org.mp4parser.boxes.iso14496.part12.MetaBox Maven / Gradle / Ivy

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A generic parser and writer for all ISO 14496 based files (MP4, Quicktime, DCF, PDCF, ...)
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/*  
 * Copyright 2008 CoreMedia AG, Hamburg
 *
 * Licensed under the Apache License, Version 2.0 (the License); 
 * you may not use this file except in compliance with the License. 
 * You may obtain a copy of the License at 
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0 
 * 
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an AS IS BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and 
 * limitations under the License. 
 */

package org.mp4parser.boxes.iso14496.part12;

import org.mp4parser.BoxParser;
import org.mp4parser.RewindableReadableByteChannel;
import org.mp4parser.support.AbstractContainerBox;
import org.mp4parser.tools.IsoTypeReader;
import org.mp4parser.tools.IsoTypeWriter;

import java.io.IOException;
import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;


/**
 * 4cc = "{@value #TYPE}"
 * A common base structure to contain general metadata. See ISO/IEC 14496-12 Ch. 8.44.1.
 */
public class MetaBox extends AbstractContainerBox {
    public static final String TYPE = "meta";

    private int version;
    private int flags;
    private boolean quickTimeFormat;

    public MetaBox() {
        super(TYPE);
    }

    public int getVersion() {
        return version;
    }

    public void setVersion(int version) {
        this.version = version;
    }

    public int getFlags() {
        return flags;
    }

    public void setFlags(int flags) {
        this.flags = flags;
    }

    /**
     * Parses the version/flags header and returns the remaining box size.
     *
     * @param content the ByteBuffer that contains the version & flag
     * @return number of bytes read
     */
    protected final long parseVersionAndFlags(ByteBuffer content) {
        version = IsoTypeReader.readUInt8(content);
        flags = IsoTypeReader.readUInt24(content);
        return 4;
    }

    protected final void writeVersionAndFlags(ByteBuffer bb) {
        IsoTypeWriter.writeUInt8(bb, version);
        IsoTypeWriter.writeUInt24(bb, flags);
    }

    @Override
    public void parse(ReadableByteChannel dataSource, ByteBuffer header, long contentSize, BoxParser boxParser) throws IOException {
        // Read first 20 bytes to determine whether the file is formatted according to QuickTime File Format.
        RewindableReadableByteChannel rewindableDataSource = new RewindableReadableByteChannel(dataSource, 20);
        ByteBuffer bb = ByteBuffer.allocate(20);
        int bytesRead = rewindableDataSource.read(bb);
        if (bytesRead == 20) {
            // If the second and the fifth 32-bit integers encode 'hdlr' and 'mdta' respectively then the MetaBox is
            // formatted according to QuickTime File Format.
            // See https://developer.apple.com/library/content/documentation/QuickTime/QTFF/Metadata/Metadata.html
            ((Buffer)bb).position(4);
            String second4cc = IsoTypeReader.read4cc(bb);
            ((Buffer)bb).position(16);
            String fifth4cc = IsoTypeReader.read4cc(bb);
            if ("hdlr".equals(second4cc) && "mdta".equals(fifth4cc)) {
                quickTimeFormat = true;
            }
        }
        rewindableDataSource.rewind();

        if (!quickTimeFormat) {
            bb = ByteBuffer.allocate(4);
            rewindableDataSource.read(bb);
            parseVersionAndFlags((ByteBuffer) ((Buffer)bb).rewind());
        }

        int bytesUsed = quickTimeFormat ? 0 : 4;
        initContainer(rewindableDataSource, contentSize - bytesUsed, boxParser);
    }

    @Override
    public void getBox(WritableByteChannel writableByteChannel) throws IOException {
        writableByteChannel.write(getHeader());
        if (!quickTimeFormat) {
            ByteBuffer bb = ByteBuffer.allocate(4);
            writeVersionAndFlags(bb);
            writableByteChannel.write((ByteBuffer) ((Buffer)bb).rewind());
        }
        writeContainer(writableByteChannel);
    }

    @Override
    public long getSize() {
        long s = getContainerSize();
        long t = quickTimeFormat ? 0 : 4; // bytes to container start
        return s + t + ((largeBox || (s + t) >= (1L << 32)) ? 16 : 8);

    }
}