Title:
音声符号化のための利得-適応性量子化及び不均一符号長の使用
Document Type and Number:
Japanese Patent JP4843142
Kind Code:
B2
Abstract:
Techniques like Huffman coding can be used to represent digital audio signal components more efficiently using non-uniform length symbols than can be represented by other coding techniques using uniform length symbols. Unfortunately, the coding efficiency that can be achieved by Huffman coding depends on the probability density function of the information to be coded and the Huffman coding process itself requires considerable processing and memory ressources. A coding process that uses gain-adaptive quantization according to the present invention can realize the advantage of using non-uniform length symbols while overcoming the shortcomings of Huffman coding. In gain-adaptive quantization, the magnitudes of signal components to be encoded are compared to one or more thresholds and placed into classes according to the results of the comparison. The magnitudes of the components placed into one of the classes are modified according to a gain factor that is related to the threshold used to classify the components. Preferably, the gain factor may be expressed as a function of only the threshold value. Gain-adaptive quantization may be used to encode frequency subband signals in split-band audio coding systems. Additional features including cascaded gain-adaptive quantization, intra-frame coding, split-interval and non-overloading quantizers are disclosed.
Inventors:
Davidson, Grant Allen
Robinson, Charles Quito
Truman, Michael Meade
Robinson, Charles Quito
Truman, Michael Meade
Application Number:
JP2000612930A
Publication Date:
December 21, 2011
Filing Date:
April 11, 2000
Export Citation:
Assignee:
DOLBY LABORATORIES LICENSING CORPORATION
International Classes:
G10L19/032; G10L19/02; H03M7/30; H04B14/04
Domestic Patent References:
| JPH08237132A | 1996-09-13 |
Attorney, Agent or Firm:
Yuzo Yamazaki
Kiko Okada
Naomi Mae
Hideo Hayashi
Kenkyo Kanayama
Kiko Okada
Naomi Mae
Hideo Hayashi
Kenkyo Kanayama