公开(公告)号：DE69928842D1

公开(公告)日：2006-01-12

申请号：DE69928842

申请日：1999-10-30

Applicant: ST MICROELECTRONICS ASIA

Inventor： ABSAR JAVED ,  GEORGE SAPNA

IPC: G10L19/008 ,  G10L19/16 ,  H04B1/66

Abstract: Channel coupling for an AC-3 encoder, using mixed precision computations and 16-bit coupling coefficient calculations for channels with 32-bit frequency coefficients.

公开(公告)号：DE69823557T2

公开(公告)日：2005-02-03

申请号：DE69823557

申请日：1998-02-21

Applicant: ST MICROELECTRONICS ASIA

Inventor： ABSAR JAVED ,  GEORGE SAPNA ,  ALVAREZ-TINOCO MARIO

IPC: H04H5/00 ,  H04H20/89 ,  H04H1/00

公开(公告)号：DE69808146T2

公开(公告)日：2003-05-15

申请号：DE69808146

申请日：1998-01-12

Applicant: ST MICROELECTRONICS ASIA

Inventor： ABSAR JAVED ,  GEORGE SAPNA ,  ALVAREZ-TINOCO MARIO

IPC: H03M7/00 ,  H04B1/66

Abstract: A method and apparatus for coding audio data in a frequency transform digital audio coder employing differential frequency coefficient exponent coding. Differential coding of exponents places constraints on possible values an exponent can take, which can lead to distortion in the decoded and reconstructed audio signal. The method and apparatus herein can overcome this restriction by mapping the input exponent set to a new set of values which satisfy the differential constraint as well as reducing information loss, thereby minimizing overall signal distortion due to coding restrictions.

公开(公告)号：DE69711102T2

公开(公告)日：2002-11-07

申请号：DE69711102

申请日：1997-12-27

Applicant: ST MICROELECTRONICS ASIA

Inventor： ABSAR JAVED ,  GEORGE SAPNA ,  ALVAREZ-TINOCO MARIO

IPC: H04B1/66 ,  H04S1/00

Abstract: A method and apparatus for determining parameters for coupling of channels in a digital audio encoder. A frequency range of two audio channels is coupled together in a coupling channel, and a systematic method of determining optimum coupling parameters is employed. Sub-bands of the channels are processed individually, and a measure of the power of each sub-band is used to determine a coupling coefficient generation scheme for each individual sub-band. Adjacent ones of the sub-bands using the same coupling scheme are combined to form bands in the coupling channel, which dictate the generation of the coupling coordinates for the audio channels. The arrangement of the sub-bands in bands also facilitates the generation of phase flags for each band, on the basis of the coupling scheme used in the band.