Posts by racko

  • Raspberry Pi 4 - no sound over USB Audio S/PDIF

    [NOT SOLVED, I just found out the problem]

    Post

    RE: Raspberry Pi 4 - no sound over USB Audio S/PDIF

    Hi Hias! Believe it or not, I found the problem. You can see it in the attached picture.

    It's beyond my understanding, it didn't crossed my mind that this wireless keyboard could interfere with another USB device and cause such a problem. I used it in the last two years on my Rpi3 without any problems and when I bought the Rpi4 I've just hooked it in an USB port and left it there.

    A few minutes ago I said to try one more time the RPi4 from the ground, without HifiBerry Digi+ Pro attached and I…
    racko
    May 14, 2021 at 7:19 PM

    * * *

    Hi all!

    I just bought a Raspberry Pi 4 8GB and I installed LibreELEC 9.2.

    I configured the audio output device via USB (shown as ALSA: DigiHug USB Audio, Analog) because I use an external USB DAC. The problem is that all audio files are resampled at 48kHz, no matter they are 44.1/16, 96/24 or 192/24. "Output configuration" is set to "Best match"and "Limit sampling rate" at 192kHz (maximum sample rate supported by my DAC). I tried also with ALSA: DigiHug USB Audio, S/PDIF as audio output device, with same result, the audio files are resampled at 48kHz.

    With LibreELEC 10 Beta I don't have audio output at all over DigiHug USB Audio S/PDIF.

    On my Raspberry Pi 3B+ I don't have this problem, the audio files are sent at their original sample rate to the DAC with the same settings ("Best match" and limit sample rate 192kHz).

    I know that if I use "Best match" at output configuration and the software volume in Kodi is set 100%, the audio output should be passed unaltered, bit perfect, and this is my goal.

    Does anyone knows what is happening?

    Thank you!

  • LibreELEC and Hi-Res audio files / digital optical passthrough

    Sure, sorry ...

    It seems that audio capabilities are software limited because of the presence of analog audio chip in Minix Neo U1 and the way of how kernel driver is implemented.

    Running LibreELEC from microSD card, I replaced the U1 device tree (dtb.img) gxbb_p200_2G_minix_neo_u1.dtb with this generic version gxbb_p200_2G_1Gbit_OTG_Port.dtb which bypasses the analog audio chip and omits analog audio in output path.

    Amlogic S905 Device Trees: Index of /s905/8.2/device_trees/S905

    As a result, I lost analog audio on Minix Neo U1 (mic input and headphones output are not working anymore) but I have full capabilities over optical digital (TOSlink) output.

    And with the new device tree RTC (Real Time Clock) is not working also.

    It's important to mention this workaround worked for my Minix Neo U1, I don't know for other boxes. And another thing is other boxes with the same Amlogic S905 don't have this problem:
    [8.0.2e] LibreELEC 8.0 for S905/S905X

    Running Kodi (Google Play version), all audio files are resampled to 16-bit/48KHz over optical digital (TOSlink) output.

  • [8.2.3.1] LibreELEC 8.2 for S905/S905X

    Quote from kszaq

    racko Audio capabilities can be limited by analog audio chip which is present in Minix U1 (gives you higher quality analog audio) and all S905X/S912 devices. This is a software limitation, a result of how kernel driver is implemented by Amlogic. If you don't mind losing analog audio, you can try using gxbb_p200_2G_1Gbit_OTG_Port device tree on your Minix U1 which would omit analog audio in output path and might result in higher resolution optical out.

    , I don't know how to say it ... it's woooooorking!!! Finally!!! I have 24/192 over optical digital output! Yessir! I'm so happy ... :)

    @kszaq, chapeau! A big, big thank you!

    So, just to be sure I understood correctly ...

    With this device tree, the analog audio chip is bypassed and, because of this, the analog input (mic) and output (phones) from Minix Neo U1 are not working anymore. It's correct? If this is the only change, I don't mind and I really don't care because I don't use them anyway.

    Thank you again to all of you for help and support! :thumbup:

    P.S. Tager, just for my curiosity, I assume your boxes with Amlogic S905 are also having analog audio and this didn't affected digital audio in your case ...

  • [8.2.3.1] LibreELEC 8.2 for S905/S905X

    Quote from Tager

    Here are the my settings to guarantee output Stereo 44-192 without resampling (bitperfect) via SPDIF TOSLINK. (pic1, pic2)

    For tests it is possible to record force output in 192kHz (pic3) "Output configuration - Fixed"

    upd.

    As 192/24 files you transferred to the player? From network?

    I have from the HDD-USB or Flash-USB. To experiment try the same.

    So ...

    I've tried with the same settings as yours (and "Best match"), no sound for 24/192.

    With "Output configuration - Fixed" and "Limit sample rate" - 192KHz", no sound at all. Everything ok with any limit sample rates below 192KHz.

    My music library is on a Synology NAS, both TV Box and NAS are wired to my local network. I've tried right now with an HDD-USB, same results.

    But ... this is an interesting part. I tried again with my old media player, which I used before and I had a surprise (I don't know yet if it's a bad or a good one. :D ).

    As I said, my old media player was able to output bit-perfect up to 24-bit/192KHz over optical digital.

    Now, the audio stream is played but resampled as follows, it's a mess: :D

    - 44.1KHz > 44.1KHz

    - 88.2KHz > 44.1KHz

    - 96KHz > 48KHz

    - 192KHz > 48KHz

    Now I'm wondering if something happened with my optical cable when I changed the cables to the new media box. It's an old optical cable but I didn't had any reason to change it. I'm thinking to buy a new one, maybe this is the problem.

    But, there are other question marks. If the optical cable is faulty but still passes audio stream, there should be an audible sound for 24/192, even downsampled. But my DAC doesn't show anything, all four LED's which are showing the sample rate are off and I don't have sound at all. And it's also interesting the same cable it's working correctly up to 96Khz on with the new tv box. In this case, maybe the optical transmitter of my old media player has broken. Or both transmitter and optical cable are faulty. :D So, I don't know, there are a few variables here ... I need to see how to figure it out. I think I'll try with a new optical cable first, I don't have any other idea at this moment.

    Tager , thank you very much your efforts and help, I really appreciate it. :)

    P.S. I also asked, on the official Minix forum, if there is some kind of limitation regarding the optical digital output on Neo U1. Nobody from the company staff answered to my question till now ...

  • [8.2.3.1] LibreELEC 8.2 for S905/S905X

    Yes, I know, you're right. I was planning to use this TV Box as an additional audio source just for comfort. :)

    I have a PC configured as source for hi-res audio, FiiO E17K Alpen 2 DAC/headamp > Grado SR225e as mobile setup and Rokna RD-2 DAC > Exposure amp > Odyssey Nightingale loudspeakers.

  • [8.2.3.1] LibreELEC 8.2 for S905/S905X

    Quote from Tager

    Only one option, the manufacturer has put very ancient optical SPDIF-transmitter which can not work with a frequency of 192.

    Pretty hard to believe they found such an ancient optical transmitter to put on Minix Neo U1 but still possible, as @adamg said.

    Most of my hi-res audio library is 24/96 FLAC but I still have a pretty long list of albums on 24/192. Hmmm, I don't know what to do ... :(

    Anyway, thank you for your help! :)

  • [8.2.3.1] LibreELEC 8.2 for S905/S905X

    Quote from Tager

    Look in the audio settings - paragraph do not remember exactly - "limit sampling rate" - maybe there you have 96 khz? In this case, set 192 (or 352, 384)

    I don't have an option like this in LibreELEC, System settings > Audio

    These are my main audio settings:

    Audio output device:

    • ALSA: Default (AML-M8AUDIO Analog), PCM (X)
    • ALSA: AML-M8AUDIO, HDMI
    • PULSE: Default, Bluetooth Audio (PULSEAUDIO)

    Number of channels: 2.0

    Output configuration:

    • Fixed
    • Optimized
    • Best Match (X)

    Allow passthrough: ON

  • [8.2.3.1] LibreELEC 8.2 for S905/S905X

    Quote from Tager

    Amlogic S905, S905X great outputs 192/24 on optics SPDIF (TOSLINK), starting with version 7.0.X. (see pic.1)

    My report -> [8.0.2e] LibreELEC 8.0 for S905/S905X

    In recent releases of 8.1.x ower USB can be output to the DAC the frequency of 352.8 khz and 384khz - (see pic.2)

    It works on all my players, and a few of my devices DAC.

    That's great! So what could be the problem with my Minix Neo U1?

    My DAC is Rokna RD-2 and definitely is capable of 192/24 over TOSlink input, it works with my old media player (Xtreamer Sidewinder MK1).

    ROCKNA RD-2 DAC (2007): Company | Rockna Audio

    Specs: AudioStereo - AD LABS RD-2 SE DAC

  • [8.2.3.1] LibreELEC 8.2 for S905/S905X

    Quote from adamg


    As far as I'm aware this issue is not specifically related to just Amlogic, 24bit/48KHz was the original design spec for S/PDIF but as technology progressed higher bit rates where supported but both the sender and receiver have to support it. These boxes are cheap chinese devices hence I said don't expect miracles. I'm not 100% sure if these boxes are capable of a 24/192 stream, I think your best option is to build a media PC with a high end sound card, sorry I couldn't be of more help.

    Yes, regarding the 24/192 audio stream on these boxes it could be like that, you're probably right. But I'll try to find a solution anyway, I'm curious ... who knows.

    I already have a PC configured for hi-end audio which I'm mainly using for listening on headphones (with another DAC and headamp) and sometimes as source for my stereo audio system. But is was the time to change my old media player and I thought I could also using it for audio stuff, just for my comfort.

    Thanks!

  • [8.2.3.1] LibreELEC 8.2 for S905/S905X

    Quote from adamg

    I have used that under a different brand name, you can also purchase it for much cheaper on eBay, don't expect miracles with it though, I used it on an Nvidia Shield, it did allow me to extract 5.1 audio from HDMI to TOS for the surround sound system I was using at the time but you have to select the correct Kodi settings otherwise you will be scratching your head for hours thinking it doesn't work. In Audio settings number of channels 2.0, allow passthrough, enable DD AC3 transcoding and change the mode to 5.1 on the extractor. I would get some surround sound sample files to make sure sound is routed to individual speakers as well.

    Thank you for you info.

    I'm particulary interesed in 2 channels output for "normal" and hi-res audio files, not for surround. I only have an external DAC and a stereo amplifier, I'm not using a receiver.

    I have an important lossless music library (FLAC and WAV), almost 30% of it in hi-res audio formats (24-bit/96KHz, 24-bit/88.2KHz and 24-bit/192KHz). That's why is so important to me to find a solution to output audio files over optical digital (or coaxial digital) bit-perfect, with no resampling. That's why I've choosed Minix Neo U1 and LibreELEC (btw, thanks kszaq for doing this :thumbup:).

    I just wanted a single device who can handle all kind of media files and it was very difficult to find clear informations regarding this audio requirement and to find a suitable combination of hardware and software for my needs And, despite my efforts, I had a final surprise ...:P

    Sorry for this small offtopic but maybe this info which came up (Amlogic does not support 24-bit/192KHz over S/DIF TOSlink) could be important for other users too.

  • [8.2.3.1] LibreELEC 8.2 for S905/S905X

    Quote from Tim_Taylor

    Try it.

    I guess 192khz is only supported @coax

    Yes, I think I'll try a HDMI Audio Extractor. I've found another few models with TOSlink output up to 24/192, at least in their specs. :)

    My old media player (Xtreamer Sidewinder) can output 24/192 with no problems over TOSlink, I've use it {too} many years. And there are plenty of DAC's with specified 24/192 optical digital inputs.

    It seems TOSlink is capable of 24/192, though ...

    ESI - Knowledge Base: 192kHz support of S/PDIF output of Juli@ / Juli@ XTe

    24/192 over SPDIF - already possible? | Steve Hoffman Music Forums