[GiGaBlue UHD QUAD 4K] No Volume Control on Only Optical Output

[CRMS]

What type of support thread are you creating?

Possible bug

What OpenViX Image build number are you using?

6.8.006

Have you tried re-flashing WITHOUT settings restore?

NO

Have you tried re-flashing WITH a settings restore?

NO

I have noticed this for quite a few years in several OV versions.
I use the GB optical output into a BT transmitter to BT speakers and leave a Samsung TV sound set to external audio.
When I view TV live or a recording on the TV or projector, the GB remote adjusts the volume.
When I listen to a radio recording, TV switched off, the GB remote doesn't adjust the volume and I have to use the BT transmitter or speaker volume.
I guess that the HDMI circuit when live and providing a picture is also influencing the optical output, and so the GB volume control works.
It would be great if this can be investigated and if possible the volume control can adjust the optical output in the absence of an HDMI signal.

 

[twol]

Google AI says…
Adjusting volume over an optical output can be tricky because optical (Toslink) cables transmit audio as a fixed digital signal rather than an analog voltage. Because of this, your TV or source device usually cannot adjust the volume directly, and you will need to control it at the receiving end (e.g., your soundbar, AV receiver, or powered speakers).

 

[CRMS]

Thanks and interesting.
I also asked Chat GPT and got this:
"When the TV is on:

1. The Gigablue establishes a full HDMI handshake with the TV
2. HDMI-CEC becomes active
3. The receiver outputs audio in a mode linked to the HDMI subsystem
4. The Gigablue remote volume buttons affect the active audio path
5. The optical output level changes along with it (either directly or indirectly)

So:

• GB remote → modifies receiver audio level → optical output changes → BT transmitter level changes

Everything behaves normally.

When the TV is off:

1. HDMI handshake disappears or changes state
2. The Gigablue may switch to:
   • “raw passthrough”
   • fixed S/PDIF level
   • inactive HDMI audio control mode
3. The optical output becomes fixed-level digital audio
4. The GB remote volume buttons no longer affect output level

So now:

• Optical output stays constant
• Only the BT transmitter/speaker volume can change loudness

That’s why the system suddenly behaves like a standard hi-fi digital output.
I have HDMI-CEC off and a couple of other suggestions for audio processing which I'll try.

 

[Joe_90]

The only situation where the receiver volume control definitely won't work over HDMI or S/PDIF (apart from fixed output or mute) is where the source audio is DD (or possibly AAC, but I don't have sat/terrestrial AAC to verify) unless you have it set to downmix or otherwise to analog audio. The analog outputs, where supported, such as SCART or audio over RCA (phono) type should have full audio level control in all circumstances.

Now, I have a similar setup to yours, where I occasionally listen over bluetooth headphones late at night. The particular receiver is my AX HD61 and I have it connected via HDMI to a TV and also to a cheapo optical to bluetooth transmitter. I mute the TV audio and listen via bluetooth headphones and the audio level is completely controllable. It doesn't matter whether the TV is on or off. The bluetooth transmitter is really cheap (£20 - ish) and does not support DD audio at all, so I have to downmix to PCM. If I don't do this, then I get no audio if I tune, say BBC, ITV or C4/5 on satellite if DD audio is being transmitted. Other channels using MP2 are fine irrespective of audio setting on the receiver. This would include all radio channels on satellite.

Now, if you are listening on terrestrial Freeview (but I recall you use satellite on a boat), it may be that the AAC audio is fixed on your GB. Try checking your audio settings to see if your AC3 and AAC settings are set to downmix, rather than passthrough. However, on my setup, I get no audio from my bluetooth transmitter if my AC3 settings are set to passthrough and DD is being received.

Treat AI answers with caution!