I have my videos file with Default AC3 5.1 audio. I’ve added AC3 2.0 to avoid trans-coding, if necessary. I don’t know when but after an update now sounds always defaults to 2.0.
Why is Plex defaulting to 2.0 ? If I remove the 2.0 thew 5.1 plays fine.
(There has got to be a better way to control default audio.)
When you add the AC3 2.0 track, do you also set the new track as “Default track”? I use FFMPEG and MKVToolNix for injecting AC3 5.1 audio track, but I always ensure, that the new track is set as default audio track and moved a bow any other audio tracks (track number).
Screenshot from MKVToolNix
I don’t believe Plex actually uses the default audio flag in an MKV file. That is, it plays the first available audio track in the preferred language. So, in the example above, the AC3 track is used because it’s the first track, not necessarily because it’s flagged as default.
Some apps (the Roku, for sure) will auto select the best quality audio. If the video file contains a stereo and surround track, the Roku will select the 5.1 audio, regardless of what position it is in the mix. Apps without the auto-select feature will usually fall back to the first audio track. If that happens to be stereo, that is what will be used.
Most people place a stereo track as the first audio in an MP4 video file. That ensures that the stereo track is selected (again, for apps that do not auto-select) so that no transcoding is required for stereo only players.
I have no “official” proof of any of the above, only my own experience through trial and error. Perhaps a Plex Ninja or Plex employee will jump in and correct any errors in my observations. 
Pet Peeve of mine since the beginning of time.
Every client needs to show a list of default audio types and allow you to set the order of preference for THAT device.
This way you could set your preference from atmos to dts to dolby to ac2 to aac, etc depending on the equipment attached.
Thanks For Your Input Everyone
“mm98” - The Default Flag Is Always Set To The Higher Audio, in most cases 5.1. I’m also using MKVToolNix
“leelynds” - If that were the case then I could plan around it but its not consistent. [all my players are Roku.]
“cayars” - I agree, my growing annoyance is that the behavior keeps changing.
Originally for BluRay I used to have [AC3 2.0 5.1 DTS] in that order with 5.1 as the default. About a year ago I noticed that if I only kept 2 audios then Plex selected the option according to my Roku player. So I started having only 2 audios, [2.0 5.1] for 720p & [5.1 DTS] for 1080p, with the highest flagged as the default. This worked great for about half a year, now everything wants to play in AAC (thus gets transcoded) even though none of my sound systems play AAC.
Since this post, I read somewhere that it may have to do with the “Maximum H.264 Level” - in part the ones having the most issues are 4.1… changing my max setting to 4.2 fixes the issue some of the times. I played 18 episodes of a show with [2.0 5.1], the result 11 played the 5.1 but gave no Audio options to change, the rest selected the 2.0 but had the option to switch to 5.1.
Most of these issues are with the Roku 3 and after there last update… The Roku 1 & for seem to be selecting the correct option all the time but they also don’t give the option for changing the Audio.
That’s odd. I tested about 20 movies on 3 Rokus, and each one auto selected the best format for the system the device was connected to. Surround audio on surround systems, stereo audio on stereo systems. I have an older Roku 3 model, one of the newer Roku sticks (not 4K) and a really old Roku 2. Roku’s model numbering is weird so I don’t know what they are called now…
One thing I do know, that if you have ever changed the audio manually, Plex will remember that, and stubbornly insist that is the audio you want to use. It doesn’t matter which app or device you changed the audio manually on, from that point on that is the track that will be used on every other device. That’s why I don’t use the Plex Media Player. It doesn’t (or at least it didn’t a while ago) auto select the best audio. I had to manually select the track I wanted, and once I did that, every other device used that track, forcing a manual selection on every other device.
Maybe you have changed the audio track manually at some point in time? That might explain the problem.
Perhaps you should get this moved to the Roku forums for better visibility if you think it’s a Roku problem.
“leelynds”
I have 2 or 3 of every version of Roku’s (its okay to judge me)
If I connect directly to the Roku everything works as expected.
The Plex Player is what is annoying … the issue seems to be narrowing down to Roku 3 with multiple audio and H.264 at or above 4.1. Today for the first time I saw it convert AAC LC to AC3 ( I was happy).
remotely I’ve given up since Plex wants to use AAC as a universal audio maybe time to start experimenting with other options since I’ll never move towards AAC audio equipment.
Throwing my 2 cents in here.
I’ve got AAC-LC (or AAC on some older rips) as first track, and AC3 for a second track, on all 570-plus-something x264 MP4 video’s I’'ve manually ripped over the past 5+ years. DVD or BRay.
I have never had a problem with Plex selecting the proper sound as set by the Roku main audio settings, unless I changed purposely in Plex for roku to do otherwise.
Surround on my Roku 3 connected to my Yamaha surround receiver.
Stereo on my ‘test’ Roku 2 XS connected to my 24" pc monitor that has speakers.
Both by HDMI.
I do NOT use higher than 4.0 (3.1 on DVD) however, as many sites state hardware compatibility issues abound (not just on Roku)
(all my encodes are based on, with my own QSV tweaks once Handbrake included it, settings found at www.rokoding.com
@JamminR said:
I’ve got AAC-LC (or AAC on some older rips) as first track, and AC3 for a second track,…
I have never had a problem with Plex selecting the proper sound as set by the Roku main audio settings, unless I changed purposely in Plex for roku to do otherwise.
I’ve got about 1000 done that way, and It’s never failed to auto-select the correct audio. As you say, the only time there’s a problem is when I have had to manually select a track for other apps that can’t auto select. And once you have selected an audio track manually on any device, Plex will use that track as the preferred audio on every other device.
Surround on my Roku 3 connected to my Yamaha surround receiver.
Stereo on my ‘test’ Roku 2 XS connected to my 24" pc monitor that has speakers.
Both by HDMI.
That may be an important fact. I’ve never had much luck with connecting the Roku to the TV and then to the receiver, It might work on some TVs, but usually the Roku will insist it is connected to a stereo only device.
@JamminR said:
I do NOT use higher than 4.0 (3.1 on DVD) however, as many sites state hardware compatibility issues abound (not just on Roku)
@GoRichard said:
… the issue seems to be narrowing down to Roku 3 with multiple audio and H.264 at or above 4.1. Today for the first time I saw it convert AAC LC to AC3 ( I was happy).
90% of the content on my server is at Level 4.1, with 2 or more audio tracks. All of the people I share with use Rokus most of the time, and everything is streamed direct play to them, no transcoding (unless it’s an Apple device, they seem a little more picky). Surround audio if the Roku is connected to a surround capable system, and stereo for the others. No one ever has to select an audio track manually.
Sorry to hear you are having troubles, but it has been virtually flawless in my experience. 
@leelynds
the issue is only with Roku3 and was working fine for years and still works fine if connected directly. So its has to do with Plex and the new changes. If I could just disable AAC all together I would be fine.
for the most part I try to have 2 copies of files [1080p & 720p] the main goal to minimize transcoding. Lately I’ve been adding a 720p [AAC 5.1] for remote users.
3000 Movies -1080p [AC3 5.1 DTS]
3000 Movies - 720p [AC3 2.0 5.1]
21500 TV Episodes -1080p [AC3 5.1]
21500 TV Episodes - 720p [AC3 2.0 5.1]
The machine is graphic machine with:
dual Quad Xeon 3.5
dual nVidia Quadro K2200
dual Solid State Drives 512GB
32GB Memory
storage is 2x12TB Raid5 and 8x8TB external drives
I can simultaneously serve 4 people local and 4 external [internet is the limitation] with Plex set to make me hurt.
Even if I re-encoding 2 movies at the same time and surfing the CPU’s have never gone above 50% usually stays at around 5-10%.
@GoRichard … like you, I’m just a Plex user, so I can’t provide an authoritative answer, just speculation
If you think it’s a Roku issue, you should try and get this thread moved to the Plex for Roku section where it may get some better advice. If you hit the “Flag” button one of the forum admins should be able to move the thread for you.
Just a few thoughts –
AAC 5.1 is not really a standard format. At least not yet. I would probably avoid that format all together, but your choice. Apparently some models of Roku will (or are supposed to) transcode the AAC 5.1 to AC3 5.1 on the fly, but most will transcode to stereo. Look here:
Are you sure you have never changed the audio track manually? Once you have made a manual choice for audio, Plex will remember that forever. It doesn’t matter if it was on a Roku, the Plex web app or any other device. From that point on, the selected audio will be the default on all devices. As far as I know, there is no way to make Plex forget that manual change.
Do the files have the proper “Language” tag on the audio tracks? If any are tagged as “unknown” or a different language than that set in your preferences for Plex, the first track that is properly identified as the preferred language will be used, regardless of what is flagged as default in the file.
I doubt that there’s anything wrong with your server. It would likely be more beneficial to provide the xml info for a file that won’t play properly in case there’s something screwy there.
@leelynds said:
Plex will remember that forever. It doesn’t matter if it was on a Roku, the Plex web app or any other device. From that point on, the selected audio will be the default on all devices. As far as I know, there is no way to make Plex forget that manual change.
Not true. Perhaps your experience, but not ‘standard’ behavior.
I use multiple devices for playback of my dual track media - changing one Roku does not affect my others playback clients, which include but not limited to other Rokus, IOS, Android, PS3, Plex/Web …
I do agree about AAC 5.1.
It’s not a common hardware supported feature. AAC 2.0, sure, but I’d never recommend AAC 5.1
Why some release groups now use it is beyond me.
@JamminR said:
Not true. Perhaps your experience, but not ‘standard’ behavior.
I use multiple devices for playback of my dual track media - changing one Roku does not affect my others playback clients, which include but not limited to other Rokus, IOS, Android, PS3, Plex/Web …
I actually hope you are right, but I believe it is the standard and intended behaviour.
If I deliberately choose the “Director’s Comments” track, then Plex remembers that and will choose that track automatically on all devices. Some may call it a feature, I call it a bug. This feature over-rides any language preferences, as well as the surround and stereo capabilities of the unit and equipment it is connected to. I just tested on several movies, and once selected, that audio track more or less becomes the “Default” audio.
If I let the device automatically choose, that is I haven’t touched it manually, then every other device will play the best audio for the equipment, because a manual choice was never made.
Test it yourself, because I’m curious. Choose an audio track on the Roku that is not the automatic default, let it play for more than a minute so Plex registers it as a partially played item, and then play that same movie on a different device. The audio you selected will be the default audio.
Here’s the relevant XML info from one movie I tested, showing that the AC3 audio is now selected automatically in Plex Web, which is incapable of playing the audio, and forces a stereo transcode.
<Stream id="2804919" streamType="2" default="1" codec="aac" index="1" channels="2" bitrate="171" language="English"
languageCode="eng" audioChannelLayout="stereo" profile="lc" samplingRate="48000" streamIdentifier="2"/>
<Stream id="2804920" streamType="2" selected="1" codec="ac3" index="2" channels="6" bitrate="384" language="English"
languageCode="eng" audioChannelLayout="5.1(side)" samplingRate="48000" streamIdentifier="3"/>
Clearly, the AAC track is considered default, but now Plex has assumed that the audio I want to use is the AC3 track, which will be used on all devices.
@leelynds - (Sheesh, now I know why your nickname looked familiar, you’re the only one to give a decent (but half-a$$ed due to Plex, not you) work-around to a [“it’s a feature not a bug” discussion many years ago regarding my On Deck](https://forums.plex.tv/discussion/183530/bug-0-9-12-16-on-deck-shows-twice-same-video-from-two-different-library-directories ““it’s a feature not a bug” discussion many years ago regarding my On Deck”) )
wow, ok. If I play between my two Roku’s, selecting different tracks, I see no difference.
However, if I go to plex web, select 5.1, then go back to my stereo Roku, not only does the audio transcode, Roku plexpass 5.1.5 transcodes the container, the video stream, and audio. Really odd.
Have you started this as a bug anywhere? Were we told this is a “feature” just like previous?
This to me is an annoying feature, just like if I put the same movie in two different libraries and watch one, it shows up in On Deck twice (which you helped with before)
I don’t want to de-rail the thread, but a brief reply as possible…
I understand the rationale for maintaining the audio track selection. For example, my daughter-in-law is from Taiwan, and naturally prefers Mandarin audio if it’s option. I have a few videos with both English and Mandarin audio. She can start to watch on her iPad, then switch to the Roku, and her audio selection is maintained - no fuss, no muss.
However, if the kids want to watch the same video and they prefer English, they have to re-select the right audio for them, no matter the device they watch on. The same idea applies to stereo and surround audio tracks. The manual audio selection seems permanent in my experience, a good thing for my daughter-in-law, a bad thing for the kids, and a confusing mess when you throw in stereo and surround tracks that have been selected once manually.
The same principle applies to subtitles. Once manually selected, they are there to stay. My grandkids will tell you that once the Chinese subtitle is selected, the option for no subtitles or English has to be done manually.
What Plex needs to do is remember subtitle and audio language choice PER USER. It needs to have audio track selections per device. For example you could check AAC, AC3, DTS for a specific codecs and stereo, 2.0, 2.1, 5.1 for audio spatial setups. This way it can figure the best audio track based on language for the user and turn on subtitles if the audio language doesn’t match the user’s selection.
So Thanks To Everyone And Their Observations… Which I View As All True (Depending On Your Setup Anything Crazy Can Happen). FYI I Apologize For Even Having AAC Files, They Just Seem To Work For Remote Playstation & Iphone Users. I Only Keep Them Around Some Of Current Movies.
AnyWhoo Back To The Important Issue.
So Here Is A Good Example Of What I Tried This Weekend…
There Are 3 Versions Of The Same Show. Everything Has Been Processed & Labeled Properly With MKVToolNix, Verified With Media Tab Info & Confirmed With Tautulli. All The Rokus Are Connected Via Ethernet To An Audio Amp Which Then Is Conneceted To The TV Using HDMI Arc. Roku Is Setup For 1080p DTS And Has Zero Issues With Any Other Application.
Results…
a) Plex Avoids DTS Like The Plague Except On The Web Browser. Strange Because The PC Is Setup As 2.0 DVD Stereo.
b) Server Status, Tautulli & Player Setting Report “Direct Play” With AC3 5.1
c) ‘Closed Caption/ Audio Configuration’ (When You Hit * On The Remote) Is The Only One Out Of Line And The One That I Have To Always Change To Get 5.1 - this button used to go to the Player Settings only on the Roku 3 & 4 but now opens the new option on all players.
Audio selection does not stick anywhere except the web browser. SRT language does stick but 99.7% of my fiiles only have English and or English SDH.
5 Audio Configuration
My Main Reason For All This Is That There Are 2 Part To HD - Visual & Audio. 2.0 & AAC Are By No Means Part Of HD. Plex Just Wants To Sacrifice Audio At All Cost… If I’m Watching A 14GB Movie Reducing The Audio To Save Band With Or Space Is Just Plan Useless.
For Me Audio Is The Last Things I Want To Sacrifice Because It Has The Least Payback At Home… On A Phone Or Tablet You Can’t Tell But Through An Audio System It Makes A Huge Difference.
So Following Your Comment I Checked Mine… But Even Though I Keep Selecting 5.1 This Is What The XML Is Showing - But Again This Unwanted Selection Is Only Affecting The Roku 3 & DTS is Still Being Displayed As Primary Choice. Here It’s Saying 5.1 Is, ‘Default’ But 2.0 Is, ‘Selected’
<Stream title="AC3_2.0" id="924337" language="English" bitrate="448" index="1"
codec="ac3" streamType="2" samplingRate="48000" audioChannelLayout="stereo"
languageCode="eng" channels="2" selected="1"/>
<Stream title="AC3_5.1" id="924338" language="English" bitrate="640" index="2"
codec="ac3" default="1" streamType="2" samplingRate="48000" audioChannelLayout="5.1(side)"
languageCode="eng" channels="6"/>
BTW
Not Sure How You Embedded The Info, Mine Kept Disappearing. (edit: I figured it out)
gotta see what happens with a file with 4 audio options.
@GoRichard - like you, I feel the audio is a crucial part, and I actually would prefer lower quality video and keep my surround sound.
I’m not sure what I have set up right (or possibly wrong) but I can’t reproduce your results. In fact, mine are virtually the opposite of yours. The Roku always auto-selects the best audio track as long as I have never manually made a selection. The web app always auto-selects the stereo track (AAC or AC3) unless I have manually selected another on any device. In all cases, once I have manually made a selection, that sticks on all devices, which may force a transcode or a less than optimal choice.
I made 4 test files after reading your last post to try and get your results;
Test1.mkv - 1080p high@4.1, 5 ref frames, AAC Stereo, AC3 5.1, DTS 5.1 (default track DTS)
Test2.mkv - 1080p high@4.1, 5 ref frames, AAC Stereo, DTS 5.1, AC3 5.1 (default track DTS)
Test3.mkv - 1080p high@4.1, 5 ref frames, AC3 Stereo, DTS 5.1, AC3 5.1 (default track DTS)
Test4.mkv - 1080p high@4.1, 5 ref frames, AC3 Stereo, DTS 5.1 (default track DTS)
Both Rokus connected to a surround system chose the DTS track automatically. The Roku connected to a stereo only TV chose the stereo track. As I said before, Plex Web always auto-selected the stereo track. Plex web activity reported direct play in all cases, as did Tautulli, indicating the proper audio track for the device the video was playing on was being used.
One glitch to report though. The Test1.mkv video wanted to auto-select the AC3 5.1 track on the Roku. That might be a bug. It may be because the surround AC3 track was the 2nd audio track, and the Roku didn’t look any farther for a better audio track. I mentioned it before, I don’t think Plex actually pays attention to the default flag in MKV’s.
The only other thing I can think of is that maybe you are trying to get Plex (or the Roku) to select the best version of a video based on the audio tracks it contains. I don’t think that is an option that works. If you want the audio to be the deciding factor, make sure you add the version with the best audio and video first. Plex has a nasty habit of considering the first copy (regardless of quality) as the primary source.
