/*
* @(#)RunLengthCodec.java
*
* Copyright © 2011 Werner Randelshofer, Goldau, Switzerland.
* All rights reserved.
*
* You may not use, copy or modify this file, except in compliance with the
* license agreement you entered into with Werner Randelshofer.
* For details see accompanying license terms.
*/
package org.monte.media.avi;
import org.monte.media.Format;
import org.monte.media.io.ByteArrayImageOutputStream;
import javax.imageio.stream.ImageOutputStream;
import java.awt.image.WritableRaster;
import java.awt.Rectangle;
import org.monte.media.AbstractVideoCodec;
import org.monte.media.Buffer;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.ByteOrder;
import static java.lang.Math.*;
import static org.monte.media.VideoFormatKeys.*;
import static org.monte.media.BufferFlag.*;
/**
* {@code RunLengthCodec} encodes a BufferedImage as a byte[] array.
* <p>
* This codec only works with the AVI file format. Other formats, such as
* QuickTime, use a different encoding for run-length compressed video.
* <p>
* This codec currently only supports encoding from a {@code BufferedImage} into
* the file format. Decoding support may be added in the future.
* <p>
* Supported input formats:
* <ul>
* {@code Format} with {@code BufferedImage.class}, any width, any height,
* depth=8.
* </ul>
* Supported output formats:
* <ul>
* {@code Format} with {@code byte[].class}, same width and height as input
* format, depth=8.
* </ul>
* The codec supports lossless delta- and key-frame encoding of images with 8
* bits per pixel.
* <p>
* The codec does not encode the color palette of an image. This must be done
* separately.
* <p>
* A frame is compressed line by line from bottom to top.
* <p>
* Each line of a frame is compressed individually. A line consists of two-byte
* op-codes optionally followed by data. The end of the line is marked with
* the EOL op-code.
* <p>
* The following op-codes are supported:
* <ul>
* <li>{@code 0x00 0x00}
* <br>Marks the end of a line.</li>
*
* <li>{@code 0x00 0x01}
* <br>Marks the end of the bitmap.</li>
*
* <li>{@code 0x00 0x02 x y}
* <br> Marks a delta (skip). {@code x} and {@code y}
* indicate the horizontal and vertical offset from the current position.
* {@code x} and {@code y} are unsigned 8-bit values.</li>
*
* <li>{@code 0x00 n data{n} 0x00?}
* <br> Marks a literal run. {@code n}
* gives the number of data bytes that follow. {@code n} must be between 3 and
* 255. If n is odd, a pad byte with the value 0x00 must be added.
* </li>
* <li>{@code n data}
* <br> Marks a repetition. {@code n}
* gives the number of times the data byte is repeated. {@code n} must be
* between 1 and 255.
* </li>
* </ul>
* Example:
* <pre>
* Compressed data Expanded data
*
* 03 04 04 04 04
* 05 06 06 06 06 06 06
* 00 03 45 56 67 00 45 56 67
* 02 78 78 78
* 00 02 05 01 Move 5 right and 1 down
* 02 78 78 78
* 00 00 End of line
* 09 1E 1E 1E 1E 1E 1E 1E 1E 1E 1E
* 00 01 End of RLE bitmap
* </pre>
*
* References:<br/>
* <a href="http://wiki.multimedia.cx/index.php?title=Microsoft_RLE">http://wiki.multimedia.cx/index.php?title=Microsoft_RLE</a><br>
*
*
* @author Werner Randelshofer
* @version $Id: RunLengthCodec.java 299 2013-01-03 07:40:18Z werner $
*/
public class RunLengthCodec extends AbstractVideoCodec {
private byte[] previousPixels;
private int frameCounter;
public RunLengthCodec() {
super(new Format[]{
new Format(MediaTypeKey, MediaType.VIDEO, MimeTypeKey, MIME_JAVA,
EncodingKey, ENCODING_BUFFERED_IMAGE, FixedFrameRateKey, true), //
},
new Format[]{
new Format(MediaTypeKey, MediaType.VIDEO, MimeTypeKey, MIME_AVI,
EncodingKey, ENCODING_AVI_RLE, DataClassKey, byte[].class,
FixedFrameRateKey, true, DepthKey,8), //
});
}
@Override
public void reset() {
frameCounter = 0;
}
@Override
public int process(Buffer in, Buffer out) {
if (outputFormat==null) return CODEC_FAILED;
if (outputFormat.get(EncodingKey).equals(ENCODING_AVI_RLE)) {
return encode(in, out);
} else {
return decode(in, out);
}
}
private int encode(Buffer in, Buffer out) {
out.setMetaTo(in);
out.format=outputFormat;
if (in.isFlag(DISCARD)) {
return CODEC_OK;
}
ByteArrayImageOutputStream tmp;
if (out.data instanceof byte[]) {
tmp = new ByteArrayImageOutputStream((byte[]) out.data);
} else {
tmp = new ByteArrayImageOutputStream();
}
// Handle sub-image
Rectangle r;
int scanlineStride;
if (in.data instanceof BufferedImage) {
BufferedImage image = (BufferedImage) in.data;
WritableRaster raster = image.getRaster();
scanlineStride = raster.getSampleModel().getWidth();
r = raster.getBounds();
r.x -= raster.getSampleModelTranslateX();
r.y -= raster.getSampleModelTranslateY();
out.header = image.getColorModel();
} else {
r = new Rectangle(0, 0, outputFormat.get(WidthKey), outputFormat.get(HeightKey));
scanlineStride = outputFormat.get(WidthKey);
out.header = null;
}
int offset = r.x + r.y * scanlineStride;
boolean isKeyframe = frameCounter== 0
|| frameCounter % outputFormat.get(KeyFrameIntervalKey,outputFormat.get(FrameRateKey).intValue()) == 0;
frameCounter++;
try {
byte[] pixels = getIndexed8(in);
if (pixels == null) {
return CODEC_FAILED;
}
if (isKeyframe) {
writeKey8(tmp, pixels, r.width, r.height, offset, scanlineStride);
out.setFlag(KEYFRAME);
} else {
writeDelta8(tmp, pixels, previousPixels, r.width, r.height, offset, scanlineStride);
out.clearFlag(KEYFRAME);
}
out.data = tmp.getBuffer();
out.offset = 0;
out.length = (int) tmp.getStreamPosition();
//
if (previousPixels == null) {
previousPixels = pixels.clone();
} else {
System.arraycopy(pixels, 0, previousPixels, 0, pixels.length);
}
return CODEC_OK;
} catch (IOException ex) {
ex.printStackTrace();
out.setFlag(DISCARD);
return CODEC_FAILED;
}
}
private int decode(Buffer in, Buffer out) {
return CODEC_FAILED;
}
/** Encodes an 8-bit key frame.
*
* @param out The output stream.
* @param data The image data.
* @param offset The offset to the first pixel in the data array.
* @param width The width of the image in data elements.
* @param scanlineStride The number to append to offset to get to the next scanline.
*/
public void writeKey8(OutputStream out, byte[] data, int width, int height, int offset, int scanlineStride) throws IOException {
ByteArrayImageOutputStream buf = new ByteArrayImageOutputStream(data.length);
writeKey8(buf, data, width, height, offset, scanlineStride);
buf.toOutputStream(out);
}
/** Encodes an 8-bit key frame.
*
* @param out The output stream.
* @param data The image data.
* @param offset The offset to the first pixel in the data array.
* @param width The width of the image in data elements.
* @param scanlineStride The number to append to offset to get to the next scanline.
*/
public void writeKey8(ImageOutputStream out, byte[] data, int width, int height, int offset, int scanlineStride)
throws IOException {
out.setByteOrder(ByteOrder.LITTLE_ENDIAN);
int ymax = offset + height * scanlineStride;
int upsideDown = ymax - scanlineStride + offset;
// Encode each scanline separately
for (int y = offset; y < ymax; y += scanlineStride) {
int xy = upsideDown - y;
int xymax = xy + width;
int literalCount = 0;
int repeatCount = 0;
for (; xy < xymax; ++xy) {
// determine repeat count
byte v = data[xy];
for (repeatCount = 0; xy < xymax && repeatCount < 255; ++xy, ++repeatCount) {
if (data[xy] != v) {
break;
}
}
xy -= repeatCount;
if (repeatCount < 3) {
literalCount++;
if (literalCount == 254) {
out.write(0);
out.write(literalCount); // Literal OP-code
out.write(data, xy - literalCount + 1, literalCount);
literalCount = 0;
}
} else {
if (literalCount > 0) {
if (literalCount < 3) {
for (; literalCount > 0; --literalCount) {
out.write(1); // Repeat OP-code
out.write(data[xy - literalCount]);
}
} else {
out.write(0);
out.write(literalCount); // Literal OP-code
out.write(data, xy - literalCount, literalCount);
if (literalCount % 2 == 1) {
out.write(0); // pad byte
}
literalCount = 0;
}
}
out.write(repeatCount); // Repeat OP-code
out.write(v);
xy += repeatCount - 1;
}
}
// flush literal run
if (literalCount > 0) {
if (literalCount < 3) {
for (; literalCount > 0; --literalCount) {
out.write(1); // Repeat OP-code
out.write(data[xy - literalCount]);
}
} else {
out.write(0);
out.write(literalCount);
out.write(data, xy - literalCount, literalCount);
if (literalCount % 2 == 1) {
out.write(0); // pad byte
}
}
literalCount = 0;
}
out.write(0);
out.write(0x0000);// End of line
}
out.write(0);
out.write(0x0001);// End of bitmap
}
/** Encodes an 8-bit key frame.
*
* @param out The output stream.
* @param data The image data.
* @param offset The offset to the first pixel in the data array.
* @param width The width of the image in data elements.
* @param scanlineStride The number to append to offset to get to the next scanline.
*/
public void writeDelta8(OutputStream out, byte[] data, byte[] prev, int width, int height, int offset, int scanlineStride) throws IOException {
ByteArrayImageOutputStream buf = new ByteArrayImageOutputStream(data.length);
writeDelta8(buf, data, prev, width, height, offset, scanlineStride);
buf.toOutputStream(out);
}
/** Encodes an 8-bit delta frame.
*
* @param out The output stream.
* @param data The image data.
* @param prev The image data of the previous frame.
* @param offset The offset to the first pixel in the data array.
* @param width The width of the image in data elements.
* @param scanlineStride The number to append to offset to get to the next scanline.
*/
public void writeDelta8(ImageOutputStream out, byte[] data, byte[] prev, int width, int height, int offset, int scanlineStride)
throws IOException {
out.setByteOrder(ByteOrder.LITTLE_ENDIAN);
int ymax = offset + height * scanlineStride;
int upsideDown = ymax - scanlineStride + offset;
// Encode each scanline
int verticalOffset = 0;
for (int y = offset; y < ymax; y += scanlineStride) {
int xy = upsideDown - y;
int xymax = xy + width;
// determine skip count
int skipCount = 0;
for (; xy < xymax; ++xy, ++skipCount) {
if (data[xy] != prev[xy]) {
break;
}
}
if (skipCount == width) {
// => the entire line can be skipped
++verticalOffset;
continue;
}
while (verticalOffset > 0 || skipCount > 0) {
if (verticalOffset == 1 && skipCount == 0) {
out.write(0x00);
out.write(0x00); // End of line OP-code
verticalOffset = 0;
} else {
out.write(0x00);
out.write(0x02); // Skip OP-code
out.write(min(255, skipCount)); // horizontal offset
out.write(min(255, verticalOffset)); // vertical offset
skipCount -= min(255, skipCount);
verticalOffset -= min(255, verticalOffset);
}
}
int literalCount = 0;
int repeatCount = 0;
for (; xy < xymax; ++xy) {
// determine skip count
for (skipCount = 0; xy < xymax; ++xy, ++skipCount) {
if (data[xy] != prev[xy]) {
break;
}
}
xy -= skipCount;
// determine repeat count
byte v = data[xy];
for (repeatCount = 0; xy < xymax && repeatCount < 255; ++xy, ++repeatCount) {
if (data[xy] != v) {
break;
}
}
xy -= repeatCount;
if (skipCount < 4 && xy + skipCount < xymax && repeatCount < 3) {
literalCount++;
} else {
while (literalCount > 0) {
if (literalCount < 3) {
out.write(1); // Repeat OP-code
out.write(data[xy - literalCount]);
literalCount--;
} else {
int literalRun = min(254, literalCount);
out.write(0);
out.write(literalRun); // Literal OP-code
out.write(data, xy - literalCount, literalRun);
if (literalRun % 2 == 1) {
out.write(0); // pad byte
}
literalCount -= literalRun;
}
}
if (xy + skipCount == xymax) {
// => we can skip until the end of the line without
// having to write an op-code
xy += skipCount - 1;
} else if (skipCount >= repeatCount) {
while (skipCount > 0) {
out.write(0);
out.write(0x0002); // Skip OP-code
out.write(min(255, skipCount));
out.write(0);
xy += min(255, skipCount);
skipCount -= min(255, skipCount);
}
xy -= 1;
} else {
out.write(repeatCount); // Repeat OP-code
out.write(v);
xy += repeatCount - 1;
}
}
}
// flush literal run
while (literalCount > 0) {
if (literalCount < 3) {
out.write(1); // Repeat OP-code
out.write(data[xy - literalCount]);
literalCount--;
} else {
int literalRun = min(254, literalCount);
out.write(0);
out.write(literalRun); // Literal OP-code
out.write(data, xy - literalCount, literalRun);
if (literalRun % 2 == 1) {
out.write(0); // pad byte
}
literalCount -= literalRun;
}
}
out.write(0);
out.write(0x0000); // End of line OP-code
}
out.write(0);
out.write(0x0001);// End of bitmap
}
}