Android设备之间投屏功能实现

2023-08-29 21:23| 来源: 网络整理| 查看: 265

简介

简单实现两个android设备之间的投屏功能。设备间通信是通过局域网，需要连接同一个wifi。

录屏用到系统的MediaProjection，MediaProjectionManager，而编解码用的是MediaCodec，所以设备需要有DSP芯片，大部分手机应该都有。两台设备间通信使用websocket，录屏端作为服务器进行推流，显示端就是客户端，收到码流进行解码并显示。

先看看最终效果：

在这里插入图片描述

实现

首先需要先导入Java-WebSocket库,WebSocket是一种在单个TCP连接上进行全双工通信的协议,允许服务端主动向客户端推送数据。

implementation "org.java-websocket:Java-WebSocket:1.4.0"

整个工程有两个module，app是作为服务端。playscreen是客户端。需要分别运行在两台机器上面。

在这里插入图片描述

服务端 app module

MainActivity 就一个button布局就不贴出来了。

import androidx.annotation.Nullable; import androidx.appcompat.app.AppCompatActivity; import android.content.Intent; import android.media.projection.MediaProjection; import android.media.projection.MediaProjectionManager; import android.os.Bundle; import android.view.View; import com.example.castscreen.socket.SocketService; public class MainActivity extends AppCompatActivity { private int permissionRequestCode = 100; private int captureRequestCode = 1; private MediaProjectionManager mediaProjectionManager; private SocketService socketService; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); init(); } private void init() { //拿到MediaProjectionManager mediaProjectionManager = (MediaProjectionManager) getSystemService(MEDIA_PROJECTION_SERVICE); } public void onClick(View view) { switch (view.getId()){ case R.id.btn_start: startCast(); break; } } //请求开始录屏 private void startCast(){ PermissionUtil.checkPermission(this,PermissionUtil.storagePermissions,permissionRequestCode); Intent intent = mediaProjectionManager.createScreenCaptureIntent(); startActivityForResult(intent,captureRequestCode); } @Override protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) { super.onActivityResult(requestCode, resultCode, data); if (resultCode != RESULT_OK){ return; } if(requestCode == this.captureRequestCode){ startCast(resultCode,data); } } //录屏开始后进行编码推流 private void startCast(int resultCode,Intent data){ //这里需要传入resultCode而不是requestCode，在这里踩了个坑大家注意 MediaProjection mediaProjection = mediaProjectionManager.getMediaProjection(resultCode,data); if (mediaProjection == null){ return; } //初始化服务器端 socketService = new SocketService(); //将MediaProjection传给 socketService socketService.start(mediaProjection); } @Override protected void onDestroy() { super.onDestroy(); if (socketService != null){ socketService.colse(); } } }

SocketService 作用是启动SocketServer并设置端口号。启动CodecH265 进行编码，CodecH265 编码完一帧再通过SocketServer将数据发送出去。

import android.media.projection.MediaProjection; import com.example.castscreen.encode.CodecH265; import java.io.IOException; import java.net.InetSocketAddress; public class SocketService { private static final String TAG = "SocketService"; //端口号，尽量设大一些 private int port = 11006; private CodecH265 codecH265; private SocketServer webSocketServer; public SocketService(){ webSocketServer = new SocketServer(new InetSocketAddress(port)); } public void start(MediaProjection mediaProjection){ //启动webSocketServer 此时当前设备就可以作为一个服务器了 webSocketServer.start(); codecH265 = new CodecH265(this,mediaProjection); //开始编码 codecH265.startEncode(); } //关闭服务端 public void colse(){ try { webSocketServer.stop(); webSocketServer.close(); } catch (IOException e) { e.printStackTrace(); } catch (InterruptedException e) { e.printStackTrace(); } codecH265.stopEncode(); } //发送编码后的数据 public void sendData(byte[] bytes){ webSocketServer.sendData(bytes); } }

SocketServer 继承自WebSocketServer，调用它的start方法就启动服务端了。

import android.util.Log; import org.java_websocket.WebSocket; import org.java_websocket.handshake.ClientHandshake; import org.java_websocket.server.WebSocketServer; import java.net.InetSocketAddress; public class SocketServer extends WebSocketServer { private final String TAG = "SocketServer"; private WebSocket webSocket; public SocketServer(InetSocketAddress inetSocketAddress){ super(inetSocketAddress); } @Override public void onOpen(WebSocket conn, ClientHandshake handshake) { Log.d(TAG,"SocketServer onOpen"); this.webSocket = conn; } @Override public void onClose(WebSocket conn, int code, String reason, boolean remote) { } @Override public void onMessage(WebSocket conn, String message) { } @Override public void onError(WebSocket conn, Exception ex) { } @Override public void onStart() { } public void sendData(byte[] bytes){ if(webSocket != null && webSocket.isOpen()){ //通过WebSocket 发送数据 webSocket.send(bytes); } } public void close(){ webSocket.close(); } }

CodecH265是实现编码的类，这里用的是video/hevc，也就是H265编码。需要注意的是因为H265编码只有第一帧才有vps,sps,pps，其他帧不带这些信息，所以需要我们在发送时候为每个I帧添加上vps信息，否则如果客户端不是从头开始接受的数据，那么就没办法进行解码操作。而且H265用的是哥伦布编码，如果对reEncode方法有疑问可以先了解一下哥伦布编码。另外因为编码是比较耗时的操作，肯定要方法子线程中去做。

import android.hardware.display.DisplayManager; import android.hardware.display.VirtualDisplay; import android.media.MediaCodec; import android.media.MediaCodecInfo; import android.media.MediaFormat; import android.media.projection.MediaProjection; import android.util.Log; import android.view.Surface; import com.example.castscreen.socket.SocketService; import java.io.IOException; import java.nio.ByteBuffer; public class CodecH265 extends Thread { private static final String TAG = "gsy"; //图省事宽高直接固定了 private int width = 720; private int height = 1280; //h265编码 private final String enCodeType = "video/hevc"; private MediaCodec mediaCodec; private MediaProjection mediaProjection; private SocketService socketService; private boolean play = true; private long timeOut = 10000; //记录vps pps sps private byte[] vps_pps_sps; //I帧 private final int NAL_I = 19; //vps帧 private final int NAL_VPS = 32; public CodecH265(SocketService socketService, MediaProjection mediaProjection) { this.socketService = socketService; this.mediaProjection = mediaProjection; } public void startEncode() { //声明MediaFormat，创建视频格式。 MediaFormat mediaFormat = MediaFormat.createVideoFormat(MediaFormat.MIMETYPE_VIDEO_HEVC, width, height); //描述视频格式的内容的颜色格式 mediaFormat.setInteger(MediaFormat.KEY_COLOR_FORMAT, MediaCodecInfo.CodecCapabilities.COLOR_FormatSurface); //比特率（比特/秒） mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, width * height); //帧率 mediaFormat.setInteger(MediaFormat.KEY_FRAME_RATE, 20); //I帧的频率 mediaFormat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 1); try { //创建编码MediaCodec 类型是video/hevc mediaCodec = MediaCodec.createEncoderByType(enCodeType); //配置编码器 mediaCodec.configure(mediaFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE); //创建一个目的surface来存放输入数据 Surface surface = mediaCodec.createInputSurface(); //获取屏幕流 mediaProjection.createVirtualDisplay("screen", width, height, 1, DisplayManager.VIRTUAL_DISPLAY_FLAG_PUBLIC , surface, null, null); } catch (IOException e) { Log.d(TAG,"initEncode IOException"); e.printStackTrace(); } //启动子线程 this.start(); } @Override public void run() { //编解码器立即进入刷新子状态 mediaCodec.start(); //缓存区的元数据 MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo(); //子线程需要一直运行，进行编码推流，所以要一直循环 while (play) { //查询编码输出 int outPutBufferId = mediaCodec.dequeueOutputBuffer(bufferInfo, timeOut); if (outPutBufferId >= 0) { //获取编码之后的数据输出流队列 ByteBuffer byteBuffer = mediaCodec.getOutputBuffer(outPutBufferId); //添加上vps,sps,pps reEncode(byteBuffer, bufferInfo); //处理完成，释放ByteBuffer数据 mediaCodec.releaseOutputBuffer(outPutBufferId, false); } } } private void reEncode(ByteBuffer byteBuffer, MediaCodec.BufferInfo bufferInfo) { //偏移4 00 00 00 01为分隔符需要跳过 int offSet = 4; if (byteBuffer.get(2) == 0x01) { offSet = 3; } //计算出当前帧的类型 int type = (byteBuffer.get(offSet) & 0x7E) >> 1; if (type == NAL_VPS) { //保存vps sps pps信息 vps_pps_sps = new byte[bufferInfo.size]; byteBuffer.get(vps_pps_sps); } else if (type == NAL_I) { //将保存的vps sps pps添加到I帧前 final byte[] bytes = new byte[bufferInfo.size]; byteBuffer.get(bytes); byte[] newBytes = new byte[vps_pps_sps.length + bytes.length]; System.arraycopy(vps_pps_sps, 0, newBytes, 0, vps_pps_sps.length); System.arraycopy(bytes, 0, newBytes, vps_pps_sps.length, bytes.length); //将重新编码好的数据发送出去 socketService.sendData(newBytes); } else { //B帧 P帧直接发送 byte[] bytes = new byte[bufferInfo.size]; byteBuffer.get(bytes); socketService.sendData(bytes); } } public void stopEncode() { play = false; } }

客户端 playescreen module

客户端的页面只有一个SurfaceView，用来显示，布局代码就不贴了。MainActivity 实现了SocketServer.SocketCallback接口，当SocketServer收到数据后，通过回调将收到的码流传给MainActivity 进行解码渲染到SurfaceView。

import androidx.annotation.NonNull; import androidx.appcompat.app.AppCompatActivity; import android.media.MediaCodec; import android.media.MediaFormat; import android.os.Bundle; import android.util.Log; import android.view.Surface; import android.view.SurfaceHolder; import android.view.SurfaceView; import java.io.IOException; import java.nio.ByteBuffer; public class MainActivity extends AppCompatActivity implements SocketServer.SocketCallback{ private static final String TAG = "gsy"; private Surface surface; private SurfaceView surfaceView; private MediaCodec mediaCodec; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); init(); } private void init() { surfaceView = findViewById(R.id.sfv_play); surfaceView.getHolder().addCallback(new SurfaceHolder.Callback() { @Override public void surfaceCreated(@NonNull SurfaceHolder holder) { surface = holder.getSurface(); //连接到服务端 initSocket(); //配置MediaCodec initDecoder(surface); } @Override public void surfaceChanged(@NonNull SurfaceHolder holder, int format, int width, int height) { } @Override public void surfaceDestroyed(@NonNull SurfaceHolder holder) { } }); } private void initDecoder(Surface surface) { try { //配置MediaFormat MediaCodec mediaCodec = MediaCodec.createDecoderByType(MediaFormat.MIMETYPE_VIDEO_HEVC); MediaFormat mediaFormat = MediaFormat.createVideoFormat(MediaFormat.MIMETYPE_VIDEO_HEVC,720,1280); mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE,720*1280); mediaFormat.setInteger(MediaFormat.KEY_FRAME_RATE,20); mediaFormat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL,1); mediaCodec.configure(mediaFormat,surface,null,0); mediaCodec.start(); } catch (IOException e) { Log.d(TAG,"initDecoder IOException "); e.printStackTrace(); } } private void initSocket() { Log.d(TAG,"initSocket"); //启动客户端 SocketServer socketServer = new SocketServer(); socketServer.setSocketCallback(this); socketServer.start(); } @Override public void callBack(byte[] data) { Log.d(TAG,"mainActivity callBack"); //得到填充了有效数据的input buffer的索引 int index = mediaCodec.dequeueInputBuffer(10000); if (index >= 0){ //获取输入缓冲区 ByteBuffer inputBuffer = mediaCodec.getInputBuffer(index); //清除原来的内容以接收新的内容 inputBuffer.clear(); inputBuffer.put(data,0,data.length); //将其提交给编解码器把缓存数据入队 mediaCodec.queueInputBuffer(index,0,data.length,System.currentTimeMillis(),0); } MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo(); //请求一个输出缓存 int outputBufferIndex = mediaCodec.dequeueOutputBuffer(bufferInfo,10000); //直到outputBufferIndex < 0 才算处理完所有数据 while (outputBufferIndex > 0){ mediaCodec.releaseOutputBuffer(outputBufferIndex,true); outputBufferIndex = mediaCodec.dequeueOutputBuffer(bufferInfo,0); } } }

SocketServer 就是客户端了，作用就是连接服务器，获取视频码流进行回调。注意ip地址不要，是服务端的ip地址，可以在设置中查看，比如：

在这里插入图片描述

import android.util.Log; import org.java_websocket.client.WebSocketClient; import org.java_websocket.handshake.ServerHandshake; import java.net.URI; import java.net.URISyntaxException; import java.nio.ByteBuffer; public class SocketServer { private final String TAG = "gsy"; private SocketClient socketClient; private SocketCallback socketCallback; //设置回调 public void setSocketCallback(SocketCallback socketCallback){ this.socketCallback = socketCallback; } public void start(){ try { //这里要填服务端的ip URI uri = new URI("ws://192.168.1.103:11006"); socketClient = new SocketClient(uri); socketClient.connect(); } catch (URISyntaxException e) { Log.e(TAG,"error:"+e.toString()); e.printStackTrace(); } } private class SocketClient extends WebSocketClient{ public SocketClient(URI serverUri) { super(serverUri); Log.d(TAG,"new SocketClient"); } @Override public void onOpen(ServerHandshake handshakedata) { Log.d(TAG,"SocketClient onOpen"); } @Override public void onMessage(String message) { Log.d(TAG,"onMessage"); } @Override public void onMessage(ByteBuffer bytes) { Log.d(TAG,"onMessage"); //收到数据进行回调 byte[] buf = new byte[bytes.remaining()]; bytes.get(buf); socketCallback.callBack(buf); } @Override public void onClose(int code, String reason, boolean remote) { Log.d(TAG,"onClose ="+reason); } @Override public void onError(Exception ex) { Log.d(TAG,"onerror ="+ex.toString()); } } //回调 public interface SocketCallback{ void callBack(byte[] data); } }

总共代码大概就这么多，推荐一个在线测试websocket的网站，http://www.websocket-test.com/ chrome浏览器打不开，可以使用IE浏览器，首先要保证服务端可以访问。今天太冷了，就不再多说了，下面是源码，有兴趣的同学可以玩一下。

源码：demo源码

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