EasyPusher进行Android UVC外接摄像头直播推送实现方法

最近EasyPusher针对UVC摄像头做了适配.我们结合了UVCCamera与EasyPusher,支持将UVC摄像头的视频推送到RTSP服务器上.在此特别感谢UVCCamera这个牛逼的项目!

来看看是怎么操作UVC摄像头的吧.我们实现了一个专门检测UVC摄像头的服务:UVCCameraService类,主要代码如下:

监听

mUSBMonitor = new USBMonitor(this, new USBMonitor.OnDeviceConnectListener() {
            @Override
            public void onAttach(final UsbDevice device) {
                Log.v(TAG, "onAttach:" + device);
                mUSBMonitor.requestPermission(device);
            }

            @Override
            public void onConnect(final UsbDevice device, final USBMonitor.UsbControlBlock ctrlBlock, final boolean createNew) {
                releaseCamera();
                if (BuildConfig.DEBUG) Log.v(TAG, "onConnect:");
                try {
                    final UVCCamera camera = new MyUVCCamera();
                    camera.open(ctrlBlock);
                    camera.setStatusCallback(new IStatusCallback() {
                    // ... uvc 摄像头链接成功

                    Toast.makeText(UVCCameraService.this, "UVCCamera connected!", Toast.LENGTH_SHORT).show();
                    if (device != null)
                        cameras.append(device.getDeviceId(), camera);
                }catch (Exception ex){
                    ex.printStackTrace();
                }
            }

            @Override
            public void onDisconnect(final UsbDevice device, final USBMonitor.UsbControlBlock ctrlBlock) {
              // ... uvc 摄像头断开链接
                if (device != null) {
                    UVCCamera camera = cameras.get(device.getDeviceId());
                    if (mUVCCamera == camera) {
                        mUVCCamera = null;
                        Toast.makeText(UVCCameraService.this, "UVCCamera disconnected!", Toast.LENGTH_SHORT).show();
                        liveData.postValue(null);
                    }
                    cameras.remove(device.getDeviceId());
                }else {
                    Toast.makeText(UVCCameraService.this, "UVCCamera disconnected!", Toast.LENGTH_SHORT).show();
                    mUVCCamera = null;
                    liveData.postValue(null);
                }
            }

            @Override
            public void onCancel(UsbDevice usbDevice) {
                releaseCamera();
            }

            @Override
            public void onDettach(final UsbDevice device) {
                Log.v(TAG, "onDettach:");
                releaseCamera();
//                AppContext.getInstance().bus.post(new UVCCameraDisconnect());
            }
        });

这个类主要实现UVC摄像头的监听\链接\销毁\反监听.当有UVC摄像头链接成功后,会创建一个mUVCCamera对象.

然后在MediaStream里, 我们改造了switchCamera,当参数传2时,表示要切换到UVCCamera(0,1分别表示切换到后置\前置摄像头).

创建

在创建摄像头时,如果是要创建uvc摄像头,那直接从服务里面获取之前创建的mUVCCamera实例:

 if (mCameraId == 2) {
   UVCCamera value = UVCCameraService.liveData.getValue();
   if (value != null) {
     // uvc camera.
     uvcCamera = value;
     value.setPreviewSize(width, height,1, 30, UVCCamera.PIXEL_FORMAT_YUV420SP,1.0f);
     return;
     //            value.startPreview();
   }else{
     Log.i(TAG, "NO UVCCamera");
     uvcError = new Exception("no uvccamera connected!");
     return;
   }
   //            mCameraId = 0;
 }

预览

在预览时,如果uvc摄像头已经创建了,那执行uvc摄像头的预览操作:

UVCCamera value = uvcCamera;
if (value != null) {
  SurfaceTexture holder = mSurfaceHolderRef.get();
  if (holder != null) {
    value.setPreviewTexture(holder);
  }
  try {
    value.setFrameCallback(uvcFrameCallback, UVCCamera.PIXEL_FORMAT_YUV420SP/*UVCCamera.PIXEL_FORMAT_NV21*/);
    value.startPreview();
    cameraPreviewResolution.postValue(new int[]{width, height});
  }catch (Throwable e){
    uvcError = e;
  }
}

这里我们选的colorFormat为PIXEL_FORMAT_YUV420SP 相当于标准摄像头的NV21格式.

关闭预览

同理,关闭时,调用的是uvc摄像头的关闭.

        UVCCamera value = uvcCamera;
        if (value != null) {
            value.stopPreview();
        }

销毁

因为我们这里并没有实质性的创建,所以销毁时也仅将实例置为null就可以了.

UVCCamera value = uvcCamera;
if (value != null) {
  //            value.destroy();
  uvcCamera = null;
}

有了这些操作,我们看看上层怎么调用,

首先需要在Manifest里面增加若干代码,具体详见UVCCamera工程说明.如下:

<activity android:name=".UVCActivity" android:launchMode="singleInstance">

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

            <intent-filter>
                <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.hardware.usb.action.USB_DEVICE_DETACHED" />
            </intent-filter>

            <meta-data
                android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
                android:resource="@xml/device_filter" />

        </activity>

然后,的代码在UVCActivity里,这个类可以在library分支的myapplication工程里找到.即这里.

启动或者停止UVC摄像头推送:

    public void onPush(View view) {
      // 异步获取到MediaStream对象.
        getMediaStream().subscribe(new Consumer<MediaStream>() {
            @Override
            public void accept(final MediaStream mediaStream) throws Exception {
              // 判断当前的推送状态.
                MediaStream.PushingState state = mediaStream.getPushingState();
                if (state != null && state.state > 0) { // 当前正在推送,那终止推送和预览
                    mediaStream.stopStream();
                    mediaStream.closeCameraPreview();
                }else{
                    // switch 0表示后置,1表示前置,2表示UVC摄像头
                    // 异步开启UVC摄像头
                    RxHelper.single(mediaStream.switchCamera(2), null).subscribe(new Consumer<Object>() {
                        @Override
                        public void accept(Object o) throws Exception {
                          // 开启成功,进行推送.
                            // ...
                            mediaStream.startStream("cloud.easydarwin.org", "554", id);
                        }
                    }, new Consumer<Throwable>() {
                        @Override
                        public void accept(final Throwable t) throws Exception {
                          // ooop...开启失败,提示下...
                            t.printStackTrace();
                            runOnUiThread(new Runnable() {
                                @Override
                                public void run() {
                                    Toast.makeText(UVCActivity.this, "UVC摄像头启动失败.." + t.getMessage(), Toast.LENGTH_SHORT).show();
                                }
                            });
                        }
                    });
                }
            }
        });
    }

这样,整个推送就完成了.如果一切顺利,应当能在VLC播放出来UVC摄像头的视频了~~

我们再看看如何录像.也非常简单…

    public void onRecord(View view) {       // 开始或结束录像.
        final TextView txt = (TextView) view;
        getMediaStream().subscribe(new Consumer<MediaStream>() {
            @Override
            public void accept(MediaStream mediaStream) throws Exception {
                if (mediaStream.isRecording()){ // 如果正在录像,那停止.
                    mediaStream.stopRecord();
                    txt.setText("录像");
                }else { // 没在录像,开始录像...
                    // 表示最大录像时长为30秒,30秒后如果没有停止,会生成一个新文件.依次类推...
                    // 文件格式为test_uvc_0.mp4,test_uvc_1.mp4,test_uvc_2.mp4,test_uvc_3.mp4
                    String path = getExternalFilesDir(Environment.DIRECTORY_MOVIES) + "/test_uvc.mp4";
                    mediaStream.startRecord(path, 30000);

                    final TextView pushingStateText = findViewById(R.id.pushing_state);
                    pushingStateText.append("\n录像地址:" + path);
                    txt.setText("停止");
                }
            }
        });
    }

UVC摄像头还支持后台推送,即不预览的情况下进行推送,同时再切换到前台继续预览.只需要调用一个接口即可实现,如下:

@Override
public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int i, int i1) {
  ms.setSurfaceTexture(surfaceTexture); // 设置预览的surfaceTexture
}
@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {
  ms.setSurfaceTexture(null);           // 设置预览窗口为null,表示关闭预览功能
  return true;
}

如果要彻底退出uvc摄像头的预览\推送,那只需要同时退出服务即可.

public void onQuit(View view) {     // 退出
  finish();

  // 终止服务...
  Intent intent = new Intent(this, MediaStream.class);
  stopService(intent);
}

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