# Plex AAC 5.1 Surround comes out stereo



## enigma9o7 (Nov 28, 2015)

If I play video files with AAC 5.1/6.1/7.1 surround sound, plex plays direct and I get two channel PCM at my receiver. How do I get plex to transcode to 5.1 AC3? (I have this working already for dts & opus).


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## Diana Collins (Aug 21, 2002)

To which client? The Plex server adjusts what it does based upon the client capabilities. Web clients have different capabilities than Tivo clients or IOS clients. As a result, most settings that control transcoding are in the client apps. AAC is supported by most phone OS and late model game consoles but I'm pretty sure TiVo does not support it and so does not support Direct Play of AAC sources. I can't find any AAC titles on my server (only DTS-MA, AC3 and a few miscellaneous ones like FLAC and MP3) so I can't verify the settings.

The only server side transcoder setting that affects the output at view time is "Transcoder quality" which should be set to Automatic. Try turning off Direct Play in the TiVo client.


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## enigma9o7 (Nov 28, 2015)

Thanks Diana,

I'm using Plex for Tivo 3.13.13 on a Roamio OTA with Tivo version 21.8.

I have transcoder at automatic. If I use a file with x264 video and aac 5.1 audio, Plex Server shows Direct Play. Unchecking "Allow Direct Play" on the Tivo Client results in Plex Server transcoding video but audio still doing "direct stream". Unchecking allow Direct Stream is the same. Note both of those settings are under Video; there is no similar audio setting.








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(If I use my Roku then plex will transcode AAC audio, fwiw, thats what I want Tivo to do)


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## enigma9o7 (Nov 28, 2015)

I found a public domain sample file at 5.1 Surround Sound test files various formats AAC,AC3,MP4,DTS WAV : Sir Round : Free Download, Borrow, and Streaming : Internet Archive however it I couldn't figure out how to direct download with surround. The torrent works, just select the file "5.1 Surround Sound AAC Test.mp4" from magnet:?xt=urn:btih:6dab7e06b6bb6514c46f7fffa45a038ffe25dad8&dn=5.1SurroundSoundTestFilesVariousFormatsAACAC3MP4DTSWAV&tr=http%3a%2f%2fbt1.archive.org%3a6969%2fannounce&ws=http%3a%2f%2fia600406.us.archive.org%2f7%2fitems%2f&ws=http%3a%2f%2fia800406.us.archive.org%2f7%2fitems%2f&ws=https%3a%2f%2fia800406.us.archive.org%2f7%2fitems%2f

When I play that sample file, plex says it's audio transcoding AAC to AAC (and video h264 to h264, no idea about that, but not important as my videos dont have that problem.) [On roku, plex shows Video as direct stream and transcoding AAC to AC3, that's what I want Tivo to do.]


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## enigma9o7 (Nov 28, 2015)

Anyone? I'd really like plex to transcode surround aac to ac3 for Tivo. I think the problem is that Tivo reports it can handle AAC so plex doesn't transcode, but in reality Tivo can only handle stereo AAC. Either that or it's passing it thru and my receiver can't handle it, but I looked into that, it seems very very few receivers can handle surround AAC directly.


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## enigma9o7 (Nov 28, 2015)

Still haven't solved this. Unless someone reports otherwise, I assume this is a problem for all tivo plex users?


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## Diana Collins (Aug 21, 2002)

Sorry to be gone for so long, but real life intervenes....

I've done some tests and you are correct, AAC 5.1 ends up coming out of the TiVo as stereo PCM. All of my 5.1 sources are various flavors of DTS with my only AAC titles being in stereo to begin with, so I never noticed this before. There are utilities that can convert AAC to AC3 (like Wondershare Video Converter).

That said, AAC 5.1 is probably the most troublesome audio format. The Tivo is not the only client for which AAC 5.1 gets down-mixed to stereo, the same happens on Apple TV, and FireTV according to some reports. You mentioned an AVR in one of your posts...most AVRs don't support AAC 5.1. When I rip a BD I keep two audio tracks, one in the highest quality multiplex codec available and the other in stereo AAC. That way the content will play on anything, thanks to the AAC track, but Plex (and a lot of other devices) uses the multichannel track.


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## enigma9o7 (Nov 28, 2015)

I realize I could convert or re-encode before streaming. But that's what Plex is for, the server is supposed to transcode it if the client doesn't support the format. 

So basically you've confirmed there's a problem with the tivo plex client, that it's not just me. It surprises me there is a similar issue in apple tv/etc but I don't have one of those, it's my Tivo I want to work right, and as mentioned my Roku does work right so the server is able to do it. 

So I'm wondering if there's a workaround like there is for DTS, or better yet how to get the actual client fixed thru an update or whatever.


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## Diana Collins (Aug 21, 2002)

The Plex client on TiVo is based on the OperaTV Smart TV client, so I wouldn’t hold my breath for changes there. As with the AppleTV client, the problem is Plex’s client profiles.


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## eherberg (Feb 17, 2011)

You could always write your own profile ... or just use the Roku like the rest of us do.


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## enigma9o7 (Nov 28, 2015)

Ok, seems like creating a user profile could be the solution. I'll try to figure that out. I'm surprised nobody has done that already tho, that thread is over 5 years old...


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## eherberg (Feb 17, 2011)

Writing xml files for profiles is an awful bit of fiddly work. To most - it's not worth the hassle when plenty of better clients exist on other devices.


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## Diana Collins (Aug 21, 2002)

The XML profiles are for DLNA clients, not Plex clients. Plex clients effectively "upload" their profile to the server.


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## enigma9o7 (Nov 28, 2015)

Ok so that's not an option then. Argh.


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## enigma9o7 (Nov 28, 2015)

A year later, and still no surround sound. Disappointing.


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## enigma9o7 (Nov 28, 2015)

Another year later, and still not working. Tivo still telling plex it can play surround AAC but then only playing stereo.

Tivo software version is now 21.10.2
Plex for Tivo 3.13.14

I see these are both newer versions than when I first posted this couple years ago. But still not fixed.


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