Apparatus and method of embedded quantization for the improved SNR scalbility

An encoder providing SNR scalability, comprising:

• a quantization unit performing R-D optimization based on a distribution of DCT coefficients of each slice, calculating quantization coefficient values and reference values respectively indicating a start value and an end value of DCT coefficients quantized to “0”, and performing quantization;
• and
• a dequantization unit performing dequantization based on average values of DCT coefficients of respective intervals divided according to the reference values and the quantization coefficient values, and
• wherein the distribution of DCT coefficients is configured to generate an average value, and
• wherein the average value of the DCT coefficients is configured according to the reference values are σ, and compressed values of the average values are Y,
• Y
• =
• σ
• -
• 2
• 15
• +
• floor
• (
• Q
• P
• /
• 6
• )
• 2
• 15
• +
• floor
• ⁡
• (
• Q
• P
• /
• 6
• )
• .

A codec providing improved SNR scalability, comprising:

• an R-D optimization unit performing R-D optimization based on a distribution of DCT coefficients of each slice and calculating a first reference value and a second reference value respectively indicating a start point and an end point of DCT coefficients quantized to “0” and
• wherein the each slice is a slice of an image frame as specified by H.264 video compression standard;
• a quantization interval setting unit setting adaptive quantization intervals based on a minimum value and a maximum value of the DCT coefficients, the first reference value, and the second reference value;
• a mapping unit mapping the DCT coefficients to the adaptive quantization intervals;
• an entropy encoding unit adding, to a bit stream, values encoded based on average values of DCT coefficients of respective intervals divided according to the reference values, and
• wherein the average values are configured to be generated based on to the minimum value and the first reference value of the DCT coefficient;
• and
• a dequantization unit performing dequantization based on both the average value of the DCT coefficients and quantization coefficient values extracted from the bit stream.

A decoder providing improved SNR scalability comprising:

• a receiver receiving an encoded bit stream;
• an extractor extracting a DCT coefficient average value and a quantization coefficient value from the received bit stream;
• and
• a dequantization unit performing dequantization on the basis of the DCT coefficient average value and the quantization coefficient value,
• wherein the DCT coefficient average value of each section of adaptive quantization intervals is an average value of DCT coefficient present in a corresponding section, and the sections of the adaptive quantization interval are set using a maximum value and a minimum value of the DCT coefficients of the residues of each SNR enhancement and a start point and an end point of a range of DCT coefficients to be quantized to “0”, the start point and the end point being extracted by performing R-D optimization,
• wherein the DCT coefficients generate an average distortion value and an average bit rate
• wherein the R-D optimization calculates a first reference value and a second reference value,
• wherein the minimum value is less than the calculated first reference value, and
• wherein the maximum value is greater than the calculated second reference value, and
• wherein the average distortion value and the average bit rate are based on to the minimum value and the first reference value.

A quantization method providing improved SNR scalability comprising:

• performing R-D optimization based on a distortion of DCT coefficients of each slice and calculating a first reference value and a second reference value respectively indicating a start point and an end point of DCT coefficients quantized to “0”,
• wherein the distribution of DCT coefficients generate an average distortion value and an average bit rate, and
• wherein the each slice is a slice of an image frame as specified by H.264 video compression standard;
• setting adaptive quantization intervals based on of a minimum value and a maximum value of the DCT coefficients, the first reference value, and the second reference value, and
• wherein the minimum value is less than the calculated first reference value, and
• wherein the maximum value is greater than the calculated second reference value;
• and
• mapping the DCT coefficients to the adaptive quantization intervals, and
• wherein the average distortion value and the average bit rate are generated based on to the minimum value and the first reference value.

A coding method of providing improved SNR scalability, comprising:

• performing quantization after calculating by performing R-D optimization on the basis of a distribution of DCT coefficients of each slice, calculating quantization coefficient values and reference values respectively indicating a start point and an end point of a range of DCT coefficients quantized to “0”;
• and performing dequantization on the basis of average values of DCT coefficients of each section divided based on the reference values and the quantization coefficient values,
• entropy encoding for adding, to a bit stream, values encoded based on average values of DCT coefficients of each of sections divided according to the first and second reference values, and
• wherein the average values of the DCT coefficients of each of sections divided according to the first and second reference values are σ, and compressed values of the average values are Y,
• Y
• =
• σ
• -
• 2
• 15
• +
• floor
• ⁡
• (
• Q
• P16
• )
• 2
• 15
• +
• floor
• ⁡
• (
• Q
• P16
• )
• .

A dequantization method providing improved SNR scalability, comprising:

• extracting a quantization coefficient value and a DCT coefficient average value of each of sections divided on the basis of a start point and an end point of a range of DCT coefficients quantized to “0”, in an adaptive quantization interval set based on a distribution of the DCT coefficients, from an encoded bit stream,
• wherein the adaptive quantization interval is set using a maximum value and a minimum value of the DCT coefficients of the residues of each SNR enhancement and a start point and an end point of a range of DCT coefficients to be quantized to “0” based on, the start point and the end point being extracted by performing R-D optimization,
• wherein the DCT coefficients generate an average distortion value and an average bit rate, and
• wherein the average distortion value and the average bit rate generated based on to the minimum value and a first reference value.

A decoding method of providing improved SNR scalability comprising:

• receiving an encoded bit stream;
• extracting a DCT coefficient average value and a quantization coefficient value from the bit stream;
• and
• performing dequantization based on the DCT coefficient average value and the quantization coefficient value,
• wherein the DCT coefficient average value is set using a maximum value and a minimum value of the DCT coefficients of the residues of each SNR enhancement and a start point and an end point of a range of DCT coefficients to be quantized to “0”, the start point and the end point being extracted by performing R-D optimization,
• wherein the DCT coefficients generate an average distortion value and an average bit rate
• wherein the R-D optimization is performed by calculating a first reference value and a second reference value,
• wherein the minimum value is less than the calculated first reference value, and
• wherein the maximum value is greater than the calculated second reference value, and
• wherein the average distortion value and the average bit rate are based on to the minimum value and the first reference value.