Media Architecture

Understanding the media architecture of Reachy Mini is essential for effectively utilizing its audio and visual capabilities.

Unified Architecture

The daemon always manages the camera and audio hardware via GstMediaServer (media_server.py), regardless of whether you are using a Reachy Mini (Wireless) or Reachy Mini Lite. This unification means both models work the same way:

• The daemon owns the physical camera and audio devices.
• Local clients (same machine) read camera frames from a local IPC endpoint and open the audio device directly via GStreamer — the LOCAL backend.
• Remote clients stream camera + audio over WebRTC from the daemon — the WEBRTC backend.
• The SDK auto-detects which backend to use based on whether the daemon’s IPC endpoint is reachable.

Daemon Side

The daemon starts its media pipeline automatically unless the --no-media flag is passed. It:

1. Opens the camera (platform-aware: v4l2, libcamera, DirectShow, AVFoundation, or UDP for simulation).
2. Opens the audio device (platform-aware: PulseAudio, ALSA, WASAPI, CoreAudio).
3. Feeds both into a WebRTC server (webrtcsink) for remote streaming.
4. Exposes raw camera frames via a local IPC endpoint (unixfdsink on Linux/macOS, win32ipcvideosink on Windows).

Client Side

The SDK MediaManager selects the backend automatically:

• LOCAL: Used when the client runs on the same machine as the daemon. Reads camera frames from IPC and opens the audio device directly via GStreamer. No encode/decode overhead.
• WEBRTC: Used when the client is remote. Streams camera + audio over WebRTC.
• NO_MEDIA: Skips all media initialisation (headless operation).

Web Access

Thanks to WebRTC, the audio and video streams can also be accessed directly from a web browser. For instance the desktop application uses this feature.

Disabling Media / Direct Hardware Access

By default the daemon owns the camera and audio devices. If you need direct access to the hardware — for example to use OpenCV, sounddevice, or a custom vision pipeline — you can deactivate the built-in media manager:

from reachy_mini import ReachyMini

with ReachyMini(media_backend="no_media") as mini:
    # The daemon has released camera and audio hardware.
    # Use OpenCV, sounddevice, or any other library directly.
    import cv2
    cap = cv2.VideoCapture(0)
    ret, frame = cap.read()
    cap.release()

    # Robot control still works normally.
    mini.goto_target(antennas=[0.3, -0.3], duration=0.5)

# On exit, the daemon automatically re-acquires the hardware.

When media_backend="no_media" is passed, the SDK:

1. Asks the daemon to release the camera and audio devices (stops the GStreamer pipeline).
2. Sets the local MediaManager to NO_MEDIA (no camera/audio through the SDK).
3. On context manager exit (__exit__), tells the daemon to re-acquire the hardware automatically.

You can also call release_media() and acquire_media() manually at any point:

mini = ReachyMini()

# ... use the built-in media manager ...
frame = mini.media.get_frame()

# Switch to direct access
mini.release_media()
# ... use OpenCV, sounddevice, etc. ...

# Switch back to the SDK media manager
mini.acquire_media()
frame = mini.media.get_frame()

⚠️ Note: Both methods are idempotent — calling release_media() twice is safe.

For a complete example with both OpenCV and sounddevice, see Custom Media Manager.

Advanced Controls

Please refer to the dedicated pages to fine-tune camera and microphone parameters for Reachy Mini and Reachy Mini Lite.