[PROBLEM] Crackling audio when playing 5.1 FLAC over HDMI

[DavidGA]

When playing a 5.1 channel FLAC file over HDMI, the surround channels are reproduced correctly, but with a constant crackling noise over the audio.

Moode r710 on a Raspberry Pi 4 connected by HDMI to a Denon surround receiver.

Stereo files play perfectly fine.

[DRONE7]

Afaik MPD does not support surround....stereo output only.

A quick search of the forums finds this thread...

http://moodeaudio.org/forum/showthread.p...++surround

The MPD docs are here...
https://www.musicpd.org/doc/html/user.html

[DavidGA]

That thread is about creating an AC3 or DTS stream over an optical toslink connection.

HDMI supports uncompressed surround output, and as I said in the original post, it's *already* doing so. The surround is there, it's just all crackly and noisy.

[DRONE7]

That thread is about creating an AC3 or DTS stream over an optical toslink connection.

HDMI supports uncompressed surround output, and as I said in the original post, it's *already* doing so. The surround is there, it's just all crackly and noisy.

1) correct, but a search failed to find any other threads relevant to HDMI and surround.
2)"HDMI supports uncompressed surround output" but AFAIK MPD does not.
3) I'm happy to be proved wrong   and if you can find any reference in the linked MPD documents to surround over HDMI then please post and we can take it from there...

[DRONE7]

Post the output when you run...

Code:

alsacap

[DavidGA]

I restested with r730 and the problem persists. Here's the output of alsacap:

Code:

*** Scanning for playback devices ***
Card 0, ID `b1', name `bcm2835 HDMI 1'
  Device 0, ID `bcm2835 HDMI 1', name `bcm2835 HDMI 1', 4 subdevices (3 available)
    1..8 channels, sampling rate 8000..192000 Hz
    Sample formats: U8, S16_LE
    Buffer size range from 80 to 131072
    Period size range from 80 to 131072

      Subdevice 0, name `subdevice #0'
      Subdevice 1, name `subdevice #1'
      Subdevice 2, name `subdevice #2'
      Subdevice 3, name `subdevice #3'
Card 1, ID `Headphones', name `bcm2835 Headphones'
  Device 0, ID `bcm2835 Headphones', name `bcm2835 Headphones', 4 subdevices (4 available)
    1..8 channels, sampling rate 8000..192000 Hz
    Sample formats: U8, S16_LE
    Buffer size range from 80 to 131072
    Period size range from 80 to 131072

      Subdevice 0, name `subdevice #0'
      Subdevice 1, name `subdevice #1'
      Subdevice 2, name `subdevice #2'
      Subdevice 3, name `subdevice #3'

[Tim Curtis]

You should prolly post in the MPD repo.
https://github.com/MusicPlayerDaemon/MPD/issues

[DRONE7]

Agree with Tim's recommendation.seems your available formats/card specs may not align with surround output....

Perhaps the available formats in hardware do not align..?

Code:

Sample formats: U8, S16_LE

I have not used this (yet) but it may be of some help ?

https://www.mythtv.org/wiki/Using_ALSA%2...st_utility