Class HeaderEncoder

  • All Implemented Interfaces:
    Markers, StdEntropyCoderOptions

    public class HeaderEncoder
    extends Object
    implements Markers, StdEntropyCoderOptions
    This class writes almost of the markers and marker segments in main header and in tile-part headers. It is created by the run() method of the Encoder instance.

    A marker segment includes a marker and eventually marker segment parameters. It is designed by the three letter code of the marker associated with the marker segment. JPEG 2000 part I defines 6 types of markers:

    • Delimiting : SOC,SOT,SOD,EOC (written in FileCodestreamWriter).
    • Fixed information: SIZ.
    • Functional: COD,COC,RGN,QCD,QCC,POC.
    • In bit-stream: SOP,EPH.
    • Pointer: TLM,PLM,PLT,PPM,PPT.
    • Informational: CRG,COM.

    Main Header is written when Encoder instance calls encodeMainHeader whereas tile-part headers are written when the EBCOTRateAllocator instance calls encodeTilePartHeader.

    See Also:
    Markers, EBCOTRateAllocator
    • Field Detail

      • nComp

        protected int nComp
        The number of components in the image
      • baos

        protected ByteArrayOutputStream baos
        The ByteArrayOutputStream to store header data. This handler is kept in order to use methods not accessible from a general DataOutputStream. For the other methods, it's better to use variable hbuf.
        See Also:
        hbuf
      • hbuf

        protected DataOutputStream hbuf
        The DataOutputStream to store header data. This kind of object is useful to write short, int, .... It's constructor takes baos as parameter.
        See Also:
        baos
      • origSrc

        protected ImgData origSrc
        The image data reader. Source of original data info
      • isOrigSig

        protected boolean[] isOrigSig
        An array specifying, for each component,if the data was signed or not
      • dwt

        protected ForwardWT dwt
        Reference to the DWT module
      • tiler

        protected Tiler tiler
        Reference to the tiler module
      • roiSc

        protected ROIScaler roiSc
        Reference to the ROI module
    • Constructor Detail

      • HeaderEncoder

        public HeaderEncoder​(ImgData origsrc,
                             boolean[] isorigsig,
                             ForwardWT dwt,
                             Tiler tiler,
                             J2KImageWriteParamJava wp,
                             ROIScaler roiSc,
                             PostCompRateAllocator ralloc)
        Initializes the header writer with the references to the coding chain.
        Parameters:
        origsrc - The original image data (before any component mixing, tiling, etc.)
        isorigsig - An array specifying for each component if it was originally signed or not.
        dwt - The discrete wavelet transform module.
        tiler - The tiler module.
        wp - The encoder specifications
        roiSc - The ROI scaler module.
        ralloc - The post compression rate allocator.
    • Method Detail

      • reset

        public void reset()
        Resets the contents of this HeaderEncoder to its initial state. It erases all the data in the header buffer and reactualizes the headerLength field of the bit stream writer.
      • getBuffer

        protected byte[] getBuffer()
        Returns the byte-buffer used to store the codestream header.
        Returns:
        A byte array countaining codestream header
      • getLength

        public int getLength()
        Returns the length of the header.
        Returns:
        The length of the header in bytes
      • writeTo

        public void writeTo​(BinaryDataOutput out)
                     throws IOException
        Writes the header to the specified BinaryDataOutput.
        Parameters:
        out - Where to write the header.
        Throws:
        IOException
      • getBufferLength

        protected int getBufferLength()
        Returns the number of bytes used in the codestream header's buffer.
        Returns:
        Header length in buffer (without any header overhead)
      • writeTo

        public void writeTo​(OutputStream out)
                     throws IOException
        Writes the header to the specified OutputStream.
        Parameters:
        out - Where to write the header.
        Throws:
        IOException
      • writeCOD

        protected void writeCOD​(boolean mh,
                                int tileIdx)
                         throws IOException
        Writes COD marker segment. COD is a functional marker segment containing the code style default (coding style, decomposition, layering) used for compressing all the components in an image.

        The values can be overriden for an individual component by a COC marker in either the main or the tile header.

        Parameters:
        mh - Flag indicating whether this marker belongs to the main header
        tileIdx - Tile index if the marker belongs to a tile-part header
        Throws:
        IOException
        See Also:
        writeCOC(boolean, int, int)
      • writeCOC

        protected void writeCOC​(boolean mh,
                                int tileIdx,
                                int compIdx)
                         throws IOException
        Writes COC marker segment . It is a functional marker containing the coding style for one component (coding style, decomposition, layering).

        Its values overrides any value previously set in COD in the main header or in the tile header.

        Parameters:
        mh - Flag indicating whether the main header is to be written
        tileIdx - Tile index
        compIdx - index of the component which need use of the COC marker segment.
        Throws:
        IOException
        See Also:
        writeCOD(boolean, int)
      • writeMainQCD

        protected void writeMainQCD()
                             throws IOException
        Writes QCD marker segment in main header. QCD is a functional marker segment countaining the quantization default used for compressing all the components in an image. The values can be overriden for an individual component by a QCC marker in either the main or the tile header.
        Throws:
        IOException
      • writeMainQCC

        protected void writeMainQCC​(int compIdx)
                             throws IOException
        Writes QCC marker segment in main header. It is a functional marker segment countaining the quantization used for compressing the specified component in an image. The values override for the specified component what was defined by a QCC marker in either the main or the tile header.
        Parameters:
        compIdx - Index of the component which needs QCC marker segment.
        Throws:
        IOException
      • writeTileQCD

        protected void writeTileQCD​(int tIdx)
                             throws IOException
        Writes QCD marker segment in tile header. QCD is a functional marker segment countaining the quantization default used for compressing all the components in an image. The values can be overriden for an individual component by a QCC marker in either the main or the tile header.
        Parameters:
        tIdx - Tile index
        Throws:
        IOException
      • writeTileQCC

        protected void writeTileQCC​(int t,
                                    int compIdx)
                             throws IOException
        Writes QCC marker segment in tile header. It is a functional marker segment countaining the quantization used for compressing the specified component in an image. The values override for the specified component what was defined by a QCC marker in either the main or the tile header.
        Parameters:
        t - Tile index
        compIdx - Index of the component which needs QCC marker segment.
        Throws:
        IOException
      • writePOC

        protected void writePOC​(boolean mh,
                                int tileIdx)
                         throws IOException
        Writes POC marker segment. POC is a functional marker segment containing the bounds and progression order for any progression order other than default in the codestream.
        Parameters:
        mh - Flag indicating whether the main header is to be written
        tileIdx - Tile index
        Throws:
        IOException
      • encodeMainHeader

        public void encodeMainHeader()
                              throws IOException
        Write main header. JJ2000 main header corresponds to the following sequence of marker segments:
        1. SOC
        2. SIZ
        3. COD
        4. COC (if needed)
        5. QCD
        6. QCC (if needed)
        7. POC (if needed)
        Throws:
        IOException
      • encodeTilePartHeader

        public void encodeTilePartHeader​(int tileLength,
                                         int tileIdx)
                                  throws IOException
        Writes tile-part header. JJ2000 tile-part header corresponds to the following sequence of marker segments:
        1. SOT
        2. COD (if needed)
        3. COC (if needed)
        4. QCD (if needed)
        5. QCC (if needed)
        6. RGN (if needed)
        7. POC (if needed)
        8. SOD
        Parameters:
        tileLength - The length of the current tile-part.
        tileIdx - Index of the tile to write
        Throws:
        IOException