Shield won't passthru 5.1 AAC?

[justinrh 174]

I'm trying to figure out this audio mess.  I have some MP4s with AAC 5.1 audio where the Shield downgrades to stereo unless I turn on "Dolby Processing".  I re-encoded one file with clone.AD to have AC-3 audio and Shield passes it thru as DD.  Why would the AAC be incompatible?  Is there more to the story than just codec?

original MP4:
Audio
ID                                       : 2
Format                                   : AAC LC
Format/Info                              : Advanced Audio Codec Low Complexity
Codec ID                                 : mp4a-40-2
Duration                                 : 1 h 24 min
Bit rate mode                            : Constant
Bit rate                                 : 256 kb/s
Channel(s)                               : 6 channels
Channel layout                           : C L R Ls Rs LFE
Sampling rate                            : 48.0 kHz
Frame rate                               : 46.875 FPS (1024 SPF)
Compression mode                         : Lossy
Stream size                              : 154 MiB (6%)
Title                                    : Surround

new file:
Audio
ID                                       : 2
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Commercial name                          : Dolby Digital
Codec ID                                 : A_AC3
Duration                                 : 1 h 24 min
Bit rate mode                            : Constant
Bit rate                                 : 448 kb/s
Channel(s)                               : 6 channels
Channel layout                           : L R C LFE Ls Rs
Sampling rate                            : 48.0 kHz
Frame rate                               : 31.250 FPS (1536 SPF)
Compression mode                         : Lossy
Delay relative to video                  : -5 ms
Stream size                              : 270 MiB (18%)
Title                                    : Surround

 

Recommendations on how to fix the audio w/o re-encoding the video?

Edited January 22, 2023 by justinrh

[Luke 37094]

Hi, is this playing through Emby?

[justinrh 174]

yes

[Luke 37094]

Hi.  Can you try sideloading our standard android app on the same device and see how that compares?

https://emby.media/emby-for-android.html

Thanks.

 

[justinrh 174]

Same result.

Interestingly (and frustrating!), I have a video that is AC3 and it would not produce sound unless I had "Dolby Processing" on.

[seanbuff 840]

Have you reviewed the Shield's audio settings and set them according to your AVR setup?

Edited January 16, 2023 by seanbuff

[justinrh 174]

Yeah buddy!  And that is another mass of confusion.  Yes, I have those same settings.

[ebr 14921]

Hi.  I'm not sure if it is the Shield or the outbound equipment but I don't think much will accept multi-channel AAC. 

[justinrh 174]

9 hours ago, ebr said:

I don't think much will accept multi-channel AAC

That's the conclusion I am arriving at.  Phooey!  I guess that Shield switch does some kind of massaging to make it palatable to the hardware.

[seanbuff 840]

I have quite a bit of multi-channel AAC content and the only way I get my (very old) AVR to accept it is with:

• Shield TV - Dolby Audio Processing = Enabled
• Emby Android TV app: Audio Output = "Auto"

[justinrh 174]

Does it sound good, like you would expect the 5.1 to sound?

[seanbuff 840]

1 minute ago, justinrh said:

Does it sound good, like you would expect the 5.1 to sound?

Yup, I can't discern any noticeable difference between that and a native AC3 5.1 track - but of course I'm by no means an audiophile.