Class PostCompRateAllocator

  • All Implemented Interfaces:
    ImgData
    Direct Known Subclasses:
    EBCOTRateAllocator

    public abstract class PostCompRateAllocator
    extends ImgDataAdapter
    This is the abstract class from which post-compression rate allocators which generate layers should inherit. The source of data is a 'CodedCBlkDataSrcEnc' which delivers entropy coded blocks with rate-distortion statistics.

    The post compression rate allocator implementation should create the layers, according to a rate allocation policy, and send the packets to a CodestreamWriter. Since the rate allocator sends the packets to the bit stream then it should output the packets to the bit stream in the order imposed by the bit stream profiles.

    See Also:
    CodedCBlkDataSrcEnc, CodestreamWriter
    • Field Detail

      • OPT_PREFIX

        public static final char OPT_PREFIX
        The prefix for rate allocation options: 'A'
        See Also:
        Constant Field Values
      • numLayers

        protected int numLayers
        The number of layers.
    • Constructor Detail

      • PostCompRateAllocator

        public PostCompRateAllocator​(CodedCBlkDataSrcEnc src,
                                     int nl,
                                     CodestreamWriter bw,
                                     J2KImageWriteParamJava wp)
        Initializes the source of entropy coded data.
        Parameters:
        src - The source of entropy coded data.
        nl - The number of layers to create
        bw - The packet bit stream writer.
        wp - The parameters list
        See Also:
        ProgressionType
    • Method Detail

      • setHeaderEncoder

        public void setHeaderEncoder​(HeaderEncoder headEnc)
        Keep a reference to the header encoder.
        Parameters:
        headEnc - The header encoder
      • initialize

        public abstract void initialize()
                                 throws IOException
        Initializes the rate allocation points, taking into account header overhead and such. This method must be called after the header has been simulated but before calling the runAndWrite() one. The header must be rewritten after a call to this method since the number of layers may change.
        Throws:
        IOException
        See Also:
        runAndWrite()
      • runAndWrite

        public abstract void runAndWrite()
                                  throws IOException
        Runs the rate allocation algorithm and writes the data to the bit stream. This must be called after the initialize() method.
        Throws:
        IOException
        See Also:
        initialize()
      • getNumLayers

        public int getNumLayers()
        Returns the number of layers that are actually generated.
        Returns:
        The number of layers generated.
      • getParameterInfo

        public static String[][] getParameterInfo()
        Returns the parameters that are used in this class and implementing classes. It returns a 2D String array. Each of the 1D arrays is for a different option, and they have 3 elements. The first element is the option name, the second one is the synopsis, the third one is a long description of what the parameter is and the fourth is its default value. The synopsis or description may be 'null', in which case it is assumed that there is no synopsis or description of the option, respectively. Null may be returned if no options are supported.
        Returns:
        the options name, their synopsis and their explanation, or null if no options are supported.
      • createInstance

        public static PostCompRateAllocator createInstance​(CodedCBlkDataSrcEnc src,
                                                           float rate,
                                                           CodestreamWriter bw,
                                                           J2KImageWriteParamJava wp)
        Creates a PostCompRateAllocator object for the appropriate rate allocation parameters in the parameter list 'pl', having 'src' as the source of entropy coded data, 'rate' as the target bitrate and 'bw' as the bit stream writer object.
        Parameters:
        src - The source of entropy coded data.
        rate - The target bitrate for the rate allocation
        bw - The bit stream writer object, where the bit stream data will be written.
        wp - The parameter list (or options).