This section describes the image processing functions that perform arithmetic encoding and decoding procedures and are specific for JPEG 2000 image coding system. These functions are listed in the Table “Entropy Coder Functions”.
| Function Base Name | Description |
|---|---|
| EncodeInitAlloc_JPEG2K | Allocates memory and initializes an entropy encoder state structure |
| EncodeFree_JPEG2K | Deallocates memory allocated for an entropy encoding state structure |
| EncodeLoadCodeBlock_JPEG2K | Loads code block and prepares data for entropy encoding |
| EncodeStoreBits_JPEG2K | Produces output codestream |
| EncodeGetTermPassLen_JPEG2K | Returns the length of the specified terminated coding pass. |
| EncodeGetRate_JPEG2K | Returns estimated target bit rate for the specified coding pass |
| EncodeGetDist_JPEG2K | Returns estimated distortion of the image for the specified coding pass |
| DecodeGetBufSize_JPEG2K | Computes the size of the working buffer for decoding routine |
| DecodeCodeBlock_JPEG2K | Decodes the compressed code block data |
| Decoder Functions for Progressive Mode | |
| DecodeCBProgrGetStateSize_JPEG2K | Computes the size of the external buffer for the decoder state structure. |
| DecodeCBProgrInit_JPEG2K | Initializes the decoder state structure in the external buffer/ |
| DecodeCBProgrInitAlloc_JPEG2K | Allocates memory and initializes the decoder state structure in the external buffer. |
| DecodeCBProgrFree_JPEG2K | Frees memory allocated for the decoder state structure. |
| DecodeCBProgrAttach_JPEG2K | Attaches the buffer with data for progressive decoding. |
| DecodeCBProgrSetPassCounter_JPEG2K | Sets the value of internal coding pass counter |
| DecodeCBProgrGetPassCounter_JPEG2K | Returns the value of the internal coding pass counter. |
| DecodeCBProgrGetCurBitPlane_JPEG2K | Returns the number of the current bit plane |
| DecodeCBProgrStep_JPEG2K | Performs a single step of decoding. |
The implemented adaptive arithmetic encoding is performed as two successive procedures. First, the prepared code block is pre-processed by the function ippiEncodeLoadCodeBlock_JPEG2K. After that, the function ippiEncodeStoreBits_JPEG2K performs final stages of encoding and produces the output codestream. In the course of encoding, the state structure pState is used, which is allocated and initialized by the function ippiEncodeInitAlloc_JPEG2K.
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