Can someone please advise why I cannot transcode a 4k video on my DS416+ on the fly?

Plex Media Server NAS & Devices
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1

Hi everyone

Can someone please advise me how to get my DS916+ to transcode 4k video to my PS4 Pro without immense stuttering?

My PMS is installed on my Synology DS916+ NAS. It has an Intel CPU that supports Intel Sync Video.

The NAS is connected to my Gigabit network through link aggregation to my Gigabit switch, and the network speed is perfect.

I upgraded from a 412+ last year with the knowledge that it should transcode one channel of 4k video?

I’ve researched extensively how to fix this, bought a Plex pass to enable Hardware acceleration, but no matter what I do, it cannot stream/transcode 4k video?

The only way I can watch the 4k movie through any peripheral, PS4 Pro or the Plex app on my 4k DVD player, is to transcode the movie overnight, which might take 6-8 hours, then watch it the next day as an OPTIMISED version?

What am I doing wrong?

The file could either be MP4 or MKV, usually x264 but also x265 HEVC, anywhere from 20GB to 40GB, and I cannot transcode it on the fly at all?

It plays, but pauses every 5 seconds for 5 seconds at least?

**Doesn’t the Synology info page state that the 416+ is in Group 1, which should transcode 4k at 30fps?
**
Thanks

2

I cannot help you with the PS4 but can help you with the Synology.

The CPU in your DS916+ :

DS916+ Intel Pentium N3710 Quad Core 4 Yes Braswell DDR3 2 / 8 GB

The N3710 is a Pentium processor with the Braswell GPU glued on. It has hardware transcoding ability for 2K but not 4K . To further complicate it, there are two types of “4K” (8 bit color and 10 bit color) . 10 bit color is known as HDR. Another pain point; 4K UHD is encoded with the HEVC codec. HEVC requires a) massive CPU power or b) a KabyLake or better GPU power to decode. KabyLake CPUs are those with the -7xxx designator after them.

That having been said, we need to first see what type of 4K you have: Hover over the movie, click the ellipsis, and click Get Info.
Find the Encoding ( HEVC / H.265, H.264, or VC-1 ).

Next find the profile (left column of the media info). “Main” = 8 bit. “Main 10” = 10 bit = HDR (a problem for your CPU )

Below is what 4K HDR (10 bit color) looks like to guide you.

ux6ipckh4r5j.png752×537 73.4 KB

3

@ChuckPa said:
I cannot help you with the PS4 but can help you with the Synology.

The CPU in your DS916+ :

DS916+ Intel Pentium N3710 Quad Core 4 Yes Braswell DDR3 2 / 8 GB

The N3710 is a Pentium processor with the Braswell GPU glued on. It has hardware transcoding ability for 2K but not 4K . To further complicate it, there are two types of “4K” (8 bit color and 10 bit color) . 10 bit color is known as HDR. Another pain point; 4K UHD is encoded with the HEVC codec. HEVC requires a) massive CPU power or b) a KabyLake or better GPU power to decode. KabyLake CPUs are those with the -7xxx designator after them.

That having been said, we need to first see what type of 4K you have: Hover over the movie, click the ellipsis, and click Get Info.
Find the Encoding ( HEVC / H.265, H.264, or VC-1 ).

Next find the profile (left column of the media info). “Main” = 8 bit. “Main 10” = 10 bit = HDR (a problem for your CPU )

Below is what 4K HDR (10 bit color) looks like to guide you.

752×537 73.4 KB

Thank you for your reply

Where can I get the info you requested?

You said: Hover over the movie and click the ellipsis?

Sorry, what does that mean?

Thanks

4

Ok, i think I got what you mean. Here’s an XML:

This XML file does not appear to have any style information associated with it. The document tree is shown below.
<MediaContainer size="1" allowSync="1" identifier="com.plexapp.plugins.library" librarySectionID="8" librarySectionTitle="Movies" librarySectionUUID="da6a49d7-8e5e-4ed6-ab41-4951e5097839" mediaTagPrefix="/system/bundle/media/flags/" mediaTagVersion="1513172012">
<Video ratingKey="133829" key="/library/metadata/133829" guid="local://133829" librarySectionID="8" librarySectionKey="/library/sections/8" librarySectionTitle="Movies" type="movie" title="Arrival 2016 2160p 4k Uhd Hevc" summary="" thumb="/library/metadata/133829/thumb/1515926848" art="/library/metadata/133829/art/1515926848" duration="6982976" addedAt="1515926819" updatedAt="1515926848" chapterSource="media">
<Media videoResolution="4k" id="332985" duration="6982976" bitrate="28856" width="3840" height="1600" aspectRatio="2.35" audioChannels="8" audioCodec="dca-ma" videoCodec="hevc" container="mkv" videoFrameRate="24p" audioProfile="ma" videoProfile="main">
<Part accessible="1" exists="1" id="334180" key="/library/parts/334180/1487732573/file.mkv" duration="6982976" file="/volume1/video/Movies/Arrival 2016 2160p 4K UHD Bluray HEVC Multi DTSHD 7.1 -DDR.mkv" size="25187560759" audioProfile="ma" container="mkv" videoProfile="main">
<Stream id="482477" streamType="1" default="1" codec="hevc" index="0" bitrate="26040" language="English" languageCode="eng" bitDepth="8" chromaSubsampling="4:2:0" colorRange="pc" colorSpace="bt709" frameRate="23.976" height="1600" level="153" profile="main" refFrames="1" width="3840"/>
<Stream id="482478" streamType="2" selected="1" codec="dca" index="1" channels="8" bitrate="1536" language="English" languageCode="eng" audioChannelLayout="7.1" bitDepth="24" profile="ma" samplingRate="48000"/>
<Stream id="482482" streamType="2" codec="ac3" index="5" channels="6" bitrate="640" language="Français" languageCode="fre" audioChannelLayout="5.1(side)" samplingRate="48000"/>
<Stream id="482483" streamType="2" codec="ac3" index="6" channels="6" bitrate="640" language="Español" languageCode="spa" audioChannelLayout="5.1(side)" samplingRate="48000"/>
<Stream id="482479" streamType="3" default="1" codec="pgs" index="2" bitrate="10" language="English" languageCode="eng" headerCompression="1"/>
<Stream id="482480" streamType="3" codec="pgs" index="3" language="English" languageCode="eng" headerCompression="1"/>
<Stream id="482481" streamType="3" codec="pgs" index="4" bitrate="10" language="Français" languageCode="fre" headerCompression="1"/>
<Stream id="482484" streamType="3" codec="pgs" index="7" bitrate="10" language="English" languageCode="eng" headerCompression="1"/>
<Stream id="482485" streamType="3" codec="pgs" index="8" bitrate="12" language="English" languageCode="eng" headerCompression="1"/>
<Stream id="482486" streamType="3" codec="pgs" index="9" bitrate="10" language="Français" languageCode="fre" headerCompression="1"/>
<Stream id="482487" streamType="3" codec="pgs" index="10" bitrate="9" language="Español" languageCode="spa" headerCompression="1"/>
</Part>
</Media>
<Extras size="0"></Extras>
</Video>
</MediaContainer>
5


Here;s the pic

6

and there were many audio files also, so attached those

69y9u4i1td1k.png608×746 22.6 KB

ysmqppzbzc20.png614×684 22.9 KB

ohk307k23br0.png624×712 21.5 KB

16iavwx7gyjb.png664×618 18.7 KB

7

I see what’s happening. I will try to educate you as I explain why.

A. Look at the ‘Profile’. It is Main 10. This tells us it’s the 10 bit color space used by HEVC HDR (High Dynamic Range). Yes it is the best video color range currently available but it’s the hardest to work with because it’s both the HEVC codec (H.265 not H.264) and 10 bit color. The only processors capable of decoding it are the KabyLake and ApolloLake CPUs. Your CPU is the Braswell. It’s several generations older. I have a “SkyLake” CPU, immediate predecessor to “KabyLake” and it can only handle up to HEVC Main (8 bit) color.

B. The file has many PGS tracks subtitle tracks. There are two types of subtitles; Text (SRT, ASS, and SSA), and bitmap (VOBSUB, and PGS). Bitmap subtitles are intended to be overlayed onto the video image by a hardware player. What you have in that file are are subtitles for numerous languages as well as the audio tracks for numerous languages as well.

C. Without seeing your log files to know exactly what is happening, the best guess is:

Your CPU is trying to do the following:

  1. Convert 4K to 2K
  2. Convert 10 bit color to 8 bit color
  3. Convert 7.1 audio to whatever the PS4 needs / can pass through
  4. Burn in the subtitle images into the video stream.

Synology’s marketing information regarding HW transcoding is for their proprietary hardware and software in the NAS only. It also does not specifically state HEVC HDR capability (clever omission on their part). PMS does not have access to them. PMS only has access to the CPU and integrated GPU.

D. What this all means to you is:

Your NAS processor is not strong enough to perform all those tasks at once even with hardware assistance.

If you are careful, strip out those streams from the video files which you don’t need, be mindful of the 8 bit (Main not Main 10 ) color space limitation of the processor, you will have considerably more success.

A number of tools exist to help. MakeMKV will allow you to select what you rip from the disc. You can opt not to include those tracks you don’t need.
HandBrake, while I resist suggesting it, will allow you to convert the HDR (Main 10) color range back to normal (Main) color range.

Does this make sense?

8

Hi
Thanks for your comments.
Since I’ve last posted, I did some research and read somewhere here that SUBTITLES can be a problem, something about HARDWARE BURNING?
I think it was your advice to another forum member to avoid using subtitles.

So, here’s what I did a little earlier:

I copied the file to my Mac, used a software called MKVTools, and removed ALL subtitles and French and Spanish audio.

Took about 2 minutes. File was initially about 24GB, new file is about 22GB.

I copied the new MKV file to the NAS, and Plex played it with absolutely no problem!!!

Amazing stuff…

I did not touch a single thing in the MKVTools software apart from unticking the subtitles issue.

How could subtitles be such a big factor?

Thanks again.

I’ll try this with more files. Isn’t there someways to tell PMS to ignore subtitles all together? I never need them?

9

MKVtools (mkvtoolnix is the package name) is amazing. It is indeed extremely fast. All it does is copy the selected input streams to the output file. It make no other alterations.

One of the things you may have noticed, which i do advise you to look for, is the Default track flag as well as the Default language assigned to a track (in the left pane).

English is my primary language. I make sure my files look like this:

wszklbjq24l5.png874×471 31.4 KB

I’ve kept all the important pieces and nothing else. As an additional option you can specify (Preferences - Multiplexer - Default Values - Default additional command line options: --disable-track-statistics-tags --no-global-tags This keeps all those extra annoying tags from being written. They add nothing to the content or playback.

When I run this job ^^, those 3 tags will disappear. They will no longer exist in the output file.

We cannot turn off subtitle evaluation. We can prevent PMS from attempting to burn-in/play the subtitles (render them) by making sure the default language and the playback language are the same. As added insurance, if subtitles aren’t needed, don’t include them.

The same is true of language tracks. If you know your player can’t handle a 7.1 track but an AC-3 track is available, and you have a weak processor or would like to configure for DirectPlay (best playback mode possible), Don’t include it either. Pick the AC-3 track. MKVTools will handle it.

One last point about using MKVTools, you can reorder tracks by sliding them up & down in the lower left pane. This way, you can control what PMS sees first. First audio track encountered, if no default is identified, will be played. When you have multiple tracks, this makes controlling what PMS sees and does much easier.

10

im looking at the synology DS918+ this is the specs

CPU Model Intel Celeron J3455
CPU Architecture 64-bit
CPU Frequency Quad Core 1.5 burst up to 2.3 GHz
Hardware Encryption Engine (AES-NI)
Hardware Transcoding Engine H.264 (AVC), H.265 (HEVC), MPEG-2 and VC-1; maximum resolution: 4K (4096 x 2160); maximum frame rate per second (FPS): 30

It states it can transcode H265 , would this be ok for 4K transcoding ?

11

The J3455 is a great NAS CPU with one caveat. It’s a Celeron processor with an ApolloLake iGPU attached. The Celeron is not strong when subtitle burning is needed.

If you do not need subtitle burning-in, you will be fine. It will decode HEVC HDR and transcode to 1080p extremely well.

The J3455 CPU will transcode a couple (2) HD audio streams to stereo pretty nicely.