androidcam: use an Android phone as a Linux webcam via scrcpy + v4l2loopback

androidcam

#!/usr/bin/env bash

# Android phone as webcam for Linux via scrcpy + v4l2loopback.
#
# Initial setup recap:
# 1. Install build/runtime dependencies if needed:
#      sudo apt install ffmpeg libsdl2-2.0-0 adb wget \
#        gcc git pkg-config meson ninja-build libsdl2-dev \
#        libavcodec-dev libavdevice-dev libavformat-dev libavutil-dev \
#        libswresample-dev libusb-1.0-0 libusb-1.0-0-dev \
#        v4l2loopback-dkms v4l-utils
# 2. Install scrcpy from source if needed:
#      git clone https://github.com/Genymobile/scrcpy
#      cd scrcpy
#      ./install_release.sh
# 3. On the phone, enable Developer options and USB/Wireless debugging.
# 4. Pair/connect the phone once via ADB.
# 5. This script creates /dev/video10 with v4l2loopback if needed and
#    streams the selected Android camera into that virtual webcam.
#    Default resolution: 1280x720.
# 6. Update the public gist after local changes with:
#      gh gist edit 807acb0055a0b6ce0c78bd2e4af075e5 /home/tin/.local/bin/androidcam
#
# Usage:
#   androidcam                # back camera over Wi-Fi
#   androidcam front          # front camera over Wi-Fi
#   androidcam back usb       # back camera over USB
#   androidcam front wifi
#   androidcam --disable-internal
#   androidcam --rotate
#   androidcam --flip
#   androidcam --help

set -euo pipefail

device_mode="wifi"
camera_name="back"
camera_id="0"
video_device="/dev/video10"
card_label="AndroidCam"
camera_size="1280x720"
disable_internal="no"
internal_disabled="no"
rotate_video="no"
flip_video="no"

usage() {
  cat <<'EOUSAGE'
Usage:
  androidcam [front|back] [wifi|usb] [--disable-internal] [--rotate] [--flip]

Examples:
  androidcam
  androidcam front
  androidcam back usb
  androidcam --disable-internal
  androidcam front --rotate
  androidcam front --flip

Notes:
  - Uses camera-id 0 for back and 1 for front on this Motorola.
  - Exposes the phone as /dev/video10 (label: AndroidCam).
  - By default, keeps the internal webcam visible.
  - Use --disable-internal to unload uvcvideo while AndroidCam runs.
  - Use --rotate to rotate the captured video 90 degrees for portrait use.
  - Use --flip to mirror the captured video horizontally.
  - Select "AndroidCam" in Meet/Chrome.
EOUSAGE
}

for arg in "$@"; do
  case "$arg" in
    front)
      camera_name="front"
      camera_id="1"
      ;;
    back)
      camera_name="back"
      camera_id="0"
      ;;
    wifi|tcpip)
      device_mode="wifi"
      ;;
    usb)
      device_mode="usb"
      ;;
    --disable-internal)
      disable_internal="yes"
      ;;
    --rotate)
      rotate_video="yes"
      ;;
    --flip)
      flip_video="yes"
      ;;
    -h|--help|help)
      usage
      exit 0
      ;;
    *)
      echo "Unknown argument: $arg" >&2
      usage >&2
      exit 1
      ;;
  esac
done

require_cmd() {
  if ! command -v "$1" >/dev/null 2>&1; then
    echo "Missing required command: $1" >&2
    exit 1
  fi
}

require_cmd scrcpy
require_cmd adb

restore_internal_camera() {
  if [ "$internal_disabled" = "yes" ]; then
    sudo modprobe uvcvideo || true
  fi
}

trap restore_internal_camera EXIT

if [ ! -e "$video_device" ]; then
  echo "Creating virtual webcam on $video_device..."
  sudo modprobe v4l2loopback video_nr=10 card_label="$card_label" exclusive_caps=1
fi

if [ "$disable_internal" = "yes" ]; then
  if lsmod | awk '{print $1}' | grep -qx 'uvcvideo'; then
    echo "Disabling internal webcam (uvcvideo) so apps prefer AndroidCam..."
    sudo modprobe -r uvcvideo || true
    internal_disabled="yes"
  fi
fi

effective_rotate="$rotate_video"

orientation_value="0"
if [ "$effective_rotate" = "yes" ] && [ "$flip_video" = "yes" ]; then
  orientation_value="flip90"
elif [ "$effective_rotate" = "yes" ]; then
  orientation_value="90"
elif [ "$flip_video" = "yes" ]; then
  orientation_value="flip0"
fi

orientation_args=()
if [ "$orientation_value" != "0" ]; then
  orientation_args=(--capture-orientation="$orientation_value")
fi

if ! adb devices | awk 'NR>1 && $2=="device" {found=1} END{exit !found}'; then
  cat >&2 <<'EOERR'
No ADB device is ready.

Quick checklist:
  - Connect the phone by USB at least once
  - Enable USB or Wireless debugging on Android
  - Accept the trust prompt on the phone
  - Verify with: adb devices
EOERR
  exit 1
fi

scrcpy_device_flag="-e"
if [ "$device_mode" = "usb" ]; then
  scrcpy_device_flag="-d"
fi

echo "Starting Android webcam:"
echo "  Camera: $camera_name (camera-id=$camera_id)"
echo "  Mode:   $device_mode"
echo "  Device: $video_device"
echo "  Disable internal: $disable_internal"
echo "  Rotate: $effective_rotate"
echo "  Flip: $flip_video"
echo

scrcpy_args=(
  "$scrcpy_device_flag"
  --video-source=camera
  --camera-id="$camera_id"
  --camera-size="$camera_size"
  --v4l2-sink="$video_device"
  --no-playback
)

if [ ${#orientation_args[@]} -gt 0 ]; then
  scrcpy_args+=("${orientation_args[@]}")
fi

exec scrcpy "${scrcpy_args[@]}"