Google Meet running in Firefox inside Tiny Computer on a Galaxy Tab S8, with video from the tablet's camera.

Tiny Container Camera

Use your Android phone/tablet camera as a webcam on any website (Microsoft Teams, Google Meet, Zoom web, ...) in Firefox running inside Tiny Computer / tiny_container or any other proot environment. No extra Android app, no root.

Firefox Add-on

Running Linux on Android with Tiny Computer, Termux or another proot container is great for coding, until you need to join a video call with your team: Android does not let apps inside the container use the camera.

Tiny Container Camera fixes that. It reads the device camera over ADB (wireless debugging) and turns it into a webcam that every website can use.

Features

• Virtual camera named "Android Camera (Tiny Container)" on every HTTPS site: Microsoft Teams, Google Meet, Zoom, Jitsi and others.
• No extra Android app: the camera is read over ADB with scrcpy's server, started and stopped automatically when a site needs the camera.
• Asks before a site can use the camera, like Firefox does for a real webcam. Decisions are remembered per site and can be changed on the options page.
• The device camera turns off by itself shortly after the last page stops using it.
• Toolbar button to connect or pair ADB and switch between the front and back camera.
• Also works with any MJPEG stream, such as the IP Webcam app.
• Your microphone keeps working as usual.
• No root, no kernel modules, no v4l2loopback.
• No data collection. Video only travels from your device to the page that asked for it.

Quick start

1. Enable Wireless debugging on Android and connect ADB from the container.
2. Run sh camera-bridge/install.sh from this repository (once).
3. Install the add-on and click Save and grant access on the options page.
4. Choose Android Camera (Tiny Container) in your meeting settings.

Video calls in proot: on Android 11 and newer, WebRTC calls from Firefox inside proot fail to connect because Android blocks netlink sockets. This repository includes a small fix, webrtc-fix, that makes calls work.

Tested on

Device	Samsung Galaxy Tab S8 5G (SM-X706B)
Chipset	Qualcomm Snapdragon 8 Gen 1 (SM8450)
RAM	8 GB
OS	Android 16, One UI 8.0 (not rooted)
Container	Tiny Computer (com.fct.tc4), Debian in proot
Browser	Firefox ESR 153.5
Camera source	ADB + scrcpy 3.3.4 (1280x720, 30 fps); IP Webcam (com.pas.webcam)
Sites	Google Meet (call), webcamtoy.com

How it works

Inside proot, Android's /dev/video* devices are not accessible without root, and v4l2loopback cannot be installed because kernel modules cannot be loaded. So the camera cannot be passed through as a regular V4L2 device (this includes scrcpy --v4l2-sink).

ADB still can reach the camera: camera-bridge/tcc_camera.py runs scrcpy-server on the device with the camera as video source, decodes the H.264 stream with ffmpeg and serves MJPEG on http://127.0.0.1:8765/video. The extension reads that stream and exposes it to web pages as a virtual camera through getUserMedia(). It starts the bridge through Firefox native messaging when a page asks for the camera, and stops it 15 seconds after the last page lets go of it.

camera ─▶ scrcpy-server ─adb─▶ ffmpeg ─MJPEG─▶ background.js ─▶ isolated.js ─▶ main.js
          (on the device)       (tcc_camera.py)                                 canvas.captureStream()
                                                                                → getUserMedia() on the page

Video calls need one more fix. Android 11+ forbids apps from using netlink sockets, which Firefox uses to list local network addresses for WebRTC. With no addresses, Firefox gathers no ICE candidates and every call fails ("Sorry, we encountered a problem joining this video call."). webrtc-fix/ is a small LD_PRELOAD library that answers those netlink requests using ioctls that Android still allows.

Setup

1. ADB

sudo apt install adb scrcpy ffmpeg

On Android, open Settings → Developer options → Wireless debugging and turn it on. The first time, tap Pair device with pairing code and pair, either from the extension's toolbar button (Pair a new device) or with:

adb pair HOST:PAIRING_PORT CODE

Then connect with the toolbar button (Connect) or with adb connect HOST:PORT, using the port shown on the Wireless debugging screen. With the address left empty, Connect tries the last address that worked, then looks for the port by itself; that search can take up to 2 minutes inside proot, so typing the address is faster after wireless debugging was turned off and on.

2. Camera bridge

sh camera-bridge/install.sh

This copies the bridge to ~/.local/lib/tiny-container-camera/camera-bridge/ and registers it with Firefox (~/.mozilla/native-messaging-hosts/). Restart Firefox afterwards. To undo: sh camera-bridge/install.sh --uninstall.

The bridge can also run on its own, for example to use it with other programs:

python3 camera-bridge/tcc_camera.py --facing back --size 1280 --fps 30

3. Extension

Download the signed .xpi from the Releases page, then in Firefox (128+) open about:addons → gear icon → Install Add-on From File…

The options page opens after installing: click Save and grant access to let the extension read the stream from 127.0.0.1.

4. WebRTC fix

Needed for video calls (Teams, Meet, ...); not needed for camera-only sites. Requires gcc (sudo apt install gcc).

sh webrtc-fix/install.sh

This builds the library into ~/.local/lib/tiny-container-camera/ and makes Firefox ESR start with it (app menu, links opened from other apps, and the firefox-esr command). Close every Firefox window and start it again. To undo: sh webrtc-fix/install.sh --uninstall.

To try it once without installing:

gcc -O2 -shared -fPIC -o /tmp/libnetlink_shim.so webrtc-fix/netlink_shim.c -ldl -lpthread
LD_PRELOAD=/tmp/libnetlink_shim.so firefox-esr

5. Join a meeting

Pick the Android Camera (Tiny Container) camera in the meeting settings. The first time a site asks for the camera, the extension opens a small window: choose Allow. The first frame takes a few seconds while the camera starts on the device.

Privacy

Because the virtual camera bypasses Firefox's own camera prompt, the extension asks for itself: a site gets no video, and the device camera is not turned on, until you allow that site. The check runs in the extension's background script against the address Firefox reports for the page, so a page cannot grant itself access. Allowed and blocked sites are listed on the options page.

The camera bridge stops 15 seconds after the last page releases the camera, and in any case after 30 seconds without viewers (even if Firefox was closed).

Using IP Webcam instead of ADB

If you prefer an Android app, install IP Webcam (com.pas.webcam), tap Start server, then set the stream URL on the extension's options page to http://127.0.0.1:8080/video. Steps 1 and 2 above are not needed in that case.

Make sure nothing else in the container listens on port 8080 (a local web server, for example), or change the IP Webcam port.

Troubleshooting

The site says the camera is blocked

You chose Block for that site earlier. Open the extension options in about:addons, remove the site under Sites, and reload the page.

The camera shows "No access to 127.0.0.1"

Open the extension options in about:addons and click Save and grant access, then reload the page.

The camera shows "Camera bridge not installed"

Run sh camera-bridge/install.sh and restart Firefox.

The camera shows "no ADB device connected"

Connect ADB from the toolbar button or with adb connect HOST:PORT. The Wireless debugging port changes every time it is turned off and on.

Camera bridge log

The bridge writes its log to ~/.cache/tiny-container-camera/bridge.log. Run it by hand with --verbose to see the frame rate every 5 seconds:

python3 camera-bridge/tcc_camera.py --verbose

Samsung: IP Webcam stops in the background

One UI freezes background apps ("Freecess"), so the IP Webcam server stops as soon as you switch back to Tiny Computer. Exclude it from battery optimization (Settings → Battery → Background usage limits → Never sleeping apps), or via ADB:

adb shell dumpsys deviceidle whitelist +com.pas.webcam
adb shell cmd appops set com.pas.webcam RUN_ANY_IN_BACKGROUND allow

"Sorry, we encountered a problem joining this video call"

Firefox was started without the WebRTC fix, so the call cannot connect even though the camera works. Open the extension's toolbar button: WebRTC fix shows Not loaded in that case.

The usual cause is the XFCE app menu or panel caching the old Firefox entry from before webrtc-fix/install.sh was run, so it still starts /usr/lib/firefox-esr/firefox-esr directly. Fix it once with:

xfce4-panel -r

then quit Firefox completely (Ctrl+Q) and start it again from the app menu. To check a running Firefox:

tr '\0' '\n' < /proc/$(pgrep -o -f /usr/lib/firefox-esr/firefox-esr)/environ | grep LD_PRELOAD

It should print a path ending in libnetlink_shim.so.

Checking the WebRTC fix

LD_PRELOAD=~/.local/lib/tiny-container-camera/libnetlink_shim.so ip -4 addr

should list your interfaces (without the library it fails with Cannot bind netlink socket: Permission denied). Set NETLINK_SHIM_DEBUG=1 to log the netlink requests the library answers.

Development

To try code changes without signing: about:debugging → This Firefox → Load Temporary Add-on… → select extension/manifest.json. Temporary add-ons are removed when Firefox closes.

sh build.sh builds dist/tiny-container-camera.xpi (unsigned). To sign it, use web-ext sign. The addons.mozilla.org listing text is kept in amo/metadata.json.

sh build.sh --debug also writes dist/debug-extension/, which sends every getUserMedia/enumerateDevices call made by pages to python3 tools/log_server.py (written to tcc.log).

Testing without a phone

python3 tools/mock_mjpeg.py --port 8765 image1.jpg image2.jpg

Then open http://127.0.0.1:8765/tcc-test.html and click Start camera.

Limitations

• Firefox 128+ only (uses world: "MAIN" content scripts).
• The ADB camera source needs Android 12+.
• Frames are decoded inside proot, so lower resolutions run smoother.
• The WebRTC fix reports IPv4 addresses only.
• Sites still ask for microphone permission as usual. No camera permission prompt appears because the camera is virtual.

License

MIT, see LICENSE.