[PROBLEM] Getting 24 bit audio to HDMI

[oomzay]

My Onkyo TX-SR875 receiver is capable of 24 bit audio however "aplay" is reporting, and playing only U8 and S16_LE to it.

Code:

$ aplay -D hw:b1,0 /dev/zero --dump-hw-params
HW Params of device "hw:b1,0":
--------------------
...
FORMAT:  U8 S16_LE
...

How do I get 24 bit to the HDMI interface?

I see this in /boot/config.txt:

Code:

hdmi_drive=2
hdmi_blanking=1
hdmi_force_edid_audio=1
hdmi_force_hotplug=1

[Nutul]

My Onkyo TX-SR875 receiver is capable of 24 bit audio however "aplay" is reporting, and playing only U8 and S16_LE to it.

Code:

$ aplay -D hw:b1,0 /dev/zero --dump-hw-params
HW Params of device "hw:b1,0":
--------------------
...
FORMAT:  U8 S16_LE
...

How do I get 24 bit to the HDMI interface?

I see this in /boot/config.txt:

Code:

hdmi_drive=2
hdmi_blanking=1
hdmi_force_edid_audio=1
hdmi_force_hotplug=1

Searching the web lead me here. You may want to read from the marked post downwards; it seems to be resolved applying what writes there... (I didn't follow the links with the possible solution, though)

https://github.com/raspberrypi/linux/iss...1065892284

[oomzay]

@Nutul, Thanks. I found that article too, but was secretly, really, really hoping there was a simpler answer because much of it is maamajumbo to me at this point! I will go back there if no simpler/more contemporary solution shows up before long.

[Nutul]

@Nutul, Thanks. I found that article too, but was secretly, really, really hoping there was a simpler answer because much of it is maamajumbo to me at this point! I will go back there if no simpler/more contemporary solution shows up before long.

Since that solution comes from people messing around with Raspi OS I doubt there is a "simpler" solution...

[Tim Curtis]

AFAIK the HDMI implementation on RaspiOS Bullseye only supports 16/48.

On Pi5/Bookworm using an HDMI connection to my Yammy AVR and running the ALSA speaker-test utility it looks like up to 8 channels at 24/192K is supported although the exact bit depth is not reported in ALSA hw_params, instead it lists:

Code:

format: IEC958_SUBFRAME_LE
subformat: STD

[oomzay]

Thanks for the tips. I am now playing with bookworm to see if that solves 24bit audio/HDMI.

I don't know if REW (electrical-level) testing would measure the difference objectively but I will report back once I receive second-hand Onkyo TX-NR905 AVR which has an audio format display that I can hopefully trust. (as well as an extra 10W/per channel, which the various Linn speakers I have just eat for breakfast