java代码视频数据和音频数据的采集

我们经常用直播，但是直播怎么做呢？前面的文章已经搭建好了推流服务器，现在就让我们先从采集数据开始吧，然后压缩数据，然后推流数据等等，一步步来，一定会成个大胖纸的。加油！

Activity.java

public class MainActivity extends Activity {

    static final String URL = "rtmp://112.74.96.116/live/jason";
    private LivePusher live;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        SurfaceView surfaceView = (SurfaceView) findViewById(R.id.surface);
        //相机图像的预览
        live = new LivePusher(surfaceView.getHolder());
    }

    /**
     * 开始直播
     * @param btn
     */
    public void mStartLive(View view) {
        Button btn = (Button)view;
        if(btn.getText().equals("开始直播")){
            live.startPush(URL);
            btn.setText("停止直播");
        }else{
            live.stopPush();
            btn.setText("开始直播");
        }
    }

    /**
     * 切换摄像头
     * @param btn
     */
    public void mSwitchCamera(View btn) {
        live.switchCamera();
    }

}

Push业务

定义接口Pusher.java

public abstract class Pusher {
    public abstract void startPush();
    public abstract void stopPush();
    public abstract void release();
}

视频Push
VideoPusher.java

public class VideoPusher extends Pusher implements Callback, PreviewCallback{

    private SurfaceHolder surfaceHolder;
    private Camera mCamera;
    private VideoParam videoParams;
    private byte[] buffers;
    private boolean isPushing = false;
    private PushNative pushNative;

    public VideoPusher(SurfaceHolder surfaceHolder, VideoParam videoParams, PushNative pushNative) {
        this.surfaceHolder = surfaceHolder;
        this.videoParams = videoParams;
        this.pushNative = pushNative;
        surfaceHolder.addCallback(this);
    }
    @Override
    public void startPush() {
        isPushing = true;
    }
    @Override
    public void stopPush() {
        isPushing = false;
    }
    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        startPreview();
    }
    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

    }
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
    }
    @Override
    public void release() {
        stopPreview();
    }
    /**
     * 切换摄像头
     */
    public void switchCamera() {
        if(videoParams.getCameraId() == CameraInfo.CAMERA_FACING_BACK){
            videoParams.setCameraId(CameraInfo.CAMERA_FACING_FRONT);
        }else{
            videoParams.setCameraId(CameraInfo.CAMERA_FACING_BACK);
        }
        //重新预览
        stopPreview();
        startPreview();
    }
    /**
     * 开始预览
     */
    private void startPreview() {
        try {
            //SurfaceView初始化完成，开始相机预览
            mCamera = Camera.open(videoParams.getCameraId());
            mCamera.setPreviewDisplay(surfaceHolder);
            //获取预览图像数据
            buffers = new byte[videoParams.getWidth() * videoParams.getHeight() * 4];
            mCamera.addCallbackBuffer(buffers);
            mCamera.setPreviewCallbackWithBuffer(this);

            mCamera.startPreview();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    /**
     * 停止预览
     */
    private void stopPreview() {
        if(mCamera != null){            
            mCamera.stopPreview();
            mCamera.release();
            mCamera = null;
        }
    }
    @Override
    public void onPreviewFrame(byte[] data, Camera camera) {
        if(mCamera != null){
            mCamera.addCallbackBuffer(buffers);
        }

        if(isPushing){
            //回调函数中获取图像数据，然后给Native代码编码
            pushNative.fireVideo(data);
        }
    }
}

音频AudioPusher.java

public class AudioPusher extends Pusher{

    private AudioParam audioParam;
    private AudioRecord audioRecord;
    private boolean isPushing = false;
    private int minBufferSize;
    private PushNative pushNative;

    public AudioPusher(AudioParam audioParam, PushNative pushNative) {
        this.audioParam = audioParam;
        this.pushNative = pushNative;

        int channelConfig = audioParam.getChannel() == 1 ? 
                AudioFormat.CHANNEL_IN_MONO : AudioFormat.CHANNEL_IN_STEREO; 
        //最小缓冲区大小
        minBufferSize = AudioRecord.getMinBufferSize(audioParam.getSampleRateInHz(), channelConfig, AudioFormat.ENCODING_PCM_16BIT);
        audioRecord = new AudioRecord(AudioSource.MIC, 
                audioParam.getSampleRateInHz(), 
                channelConfig, 
                AudioFormat.ENCODING_PCM_16BIT, minBufferSize);
    }

    @Override
    public void startPush() {
        isPushing = true;
        //启动一个录音子线程
        new Thread(new AudioRecordTask()).start();
    }

    @Override
    public void stopPush() {
        isPushing = false;
        audioRecord.stop();
    }

    @Override
    public void release() {
        if(audioRecord != null){
            audioRecord.release();
            audioRecord = null;
        }
    }
    class AudioRecordTask implements Runnable{
        @Override
        public void run() {
            //开始录音
            audioRecord.startRecording();
            while(isPushing){
                //通过AudioRecord不断读取音频数据
                byte[] buffer = new byte[minBufferSize];
                int len = audioRecord.read(buffer, 0, buffer.length);
                if(len > 0){
                    //传给Native代码，进行音频编码
                    pushNative.fireAudio(buffer, len);
                }
            }
        }

    }
}

push总类，音频视频同时push

public class LivePusher implements Callback {

    private SurfaceHolder surfaceHolder;
    private VideoPusher videoPusher;
    private AudioPusher audioPusher;
    private PushNative pushNative;

    public LivePusher(SurfaceHolder surfaceHolder) {
        this.surfaceHolder = surfaceHolder;
        surfaceHolder.addCallback(this);
        prepare();
    }

    /**
     * 预览准备
     */
    private void prepare() {
        pushNative = new PushNative();

        //实例化视频推流器
        VideoParam videoParam = new VideoParam(480, 320, CameraInfo.CAMERA_FACING_BACK);
        videoPusher = new VideoPusher(surfaceHolder,videoParam,pushNative);

        //实例化音频推流器
        AudioParam audioParam = new AudioParam();
        audioPusher = new AudioPusher(audioParam,pushNative);
    }

    /**
     * 切换摄像头
     */
    public void switchCamera() {
        videoPusher.switchCamera();
    }
    /**
     * 开始推流
     */
    public void startPush(String url) {
        videoPusher.startPush();
        audioPusher.startPush();
        pushNative.startPush(url);
    }
    /**
     * 停止推流
     */
    public void stopPush() {
        videoPusher.stopPush();
        audioPusher.stopPush();
        pushNative.stopPush();
    }
    /**
     * 释放资源
     */
    private void release() {
        videoPusher.release();
        audioPusher.release();
        pushNative.release();
    }
    @Override
    public void surfaceCreated(SurfaceHolder holder) {

    }
    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

    }
    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        stopPush();
        release();
    }
}

参数的设置：

public class LivePusher implements Callback {

    private SurfaceHolder surfaceHolder;
    private VideoPusher videoPusher;
    private AudioPusher audioPusher;
    private PushNative pushNative;

    public LivePusher(SurfaceHolder surfaceHolder) {
        this.surfaceHolder = surfaceHolder;
        surfaceHolder.addCallback(this);
        prepare();
    }

    /**
     * 预览准备
     */
    private void prepare() {
        pushNative = new PushNative();

        //实例化视频推流器
        VideoParam videoParam = new VideoParam(480, 320, CameraInfo.CAMERA_FACING_BACK);
        videoPusher = new VideoPusher(surfaceHolder,videoParam,pushNative);

        //实例化音频推流器
        AudioParam audioParam = new AudioParam();
        audioPusher = new AudioPusher(audioParam,pushNative);
    }

    /**
     * 切换摄像头
     */
    public void switchCamera() {
        videoPusher.switchCamera();
    }

    /**
     * 开始推流
     */
    public void startPush(String url) {
        videoPusher.startPush();
        audioPusher.startPush();
        pushNative.startPush(url);
    }


    /**
     * 停止推流
     */
    public void stopPush() {
        videoPusher.stopPush();
        audioPusher.stopPush();
        pushNative.stopPush();
    }

    /**
     * 释放资源
     */
    private void release() {
        videoPusher.release();
        audioPusher.release();
        pushNative.release();
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {

    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        stopPush();
        release();
    }

}

package com.dongnaoedu.live.params;

/**
 * 视频数据参数
 */
public class VideoParam {

    private int width;
    private int height;
    private int cameraId;

    public VideoParam(int width, int height, int cameraId) {
        super();
        this.width = width;
        this.height = height;
        this.cameraId = cameraId;
    }

    public int getWidth() {
        return width;
    }

    public void setWidth(int width) {
        this.width = width;
    }

    public int getHeight() {
        return height;
    }

    public void setHeight(int height) {
        this.height = height;
    }

    public int getCameraId() {
        return cameraId;
    }

    public void setCameraId(int cameraId) {
        this.cameraId = cameraId;
    }

}

当然数据有了，我们必须通过C++代码完成操作，所以如下：

/**
 * 调用C代码进行编码与推流
 */
public class PushNative {

    public native void startPush(String url);

    public native void stopPush();

    public native void release();

    /**
     * 设置视频参数
     * @param width
     * @param height
     * @param bitrate
     * @param fps
     */
    public native void setVideoOptions(int width, int height, int bitrate, int fps);

    /**
     * 设置音频参数
     * @param sampleRateInHz
     * @param channel
     */
    public native void setAudioOptions(int sampleRateInHz, int channel);


    /**
     * 发送视频数据
     * @param data
     */
    public native void fireVideo(byte[] data);

    /**
     * 发送音频数据
     * @param data
     * @param len
     */
    public native void fireAudio(byte[] data, int len);

    static{
        System.loadLibrary("dn_live");
    }
}

上面是第一节操作，我们后面的文章将慢慢介绍C++的实现，牵扯到jni的使用，可能会单独有一篇文章进行介绍，小朋友记得加关注哦。