Apparatus for encoding and decoding key data and key value data of coordinate interpolator and recording medium containing bitstream into which coordinate interpolator is encoded

An apparatus for decoding a bitstream, into which a coordinate interpolator, which includes key data indicating the location of each keyframe on a temporal axis and key value data representing the location of each vertex of an object in each of the keyframes using coordinates of the vertices each consisting of x, y, and z components, is encoded, the apparatus comprising:

• a key data decoder, which comprises:
• a header decoder which decodes header information necessary to decode key data and key value data from an input bitstream and outputs the decoded header information;
• a first entropy decoder which entropy-decodes the input bitstream and outputs differential data of decoded key data;
• an inverse DND processor which extends the range of differential data of the entropy-decoded key data by performing an inverse DND operation on the differential data depending on the order of DND read from the input bitstream by the header decoder;
• a first inverse DPCM processor which performs an inverse DPCM operation on the differential data input from the inverse DND processor as many times as the order of DPCM input from the header decoder and outputs quantized key data;
• and
• a first inverse quantizer which inverse-quantizes the quantized key data and outputs decoded key data, and
• a key value data decoder, which comprises:
• a second entropy decoder which generates data to be dictionary-decoded, including symbols of differential data of key value data, indexes indicating the positions of the symbols, and a DPCM operation mode, by entropy-decoding the input bitstream;
• a dictionary decoder which generates differential data of key value data by performing a dictionary decoding operation depending on a dictionary decoding mode information input from the header decoder;
• a second inverse DPCM processor which generates quantized data by retrieving differential data between keyframes and differential data between vertices, which are input from the dictionary decoder, depending on the DPCM operation mode;
• and
• a second inverse quantizer which generates retrieved key value data by inverse-quantizing the quantized data.

A bitstream, into which a coordinate interpolator, which includes key data indicating the location of each keyframe on a temporal axis and key value data representing the location of each vertex of an object in each of the keyframes using coordinates of the vertices each consisting of x, y, and z components, is encoded, the bitstream comprising:

• key data encoding/decoding information, into which key data and information necessary to decode the key data are encoded;
• and
• key value data encoding/decoding information, into which key value data and information necessary to decode the key value data are encoded,
• wherein the key data encoding/decoding information comprises:
• inverse DND operation information including the order of inverse DND indicating a predetermined number of cycles of inverse DND to be performed on differential data generated by entropy-decoding the bitstream in order to extend the range of the differential data and maximum and minimum values among differential data used in each cycle of inverse DND operation;
• first inverse DPCM operation information including the order of inverse DPCM operation to be performed on the inverse-DNDed differential data so as to convert the inverse-DNDed differential data into quantized key data and intra key data which are used for each cycle of inverse DPCM operation;
• and
• first inverse quantization information used in inverse quantization to generate retrieved key data by inverse-quantizing the quantized key data, and
• the key value data encoding/decoding information comprises:
• dictionary decoding information including information on symbols representing differential data of dictionary-encoded key value data, which are entropy-decoded from the bitstream, first position indexes indicating the positions of the symbols, and a dictionary decoding mode indicating a dictionary decoding method to be performed on the first position indexes;
• second inverse DPCM operation information including second position indexes indicating the positions of symbols, which are used in an inverse DPCM operation to convert dictionary-decoded differential data of components of each vertex into quantized key value data and correspond to combinations of inverse DPCM operation modes;
• and
• second inverse quantization information used in inverse quantization to generate retrieved key value data by inverse-quantizing the quantized key value data.