使用 AsyncTask 的 Android ICS 和 MJPEG
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原文地址: http://stackoverflow.com/questions/10550139/
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时间：2020-08-20 04:08:10 来源:igfitidea点击:
Android ICS and MJPEG using AsyncTask
提问by bbodenmiller
I modified the MJPEG viewer code from Android and MJPEGto work using an AsyncTask (and thus work on Ice Cream Sandwich (ICS), 4.0.4) and here is my code.
我修改了Android 和 MJPEG 中的 MJPEG 查看器代码以使用 AsyncTask（因此适用于 Ice Cream Sandwich (ICS), 4.0.4），这是我的代码。
If anyone has any suggestions on how to optimize, cleanup, or do something more proper with the code please let me know. Two issues I'd appreciate help addressing:
如果有人对如何优化、清理或对代码做一些更合适的事情有任何建议，请告诉我。我希望帮助解决两个问题：
If you have the device on a stream then lock the screen and unlock the screen it does not resume playing until you either kill and resume the app or rotate the screen. All my attempts at using OnResume() to do something or other resulted in app crashes.
In particular I'd like to get the AsyncTask back in MjpegInputStream.java but was not able to get that to work.
如果您将设备放在流上，然后锁定屏幕并解锁屏幕，它不会继续播放，直到您杀死并恢复应用程序或旋转屏幕。我使用 OnResume() 做某事或其他的所有尝试都导致应用程序崩溃。
特别是我想在 MjpegInputStream.java 中恢复 AsyncTask，但无法让它工作。
MjpegActivity.java:
MjpegActivity.java：
package com.demo.mjpeg;
import java.io.IOException;
import java.net.URI;
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 com.demo.mjpeg.MjpegView.MjpegInputStream;
import com.demo.mjpeg.MjpegView.MjpegView;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Toast;
public class MjpegActivity extends Activity {
private static final String TAG = "MjpegActivity";
private MjpegView mv;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//sample public cam
String URL = "http://trackfield.webcam.oregonstate.edu/axis-cgi/mjpg/video.cgi?resolution=800x600&%3bdummy=1333689998337";
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
mv = new MjpegView(this);
setContentView(mv);
new DoRead().execute(URL);
}
public void onPause() {
super.onPause();
mv.stopPlayback();
}
public class DoRead extends AsyncTask<String, Void, MjpegInputStream> {
protected MjpegInputStream doInBackground(String... url) {
//TODO: if camera has authentication deal with it and don't just not work
HttpResponse res = null;
DefaultHttpClient httpclient = new DefaultHttpClient();
Log.d(TAG, "1. Sending http request");
try {
res = httpclient.execute(new HttpGet(URI.create(url[0])));
Log.d(TAG, "2. Request finished, status = " + res.getStatusLine().getStatusCode());
if(res.getStatusLine().getStatusCode()==401){
//You must turn off camera User Access Control before this will work
return null;
}
return new MjpegInputStream(res.getEntity().getContent());
} catch (ClientProtocolException e) {
e.printStackTrace();
Log.d(TAG, "Request failed-ClientProtocolException", e);
//Error connecting to camera
} catch (IOException e) {
e.printStackTrace();
Log.d(TAG, "Request failed-IOException", e);
//Error connecting to camera
}
return null;
}
protected void onPostExecute(MjpegInputStream result) {
mv.setSource(result);
mv.setDisplayMode(MjpegView.SIZE_BEST_FIT);
mv.showFps(true);
}
}
}
MjpegInputStream.java:
MjpegInputStream.java：
package com.demo.mjpeg.MjpegView;
import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;
public class MjpegInputStream extends DataInputStream {
private static final String TAG = "MjpegInputStream";
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 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) {
nfe.getStackTrace();
Log.d(TAG, "catch NumberFormatException hit", nfe);
mContentLength = getEndOfSeqeunce(this, EOF_MARKER);
}
reset();
byte[] frameData = new byte[mContentLength];
skipBytes(headerLen);
readFully(frameData);
return BitmapFactory.decodeStream(new ByteArrayInputStream(frameData));
}
}
MjpegView.java:
MjpegView.java：
package com.demo.mjpeg.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.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class MjpegView extends SurfaceView implements SurfaceHolder.Callback {
private static final String TAG = "MjpegView";
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) {
e.getStackTrace();
Log.d(TAG, "catch IOException hit in run", 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) {
e.getStackTrace();
Log.d(TAG, "catch IOException hit in stopPlayback", 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;
}
}
回答by DC84
nice work! For your problem with onResume(), isn't it enough when you move the following code from onCreate() to onResume()?
干得好！对于 onResume() 的问题，将以下代码从 onCreate() 移动到 onResume() 还不够吗？
//sample public cam
String URL = "http://trackfield.webcam.oregonstate.edu/axis-cgi/mjpg/video.cgi?resolution=800x600&%3bdummy=1333689998337";
mv = new MjpegView(this);
setContentView(mv);
new DoRead().execute(URL);
Then you simply recreate the View and new instance of the AsyncTask... I tried it and it works for me...
然后你只需重新创建 AsyncTask 的视图和新实例......我试过了，它对我有用......
回答by Ahmed
It'll be helpful for the newbies that if you want to access your ip camera having a username or password , you might want to add this to your DefaultHttpClientand the above code will work for cameras that require authentication
如果您想访问具有用户名或密码的网络摄像机，您可能希望将其添加到您DefaultHttpClient的网络摄像机中，并且上述代码适用于需要身份验证的摄像机，这对新手很有帮助
CredentialsProvider provider = new BasicCredentialsProvider();
UsernamePasswordCredentials credentials = new UsernamePasswordCredentials("yourusername", "yourpassword");
provider.setCredentials(AuthScope.ANY, credentials);
DefaultHttpClient httpclient = new DefaultHttpClient();
httpclient.setCredentialsProvider(provider);
回答by Rusty
thanks for the code, it's very helpful
感谢您的代码，它非常有帮助
I want to suggest few optimization tips, which are already used in my code, overall performance can be easily increased by a few times.
我想推荐一些优化技巧，这些技巧已经在我的代码中使用过，整体性能可以轻松提高几倍。
I removed memory allocations during frame reading, where possible
private final static int HEADER_MAX_LENGTH = 100; private final static int FRAME_MAX_LENGTH = 200000 + HEADER_MAX_LENGTH; private final String CONTENT_LENGTH = "Content-Length:"; private final String CONTENT_END = "\r\n"; private final static byte[] gFrameData = new byte[FRAME_MAX_LENGTH]; private final static byte[] gHeader = new byte[HEADER_MAX_LENGTH]; BitmapFactory.Options bitmapOptions = new BitmapFactory.Options(); public Bitmap readMjpegFrame() throws IOException { mark(FRAME_MAX_LENGTH); int headerLen = getStartOfSequence(SOI_MARKER); if(headerLen < 0) return false; reset(); readFully(gHeader, 0, headerLen); int contentLen; try { contentLen = parseContentLength(gHeader, headerLen); } catch (NumberFormatException nfe) { nfe.getStackTrace(); Log.d(TAG, "catch NumberFormatException hit", nfe); contentLen = getEndOfSequence(EOF_MARKER); } readFully(gFrameData, 0, contentLen); Bitmap bm = BitmapFactory.decodeByteArray(gFrameData, 0, contentLen, bitmapOptions); bitmapOptions.inBitmap = bm; return bm; }Optimizing parseContentLength, removing String operations as much as possible
byte[] CONTENT_LENGTH_BYTES; byte[] CONTENT_END_BYTES; public MjpegInputStream(InputStream in) { super(new BufferedInputStream(in, FRAME_MAX_LENGTH)); bitmapOptions.inSampleSize = 1; bitmapOptions.inPreferredConfig = Bitmap.Config.RGB_565; bitmapOptions.inPreferQualityOverSpeed = false; bitmapOptions.inPurgeable = true; try { CONTENT_LENGTH_BYTES = CONTENT_LENGTH.getBytes("UTF-8"); CONTENT_END_BYTES = CONTENT_END.getBytes("UTF-8"); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } private int findPattern(byte[] buffer, int bufferLen, byte[] pattern, int offset) { int seqIndex = 0; for(int i=offset; i < bufferLen; ++i) { if(buffer[i] == pattern[seqIndex]) { ++seqIndex; if(seqIndex == pattern.length) { return i + 1; } } else { seqIndex = 0; } } return -1; } private int parseContentLength(byte[] headerBytes, int length) throws IOException, NumberFormatException { int begin = findPattern(headerBytes, length, CONTENT_LENGTH_BYTES, 0); int end = findPattern(headerBytes, length, CONTENT_END_BYTES, begin) - CONTENT_END_BYTES.length; // converting string to int int number = 0; int radix = 1; for(int i = end - 1; i >= begin; --i) { if(headerBytes[i] > 47 && headerBytes[i] < 58) { number += (headerBytes[i] - 48) * radix; radix *= 10; } } return number; }
在可能的情况下，我在帧读取期间删除了内存分配
private final static int HEADER_MAX_LENGTH = 100; private final static int FRAME_MAX_LENGTH = 200000 + HEADER_MAX_LENGTH; private final String CONTENT_LENGTH = "Content-Length:"; private final String CONTENT_END = "\r\n"; private final static byte[] gFrameData = new byte[FRAME_MAX_LENGTH]; private final static byte[] gHeader = new byte[HEADER_MAX_LENGTH]; BitmapFactory.Options bitmapOptions = new BitmapFactory.Options(); public Bitmap readMjpegFrame() throws IOException { mark(FRAME_MAX_LENGTH); int headerLen = getStartOfSequence(SOI_MARKER); if(headerLen < 0) return false; reset(); readFully(gHeader, 0, headerLen); int contentLen; try { contentLen = parseContentLength(gHeader, headerLen); } catch (NumberFormatException nfe) { nfe.getStackTrace(); Log.d(TAG, "catch NumberFormatException hit", nfe); contentLen = getEndOfSequence(EOF_MARKER); } readFully(gFrameData, 0, contentLen); Bitmap bm = BitmapFactory.decodeByteArray(gFrameData, 0, contentLen, bitmapOptions); bitmapOptions.inBitmap = bm; return bm; }优化parseContentLength，尽量去掉String操作
byte[] CONTENT_LENGTH_BYTES; byte[] CONTENT_END_BYTES; public MjpegInputStream(InputStream in) { super(new BufferedInputStream(in, FRAME_MAX_LENGTH)); bitmapOptions.inSampleSize = 1; bitmapOptions.inPreferredConfig = Bitmap.Config.RGB_565; bitmapOptions.inPreferQualityOverSpeed = false; bitmapOptions.inPurgeable = true; try { CONTENT_LENGTH_BYTES = CONTENT_LENGTH.getBytes("UTF-8"); CONTENT_END_BYTES = CONTENT_END.getBytes("UTF-8"); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } private int findPattern(byte[] buffer, int bufferLen, byte[] pattern, int offset) { int seqIndex = 0; for(int i=offset; i < bufferLen; ++i) { if(buffer[i] == pattern[seqIndex]) { ++seqIndex; if(seqIndex == pattern.length) { return i + 1; } } else { seqIndex = 0; } } return -1; } private int parseContentLength(byte[] headerBytes, int length) throws IOException, NumberFormatException { int begin = findPattern(headerBytes, length, CONTENT_LENGTH_BYTES, 0); int end = findPattern(headerBytes, length, CONTENT_END_BYTES, begin) - CONTENT_END_BYTES.length; // converting string to int int number = 0; int radix = 1; for(int i = end - 1; i >= begin; --i) { if(headerBytes[i] > 47 && headerBytes[i] < 58) { number += (headerBytes[i] - 48) * radix; radix *= 10; } } return number; }
There could be mistakes in the code since I was rewriting it for stackoverflow, originally I'm using 2 threads, one is reading frames and another is rendering.
代码中可能有错误，因为我是为 stackoverflow 重写它的，最初我使用 2 个线程，一个是读取帧，另一个是渲染。
I hope it will help for someone.
我希望它会对某人有所帮助。
