我有服务器，流式传输IP摄像机视频（在这种情况下，我的笔记本电脑是IP摄像机）。并存储可通过互联网访问的JPG文件。我有这个代码应该捕获这些JPG并用它们制作视频：
我只能获得一个帧，并且程序以某种方式不刷新（如果我旋转屏幕，帧刷新）。
我想知道的是： 1.如果有更简单的方法来反映那些jpeg图片？ 2.为什么我的程序只显示一帧？
主要活动
package de.mjpegsample;
import android.app.Activity;
import android.os.Bundle;
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;
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
//sample public cam
String URL = "http://xxx.xxx.x.xx:8080/cam_1.jpg";
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();
}
}
MjpegInputStream：
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));
}
}
MjpegView
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 = true;
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; }
}
答案 0 :(得分：0)
奇怪......我改变了String URL =“http://xxx.xxx.x.xx:8080/cam_1.jpg”; to String URL =“http://xxx.xxx.x.xx:8080/cam_1.cgi”;而且它有点延迟，但没关系。
所以我的最后一个问题仍然没有答案：有没有更简单的方法来反映JPG并制作一个MJPEG？因为这个需要做很多编码：）
