Real-time Transcoding of blu-rays on QNAP TS-451+

Plex Media Server NAS & Devices
1

Server Version#: 1.14.1.5488
Player Version#: Chrome browser playback on Windows 10

Hi,
I’ve always had issues with Plex on my TS-451+ struggling to playback MKVs created from my Blu-Rays. I did some searching & saw in the compatibility list that hardware transcoding is supported on this device IF I had the Plex Pass. I subscribed for the monthly membership to try this out.

After giving it a try, I noticed the same issue occurs. I confirmed that the “Use hardware acceleration when available” box is checked.

I found a Plex support page that explains how to interpret the logs as it relates to transcoding speed. The log I downloaded showed a speed of around 0.6-0.8.

Jan 01, 2019 20:37:58.489 [0x7f4d1d132700] VERBOSE -  * speed => 0.6
Jan 01, 2019 20:37:58.489 [0x7f4d1d132700] VERBOSE -  * vdec_hw_status => 0
Jan 01, 2019 20:37:58.490 [0x7f4d1d132700] VERBOSE - We want 300 seconds ahead, last returned was 2877.002002 and max is 3119.035702.

Does this indicate that the hardware transcoding isn’t being used or is the hardware transcoding still not fast enough to reliably stream blu-ray movies? If the hardware decoding isn’t being used, what am I missing?

Thanks

1 Like
2

I need a little bit more info.

  1. Are you using image subtitles (PGS or VOBSUB)
  2. Are you using Text based subtitles (SRT, ASS, or SSA) and have subtitle burning set to ALWAYS in the player?

If either of these conditions is true, The CPU must get involved. The Intel ASIC does not support subtitle processing so the CPU must do it.

3

I’m not having any subtitles shown during playback, if that’s what you’re asking. If there’s something else I need to do to disable any use of them, then I probably haven’t done it.

4

Your speed is 0.6 and real-time speed is 1.0. So in order to stay ahead of the client you need better than 1.0.

Turn off VERBOSE logging. Try playing back another file of interest and let it play for 1 minute. Stop playback, create the log zip file and upload it here.

Give us the name of the file you played. We can then look at the complete log file and be able to tell you what’s going on. But turn off verbose first as mentioned as that just litters the log file with info not needed.

You should only turn that on when asked to do so as it logs an extreme amount of data.

5

Adding to that,

In Plex/web, hover over the item you played, Go to Get Info -> View XML.
Please provide that XML here (only down to the end of the media streams. do not include actor or genre and below)

1 Like
6 
<MediaContainer size="1" allowSync="1" identifier="com.plexapp.plugins.library" librarySectionID="6" librarySectionTitle="Blu-Ray Movies" librarySectionUUID="54d94f92-7590-4e9a-9421-579af68f573c" mediaTagPrefix="/system/bundle/media/flags/" mediaTagVersion="1544818089">
<Video ratingKey="4430" key="/library/metadata/4430" guid="com.plexapp.agents.imdb://tt0088763?lang=en" librarySectionTitle="Blu-Ray Movies" librarySectionID="6" librarySectionKey="/library/sections/6" studio="Universal Pictures" type="movie" title="Back to the Future Part 1" contentRating="PG" summary="Eighties teenager Marty McFly is accidentally sent back in time to 1955, inadvertently disrupting his parents' first meeting and attracting his mother's romantic interest. Marty must repair the damage to history by rekindling his parents' romance and - with the help of his eccentric inventor friend Doc Brown - return to 1985." rating="9.6" audienceRating="9.4" viewOffset="2891000" lastViewedAt="1546472824" year="1985" tagline="He's the only kid ever to get into trouble before he was born." thumb="/library/metadata/4430/thumb/1546195641" art="/library/metadata/4430/art/1546195641" duration="6965959" originallyAvailableAt="1985-07-03" addedAt="1546195612" updatedAt="1546195641" audienceRatingImage="rottentomatoes://image.rating.upright" chapterSource="media" primaryExtraKey="/library/metadata/4440" ratingImage="rottentomatoes://image.rating.ripe">
<Media videoResolution="1080" id="14639" duration="6965959" bitrate="33096" width="1920" height="1080" aspectRatio="1.78" audioChannels="6" audioCodec="dca-ma" videoCodec="vc1" container="mkv" videoFrameRate="24p" audioProfile="ma" videoProfile="advanced">
<Part accessible="1" exists="1" id="14715" key="/library/parts/14715/1546150562/file.mkv" duration="6965959" file="/share/CACHEDEV4_DATA/BluRays/Back to the Future Series/Back To the Future Part I/Back to the Future_t00.mkv" size="28817769267" audioProfile="ma" container="mkv" deepAnalysisVersion="2" indexes="sd" requiredBandwidths="36149,35545,35141,34962,34788,34615,34195,34195" videoProfile="advanced">
<Stream id="31556" streamType="1" codec="vc1" index="0" bitrate="29640" language="English" languageCode="eng" bitDepth="8" chromaLocation="left" chromaSubsampling="4:2:0" frameRate="23.976" height="1080" level="3" profile="advanced" refFrames="1" requiredBandwidths="29827,29170,28714,28330,28205,28104,28052,28052" scanType="progressive" width="1920" displayTitle="1080p (VC1)"/>
<Stream id="31557" streamType="2" selected="1" default="1" codec="dca" index="1" channels="6" bitrate="1536" language="English" languageCode="eng" audioChannelLayout="5.1(side)" bitDepth="24" profile="ma" requiredBandwidths="4912,4776,4619,4433,4332,4249,4249,4249" samplingRate="48000" title="Surround 5.1" displayTitle="English (DTS-HD MA 5.1)"/>
<Stream id="31558" streamType="2" codec="dca" index="2" channels="6" bitrate="1536" language="English" languageCode="eng" audioChannelLayout="5.1(side)" bitDepth="24" profile="dts" requiredBandwidths="1509,1509,1509,1509,1509,1509,1509,1509" samplingRate="48000" title="Surround 5.1" displayTitle="English (DTS 5.1)"/>
<Stream id="31559" streamType="2" codec="ac3" index="3" channels="2" bitrate="192" language="English" languageCode="eng" audioChannelLayout="stereo" requiredBandwidths="192,192,192,192,192,192,192,192" samplingRate="48000" title="Stereo" displayTitle="English (AC3 Stereo)"/>
<Stream id="31560" streamType="2" codec="ac3" index="4" channels="2" bitrate="192" language="English" languageCode="eng" audioChannelLayout="stereo" requiredBandwidths="192,192,192,192,192,192,192,192" samplingRate="48000" title="Stereo" displayTitle="English (AC3 Stereo)"/>
<Stream id="31561" streamType="3" codec="pgs" index="5" language="English" languageCode="eng" requiredBandwidths="52,52,52,52,52,52,52,52" displayTitle="English (PGS)"/>
</Part>
</Media>

I tried 3 different videos. The video that stuttered regularly was Back to the Future_t00.mkv

The 2 that seemed to work fine after about 5 minutes of playing were file names:
Jurassic World.mkv
Fantastic_Beasts_and_Where_to_Find_Them_t03.mkv

Plex Media (2.0 MB)

Thanks!

7

Any more thoughts on why Plex struggles with this movie?

8

Most likely because the GPU in your TS-251+ (intel J1900) has limited HW Decode/Encode capability and VC1 support is not part of its capabilities. You would want to run it through something like Handbrake on a PC to covert it to a supported container format.

See here for an idea of the Intel CPU family and supported hw encode/decode.

9

Interesting. I convert all my Blu-ray movies using MakeMKV and I’ve been able to play others without issues once I subscribed to Plex pass. I’ll try the sequels from the Back to the Future set and see if they play ok.

10

If it is a VC-1 issue then most of the early Warner Bros movie releases will cause you issues (like Jurassic Park 1-3, Back to the Future, The Goonies, most of the Harry Potters, etc). I ended up using MakeMKV to rip those blu rays and then running them through Handbrake using H.264 to maintain the best compatibility.

11

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