com.skalski.raspberrycontrol.Mjpeg.Mjpeg_InputStream.java Source code

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Here is the source code for com.skalski.raspberrycontrol.Mjpeg.Mjpeg_InputStream.java

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/*
 * Copyright 2014 Jerome NAHELOU, Quentin NEBOUT, Romain SOLVE, Fabien QUINTARD
 *
 * This file is part of android-camera-axis.
 *
 * android-camera-axis is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * android-camera-axis is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with android-camera-axis.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.skalski.raspberrycontrol.Mjpeg;

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.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

public class Mjpeg_InputStream 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 Mjpeg_InputStream read(String url) throws IOException {
        HttpResponse res;
        DefaultHttpClient httpclient = new DefaultHttpClient();

        res = httpclient.execute(new HttpGet(URI.create(url)));
        return new Mjpeg_InputStream(res.getEntity().getContent());
    }

    public Mjpeg_InputStream(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));
    }
}