JIU 0.14.3

net.sourceforge.jiu.codecs.jpeg
Class JPEGMarkerReader

java.lang.Object
  extended by net.sourceforge.jiu.codecs.jpeg.JPEGMarkerReader

public class JPEGMarkerReader
extends Object

Static helper methods to read various JPEG bitstream headers from a DataInput source into objects of the appropriate data classes. Objects are then added to a JPEGData object.

Since:
0.14.0
Author:
Marco Schmidt

Method Summary
static void readHuffmanTables(DataInput in, JPEGData jpegData, int length)
           
static void readQuantizationTables(DataInput in, JPEGData jpegData, int length)
          Read quantization tables from a DQT marker.
static void readStartOfFrame(DataInput in, JPEGData jpegData, int marker, int length)
           
static void readStartOfScan(DataInput in, JPEGData jpegData, int length)
          Read an SOS (start of scan) marker.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Method Detail

readHuffmanTables

public static void readHuffmanTables(DataInput in,
                                     JPEGData jpegData,
                                     int length)
                              throws InvalidFileStructureException,
                                     IOException
Throws:
InvalidFileStructureException
IOException

readQuantizationTables

public static void readQuantizationTables(DataInput in,
                                          JPEGData jpegData,
                                          int length)
                                   throws InvalidFileStructureException,
                                          IOException
Read quantization tables from a DQT marker. P&M 7.8.3, p. 118f.

Parameters:
jpegData - data object which will store the table(s)
length - length of marker
Throws:
InvalidFileStructureException - if the DQT contains invalid data
IOException - on reading errors

readStartOfFrame

public static void readStartOfFrame(DataInput in,
                                    JPEGData jpegData,
                                    int marker,
                                    int length)
                             throws InvalidFileStructureException,
                                    IOException,
                                    UnsupportedTypeException
Throws:
InvalidFileStructureException
IOException
UnsupportedTypeException

readStartOfScan

public static void readStartOfScan(DataInput in,
                                   JPEGData jpegData,
                                   int length)
                            throws InvalidFileStructureException,
                                   IOException,
                                   UnsupportedTypeException
Read an SOS (start of scan) marker. P&M 7.6, p. 113.

Parameters:
in - source to read marker information from
jpegData - JPEGData object to update with information from the marker
length - size of marker in bytes
Throws:
InvalidFileStructureException - if encountered data does not follow the JPEG standard
IOException - on I/O errors
UnsupportedTypeException - if encountered data is valid but unsupported by this package

JIU 0.14.3

Copyright © 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007 Marco Schmidt