Question

我正在尝试将视频从树莓派流式传输到android应用。服务器端是用Python编写的，如下所示：

import socket
import struct
import time
import picamera

client_socket = socket.socket()
client_socket.connect(('192.168.0.126', 8000))
connection = client_socket.makefile('wb')

try:
    with picamera.PiCamera() as camera:
        camera.resolution = (160, 120)
        camera.framerate = 30
        time.sleep(2)
        start = time.time()
        stream = io.BytesIO()
        # Use the video-port for captures...
        for foo in camera.capture_continuous(stream, 'jpeg',
                                             use_video_port=True):
            connection.write(struct.pack('<L', stream.tell()))
            connection.flush()
            stream.seek(0)
            connection.write(stream.read())
            if time.time() - start > 30:
                break
            stream.seek(0)
            stream.truncate()
    connection.write(struct.pack('<L', 0))
finally:
    connection.close()
    client_socket.close()

android端的Java类如下。我正在尝试检索图像并在android应用程序的imageview中逐帧显示相同的帧。

package com.example.videostreaming2;

import androidx.appcompat.app.AppCompatActivity;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.ImageView;

import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

public class MainActivity extends AppCompatActivity {
    public static final String TAG="VS2";
    public DataInputStream dataInputStream;
    ImageView imageView;
    int len;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }


    public class frame2video extends AsyncTask<byte[],Void, Bitmap>{

        protected void onPreExecute(){
            imageView=(ImageView)findViewById(R.id.imview);
            try{
                ServerSocket serverSocket=new ServerSocket(8000);
                Socket video_receiver=serverSocket.accept();

                while(true){
                    DataInputStream dataInputStream=new DataInputStream(video_receiver.getInputStream());
                    len=Integer.parseInt(""+dataInputStream.readInt());
                    System.out.println(len);
                    byte[] buffer=new byte[len];
                    dataInputStream.readFully(buffer,0,buffer.length);
                    frame2video f2v=new frame2video();
                    f2v.execute(buffer);


                }

            }catch (Exception e){
                e.printStackTrace();
            }

        }
        protected Bitmap doInBackground(byte[]...buffer){

            try {
                Bitmap bitmap = BitmapFactory.decodeByteArray(buffer[0], 0, len);
                ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
                outputStream.flush();
                return bitmap;
            }catch(IOException e){
                e.printStackTrace();

            }
            return null;


        }

        @Override
        protected void onPostExecute(Bitmap bitmap) {
            super.onPostExecute(bitmap);
            imageView.setImageBitmap(bitmap);
            imageView.invalidate();
        }
    }
}

我有两个问题：

我在android studio中设置了端口转发功能，但是当我在模拟器中运行Java应用程序，并且在pi上运行python代码时，我在pi上拒绝连接（ERR 111）。我已确认Mac上的防火墙已关闭。还有另一种方法可以在模拟器上测试应用程序吗？
我怀疑问题可能与模拟器设置有关，所以我插入了Android手机。现在，当我在手机上运行该应用程序（已连接到Mac和android studio）并在pi上运行python应用程序时，在Studio中出现以下错误：


09/29 21:43:44: Launching 'app' on Essential Products PH-1.
$ adb shell am start -n "com.example.videostreaming2/com.example.videostreaming2.MainActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
Waiting for process to come online...
Connected to process 5795 on device 'essential_products-ph_1-PM1LHMA812601675'.
Capturing and displaying logcat messages from application. This behavior can be disabled in the "Logcat output" section of the "Debugger" settings page.
W/videostreaming: Accessing hidden method Landroid/view/View;->computeFitSystemWindows(Landroid/graphics/Rect;Landroid/graphics/Rect;)Z (greylist, reflection, allowed)
W/videostreaming: Accessing hidden method Landroid/view/ViewGroup;->makeOptionalFitsSystemWindows()V (greylist, reflection, allowed)
I/AdrenoGLES: QUALCOMM build                   : 436c23c, I70c9d1ad86
    Build Date                       : 06/19/19
    OpenGL ES Shader Compiler Version: EV031.26.14.00
    Local Branch                     : mybranche992c040-71da-f106-bb16-1458d0b52ae8
    Remote Branch                    : quic/gfx-adreno.lnx.1.0.r85-rel
    Remote Branch                    : NONE
    Reconstruct Branch               : NOTHING
    Build Config                     : C O 9.0.3 AArch64
I/AdrenoGLES: PFP: 0x005ff110, ME: 0x005ff066
W/Gralloc3: mapper 3.x is not supported

在python端，我仍然拒绝连接：

[Errno 111] Connection refused

在imageview中显示传入图像的方法可以吗？是否有其他方法来显示流？我几乎还没有开始进行android开发，我可能会犯一些愚蠢的错误。

尝试从Raspberry Pi流式传输视频时，Android应用程序崩溃

0 个答案: