Moonlight Embedded

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Moonlight Embedded is an open source client for Sunshine and NVIDIA GameStream for embedded Linux systems, like Raspberry Pi, CuBox-i and ODROID. Moonlight allows you to stream your full collection of games and applications from your PC to other devices to play them remotely.

Moonlight also has PC, Android, and iOS clients.

Documentation

More information about installing and running Moonlight Embedded is available on the wiki.

Bugs

Please check the wiki and old bug reports before submitting a new bug report.

Bugs can be reported to the issue tracker.

See also

Moonlight-common-c is the shared codebase between different Moonlight implementations

Contribute

1. Fork us
2. Write code
3. Send Pull Requests

FFmpeg V4L2 Request + DRM PRIME Backend for moonlight-embedded

This adds a hardware-accelerated video backend for embedded Linux devices that use the V4L2 stateless Request API for hardware decode and KMS/DRM atomic modesetting for display. Tested on RK3399 (rkvdec) running LibreELEC.

How it works

Network → moonlight-embedded decode thread
              ↓
         FFmpeg (codec: h264/hevc)
         hwaccel: AV_HWDEVICE_TYPE_DRM
         get_format → AV_PIX_FMT_DRM_PRIME
              ↓
         V4L2 Request API (rkvdec / hantro / cedrus)
         /dev/media0 + /dev/video2
              ↓
         AVDRMFrameDescriptor (NV12 dma-buf)
              ↓  av_frame_clone (holds buffer ref across vsync)
         Display thread (separate from decode thread)
              ↓
         drmModeAtomicCommit (blocking, overlay plane)
         card1 / Rockchip VOP / KMS atomic

The decode thread is non-blocking — it pushes frames to a single-slot queue and immediately returns. The display thread blocks on vsync, ensuring the network/control pipeline is never stalled by display timing.

av_frame_clone is used to hold a reference to the DRM PRIME buffer while it is being scanned out by the display controller. Releasing the frame before the next vsync causes the buffer to be returned to the V4L2 pool while it is still on-screen, producing black flicker on every other frame.

On startup, all active KMS planes on the CRTC except the video overlay are blanked (FB_ID=0 AND CRTC_ID=0 in the same atomic commit) to hide the Linux framebuffer console.

Hardware compatibility

Any device where:

• FFmpeg can use AV_HWDEVICE_TYPE_DRM with a V4L2 Request API decoder
• The kernel exposes a DRM/KMS atomic interface

Known working:

• RK3399 (rkvdec) — H.264, HEVC via /dev/media0 + /dev/video2
• Should work on any device supported by LibreELEC's patched FFmpeg with V4L2 Request hwaccel (RK3588, Allwinner, Amlogic with appropriate kernel)

The backend probes /dev/media* and /dev/video* at runtime to find a device that supports the requested pixel format — no hardcoded paths.

Build

Requires: libdrm, libavcodec, libavutil (with DRM hwaccel support)

cmake -DENABLE_FFMPEG_DRM=ON ...

CMakeLists.txt checks for DRM_LIBRARY and AVCODEC_FOUND before enabling the backend. If the system FFmpeg lacks DRM hwaccel support, it will be skipped silently.

Performance (RK3399, 1080p60 HEVC @ 20 Mbps)

Metric	Result
Decode time	~2.7 ms average (rkvdec)
Frame drops	0.00%
Network latency	1 ms

CPU load during streaming is minimal — all decode is handled by rkvdec, display is a single drmModeAtomicCommit per frame.

Files changed

• src/video/ffmpeg_drm.c — new backend (this file)
• src/platform.h — added FFMPEG_DRM to platform enum
• src/platform.c — dispatch for FFMPEG_DRM in platform_check, platform_get_video, platform_prefers_codec, platform_name
• src/video/video.h — extern declaration for decoder_callbacks_ffmpeg_drm
• CMakeLists.txt — ENABLE_FFMPEG_DRM option, updated FATAL_ERROR guard to not require legacy backends when FFMPEG_DRM is available

Selecting the backend

moonlight stream -platform ffmpeg_drm -app "Desktop"

Or set it as the default in moonlight.conf:

[Moonlight]
platform = ffmpeg_drm