MaxsTechReview
adc86fc7df
* Build the DirectAudio relay from source
The relay helper shipped as a prebuilt libdirectaudiorelay.so with no source in the
repo. Its source (The412Banner/directaudio @ 3548a4a, the commit the bundled driver
names in version.txt) now lives in tools/directaudio-relay, unmodified, and CI and
build_local.sh compile it into jniLibs the way proot is built. It shares
da_relay_proto.h with the PulseAudio sink, which is byte-identical to its own copy.
* DirectAudio relay: prime before playing, one consumer, safe buffer floors
- The output stream started before the client had its ring, so every connection
opened with a run of short callbacks: six clicks per stream on a RedMagic, even idle.
The callback now plays silence until the ring holds its target, and only a real
underrun afterwards counts.
- An underrun ends the block with a short fade and waits for the ring to refill to
target before resuming with a fade in, instead of zero-padding every short callback.
Each callback spent starved grows the target, so one stall sizes it for the next.
With a producer freezing 60 ms every 2 s: 14 underruns before, 1 after.
- During a reopen the outgoing and incoming streams could both drain the ring. Only
the promoted stream reads it now; any other plays silence.
- The ring target starts at 40 ms instead of two bursts (8 ms) and keeps what it
learned across reopens.
- The device buffer is at least two bursts; 12 ms was a single burst on devices that
grant a 20 ms legacy stream.
* PulseAudio: the classic path plays through the native-rate AAudio sink
The classic path loaded the prebuilt 0.1.5 module, which opened AAudio at the daemon's
default 44.1 kHz: Android gave it a legacy stream (20 ms bursts) and resampled, after
PulseAudio had already resampled the 48 kHz clients down. Its data callback also waited
on the daemon's IO thread, and it started at two bursts and grew only after an audible
underrun. The app's own module-aaudio-sink, built by CI into the same bundle, now
carries that path:
- The stream opens at the device's rate (48 kHz) with the buffer at two bursts or
30 ms, whichever is more, still growing a burst per underrun.
- A write that times out part way keeps the rest for the next write instead of
dropping it.
- A stream reopened after a route change asks for the rate the first one got, so the
sink keeps its format instead of unloading.
* Audio: DirectAudio sink at audio priority, deeper client buffers, no decay probing
- module-directaudio-sink's IO thread asks for nice -16 like module-aaudio-sink's, so
the client's producer keeps up under game load.
- PULSE_LATENCY_MSEC=60 for the session: libpulse clients under FEX (the Steam
client, winepulse when DirectAudio is off) keep enough queued to ride out a late
wakeup.
- BANNER_AUDIO_DIRECT_DECAY=0: the driver's decay shrinks the device buffer every
10 s of quiet until it underruns again, a click by design.
Both sit ahead of Downloads/droiddeck-env and per-game environment, which still win.
* Audio: drop the session-wide PULSE_LATENCY_MSEC
On an AYN Thor it took the Steam client's stream to 110 ms (60 ms tlength on top of the
sink's 40 ms) with no underruns to show for it, and the delay was audible. Clients pick
their own buffers again; the per-game option still sets it.
* PulseAudio sinks: wait in the poll loop, never in a blocking call
Clients' audio reaches a sink as messages its IO thread handles in pa_rtpoll_run. The AAudio
sink spent each iteration inside a blocking AAudioStream_write for up to a burst, and the
DirectAudio sink inside a futex wait for up to a burst, so a client's data sat unread and its
stream ran dry: a Chromium-shaped client (44.1 kHz float, 30 ms tlength, 10 ms minreq) had
304 underflows in 30 s on the AAudio sink, heard as crackling in the Steam client. Bursts of
20 ms (a legacy stream, an AYN Thor) made it worst.
- module-aaudio-sink writes without blocking, renders only what the device has room for, and
comes back after half a burst. 0 underflows in 30 s, with and without 8 busy cores.
- module-directaudio-sink tops the ring up on the same half-burst timer instead of sleeping
on the relay's futex.
* DirectAudio relay: vendor the source the shipped binary was built from
The import took 3548a4a, the commit the bundled driver names in version.txt, but the relay
binary that shipped came from e4727e9 on the same branch (feat/linux-relay-mic): its strings
match a build of that source exactly. 3548a4a has no --mic-fifo, so with the microphone on the
relay printed its usage and exited, and DirectAudio played nothing. This is e4727e9 as
published; the fixes made on top of 3548a4a follow in the next commit.
* DirectAudio relay: prime before playing, one consumer, safe buffer floors (on e4727e9)
The same changes as ca5d39b, carried onto the e4727e9 source: playback waits until the ring
holds its target, an underrun fades out and re-primes, starved callbacks grow the target, only
the promoted stream drains the ring, the ring target starts at 40 ms and survives reopens, and
the device buffer is at least two bursts.
* Steam client audio: DirectAudio by default
A fresh install plays the Steam client through the DirectAudio relay. Choosing Classic in the
Steam cog is stored and kept; only an install that never chose falls back to DirectAudio.
DroidDeck brings the SteamOS experience to Android: Valve's Steam client in Big Picture on your Adreno handheld, with Windows games through Valve's ARM64 Proton.
Note: DroidDeck does not have a stand-alone website. Do not click on any download links from websites claiming to be the DroidDeck team.
Requirements and install
Use Android 9 or newer on a supported Adreno device (730 or newer, or 8xx). Adreno 6xx is experimental: DirectX 11 uses DXVK 2 and may run, and DirectX 12 games can still crash. Mali, Xclipse, PowerVR, and Adreno 710 are unsupported. No root is required. Allow about 3 GB for the runtime and 1.1 GB more for the desktop and emulators. Install the APK from Releases, install the Linux runtime, then press Play and sign in. Steam downloads on first launch. Install Desktop & apps to use the desktop and emulators. The Store installs Linux apps and games from Flathub (ARM64 builds) with Flatpak; with additional options to install Appimages and set up scripts.
Before Steam launches, you must turn off Restrict child processes in Developer options. If this option is not available in developer settings (Android 12 and 13 devices), first launch of Steam will present a "Fix it for me" button, which will help automate the setup process.
Community
Join the DroidDeck Discord for help, Preview builds, and device reports. Bug reports go in its #bug-reports forum; attach the session folder from Download/DroidDeck/ so the logs come with it.
Build
Run tools/build_local.sh with Docker, Java 17, the Android SDK/NDK, and zstd installed. It builds the ARM64 audio sinks from PulseAudio 13.0 and packages them into the APK at app/build/outputs/apk/release/app-release.apk. Set DROIDDECK_PA13_SOURCE_DIR to an existing PulseAudio 13.0 source directory to skip downloading it. To install the APK on an attached device, run tools/deploy_local.sh.
Limits
Compatibility and performance vary by device; hardware validation is limited. Desktop compositing uses software rendering. Firefox sandboxing is reduced under proot. See the session logs in Download/DroidDeck/ when diagnosing problems.
Credits and licence
GPL-3.0. Runtime, shim, input, and controller work build on WinNative and Bannerlator (maxjivi05). LSFG frame generation is from the work of Camille LaVey and the Eden emulator project, following lsfg-vk, ported to WinNative and DroidDeck by @maxjivi05; it needs your own copy of Lossless Scaling and ships none of its shaders. x86 AppImages, and any whose own runtime cannot unpack them, are unpacked with uruntime by VHSgunzo (MIT), shipped unmodified with its licence. See LICENSE. Steam and Proton belong to Valve Corporation; this project is not affiliated with Valve.