Multichannel AAC and DTS (DCA) transcoding to stereo (AAC)

plexconnect

#1

I have been building a new Plex server, moving from a 32bit debian8 to a 64bit debian9 VM.
Installed lastest versions of PMS (1.10.1.4602) and PlexConnect (0.5-dev-161017).

Now my new server always transcodes Multi AAC and DTS to AAC stereo (according to plexpy). Multichannel AC3 and EAC3 is playing perfectly. I've been digging thru the logfiles and it seems the standard iOS.xml profile is used. Anyone have an idea on how to add AAC and DTS to the profile? I understand multichannel AAc isn't supported by the aTV, but can I force a transcode to AC3?

I'm a little hesitant to upload the logs as it contains pretty sensitive data.


#2

Please send me a sample video via WeTransfer (see PM for my email) to test.

I will discuss with development if they are open to modify the iOS profile (this will only be made if other platforms will benefit, such as iPad and iPhone) or if we should go the profile augmentation route in PlexConnect.


#3

Thx @moody_blue.

Sample is uploaded together with plex server logs.


#4

I see the problem. With dolby=off audio does not transcode (same behaviour with my iPad), but with dolby=on AAC 6-ch is transcoded to stereo. I’ll see what I can do. Not sure however what’s best, directstream AAC 6-ch or transcode to AC3 6-ch.


#5

I’m guessing transcode. MultiAAC is a bit of a hit and miss. Not all receivers support MultiAAC.

I’ve restored my old plex server (thank you veeam) and will run some tests with the old pms and plexconnect.


#6

Although this may not be the ultimate solution (I still have to check with developers if there is a better method), here is what you can do:

  1. Modify PlexAPI.py line 483 so that it reads xargs['X-Plex-Client-Profile-Extra'] = 'add-transcode-target(type=videoProfile&context=streaming&protocol=hls&container=mpegts&videoCodec=h264&audioCodec=ac3&replace=true)' (in other words, remove aac,mp3) so that AC3 is the only target whenever audio transcoding is necessary
  2. Create a user profile, based in iOS.xml (and with the same name) where line 35 reads <VideoAudioCodec name="aac"> (instead of <VideoAudioCodec name="*">) so that the 2-ch audio limitation applies to AAC only, otherwise AAC-6ch will be transcoded to AC3-2ch

#7

Can you please test with the attached PlexAPI.py file ? Not only with AAC-6ch films, but with others as well.

Use latest PMS and PlexConnect please. And no iOS.xml user profile.