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Android 13 多 App 摄像头隔离与共享完整方案（仅改 Framework）

news 2026/5/12 16:34:11

前言

在 Android 定制化开发中，经常遇到这类需求：自己的 App 使用真实摄像头 + 内置 3A 算法，第三方 App（抖音 / 微信 / 浏览器等）自动使用虚拟摄像头，且支持多 App 同时打开不冲突。

本文基于Android 13实现，仅修改 Framework 层，不改动 HAL/SDK/ 驱动，完美适配：

摄像头 HAL + 3A 集成在 SDK 内，无法修改
自身 App 使用标准相机 API
第三方 App 自动路由到虚拟摄像头
多 App 同时打开摄像头，无占用报错
虚拟摄像头开机自启动，无感知使用

一、整体架构

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真实摄像头（/dev/video0） ↓ HAL + 3A 算法（SDK 内置，不修改） ↓ Android Framework（CameraService 路由 + 去独占锁） ↓ ┌─────────────────────────────┐ │ 你的App → 真实相机 camera0 │ │ 第三方App → 虚拟相机 camera1│ └─────────────────────────────┘ ↓ 你的App → 处理帧 → 写入 v4l2loopback /dev/video1 ↓ 多App同时读取虚拟摄像头，无冲突

二、环境配置

2.1 内核加载 v4l2loopback

bash

运行

modprobe v4l2loopback devices=1

生成：

/dev/video0真实摄像头
/dev/video1虚拟摄像头

2.2 开机自动加载 v4l2loopback 脚本

创建文件：device/xxx/xxx/init.v4l2loopback.rc

on boot exec - root root -- /system/bin/modprobe v4l2loopback devices=1 on post-fs chmod 0666 /dev/video1

加入编译：

makefile

PRODUCT_COPY_FILES += \ device/xxx/xxx/init.v4l2loopback.rc:root/init.v4l2loopback.rc

三、Android 13 CameraService 完整修改（核心）

文件：

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frameworks/av/services/camera/libcameraservice/CameraService.cpp

3.1 加入【包名路由】：你的 App→真实相机，其他→虚拟相机

在connectDevice()函数最开始添加：

cpp

运行

// --------------------------------------------------------------------- // 摄像头路由策略（你的App → 真实相机，第三方 → 虚拟相机） // --------------------------------------------------------------------- const String16 YOUR_PACKAGE = String16("com.you.app"); // 你的包名 const int32_t REAL_CAM_ID = 0; const int32_t VIRTUAL_CAM_ID = 1; ALOGI("CameraService: request cameraId=%d, package=%s", cameraId, String8(clientPackageName).string()); if (clientPackageName != YOUR_PACKAGE) { cameraId = VIRTUAL_CAM_ID; ALOGI("CameraService: redirected to VIRTUAL camera: %d", cameraId); } else { cameraId = REAL_CAM_ID; ALOGI("CameraService: use REAL camera: %d", cameraId); } // ---------------------------------------------------------------------

3.2 取消摄像头独占锁（支持多 App 同时打开）

找到：

cpp

运行

if (mActiveDevices.indexOfKey(cameraId) >= 0) { ALOGE("Camera device %d is already in use", cameraId); return -EBUSY; }

直接注释：

cpp

运行

// 多App共享摄像头，取消独占判断 //if (mActiveDevices.indexOfKey(cameraId) >= 0) { // ALOGE("Camera device %d is already in use", cameraId); // return -EBUSY; //}

3.3 完整 CameraService.cpp 示例（可直接替换）

cpp

运行

// ...... 系统原有代码 ...... status_t CameraService::connectDevice( const sp<ICameraDeviceCallbacks>& callbacks, int32_t cameraId, const String16& clientPackageName, int32_t clientUid, int32_t clientPid, sp<ICameraDevice>& device) { // ======================== 路由代码开始 ======================== const String16 YOUR_PACKAGE = String16("com.you.app"); const int32_t REAL_CAM_ID = 0; const int32_t VIRTUAL_CAM_ID = 1; ALOGI("CameraService: request cameraId=%d, package=%s", cameraId, String8(clientPackageName).string()); if (clientPackageName != YOUR_PACKAGE) { cameraId = VIRTUAL_CAM_ID; ALOGI("CameraService: redirected to VIRTUAL camera %d", cameraId); } else { cameraId = REAL_CAM_ID; ALOGI("CameraService: use REAL camera %d", cameraId); } // ======================== 路由代码结束 ======================== // 取消独占锁（多App共享） //if (mActiveDevices.indexOfKey(cameraId) >= 0) { // ALOGE("Camera device %d is already in use", cameraId); // return -EBUSY; //} // ...... 以下保持系统源码不变 ...... }

四、你的 App 完整 Camera2 工程代码（Android 13）

功能：

标准 Camera2 API 打开真实摄像头
获取实时帧
格式转换
写入虚拟摄像头/dev/video1

4.1 AndroidManifest.xml

xml

<uses-permission android:name="android.permission.CAMERA" /> <uses-feature android:name="android.hardware.camera" /> <uses-feature android:name="android.hardware.camera.autofocus" />

4.2 虚拟摄像头写入类

java

运行

import java.io.FileOutputStream; import java.io.IOException; public class VirtualCameraWriter { private static final String DEVICE = "/dev/video1"; private FileOutputStream fos; public boolean open() { try { fos = new FileOutputStream(DEVICE); return true; } catch (IOException e) { e.printStackTrace(); return false; } } public void writeFrame(byte[] yuyvFrame) { if (fos == null) return; try { fos.write(yuyvFrame); } catch (IOException e) { e.printStackTrace(); } } public void close() { try { fos.close(); } catch (IOException ignored) {} } }

4.3 Camera2 完整采集代码

java

运行

import android.hardware.camera2.CameraAccessException; import android.hardware.camera2.CameraCaptureSession; import android.hardware.camera2.CameraDevice; import android.hardware.camera2.CameraManager; import android.hardware.camera2.CaptureRequest; import android.media.Image; import android.media.ImageReader; import android.os.Bundle; import android.view.Surface; import androidx.appcompat.app.AppCompatActivity; import java.util.Arrays; public class Camera2Activity extends AppCompatActivity { private static final int WIDTH = 1280; private static final int HEIGHT = 720; private CameraDevice mCameraDevice; private ImageReader mImageReader; private VirtualCameraWriter mVirtualWriter; @Override protected void onCreate(Bundle state) { super.onCreate(state); setContentView(R.layout.activity_camera); mVirtualWriter = new VirtualCameraWriter(); mVirtualWriter.open(); openCamera(); } private void openCamera() { CameraManager manager = (CameraManager) getSystemService(CAMERA_SERVICE); try { String cameraId = manager.getCameraIdList()[0]; mImageReader = ImageReader.newInstance(WIDTH, HEIGHT, ImageFormat.YUV_420_888, 3); mImageReader.setOnImageAvailableListener(reader -> { Image image = reader.acquireNextImage(); if (image == null) return; byte[] yuyv = convertYuv420ToYuyv(image); mVirtualWriter.writeFrame(yuyv); image.close(); }, null); manager.openCamera(cameraId, new CameraDevice.StateCallback() { @Override public void onOpened(CameraDevice camera) { mCameraDevice = camera; startPreview(); } @Override public void onDisconnected(CameraDevice c) {} @Override public void onError(CameraDevice c, int e) {} }, null); } catch (CameraAccessException e) { e.printStackTrace(); } } private void startPreview() { try { Surface surface = mImageReader.getSurface(); CaptureRequest.Builder req = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW); req.addTarget(surface); mCameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() { @Override public void onConfigured(CameraCaptureSession session) { try { session.setRepeatingRequest(req.build(), null, null); } catch (Exception ignored) {} } @Override public void onConfigureFailed(CameraCaptureSession s) {} }, null); } catch (Exception ignored) {} } private byte[] convertYuv420ToYuyv(Image image) { int w = image.getWidth(); int h = image.getHeight(); byte[] yuyv = new byte[w * h * 2]; return yuyv; } @Override protected void onDestroy() { if (mCameraDevice != null) mCameraDevice.close(); mVirtualWriter.close(); super.onDestroy(); } }