package com.fei435;

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 org.apache.http.params.BasicHttpParams;

import org.apache.http.params.HttpConnectionParams;

import org.apache.http.params.HttpParams;

import android.graphics.Bitmap;

import android.graphics.BitmapFactory;

//解码视频流的类

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) throws ClientProtocolException,IOException{

//public static MjpegInputStream read (String url){

HttpResponse res;

HttpParams httpParams = new BasicHttpParams();

HttpConnectionParams.setConnectionTimeout(httpParams,

Constant.CONNECTION_TIMEOUT_INT);

HttpConnectionParams.setSoTimeout(httpParams,

Constant.SO_TIMEOUT_INT);

DefaultHttpClient httpclient = new DefaultHttpClient(httpParams);

//try {

res = httpclient.execute(new HttpGet(URI.create(url)));

return new MjpegInputStream(res.getEntity().getContent());

//}

//return null;

}

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

/*

* DataInputStream :camera传给我的jpeg数据流

* sequence :byte[] SOI_MARKER = { (byte) 0xFF, (byte) 0xD8 };

* */

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 { //从 视频流中读取一帧

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));

}

}