id = 2073
title = "Audio: missing ability to disable microphone input from host?"
state = "opened"
created_at = "2024-01-04T21:49:16.262Z"
closed_at = "n/a"
labels = ["Audio"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/2073"
host-os = "Windows Server 2022"
host-arch = "x86_64"
qemu-version = "QEMU emulator version 8.2.0"
guest-os = "Windows 10, Fedora 39"
guest-arch = "x86_64"
description = """**It appears there is no way to disable the microphone / input to the audio backend device(s).**


There are at least two cases where this matters:
1. The host has no microphone input (e.g. only HDMI audio output with video).
2. The host has a microphone input, but the user doesn't want the guest VM to have access to the microphone/input.

I tried the option in.channels=0, as that seemed the most obvious way, though that doesn't work.

For -audio dsound, it appears that CLSID_DirectSoundCapture is unconditionally acquired.

There will also be later periodic warning/text outputs from QEMU "Could not create a backend for voice virtio.in", if you're running on a host system with no audio input device.

Adding a couple backend checks for channels > 0 may work well.  Not sure if it matters that audio front end device in the VM still thinks there is an audio input."""
reproduce = "n/a"
additional = "n/a"