Android和C#基于UDP的实时图像传输
16lz
2021-01-23
实时图像传输的话还是用UDP比较好,速度比TCP快,反正丢一些帧也没有关系
照例先上图
电脑端
手机端
项目:http://pan.baidu.com/s/1pLrYrij
Android端
首先修改AndroidManifest.xml文件
添加这两个权限
然后把MainActiviy设置为横屏
android:screenOrientation="landscape"
然后修改activity_main.xml文件
<?xml version="1.0" encoding="utf-8"?>
很简单,只是一个SurfaceView
最后就是MainActivity.java了
package com.ffpy.cameratransmitclient;import android.graphics.ImageFormat;import android.graphics.Rect;import android.graphics.YuvImage;import android.hardware.Camera;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.util.Log;import android.view.SurfaceHolder;import android.view.SurfaceView;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.net.DatagramPacket;import java.net.DatagramSocket;import java.net.InetAddress;import java.net.Socket;import java.util.LinkedList;public class MainActivity extends AppCompatActivity implements SurfaceHolder.Callback, Camera.PreviewCallback { private final int TCP_PORT = 3333; //TCP通讯的端口号 private final int UDP_PORT = 4444; //UDP通讯的端口号 private final String SERVER_IP = "192.168.1.104"; //服务器端的IP地址 private Camera mCamera; private Camera.Size previewSize; //预览图像的宽高 private DatagramSocket packetSenderSocket; //发送图像帧的套接字 private long lastSendTime; //上一次发送图像帧的时间 private InetAddress serverAddress; //服务端地址 private final LinkedList packetList = new LinkedList<>(); //图像数据包队列 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); final SurfaceView surfaceView = (SurfaceView) findViewById(R.id.surfaceView); SurfaceHolder holder = surfaceView.getHolder(); holder.setKeepScreenOn(true); //保持屏幕常亮 holder.addCallback(this); //开启通讯连接线程,连接服务端 new ConnectThread().start(); } @Override public void surfaceCreated(SurfaceHolder holder) { //获取相机 if (mCamera == null) { mCamera = Camera.open(); //打开后摄像头 Camera.Parameters parameters = mCamera.getParameters(); //设置预览图大小 //注意必须为parameters.getSupportedPreviewSizes()中的长宽,否则会报异常 parameters.setPreviewSize(960, 544); previewSize = parameters.getPreviewSize(); //设置自动对焦 parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_CONTINUOUS_PICTURE); mCamera.setParameters(parameters); mCamera.cancelAutoFocus(); //设置回调 try { mCamera.setPreviewDisplay(holder); mCamera.setPreviewCallback(this); } catch (IOException e) { e.printStackTrace(); } } //开始预览 mCamera.startPreview(); } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { } @Override public void surfaceDestroyed(SurfaceHolder holder) { //释放相机 if (mCamera != null) { mCamera.setPreviewCallback(null); mCamera.stopPreview(); mCamera.release(); mCamera = null; } } /** * 获取每一帧的图像数据 */ @Override public void onPreviewFrame(byte[] data, Camera camera) { long curTime = System.currentTimeMillis(); //每20毫秒发送一帧 if (serverAddress != null && curTime - lastSendTime >= 20) { lastSendTime = curTime; //NV21格式转JPEG格式 YuvImage image = new YuvImage(data, ImageFormat.NV21, previewSize.width ,previewSize.height, null); ByteArrayOutputStream bos = new ByteArrayOutputStream(); image.compressToJpeg(new Rect(0, 0, previewSize.width, previewSize.height), 40, bos); int packMaxSize = 65500; //防止超过UDP包的最大大小 byte[] imgBytes = bos.toByteArray(); Log.i("tag", imgBytes.length + ""); //打包 DatagramPacket packet = new DatagramPacket(imgBytes, imgBytes.length > packMaxSize ? packMaxSize : imgBytes.length, serverAddress, UDP_PORT); //添加到队尾 synchronized (packetList) { packetList.addLast(packet); } } } /** * 连接线程 */ private class ConnectThread extends Thread { @Override public void run() { super.run(); try { //创建连接 packetSenderSocket = new DatagramSocket(); Socket socket = new Socket(SERVER_IP, TCP_PORT); serverAddress = socket.getInetAddress(); //断开连接 socket.close(); //启动发送图像数据包的线程 new ImgSendThread().start(); } catch (IOException e) { e.printStackTrace(); } } } /** * 发送图像数据包的线程 */ private class ImgSendThread extends Thread { @Override public void run() { super.run(); while (packetSenderSocket != null) { DatagramPacket packet; synchronized (packetList) { //没有待发送的包 if (packetList.isEmpty()) { try { Thread.sleep(10); continue; } catch (InterruptedException e) { e.printStackTrace(); } } //取出队头 packet = packetList.getFirst(); packetList.removeFirst(); } try { packetSenderSocket.send(packet); } catch (IOException e) { e.printStackTrace(); } } } }}
surfaceCreated()、surfaceChanged()、surfaceDestroyed()这三个方法是对应SurfaceView的,做过Android自定义相机的都知道的。需要注意的是,在surfaceCreated()中我设置了预览图像的宽高
parameters.setPreviewSize(960, 544);
这个值我根据我手机屏幕的大小设置的,因为预览图会在SurfaceView上拉伸成SurfaceView的宽高,所以设置成跟SurfaceView的宽高比差不多,这样看上去图像不会变形。 而且它不能随便设置,设置得不对的话会报异常,可以通过parameters.getSupportedPreviewSizes()来查看手机支持的宽高列表,不同的手机所支持的不一定相同,所以如果在这里报错的话可以修改成你手机所支持的值。
onPreviewFrame()就是获取每一帧图像的地方了,在这里获取摄像头的图像帧,并转为JPEG格式。还有因为UDP每个包的大小不能超过64K,减去一下包头那些所占用的,大概还有65500个字节。因为我这里是每一个包封装一帧图像,所以要注意压缩图像,不要超过65500个字节,否则在电脑端就看不到超出的那部分图像了。
C#
窗体很简单,就是一个PictureBox放在Form上,把PictrureBox的Name设置为pictureBox,并让它充满Form。设置Form的大小为978, 591,这样pictureBox的大小就是960, 544了,跟预览图的大小一致
Form1.cs
using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Diagnostics;using System.Drawing;using System.IO;using System.Linq;using System.Net;using System.Net.Sockets;using System.Text;using System.Threading;using System.Threading.Tasks;using System.Windows.Forms;namespace CameraTransmitServer{ public partial class Form1 : Form { private const int TCP_PORT = 3333; //TCP通讯的端口号 private const int UDP_PORT = 4444; //UDP通讯的端口号 private UdpClient client; private IPEndPoint remote; public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { //创建等待连接线程 Thread thread = new Thread(new ThreadStart(waitConnect)); thread.IsBackground = true; thread.Start(); } //等待连接 private void waitConnect() { Socket serverSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp); serverSocket.Bind(new IPEndPoint(IPAddress.Any, TCP_PORT)); serverSocket.Listen(10); Debug.WriteLine("监听中"); Socket clientSocket = serverSocket.Accept(); Debug.WriteLine("连接成功"); remote = (IPEndPoint) clientSocket.RemoteEndPoint; client = new UdpClient(new IPEndPoint(IPAddress.Any, UDP_PORT)); //关闭套接字 serverSocket.Close(); clientSocket.Close(); //启动接收线程 Thread thread = new Thread(new ThreadStart(recvImage)); thread.IsBackground = true; thread.Start(); } //接收图像帧,并显示到PictureBox上 private void recvImage() { while(true) { //接受图像帧数据 byte[] recvBuf = client.Receive(ref remote); MemoryStream ms = new MemoryStream(recvBuf); try { //显示到pictureBox上 pictureBox.Image = Image.FromStream(ms); } catch (ArgumentException) { } } } }}
这里就是等待手机端连接然后不断地接收图像数据并显示在PictureBox上
你可能会问,不是UDP吗,怎么这里还用了TCP?
我这里用TCP是为了保证连接的建立,确认连接成功后再通过UDP发送图像数据,否则的话服务端还没上线手机就开始不断地发送图像数据了。而且如果需要的话还可以用TCP的可靠连接来发送除了图像以外的其它数据,比如文字什么的。
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