MINIX U9-H outputs incorrect PCM sample rate

kjack9 · February 28, 2018 at 7:02 PM

I would REALLY appreciate some help with a PCM sound problem I'm having. In fact, I will be happy to PayPal anyone who provides a solution or a patch with a $25 donation via PayPal for their trouble (please let me know if this is against the rules). I am at my wits end.

My entire library is encoded with Opus audio at 48khz. Playing any movie with a non-bitstreamed codec outputs as PCM, as you'd expect. According to Kodi and the log file, it is reading the stream at 48khz. The receiver is only getting 32khz, and is producing noisy (clipped) audio as a result.

Note that this only occurs with multichannel audio files. Stereo files play fine as 48khz. Bitstreamed/passthrough audio for DTS, TrueHD, etc also works fine.

Here a full debug log from playing a video with 7.1 Opus audio:

kodi.log

Here is an excerpt showing that the audio stream created is 48khz:

Code

12:57:43.150 T:3656377168  NOTICE: Creating audio stream (codec id: 86077, channels: 8, sample rate: 48000, no pass-through)

Kodi's CodecInfo showing 48khz: http://imgur.com/hBp9NWI

Yamaha Receiver showing 32khz: http://imgur.com/jZ8dFNP

Interestingly, the problem happens with audio set to "Fixed" as well.

With audio set to Best Match and input file of 48khz, I get 32khz at the receiver
With audio set to Fixed @ 48khz and input file of 48khz, I get 32khz at the receiver
With audio set to Fixed @ 96khz and input file of 48khz, I get 64khz at the receiver (with stuttering, intermittent audio)
With audio set to Fixed @ 192hz and input file of 48khz, I get 128khz at the receiver

So there is clearly something not lining up between what Kodi is requesting and what the Minix is outputting.

Device: MINIX U9-H

LibreELEC Version: 9.0 Alpha-8.90.4 (although the problem also happens on 8.3)

DTB file: gxm_q200_2g_minix_neo_u9.dtb

Receiver: Yamaha RX-V681

Speaker Configuration: 7.1.0

I don't know what else to look at. Again, I will send a $25 donation to anyone who can provide me a fix or a patch to resolve the issue. My next step is to try to save up for an NVIDIA Shield, but I know that has it's own issues. I'd rather not have to do that!

Thank you,

-KJack

Edit: Replaced partial log with full log (thanks DaVu)

**DaVu** · March 1, 2018 at 7:36 AM Official Post

this is not a full debuglog. Could you please provide a full debuglog beginning at boot?

And please don´t attach files here. There are paste-services which should be used instead. For grabbing the logfile simply use:

pastebinit /storage/.kodi/temp/kodi.log

and provide the link you got.

Thanks.

kjack9 · March 1, 2018 at 7:21 PM

DaVu, thanks for responding.

As you requested, I uploaded my kodi.log from the time of boot to just after stopping my test video. Note that I stripped out filenames and some other kinda-sensitive information, so don't be surprised when you see my <Removed> tags in there.

kodi.log - Google Drive

I also got a second MINIX U9-H in the mail today. It has the exact same behavior as the old one. The issue does not appear to be related to bad hardware at this point.

Thanks for looking!

-KJack

kjack9 · March 6, 2018 at 9:33 PM

For anyone who is also having this problem, I'm currently working around it with an addon called Audio Profiles.

I setup two audio profiles - one with "Best Match" and passthrough enabled and one with "Fixed" @ 192hz. I then bound "switch profile" to one of the keys on my remote.

If the movie has a bitstream-able codec (DTS, AC3, DTS-HD, TrueHD, etc), I use the passthrough profile. If the movie has a codec that will be converted to PCM (FLAC, opus, aac, etc), I use the fixed profile. With the fixed profile, the PCM output still has to be resampled from its original 48khz, but at least it's resampling up (to 128khz) rather than down (to 32khz).

My $25 bounty on a true fix for this problem still stands.

**wrxtasy** · March 7, 2018 at 12:57 AM

Just out of interest can you try S912 Kodi Krypton with the newer AML Linux Kernel from this post:

[8.2.2.3] LibreELEC 8.2 for S912

It's a straight .img.gz update into the update folder. If you have issues go back to the previous S912 LE Kodi Krypton.

kjack9 · March 7, 2018 at 4:48 AM

Quote from wrxtasy

Just out of interest can you try S912 Kodi Krypton with the newer AML Linux Kernel from this post:

[8.2.2.3] LibreELEC 8.2 for S912

It's a straight .img.gz update into the update folder. If you have issues go back to the previous S912 LE Kodi Krypton.

Sure, I'd be happy to try it. Is it safe to apply on top of 9.0 Alpha-8.90.4 or should I use a separate SD card to prevent my database from getting corrupted?

**wrxtasy** · March 7, 2018 at 12:03 PM

Well it's Kodi Krypton only and is update compatible with @kszaq's LE 8.2.x Krypton release so yes seperate SD card would be required to flash the .img

kjack9 · March 7, 2018 at 8:32 PM

The results were...interesting!

I used the linked img.gz file you posted with and the MINIX DTB from the resulting SD card. Note that the latest DTB file posted in the LibreELEC 8.2 thread didn't work.

With your modified kernel, I do get 7.1 PCM @ 48khz at the receiver! But the sound is wrong. I get sound only about half the time, cutting out every 1 second or so. The pitch is also way too high, and it sounds like the actors are chipmunks. Which was hilarious in the drama-filled scene I tested with, but I digress.

What other information can I provide to be of help?