:27 and 8:36:14 this time.

Plex Media Server Logs_2019-09-26_20-37-30.zip (61.9 KB)

11

Stopped PMS, deleted all the codecs, restarted NAS, tried again. Still happened at 9:03:43 and 9:04:28.

It’s been very consistent in how long it takes for the buffering to happen. Meaning it’s always the same amount of time after starting to play when the first buffer happens, and then always the same amount of time when the second one happens. The duration of the buffer has always been about 14 seconds as well. The repeatability of that is interesting. Not sure what exactly that tells us, but it may be a clue as to where things are going wrong.

Plex Media Server Logs_2019-09-28_09-05-58.zip (77.7 KB)

13

I’ve upgraded to 1.17.0.1841. The 30 seconds of pixelated playback has returned.

The pixelation happens shortly after starting playback with every recording I’ve tried. Some of them are months old, some of them are brand new. And if I skip ahead 10 minutes the pixelation starts again. But if I then skip back 5 minutes and let it play through the same section that was pixelated before, it’s just fine. So to me that shows that it’s not a problem with the files.

I’ve tried it on two different Roku units and my desktop with Firefox. All three do the same thing.

If you’re not seeing anything in the logs, could the Synology be at fault here?

15

Yes, I had this same issue with 1.17.0.1709.

I just saw the same behavior last night while watching a ripped DVD MKV file. So it doesn’t appear to be DVR recording specific.

17

I have tried the Package Center version, but that was 1.16.something. Which behaved identically to the 1.16 I had downloaded from Plex website.

19

I just wanted to jump in and say I’ve been seeing this recently on 1.16 (DSM package center version), and 1.17 from plex.tv downloads and was pretty disappointed since my whole goal of getting a 918+ was to replace an older Desktop that Plex was running on.

As of the most current build (1.18.0.1913-e5cc93306), something changed since now I’m not seeing any buffering of Live TV after the initial stream setup.

20

I just installed 1.18.0.1944 from the website. Still get the same 30 seconds of pixelated video shortly after playback starts. Doesn’t matter where in the file I start playing. Same as with the 1.17.x release.

22

Winner winner chicken dinner!

That was the one. Upgrading to 1.18.1.1973 has resolved the issue.

Thank you @trumpy81 for your perseverance in helping me find a solution. My family appreciates it!

23

This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.