Surround sound oddities

[pwhodges 2012]

I did this test using a Windows client machine on my internal network running Emby Theatre and the Opera browser.  The server is 4.3.0.30, also on Windows.

 

I have a lot of surround music recordings (i.e. no video), which I have made myself; the version in my Emby server is 4-channel AAC.  I can play these in Emby Theatre, and they are reproduced correctly on my 4-speaker setup.  But if I try to play them in the browser client, I get the "no compatible stream" message.  

 

So, as a test I played videos with surround sound; these were HEVC, so the video needed transcoding.  I found that a video with AAC surround was reproduced correctly, but in the browser an AC3 surround track was reduced to stereo.

 

The attached logs show the following in sequence (starting from around 16:40):

 

Attempt to play 4.0 AAC music file through browser - "No compatible stream"

(7 more like that to finish the playlist)

Attempt to play 4.0 AAC music file through Theatre - correct

Attempt to play film with 5.1 AAC track through Theatre - correct

Switch film soundtrack to 4.0 AC3 track through Theatre - correct

Attempt to play film with 5.1 AAC track through browser - correct

Switch film soundtrack to 4.0 AC3 track through browser - plays in stereo.

 

So Theatre gets it right, but the browser, which can play AAC in a film (and my 4.0 AAC music files embedded in a website) doesn't get sent the non-video AAC files.  Also, in the transcoding the AC3 track is rendered incorrectly.

embyserver.txt

ffmpeg-transcode-3bd3c2df-5175-4d59-9f58-c3f8e4f91cf4_1.txt

ffmpeg-transcode-05d0aec8-f73c-4346-a340-8da0c9112b49_1.txt

Edited December 3, 2019 by pwhodges

[Luke 42083]

Why do you feel the ac3 track is rendered incorrectly?

[pwhodges 2012]

Because it plays four channels through Theatre and two channels through the browser.

[Luke 42083]

Did you configure your audio settings in Theater?

 

Did you check your browser to see if AC3 is supported?

[pwhodges 2012]

I haven't touched the audio settings in Theatre - it's working perfectly.

 

OK, I didn't get that the browser needs to do the decode of the AC3 stream.  Opera and Firefox both fail at this, but Edge is playing it as expected, so presumably Emby is passing it through unchanged.*

 

Anyway, my main reason for posting is the one not yet mentioned:  Emby in the browser is saying "no compatible stream" for a 4.0 AAC file in an m4a container, even though it plays 2.0 AAC m2a files and also surround AAC streams in films.  The files it's not playing also play correctly from a website in the same browser, so they're perfectly compatible.

 

 

*Curiously, Dolby's own AC3 test on YouTube doesn't work in Edge, even though the AC3 sent from Emby does!

Edited December 3, 2019 by pwhodges

[Luke 42083]

 

 

Edge is playing it as expected

Microsoft added ac3 support to Edge, so that is why. But they are the only ones doing this.