/*
* 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 com.coremedia.iso.boxes.mdat;
import com.coremedia.iso.BoxParser;
import com.coremedia.iso.ChannelHelper;
import com.coremedia.iso.boxes.Box;
import com.coremedia.iso.boxes.ContainerBox;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;
import static com.googlecode.mp4parser.util.CastUtils.l2i;
/**
* This box contains the media data. In video tracks, this box would contain video frames. A presentation may
* contain zero or more Media Data Boxes. The actual media data follows the type field; its structure is described
* by the metadata (see {@link com.coremedia.iso.boxes.SampleTableBox}).<br>
* In large presentations, it may be desirable to have more data in this box than a 32-bit size would permit. In this
* case, the large variant of the size field is used.<br>
* There may be any number of these boxes in the file (including zero, if all the media data is in other files). The
* metadata refers to media data by its absolute offset within the file (see {@link com.coremedia.iso.boxes.StaticChunkOffsetBox});
* so Media Data Box headers and free space may easily be skipped, and files without any box structure may
* also be referenced and used.
*/
public final class MediaDataBox implements Box {
public static final String TYPE = "mdat";
ContainerBox parent;
ByteBuffer header;
ByteBuffer content;
public ContainerBox getParent() {
return parent;
}
public void setParent(ContainerBox parent) {
this.parent = parent;
}
public String getType() {
return TYPE;
}
public void getBox(WritableByteChannel writableByteChannel) throws IOException {
header.rewind();
content.rewind();
writableByteChannel.write(header);
writableByteChannel.write(content);
}
public long getSize() {
return header.limit() + content.limit();
}
public void parse(ReadableByteChannel readableByteChannel, ByteBuffer header, long contentSize, BoxParser boxParser) throws IOException {
this.header = header;
if (readableByteChannel instanceof FileChannel && contentSize > 1024 * 1024) {
// It's quite expensive to map a file into the memory. Just do it when the box is larger than a MB.
content = ((FileChannel) readableByteChannel).map(FileChannel.MapMode.READ_ONLY, ((FileChannel) readableByteChannel).position(), contentSize);
((FileChannel) readableByteChannel).position(((FileChannel) readableByteChannel).position() + contentSize);
} else {
content = ChannelHelper.readFully(readableByteChannel, l2i(contentSize));
}
}
public ByteBuffer getContent() {
return content;
}
public ByteBuffer getHeader() {
return header;
}
}