Multichannel AAC conversion not working as expected

[Fweep 11]

In the Emby app on my Roku Streaming Stick 4K, I am trying to play a video whose only audio stream is 5.1 AAC. The Roku does not support multichannel AAC, so the audio needs to be converted.

In the Emby app on the Roku, I have Convert Multichannel AAC & FLAC set to YES. It is my understanding this should ensure the 5.1 AAC is converted to 5.1 AC-3. However, Emby is converting it to stereo AAC instead.

What do I need to do to get it to stay multichannel?
 

ffmpeg-remux-88d1396d-0903-47c8-98bf-f0bcfdea9034_1.txt

[ebr 16169]

9 hours ago, Fweep said:

It is my understanding this should ensure the 5.1 AAC is converted to 5.1 AC-3

Hi.  Where did you get that understanding?

[speechles 2055]

The option will convert the AAC 5.1 into AC3 5.1, but you must ensure your Roku has detected support for Dolby.

----

from a previous post of mine:

On Your Roku, press HOME and follow the steps below:

1. Start at Settings
2. Move to Audio
3. Move to Preferred streaming format
4. Choose Dolby
5. Move back once to Audio
6. Move to Digital output format
7. Move to Custom
8. Move to Dolby Digital Plus and click OK
9. Move back and make sure Dolby Digital Plus is checked
10. Move back and make sure Custom is checked
11. Press Home
12. Launch Emby and it will now support full Dolby AC3 and EAC3 and EAC3 w/ATMOS

(NOTE: You may have to fully restart your Roku to have these changes take effect. Some models and HDMI chains require the restart.)
(NOTE2: You can also enable DTS in custom if your know your equipment will support this too.)

If you are using AUTO for Audio settings it can allow the Roku to make mistakes depending on how things are connected when it detects your audio equipment. If you tell the Roku which Audio settings you desire it will support these immediately without having to detect them. The Emby app merely reads what the Roku has told it your Audio settings support. This is why the change must be done in the Audio settings of your Roku.

 

from your logs:
http://192.168.0.47:8096/emby/videos/19924/main.m3u8?DeviceId=12037a4e-df9b-5660-9e51-fea642c9179c&MediaSourceId=d10014398521b1e2485ff470026bf845&PlaySessionId=98d5b548c4f841f0a34e1f0dc909c9d9&api_key=‌4130e0435692455ba2a5f042796af085‌&VideoCodec=h264,hevc,mpeg2video&AudioCodec=aac,mp2,mp3,flac,vorbis,lpcm&VideoBitrate=59680000&AudioBitrate=320000&MaxWidth=3840&MaxHeight=2160&AudioStreamIndex=1&TranscodingMaxAudioChannels=2&SegmentContainer=ts&SegmentLength=3&MinSegments=1&AllowInterlacedVideoStreamCopy=True&BreakOnNonKeyFrames=True&SubtitleStreamIndexes=-1&ManifestSubtitles=vtt&h264-maxrefframes=16&h264-videobitdepth=8&h264-maxframerate=60&h264-profile=high,main,baseline,constrainedbaseline&h264-deinterlace=true&h264-level=41&h264-videorotation=0&mpeg2video-videorotation=0&mpeg2video-maxframerate=60&mpeg2video-deinterlace=true&hevc-videorotation=0&hevc-maxframerate=30&hevc-codectag=hvc1,hev1,hevc,hdmv,dvh1,dvhe&aac-audiochannels=2&flac-audiochannels=2&lpcm-audiochannels=2&mp3-audiochannels=2&mp2-audiochannels=2&vorbis-audiochannels=2&TranscodeReasons=AudioChannelsNotSupported

--> &AudioCodec=aac,mp2,mp3,flac,vorbis,lpcm <--

Notice in AudioCodec there is no AC3 listed. The Roku believes your equipment only supports Stereo. The transcode reason shows the Roku has not detected surround support.

 

Edited September 3, 2024 by speechles

[Fweep 11]

7 hours ago, ebr said:

Hi.  Where did you get that understanding?

A 2017 post by speechles in a similar thread.

 

1 hour ago, speechles said:

The Roku believes your equipment only supports Stereo. The transcode reason shows the Roku has not detected surround support.

All of the Roku audio settings you suggested are already set exactly as you specified.

• Settings > Audio > Preferred streaming format > Dolby
• Settings > Audio > Digital output format > Custom > Dolby > Dolby Digital Plus
• Settings > Audio > Digital output format > Custom > DTS > On

When there's AC3 audio in the file, it normally plays fine. The Roku is plugged into a receiver, and the HDMI output of the receiver goes to the TV. If I go to Settings > Audio > Digital output format > Auto, it says that it detects DD+ and DTS-HD. I don't want to use Auto because I want to make sure it picks DD+ whenever possible.

Why it's not reporting multichannel to Emby, I don't know. 

 

[speechles 2055]

Have you restarted the Roku? After changing the Roku audio settings for pass through you will need to restart the Roku.

[Fweep 11]

Yes, the Roku turns off and on with the receiver. It restarts every time I use it.

[Fweep 11]

Well fooey. I take back what I said about 5.1 AC-3 audio streams working. Emby is converting them to stereo as well. This didn't used to happen!

I also tried changing the Roku digital output format to stereo, restarting, and back to DD+, and restarting again. No change in behavior.

 

[Luke 42077]

12 hours ago, Fweep said:

Well fooey. I take back what I said about 5.1 AC-3 audio streams working. Emby is converting them to stereo as well. This didn't used to happen!

I also tried changing the Roku digital output format to stereo, restarting, and back to DD+, and restarting again. No change in behavior.

 

Hi, how are the audio settings in the app configured?

[ebr 16169]

What is the device connected to?  

17 hours ago, Fweep said:

the Roku turns off and on with the receiver. It restarts every time I use it.

It actually restarts?  Meaning it goes through the long bouncing "Roku" logo?

This shouldn't be the case and may be the problem.

[Fweep 11]

I appreciate your continued efforts to try to help.

The Roku Stick 4K's USB power supply is plugged into the USB to AC adapter it came with, which is plugged into a switched outlet on the back of the receiver. So yes, when the receiver is off, the Roku Stick plugged into one of the receiver's HDMI inputs is also powered down; and when the receiver is turned on, the Roku powers up, and I get the bouncing logo. I'm certain this is a red herring; the Roku turning off when the receiver is not in use has never caused any problems before. Settings are preserved and I was previously able to play videos with 5.1 sound when the audio track was AC3 or EAC3 or DTS. It is only recently that everything's gone stereo-only.

In the Emby app on the Roku:

• Settings > Playback > Audio and Subtitle Settings = there's nothing to adjust; it only says "To adjust please use the user menu in the web app."
• Settings > Playback > Convert Multi-Channel AAC/FLAC = YES

In the Emby app on my server (localhost:8096, under my username in the left sidebar):

• Playback > Audio: Preferred audio language = any
• Playback > Audio: ☑Play default audio track regardless of language
• Playback > Audio: ☑Remember audio track selections

I'm not sure what else to look for; I don't see any other Emby audio settings.

The Roku claiming multichannel is unsupported seems to be the issue. In fact, I just checked Netflix, Disney+, Roku Media Player ... I am unable to get any multichannel content to play as multichannel. So it's not an Emby problem, after all.

I did see in some previous discussions that some Rokus are known to lie about their capabilities. Maybe with a recent Roku OS update, it has turned into one of those stinking liar devices. I mean, like I said, it was working before, and I've got it configured for Dolby Digital and everything.

 

[speechles 2055]

1 hour ago, Fweep said:

The Roku Stick 4K's USB power supply is plugged into the USB to AC adapter it came with, which is plugged into a switched outlet on the back of the receiver. So yes, when the receiver is off, the Roku Stick plugged into one of the receiver's HDMI inputs is also powered down; and when the receiver is turned on, the Roku powers up, and I get the bouncing logo.

Bingo. We found the problem. The Roku must be the FIRST thing turned on. In fact, you should have your Roku never power down. It should remain on all the time. Then updates can happen, and you can press the HOME button on your Roku and HDMI-CEC will wake up all devices on the HDMI chain. The Roku is expected to be an always on device.

If you leave the TV on, but turn off the AVR which turns off the Roku. Then with the TV still on turn the AVR on which will turn on and boot the Roku. That should keep the HDMI-ARC happening and should allow the Roku to see Dolby is supported.

Do you turn on your TV then turn on the AVR? Or turn on the AVR, then turn on the TV?

Edited September 4, 2024 by speechles

[Fweep 11]

@speechles - Nope! Like I said, it was never a problem before.

We are correct, though, in that it's not an Emby problem. I just found the answer in the Roku community forum. There's one sound setting on the Roku that makes all the difference: When something is playing, press the * button on the Roku remote. Check the volume setting there. Is Auto Leveling or Night mode enabled? Either one of those will cause the Roku to be in a stereo-only mode. It has to be set to Off for multichannel to work.

Indeed, I was playing around with night mode a couple weeks ago and didn't notice until now that I was not getting multichannel anymore. As soon as I set it to Off and restarted what was playing, I got multichannel output again. Emby's AAC multichannel transcoding is working as it should, as is direct play of Roku-supported multichannel formats.

What a ridiculous quirk of the Roku. I mean, I understand that the volume leveling requires transcoding of the audio, but you'd think they wouldn't completely disable multichannel for that, or would at least warn that it results in stereo. Presumably they are trying to avoid encoder licensing fees or the complications of downgrading to a patent-free format like regular AC3.

Sorry to waste your time. At least we learned something else to keep in mind for future troubleshooting.

Edited September 4, 2024 by Fweep
minor copy edits

[ebr 16169]

Ah, yes - night mode.  I always forget about that.  I wish Roku had some indication that it was on.

Still, I highly recommend plugging your Roku into an always on outlet.  It is designed to sleep, not power down/up on each use and it is very possible that you could run into HDMI handshake issues doing it like you are (although, more likely if the Roku actually powers up before the receiver).

Software updates are not going to work very well the way you have it either...

[Fweep 11]

My recollection is that I put it in the switched outlet for a reason. Something with was not working right when I had it plugged into a regular outlet. I don't remember what it was. It was something like the Roku was never actually going to sleep, or the TV wouldn't turn off, or maybe it was something odd with the receiver. I don't want to mess with it again since it works as-is.

Updates work fine. They are checked for at startup. Worst case, you get an update downloaded but it doesn't install until next restart.