band_codec.h

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* $Id: band_codec.h,v 1.2 2005/01/30 05:11:40 gabest Exp $ $Name:  $
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* the specific language governing rights and limitations under the License.
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* The Original Code is BBC Research and Development code.
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* The Initial Developer of the Original Code is the British Broadcasting
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* Contributor(s): Thomas Davies (Original Author), Scott R Ladd
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#ifndef _BAND_CODEC_H_
#define _BAND_CODEC_H_

#include <libdirac_common/arith_codec.h>
#include <libdirac_common/wavelet_utils.h>

namespace dirac
{
    //Subclasses the arithmetic codec to produce a coding/decoding tool for subbands



    class BandCodec: public ArithCodec<PicArray >
    {
    public:


        BandCodec(BasicOutputManager* bits_out,
                  size_t number_of_contexts,
                  const SubbandList& band_list,
                  int band_num);


        BandCodec(BitInputManager* bits_in,
                  size_t number_of_contexts,
                  const SubbandList& band_list,
                  int band_num);

        void InitContexts();

    protected:
        // Code an individual value
        void CodeVal(PicArray& in_data, const ValueType val);
        // Decode an individual value
        void DecodeVal(PicArray& out_data);

    private:
        // Functions
        // Overridden from the base class
        virtual void DoWorkCode(PicArray& in_data);
        // Overridden from the base class
        virtual void DoWorkDecode(PicArray& in_data, int num_bits);

        void Update( const bool symbol , const int context_num );
        void Resize(const int context_num);
        void ResetAll();
        
        int ChooseContext(const PicArray& data, const int bin_number) const;
        int ChooseContext(const PicArray& data) const;
        int ChooseSignContext(const PicArray& data) const;

        // Private, bodyless copy constructor: class should not be copied
        BandCodec(const BandCodec& cpy);
        // Private, bodyless copy operator=: class should not be assigned
        BandCodec& operator=(const BandCodec& rhs);

    protected:
        int m_bnum;

        const Subband m_node;
        
        int m_xp, m_yp, m_xl, m_yl;
        
        int m_xpos, m_ypos;
        
        int m_vol;
        
        int m_reset_coeff_num;
        
        int m_coeff_count;
        
        int m_qf, m_qfinv;
        
        ValueType m_offset;
        
        ValueType m_nhood_sum;
        
        Subband m_pnode;
        
        int m_pxp, m_pyp, m_pxl, m_pyl;
        
        int m_pxpos, m_pypos;
        
        bool m_parent_notzero;
        
        ValueType m_cut_off_point;
    };


    class LFBandCodec: public BandCodec
    {
    public:

        LFBandCodec(BasicOutputManager* bits_out,
                    size_t number_of_contexts,
                    const SubbandList& band_list,
                    int band_num)
              : BandCodec(bits_out,number_of_contexts,band_list,band_num){}


        LFBandCodec(BitInputManager* bits_in,
                    size_t number_of_contexts,
                    const SubbandList& band_list,
                    int band_num)
          : BandCodec(bits_in,number_of_contexts,band_list,band_num){}

    private:
        // Overridden from the base class
        virtual void DoWorkCode(PicArray& InData);
        // Overridden from the base class
        virtual void DoWorkDecode(PicArray& OutData, int num_bits);
        // Private, bodyless copy constructor: class should not be copied
        LFBandCodec(const LFBandCodec& cpy);
        // Private, bodyless copy operator=: class should not be assigned
        LFBandCodec& operator=(const LFBandCodec& rhs);

    };


    //Finally,special class incorporating prediction for the DC band of intra frames//


    class IntraDCBandCodec: public BandCodec
    {
    public:

        IntraDCBandCodec(BasicOutputManager* bits_out,
                         size_t number_of_contexts,
                         const SubbandList& band_list)
          : BandCodec(bits_out,number_of_contexts,band_list,band_list.Length()){}


        IntraDCBandCodec(BitInputManager* bits_in,
                         size_t number_of_contexts,
                         const SubbandList& band_list)
          : BandCodec(bits_in,number_of_contexts,band_list,band_list.Length()){}

    private:
        // Overridden from the base class
        virtual void DoWorkCode(PicArray& InData);
        // Overridden from the base class
        virtual void DoWorkDecode(PicArray& OutData, int num_bits);

        // Private, bodyless copy constructor: class should not be copied
        IntraDCBandCodec(const IntraDCBandCodec& cpy);
        // Private, bodyless copy operator=: class should not be assigned
        IntraDCBandCodec& operator=(const IntraDCBandCodec& rhs);

        // Prediction of a DC value from its previously coded neighbours
        ValueType GetPrediction(const PicArray& Data) const;
    };

} // namespace dirac
#endif

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