gnome-force-remote-audio

Bring back audio when you connect to a GNOME machine over RDP from an Android or iOS device.

GNOME Remote Desktop (gnome-remote-desktop, "grd") streams the screen fine to phones/tablets, but it deliberately disables audio output redirection for clients that report themselves as Android or iOS. The result is video without sound — no matter what you do in the client.

This project neutralises that behaviour with a tiny LD_PRELOAD shim. It does not patch, recompile or replace gnome-remote-desktop, so it survives package updates and is trivial to remove.

Built for Zorin OS 18 but works on any distro with GNOME Remote Desktop 45+ (Ubuntu 24.04+, Fedora 39+, Arch, …).

By default everything is user-scoped — no sudo, no system files touched.

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The problem

You enable Remote Desktop (Desktop Sharing) or Remote Login on a GNOME machine and connect from your phone with an RDP client (Microsoft Remote Desktop, aFreeRDP, …). You get the desktop, the mouse and the keyboard — but never any sound. Playing a video on the GNOME machine produces no audio on the phone.

Why it happens

gnome-remote-desktop contains this hardcoded check in src/grd-session-rdp.c:

if (freerdp_settings_get_bool (rdp_settings, FreeRDP_AudioPlayback) &&
    (os_major_type == OSMAJORTYPE_IOS ||
     os_major_type == OSMAJORTYPE_ANDROID))
  {
    g_warning ("[RDP] Client cannot handle graphics and audio "
               "simultaneously. Disabling audio output redirection");
    freerdp_settings_set_bool (rdp_settings, FreeRDP_AudioPlayback, FALSE);
  }

If the RDP client reports its OS as Android or iOS, grd forces the FreeRDP_AudioPlayback setting to FALSE, so the audio capture stream is never created. You can see it happening in the journal:

[RDP] Client cannot handle graphics and audio simultaneously. Disabling audio output redirection

This is a deliberate workaround by grd for old mobile clients that could not handle graphics and audio at the same time. The check is still present in gnome-remote-desktop 51.x, so updating the package does not help.

Separate issue: if you run GNOME inside a VM with no sound card, there is no audio to redirect at all (your sink shows up as "Dummy Output"). See Optional: virtual sound card.

What this does

• Builds a tiny LD_PRELOAD shim (src/grd-audio-fix.c) that interposes freerdp_settings_set_bool() and ignores any attempt to turn FreeRDP_AudioPlayback OFF.
• The value already negotiated with the client (TRUE when the client asked for the rdpsnd audio channel) is preserved, so grd keeps the audio stream alive.
• Injects the shim into gnome-remote-desktop.service through a systemd drop-in — per-user by default, system-wide with --system.

It only ever touches the AudioPlayback key, and only blocks attempts to set it to FALSE. A client that genuinely does not support audio leaves the key FALSE from the start, so nothing changes for it.

Requirements

• gnome-remote-desktop 45+ (tested on 46.3).
• A systemd --user session.
• Either gcc to build the shim, or the --prebuilt flag (downloads a prebuilt x86_64 binary — see below).
  • Debian/Ubuntu: sudo apt install gcc
  • Fedora: sudo dnf install gcc
  • Arch: sudo pacman -S gcc
• Optional: FreeRDP development headers so the installer can auto-detect the numeric id of FreeRDP_AudioPlayback (otherwise it defaults to 714, correct for FreeRDP 3.x).
  • Debian/Ubuntu: sudo apt install freerdp3-dev

Install

From source (recommended)

git clone https://github.com/ArchDityaa/gnome-force-remote-audio.git
cd gnome-force-remote-audio
./install.sh

Then reconnect from your phone and play something on the GNOME machine.

Prebuilt (no gcc needed)

If you cannot (or do not want to) install gcc, pass --prebuilt to download the library from the latest release instead of compiling it:

git clone https://github.com/ArchDityaa/gnome-force-remote-audio.git
cd gnome-force-remote-audio
./install.sh --prebuilt

install.sh falls back to the prebuilt library automatically when gcc is not found, so simply running ./install.sh also works.

The prebuilt shim is x86_64 and compiled for FreeRDP_AudioPlayback = 714 (FreeRDP 3.x, used by every distro with gnome-remote-desktop 45+). On a different architecture — or a FreeRDP 2.x system — install gcc and build from source instead; the installer refuses to use the prebuilt library on non-x86_64 machines. The download is verified against a published SHA-256 checksum.

If you use Remote Login / headless sessions (you connect before logging in locally), also install the system-wide hook:

./install.sh --system

If your machine is a VM without a sound card, add a virtual one:

./install.sh --with-virtual-soundcard

You can combine flags: ./install.sh --system --with-virtual-soundcard.

The default (./install.sh) touches only files in $HOME — no sudo.

Verify

./diagnose.sh

A healthy result shows the shim as LOADED for a running gnome-remote-desktop-daemon, and recent log lines containing [RDP.AUDIO_PLAYBACK].

Manual checks (while a client is connected and audio is playing):

# the shim is mapped into the daemon:
grep libgrd-audio-fix /proc/$(pgrep -f gnome-remote-desktop-daemon | head -1)/maps

# grd set up audio:
journalctl --user -u gnome-remote-desktop.service -f | grep AUDIO_PLAYBACK

# the audio stream is running:
pw-top        # look for gnome-remote-desktop-daemon with a S16LE/audio row

Uninstall

./uninstall.sh
# mirror the flags you used, e.g.:
# ./uninstall.sh --system --with-virtual-soundcard

Troubleshooting

Symptom	What to check
Still no audio after ./install.sh	Run ./diagnose.sh; make sure the daemon shows the shim as LOADED. Restart the service: systemctl --user restart gnome-remote-desktop.service.
Works for Desktop Sharing, not Remote Login	Remote Login uses the system service — install with ./install.sh --system.
Log still shows "Disabling audio output redirection"	Expected — not an error. grd prints that g_warning before it calls the function this shim intercepts, so the line appears even when the fix works. Judge success by ./diagnose.sh (shim LOADED) and by [RDP.AUDIO_PLAYBACK] lines instead.
Sound settings show "Dummy Output", nothing plays	The machine has no sound card (common in VMs). Re-run with --with-virtual-soundcard.
Audio works but stutters/glitches	grd disabled it for a reason; some mobile clients handle graphics+audio poorly. Try another client, or use NoMachine/RustDesk.
Installer warns it defaults the id to 714	Install the FreeRDP headers (sudo apt install freerdp3-dev) so it can auto-detect, then re-run.

How it works

install.sh:

1. Detects the numeric id of FreeRDP_AudioPlayback from the installed FreeRDP headers (falls back to 714 for FreeRDP 3.x).
2. Compiles src/grd-audio-fix.c into libgrd-audio-fix.so — or, with --prebuilt (or when gcc is missing), downloads a prebuilt library and verifies its SHA-256 checksum.
3. Installs the library and a systemd drop-in that sets LD_PRELOAD=/path/to/libgrd-audio-fix.so for gnome-remote-desktop.service (user scope by default, system scope with --system).

The shim implements freerdp_settings_set_bool() and forwards every call to the real function via dlsym(RTLD_NEXT, …) — except that a request to set FreeRDP_AudioPlayback to FALSE is silently ignored. Because grd checks the setting right after it tries to clear it, audio redirection stays on.

No FreeRDP/WinPR development headers are needed at runtime: WinPR's BOOL is a plain int, so the shim's prototypes are ABI-compatible with the real functions.

Note: grd emits its Disabling audio output redirection warning before it calls freerdp_settings_set_bool(), so that line still shows up in the journal even when the shim is working. The shim stops the setting from actually being cleared — it does not (and cannot) silence the warning.

Optional: virtual sound card

A VM usually has no sound card, so PipeWire only exposes a silent "Dummy Output". --with-virtual-soundcard loads the kernel's snd-dummy module and makes it persistent via /etc/modules-load.d/snd-dummy.conf, giving the system a real sink that grd can capture.

Note: snd-dummy is an in-memory device, so audio still is not heard on the machine itself — that is expected. The point is to give PipeWire/WirePlumber a proper sink whose monitor grd can stream to the client.

Compatibility

Component	Version	Notes
gnome-remote-desktop	45–51+	The Android/iOS check exists throughout.
FreeRDP	2.x / 3.x	Id auto-detected; 714 default for 3.x.
GNOME Shell	45–48	Tested on 46 (Zorin OS 18).
Distro	Ubuntu 24.04+/Fedora 39+/Arch	Any systemd + PipeWire/WirePlumber.

Caveats

• grd disables audio for Android/iOS for a reason: some clients cannot handle graphics and audio simultaneously. If you get stutter, the shim is not the problem — the client is.
• If you want first-class mobile audio without any shim, consider a dedicated remote-desktop tool such as NoMachine or RustDesk.
• This project only fixes audio output redirection. Microphone/audio input redirection is unaffected.

License

MIT — see LICENSE.

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Bahasa Indonesia

Masalah: Saat mengakses desktop GNOME lewat RDP dari HP/tablet (Android/iOS), gambar muncul tetapi tidak ada suara. Penyebabnya: GNOME Remote Desktop (gnome-remote-desktop) sengaja mematikan redirection audio bila klien melaporkan OS-nya Android/iOS (lihat potongan kode di atas). Batasan ini masih ada sampai gnome-remote-desktop 51.x, jadi update paket tidak menolong.

Solusi: Repo ini membuat shim LD_PRELOAD kecil yang menetralkan pemaksaan AudioPlayback = FALSE tersebut, tanpa mengubah/mengompilasi ulang gnome-remote-desktop, sehingga tahan update dan mudah dibatalkan.

Pasang (default hanya menyentuh berkas di $HOME, tanpa sudo):

git clone https://github.com/ArchDityaa/gnome-force-remote-audio.git
cd gnome-force-remote-audio
./install.sh
# untuk Remote Login/headless:        ./install.sh --system
# untuk VM tanpa sound card:          ./install.sh --with-virtual-soundcard
# tanpa gcc (unduh binary siap pakai):  ./install.sh --prebuilt

Verifikasi: ./diagnose.sh — hasil sehat menampilkan shim LOADED dan ada baris log [RDP.AUDIO_PLAYBACK].

Hapus: ./uninstall.sh (samakan flag dengan saat memasang).

Catatan: Jika mesin adalah VM tanpa sound card, sink-nya hanya "Dummy Output"; gunakan --with-virtual-soundcard (memuat modul snd-dummy).