Android 和 MJPEG

Question

我需要从 IP 摄像机获取 mjpeg 流，有人知道正确的方法吗？我google了一下，我找到了这个例子

http://www.anddev.org/mjpeg_on_android_anyone-t1871.html

但是当我试图从主要 Activity 调用的另一个 Activity 中获取流时，我被卡住了。代码如下:

主要 Activity

package com.test;


public class IntentTest extends Activity {
    /** Called when the activity is first created. */
    ListView myListView = null;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        myListView = (ListView)findViewById(R.id.listView);
        final ArrayList<String> items = new ArrayList<String>();
        items.add("00408C944B9A");
        final ArrayAdapter<String> aa;
        aa = new ArrayAdapter<String>(this,
                android.R.layout.simple_list_item_1,
                items);

        myListView.setAdapter(aa);
        myListView.setOnItemClickListener(listClicked);

    }


    private OnItemClickListener listClicked = new OnItemClickListener() {
        public void onItemClick(AdapterView<?> arg0, View arg1, int position, long id) {
            // TODO Auto-generated method stub
            Intent i = new Intent(IntentTest.this, OtherActivity.class);
            i.putExtra("MAC", myListView.getItemAtPosition(position).toString());
            startActivity(i);         
        }
    };
}

第二次 Activity

package com.test;

import com.test.mjpeg.mjpegsample.MjpegView.*;
import com.test.parser.JSONParse;


public class OtherActivity extends Activity {
    /** Called when the activity is first created. */
    private MjpegView mv;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Bundle extras = getIntent().getExtras();
        if (extras != null){
            String mac = (String)extras.get("MAC");
            Log.i("Other", "---->" + mac);
            TextView tv = (TextView)findViewById(R.id.textView);
            tv.setText(mac);


            String URL = "myurl";

            requestWindowFeature(Window.FEATURE_NO_TITLE);
            getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
                    WindowManager.LayoutParams.FLAG_FULLSCREEN);

            mv = new MjpegView(this);
            setContentView(mv);        

            mv.setSource(MjpegInputStream.read(URL));
            mv.setDisplayMode(MjpegView.SIZE_BEST_FIT);
            mv.showFps(true);      

        }
    }

    public void onPause() {
        super.onPause();
        mv.stopPlayback();
    }


}

Answer 1

前段时间我在网上找到了这段代码，也许对你有帮助。

MjpegSample 类

package de.mjpegsample;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.Window;
import android.view.WindowManager;
import de.mjpegsample.MjpegView.MjpegInputStream;
import de.mjpegsample.MjpegView.MjpegView;

public class MjpegSample extends Activity {

    private MjpegView mv;
    private static final int MENU_QUIT = 1;

    /* Creates the menu items */
    public boolean onCreateOptionsMenu(Menu menu) {    
    menu.add(0, MENU_QUIT, 0, "Quit");
    return true;
    }

    /* Handles item selections */
    public boolean onOptionsItemSelected(MenuItem item) {    
        switch (item.getItemId()) {
            case MENU_QUIT:
                finish();
                return true;    
            }    
        return false;
    }

    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        //sample public cam
        String URL = "http://gamic.dnsalias.net:7001/img/video.mjpeg";

        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN, WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
        mv = new MjpegView(this);
        setContentView(mv);        
        mv.setSource(MjpegInputStream.read(URL));
        mv.setDisplayMode(MjpegView.SIZE_BEST_FIT);
        mv.showFps(false);
    }

    public void onPause() {
        super.onPause();
        mv.stopPlayback();
    }
}

MjpegView 类

package de.mjpegsample.MjpegView;

import java.io.IOException;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.Typeface;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class MjpegView extends SurfaceView implements SurfaceHolder.Callback {
    public final static int POSITION_UPPER_LEFT  = 9;
    public final static int POSITION_UPPER_RIGHT = 3;
    public final static int POSITION_LOWER_LEFT  = 12;
    public final static int POSITION_LOWER_RIGHT = 6;

    public final static int SIZE_STANDARD   = 1; 
    public final static int SIZE_BEST_FIT   = 4;
    public final static int SIZE_FULLSCREEN = 8;

    private MjpegViewThread thread;
    private MjpegInputStream mIn = null;    
    private boolean showFps = false;
    private boolean mRun = false;
    private boolean surfaceDone = false;    
    private Paint overlayPaint;
    private int overlayTextColor;
    private int overlayBackgroundColor;
    private int ovlPos;
    private int dispWidth;
    private int dispHeight;
    private int displayMode;

    public class MjpegViewThread extends Thread {
        private SurfaceHolder mSurfaceHolder;
        private int frameCounter = 0;
        private long start;
        private Bitmap ovl;

        public MjpegViewThread(SurfaceHolder surfaceHolder, Context context) { mSurfaceHolder = surfaceHolder; }

        private Rect destRect(int bmw, int bmh) {
            int tempx;
            int tempy;
            if (displayMode == MjpegView.SIZE_STANDARD) {
                tempx = (dispWidth / 2) - (bmw / 2);
                tempy = (dispHeight / 2) - (bmh / 2);
                return new Rect(tempx, tempy, bmw + tempx, bmh + tempy);
            }
            if (displayMode == MjpegView.SIZE_BEST_FIT) {
                float bmasp = (float) bmw / (float) bmh;
                bmw = dispWidth;
                bmh = (int) (dispWidth / bmasp);
                if (bmh > dispHeight) {
                    bmh = dispHeight;
                    bmw = (int) (dispHeight * bmasp);
                }
                tempx = (dispWidth / 2) - (bmw / 2);
                tempy = (dispHeight / 2) - (bmh / 2);
                return new Rect(tempx, tempy, bmw + tempx, bmh + tempy);
            }
            if (displayMode == MjpegView.SIZE_FULLSCREEN) return new Rect(0, 0, dispWidth, dispHeight);
            return null;
        }

        public void setSurfaceSize(int width, int height) {
            synchronized(mSurfaceHolder) {
                dispWidth = width;
                dispHeight = height;
            }
        }

        private Bitmap makeFpsOverlay(Paint p, String text) {
            Rect b = new Rect();
            p.getTextBounds(text, 0, text.length(), b);
            int bwidth  = b.width()+2;
            int bheight = b.height()+2;
            Bitmap bm = Bitmap.createBitmap(bwidth, bheight, Bitmap.Config.ARGB_8888);
            Canvas c = new Canvas(bm);
            p.setColor(overlayBackgroundColor);
            c.drawRect(0, 0, bwidth, bheight, p);
            p.setColor(overlayTextColor);
            c.drawText(text, -b.left+1, (bheight/2)-((p.ascent()+p.descent())/2)+1, p);
            return bm;           
        }

        public void run() {
            start = System.currentTimeMillis();
            PorterDuffXfermode mode = new PorterDuffXfermode(PorterDuff.Mode.DST_OVER);
            Bitmap bm;
            int width;
            int height;
            Rect destRect;
            Canvas c = null;
            Paint p = new Paint();
            String fps = "";
            while (mRun) {
                if(surfaceDone) {
                    try {
                        c = mSurfaceHolder.lockCanvas();
                        synchronized (mSurfaceHolder) {
                            try {
                                bm = mIn.readMjpegFrame();
                                destRect = destRect(bm.getWidth(),bm.getHeight());
                                c.drawColor(Color.BLACK);
                                c.drawBitmap(bm, null, destRect, p);
                                if(showFps) {
                                    p.setXfermode(mode);
                                    if(ovl != null) {
                                        height = ((ovlPos & 1) == 1) ? destRect.top : destRect.bottom-ovl.getHeight();
                                        width  = ((ovlPos & 8) == 8) ? destRect.left : destRect.right -ovl.getWidth();
                                        c.drawBitmap(ovl, width, height, null);
                                    }
                                    p.setXfermode(null);
                                    frameCounter++;
                                    if((System.currentTimeMillis() - start) >= 1000) {
                                        fps = String.valueOf(frameCounter)+"fps";
                                        frameCounter = 0; 
                                        start = System.currentTimeMillis();
                                        ovl = makeFpsOverlay(overlayPaint, fps);
                                    }
                                }
                            } catch (IOException e) {}
                        }
                    } finally { if (c != null) mSurfaceHolder.unlockCanvasAndPost(c); }
                }
            }
        }
    }

    private void init(Context context) {
        SurfaceHolder holder = getHolder();
        holder.addCallback(this);
        thread = new MjpegViewThread(holder, context);
        setFocusable(true);
        overlayPaint = new Paint();
        overlayPaint.setTextAlign(Paint.Align.LEFT);
        overlayPaint.setTextSize(12);
        overlayPaint.setTypeface(Typeface.DEFAULT);
        overlayTextColor = Color.WHITE;
        overlayBackgroundColor = Color.BLACK;
        ovlPos = MjpegView.POSITION_LOWER_RIGHT;
        displayMode = MjpegView.SIZE_STANDARD;
        dispWidth = getWidth();
        dispHeight = getHeight();
    }

    public void startPlayback() { 
        if(mIn != null) {
            mRun = true;
            thread.start();         
        }
    }

    public void stopPlayback() { 
        mRun = false;
        boolean retry = true;
        while(retry) {
            try {
                thread.join();
                retry = false;
            } catch (InterruptedException e) {}
        }
    }

    public MjpegView(Context context, AttributeSet attrs) { super(context, attrs); init(context); }
    public void surfaceChanged(SurfaceHolder holder, int f, int w, int h) { thread.setSurfaceSize(w, h); }

    public void surfaceDestroyed(SurfaceHolder holder) { 
        surfaceDone = false; 
        stopPlayback(); 
    }

    public MjpegView(Context context) { 
        super(context); 
        init(context); 
        }    
    public void surfaceCreated(SurfaceHolder holder) { 
        surfaceDone = true; 
        }
    public void showFps(boolean b) { 
        showFps = b; 
        }
    public void setSource(MjpegInputStream source) { 
        mIn = source; 
        startPlayback();
        }
    public void setOverlayPaint(Paint p) { 
        overlayPaint = p; 
        }
    public void setOverlayTextColor(int c) { 
        overlayTextColor = c; 
        }
    public void setOverlayBackgroundColor(int c) { 
        overlayBackgroundColor = c; 
        }
    public void setOverlayPosition(int p) { 
        ovlPos = p; 
        }
    public void setDisplayMode(int s) { 
        displayMode = s; 
        }
}

MjpegInputStream 类

package de.mjpegsample.MjpegView;

import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.util.Properties;

import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

public class MjpegInputStream extends DataInputStream {
    private final byte[] SOI_MARKER = { (byte) 0xFF, (byte) 0xD8 };
    private final byte[] EOF_MARKER = { (byte) 0xFF, (byte) 0xD9 };
    private final String CONTENT_LENGTH = "Content-Length";
    private final static int HEADER_MAX_LENGTH = 100;
    private final static int FRAME_MAX_LENGTH = 40000 + HEADER_MAX_LENGTH;
    private int mContentLength = -1;

    public static MjpegInputStream read(String url) {
        HttpResponse res;
        DefaultHttpClient httpclient = new DefaultHttpClient();     
        try {
            res = httpclient.execute(new HttpGet(URI.create(url)));
            return new MjpegInputStream(res.getEntity().getContent());              
        } catch (ClientProtocolException e) {
        } catch (IOException e) {}
        return null;
    }

    public MjpegInputStream(InputStream in) { super(new BufferedInputStream(in, FRAME_MAX_LENGTH)); }

    private int getEndOfSeqeunce(DataInputStream in, byte[] sequence) throws IOException {
        int seqIndex = 0;
        byte c;
        for(int i=0; i < FRAME_MAX_LENGTH; i++) {
            c = (byte) in.readUnsignedByte();
            if(c == sequence[seqIndex]) {
                seqIndex++;
                if(seqIndex == sequence.length) return i + 1;
            } else seqIndex = 0;
        }
        return -1;
    }

    private int getStartOfSequence(DataInputStream in, byte[] sequence) throws IOException {
        int end = getEndOfSeqeunce(in, sequence);
        return (end < 0) ? (-1) : (end - sequence.length);
    }

    private int parseContentLength(byte[] headerBytes) throws IOException, NumberFormatException {
        ByteArrayInputStream headerIn = new ByteArrayInputStream(headerBytes);
        Properties props = new Properties();
        props.load(headerIn);
        return Integer.parseInt(props.getProperty(CONTENT_LENGTH));
    }   

    public Bitmap readMjpegFrame() throws IOException {
        mark(FRAME_MAX_LENGTH);
        int headerLen = getStartOfSequence(this, SOI_MARKER);
        reset();
        byte[] header = new byte[headerLen];
        readFully(header);
        try {
            mContentLength = parseContentLength(header);
        } catch (NumberFormatException nfe) { 
            mContentLength = getEndOfSeqeunce(this, EOF_MARKER); 
        }
        reset();
        byte[] frameData = new byte[mContentLength];
        skipBytes(headerLen);
        readFully(frameData);
        return BitmapFactory.decodeStream(new ByteArrayInputStream(frameData));
    }
}

如果您需要更多信息，请告诉我，我会尽我所能提供帮助。

仅供引用:我没有编写 SimpleMjpegView，您可以找到更多最新代码 here