Preprocessing of digital audio data for improving perceptual sound quality on a mobile phone
First Claim
1. A method for preprocessing audio signal to be processed by a codec having a variable coding rate, comprising the step of:
- performing a pitch harmonic enhancement (“
PHE”
) preprocessing of the audio signal, to thereby enhance the pitch components of the audio signal.
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Abstract
Recently, with the wider use of cellular phones, more and more users listen to music via their cellular phones, and thus, the perceptual sound quality of music provided via the cellular phones became more critical. Since music signals are encoded by a voice encoding method optimized to human voice signals such as EVRC (Enhanced Variable Rate Coding) in a cellular communication system, the music signals are often distorted by such encoding method, and listeners experience pauses in music caused by such voice-optimized encoding method. To improve the perceptual sound quality of music, a method for preprocessing digital audio data is provided in order to prevent the problem of pause in music signals in a cellular phone. In particular, AGC (Automatic Gain Control) preprocessing and PHE (Pitch Harmonics Enhancement) is performed to the digital audio data having low dynamic range. By this method, the number of pauses in music signal is reduced, and the perceptual sound quality of the music is improved.
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Citations
23 Claims
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1. A method for preprocessing audio signal to be processed by a codec having a variable coding rate, comprising the step of:
performing a pitch harmonic enhancement (“
PHE”
) preprocessing of the audio signal, to thereby enhance the pitch components of the audio signal.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A system for preprocessing audio signal to be processed by a codec having a variable coding rate, comprising:
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means for performing a pitch harmonic enhancement (“
PHE”
) preprocessing of the audio signal, to thereby enhance the pitch components of the audio signal, wherein said means for performing PHE preprocessing comprises;
means for applying a smoothing filter in a frequency domain selectively depending on the property of the audio signal; and
means for performing RPE. - View Dependent Claims (19, 20, 21, 22, 23)
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Specification