Patent ID: 7613609
Filing Date: 2009-11-03
Classification: G10L

Abstract:
1. An encoding apparatus that encodes for compression a multi-channel signal including digital signals from a plurality of channels by framing the multi-channel signal, determining a number of steps of quantizing data in the frame; and performing entropy coding of the digital signals, the apparatus comprising: provisional-number-of-in-use-bits calculating means for calculating a sum of code length in a current frame as a provisional number of in-use bits for each channel by making entropy coding of the digital signals based on a provisional number of quantizing steps provisionally determined for quantizing the digital signals; inter-channel bit allocation means for allocating a number of bits usable for each channel based on a ratio of the provisional number of in-use bits for each channel with a total provisional number of in-use bits, which is a sum of the provisional numbers of the in-use bits for all the plurality of channels, and number-of-bits adjusting means for adjusting the number of in-use bits for each channel based on the number of usable bits allocated to the channel, in which the provisional-number-of-in-use-bits calculating means includes means for dividing data in the current frame into units of coding, means for normalizing data included in the units of coding using a number of scale factors, means for determining the provisional number of quantizing steps based on the number of scale factors, means for quantizing normalized data obtained from the means for normalizing on the basis of the provisional number of quantizing steps obtained from the means for determining the provisional number of quantizing steps, and means for entropy coding quantized normalized data obtained from the means for quantizing normalized data and for obtaining the provisional number of in-use bits, wherein the number-of-bits adjusting means includes means for calculating a re-calculated number of quantizing steps on the basis of the provisional number of quantizing steps for each channel and a comparison of the provisional number of in-use bits for each channel with the corresponding number of usable bits, wherein the re-calculated number of quantizing steps is greater than the provisional number of quantizing steps when the provisional number of in-use bits is less than the number of usable bits for the corresponding channel and is less than the provisional number of quantizing steps when the provisional number of in-use bits is greater than the number of usable bits for the corresponding channel, and wherein the means for quantizing is for quantizing the normalized data obtained from the means for normalizing data on the basis of the re-calculated number of quantizing steps obtained from the means for re-calculating, and wherein the means for entropy coding is for entropy encoding the re-calculated quantized normalized data and for obtaining a number of in-use bits, wherein the means for entropy encoding compares the number of in-use bits for each channel with the corresponding number of usable bits and obtains an adjusted number of in-use bits, which is less than or equal to the usable bits, by increasing the number of quantizing steps of the re-calculated quantized normalized data when the number of in-use bits for each channel is less than the corresponding number of usable bits and by decreasing the number of quantizing steps of the re-calculated quantized normalized data when the number of in-use bits for each channel is greater than the corresponding number of usable bits.