【流媒體】Android 实时视频采集方案一
【流媒體】Android 实时视频采集方案一
SkySeraph Feb 26th 2012 SZTCL
Email:zgzhaobo@gmail.com QQ:452728574
1 概述
通过Android Camera拍摄预览中设置setPreviewCallback实现onPreviewFrame接口,实时截取每一帧视频流数据
2 知识点
① Android Camera使用: 参考 Refs/Related 0-4
Camera 支持格式
拍照流程
② Android SurfaceView使用: 参考 Refs/Related 5-10
③ Camera权限
3 核心源码
① SurfaceView相关
// 定义对象 private SurfaceView mSurfaceview = null; // SurfaceView对象:(视图组件)视频显示 private SurfaceHolder mSurfaceHolder = null; // SurfaceHolder对象:(抽象接口)SurfaceView支持类 private Camera mCamera =null; // Camera对象,相机预览复制代码
// InitSurfaceView private void initSurfaceView() { mSurfaceview = (SurfaceView) this.findViewById(R.id.Surfaceview); mSurfaceHolder = mSurfaceview.getHolder(); // 绑定SurfaceView,取得SurfaceHolder对象 mSurfaceHolder.addCallback(mainActivity.this); // SurfaceHolder加入回调接口 // mSurfaceHolder.setFixedSize(176, 144); // 预览大小設置 mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);// 設置顯示器類型,setType必须设置 }复制代码
② 主Activity实现SurfaceHolder.Callback接口,编写回调函数
/*【SurfaceHolder.Callback 回调函数】*/ public void surfaceCreated(SurfaceHolder holder) // SurfaceView启动时/初次实例化,预览界面被创建时,该方法被调用。 { // TODO Auto-generated method stub mCamera = Camera.open();// 开启摄像头(2.3版本后支持多摄像头,需传入参数) try { Log.i(TAG, "SurfaceHolder.Callback:surface Created"); mCamera.setPreviewDisplay(mSurfaceHolder);//set the surface to be used for live preview } catch (Exception ex) { if(null != mCamera) { mCamera.release(); mCamera = null; } Log.i(TAG+"initCamera", ex.getMessage()); } } public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) // 当SurfaceView/预览界面的格式和大小发生改变时,该方法被调用 { // TODO Auto-generated method stub Log.i(TAG, "SurfaceHolder.Callback:Surface Changed"); //mPreviewHeight = height; //mPreviewWidth = width; initCamera(); } public void surfaceDestroyed(SurfaceHolder holder) // SurfaceView销毁时,该方法被调用 { // TODO Auto-generated method stub Log.i(TAG, "SurfaceHolder.Callback:Surface Destroyed"); if(null != mCamera) { mCamera.setPreviewCallback(null); //!!这个必须在前,不然退出出错 mCamera.stopPreview(); bIfPreview = false; mCamera.release(); mCamera = null; } }复制代码
核心子函数: 相机预览
1 /*【2】【相机预览】*/ 2 private void initCamera()//surfaceChanged中调用 3 { 4 Log.i(TAG, "going into initCamera"); 5 if (bIfPreview) 6 { 7 mCamera.stopPreview();//stopCamera(); 8 } 9 if(null != mCamera)10 {11 try12 {13 /* Camera Service settings*/ 14 Camera.Parameters parameters = mCamera.getParameters();15 // parameters.setFlashMode("off"); // 无闪光灯16 parameters.setPictureFormat(PixelFormat.JPEG); //Sets the image format for picture 设定相片格式为JPEG,默认为NV21 17 parameters.setPreviewFormat(PixelFormat.YCbCr_420_SP); //Sets the image format for preview picture,默认为NV2118 /*【ImageFormat】JPEG/NV16(YCrCb format,used for Video)/NV21(YCrCb format,used for Image)/RGB_565/YUY2/YU12*/19 20 // 【调试】获取caera支持的PictrueSize,看看能否设置??21 List<Size> pictureSizes = mCamera.getParameters().getSupportedPictureSizes();22 List<Size> previewSizes = mCamera.getParameters().getSupportedPreviewSizes();23 List<Integer> previewFormats = mCamera.getParameters().getSupportedPreviewFormats();24 List<Integer> previewFrameRates = mCamera.getParameters().getSupportedPreviewFrameRates();25 Log.i(TAG+"initCamera", "cyy support parameters is ");26 Size psize = null;27 for (int i = 0; i < pictureSizes.size(); i++)28 {29 psize = pictureSizes.get(i);30 Log.i(TAG+"initCamera", "PictrueSize,width: " + psize.width + " height" + psize.height);31 }32 for (int i = 0; i < previewSizes.size(); i++)33 {34 psize = previewSizes.get(i);35 Log.i(TAG+"initCamera", "PreviewSize,width: " + psize.width + " height" + psize.height);36 }37 Integer pf = null;38 for (int i = 0; i < previewFormats.size(); i++)39 {40 pf = previewFormats.get(i);41 Log.i(TAG+"initCamera", "previewformates:" + pf);42 }43 44 // 设置拍照和预览图片大小45 parameters.setPictureSize(640, 480); //指定拍照图片的大小46 parameters.setPreviewSize(mPreviewWidth, mPreviewHeight); // 指定preview的大小 47 //这两个属性 如果这两个属性设置的和真实手机的不一样时,就会报错48 49 // 横竖屏镜头自动调整50 if (this.getResources().getConfiguration().orientation != Configuration.ORIENTATION_LANDSCAPE) 51 {52 parameters.set("orientation", "portrait"); //53 parameters.set("rotation", 90); // 镜头角度转90度(默认摄像头是横拍) 54 mCamera.setDisplayOrientation(90); // 在2.2以上可以使用55 } else// 如果是横屏56 {57 parameters.set("orientation", "landscape"); //58 mCamera.setDisplayOrientation(0); // 在2.2以上可以使用59 } 60 61 /* 视频流编码处理 */ 62 //添加对视频流处理函数63 64 65 // 设定配置参数并开启预览66 mCamera.setParameters(parameters); // 将Camera.Parameters设定予Camera 67 mCamera.startPreview(); // 打开预览画面68 bIfPreview = true;69 70 // 【调试】设置后的图片大小和预览大小以及帧率71 Camera.Size csize = mCamera.getParameters().getPreviewSize();72 mPreviewHeight = csize.height; //73 mPreviewWidth = csize.width;74 Log.i(TAG+"initCamera", "after setting, previewSize:width: " + csize.width + " height: " + csize.height);75 csize = mCamera.getParameters().getPictureSize();76 Log.i(TAG+"initCamera", "after setting, pictruesize:width: " + csize.width + " height: " + csize.height);77 Log.i(TAG+"initCamera", "after setting, previewformate is " + mCamera.getParameters().getPreviewFormat());78 Log.i(TAG+"initCamera", "after setting, previewframetate is " + mCamera.getParameters().getPreviewFrameRate());79 } catch (Exception e)80 { 81 e.printStackTrace();82 }83 }84 }复制代码
说明1: 在/* 视频流编码处理 */中通过setPreviewCallback添加对视频流进行处理,如
mCamera.setPreviewCallback(new encoderVideo(mCamera.getParameters().getPreviewSize().width,
mCamera.getParameters().getPreviewSize().height,(ImageView) findViewById(R.id.ImageView2)));//①原生yuv420sp视频存储方式
mCamera.setPreviewCallback(new encoderH264(mCamera.getParameters().getPreviewSize().width,
mCamera.getParameters().getPreviewSize().height));//②x264编码方式
mCamera.setPreviewCallback(mJpegPreviewCallback);//③JPEG压缩方式
说明2:当然也可以不在主Acitivity中实现SurfaceHolder.Callback接口,而是在①的initSurfaceView中的addCallback函数,修改为
mSurfaceHolder.addCallback(new MyCallback); 再在这函数中实现上述三个回调函数
③视频帧回调接口
1 // 【获取视频预览帧的接口】 2 mJpegPreviewCallback = new Camera.PreviewCallback() 3 { 4 @Override 5 public void onPreviewFrame(byte[] data, Camera camera) 6 { 7 //传递进来的data,默认是YUV420SP的 8 // TODO Auto-generated method stub 9 try10 {11 Log.i(TAG, "going into onPreviewFrame");12 //mYUV420sp = data; // 获取原生的YUV420SP数据13 YUVIMGLEN = data.length;14 15 // 拷贝原生yuv420sp数据16 mYuvBufferlock.acquire();17 System.arraycopy(data, 0, mYUV420SPSendBuffer, 0, data.length);18 //System.arraycopy(data, 0, mWrtieBuffer, 0, data.length);19 mYuvBufferlock.release();20 21 // 开启编码线程,如开启PEG编码方式线程22 mSendThread1.start();23 24 } catch (Exception e)25 {26 Log.v("System.out", e.toString());27 }// endtry 28 }// endonPriview 29 };复制代码
Refs/Related
0 http://developer.android.com/reference/android/graphics/Camera.html
1 http://wenku.baidu.com/view/5551eb59be23482fb4da4c89.html
2 http://www.cnblogs.com/franksunny/archive/2011/11/17/2252926.html
3 http://blog.csdn.net/yf210yf/article/details/7304437
4 http://topic.csdn.net/u/20111104/13/fdf356b5-ea77-4ee9-ba8e-c44d0f1b7a19.html
5 http://developer.android.com/reference/android/view/SurfaceView.html
6 http://developer.android.com/reference/android/view/SurfaceHolder.html
7 http://blog.csdn.net/xiaominghimi/article/details/6089594
8 http://blog.csdn.net/xiaominghimi/article/details/6090575
9 http://www.cnblogs.com/emily1314/archive/2012/03/03/2378147.html
10 http://blog.csdn.net/hellogv/article/details/5985090
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