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公开(公告)号：DE69808146D1
公开(公告)日：2002-10-24
申请号：DE69808146
申请日：1998-01-12
Applicant: ST MICROELECTRONICS ASIA
Inventor： ABSAR JAVED , GEORGE SAPNA , ALVAREZ-TINOCO MARIO
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.
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公开(公告)号：DE69928842T2
公开(公告)日：2006-08-17
申请号：DE69928842
申请日：1999-10-30
Applicant: ST MICROELECTRONICS ASIA
Inventor： ABSAR JAVED , GEORGE SAPNA
IPC: H04B1/66 , G10L19/008 , G10L19/16
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.
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公开(公告)号：DE69823557D1
公开(公告)日：2004-06-03
申请号：DE69823557
申请日：1998-02-21
Applicant: ST MICROELECTRONICS ASIA
Inventor： ABSAR JAVED , GEORGE SAPNA , ALVAREZ-TINOCO MARIO
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公开(公告)号：DE69909849T2
公开(公告)日：2004-05-27
申请号：DE69909849
申请日：1999-11-24
Applicant: ST MICROELECTRONICS ASIA
Inventor： ABSAR JAVED , GEORGE SAPNA , ALVAREZ-TINOCO MARIO
Abstract: A method for effecting aliasing cancellation in an audio effects algorithm using a delay modulated signal, derived from interpolation of a delay modulator at an instantaneous sampling frequency, including: determining the instantaneous sampling frequency 1/T isf and band limiting an input signal, to which the audio effects algorithm is to be applied to ½ T isf prior to interpolation.
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公开(公告)号：DE69722973T2
公开(公告)日：2004-05-19
申请号：DE69722973
申请日：1997-12-19
Applicant: ST MICROELECTRONICS ASIA
Inventor： ABSAR JAVED , GEORGE SAPNA , ALVAREZ-TINOCO MARIO
Abstract: A method and apparatus for subband phase flag determination for coupling of channels in a dual channel audio encoder is based on a psychoacoustic model of the human auditory system. The method and apparatus are applicable to audio encoders which utilize a coupling channel to combine certain frequency components of the input audio signals. The method ensures a least square error between the original channel frequency coefficients at the encoder and the estimated coefficients at the decoder by determining the sign of the dot product of the coefficients for one of the channels and the coupling coefficients. No restriction is placed on the strategy utilized for generating the coupling channel coefficients or the coupling coordinates.
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Patent Agency Ranking
公开(公告)号：DE69909849D1
公开(公告)日：2003-08-28
申请号：DE69909849
申请日：1999-11-24
Applicant: ST MICROELECTRONICS ASIA
Inventor： ABSAR JAVED , GEORGE SAPNA , ALVAREZ-TINOCO MARIO
Abstract: A method for effecting aliasing cancellation in an audio effects algorithm using a delay modulated signal, derived from interpolation of a delay modulator at an instantaneous sampling frequency, including: determining the instantaneous sampling frequency 1/T isf and band limiting an input signal, to which the audio effects algorithm is to be applied to ½ T isf prior to interpolation.
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公开(公告)号：DE69813912T2
公开(公告)日：2004-05-06
申请号：DE69813912
申请日：1998-10-26
Applicant: ST MICROELECTRONICS ASIA
Inventor： ABSAR JAVED , GEORGE SAPNA , ALVAREZ-TINOCO MARIO
Abstract: AC-3 is a high quality audio compression format widely used in feature films and, more recently, on Digital Versatile Disks (DVD). For consumer applications the algorithm is usually coded into the firmware of a DSP Processor, which due to cost considerations may be capable of only fixed point arithmetic. It is generally assumed that 16-bit processing is incapable of delivering the high fidelity audio, expected from the AC-3 technology. Double precision computation can be utilized on such processors to provide the high quality; but the computational burden of such implementation will be beyond the capacity of the processor to enable real-time operation. Through extensive simulation study of a high quality AC-3 encoder implementation, a multi-precision technique for each processing block is presented whereby the quality of the encoder on a 16-bit processor matches the single precision 24-bit implementation very closely without excessive additional computational complexity.
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公开(公告)号：DE69722973D1
公开(公告)日：2003-07-24
申请号：DE69722973
申请日：1997-12-19
Applicant: ST MICROELECTRONICS ASIA
Inventor： ABSAR JAVED , GEORGE SAPNA , ALVAREZ-TINOCO MARIO
Abstract: A method and apparatus for subband phase flag determination for coupling of channels in a dual channel audio encoder is based on a psychoacoustic model of the human auditory system. The method and apparatus are applicable to audio encoders which utilize a coupling channel to combine certain frequency components of the input audio signals. The method ensures a least square error between the original channel frequency coefficients at the encoder and the estimated coefficients at the decoder by determining the sign of the dot product of the coefficients for one of the channels and the coupling coefficients. No restriction is placed on the strategy utilized for generating the coupling channel coefficients or the coupling coordinates.
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公开(公告)号：DE69813912D1
公开(公告)日：2003-05-28
申请号：DE69813912
申请日：1998-10-26
Applicant: ST MICROELECTRONICS ASIA
Inventor： ABSAR JAVED , GEORGE SAPNA , ALVAREZ-TINOCO MARIO
Abstract: AC-3 is a high quality audio compression format widely used in feature films and, more recently, on Digital Versatile Disks (DVD). For consumer applications the algorithm is usually coded into the firmware of a DSP Processor, which due to cost considerations may be capable of only fixed point arithmetic. It is generally assumed that 16-bit processing is incapable of delivering the high fidelity audio, expected from the AC-3 technology. Double precision computation can be utilized on such processors to provide the high quality; but the computational burden of such implementation will be beyond the capacity of the processor to enable real-time operation. Through extensive simulation study of a high quality AC-3 encoder implementation, a multi-precision technique for each processing block is presented whereby the quality of the encoder on a 16-bit processor matches the single precision 24-bit implementation very closely without excessive additional computational complexity.
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公开(公告)号：DE69711102D1
公开(公告)日：2002-04-18
申请号：DE69711102
申请日：1997-12-27
Applicant: ST MICROELECTRONICS ASIA
Inventor： ABSAR JAVED , GEORGE SAPNA , ALVAREZ-TINOCO MARIO
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.
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