System and method for enhanced streaming audio

Abstract

A system and method for enhancement and management of streaming audio is disclosed. In one embodiment, the system provides a client-side decoder that is compatible with numerous audio formats, so that a user can enjoy relatively high-quality audio from various sources, even from sources that do not provide multi-channel or high-quality audio data. The system and method also include a management system for managing and controlling the use of licensed signal processing software to further enhance an audio stream. In one embodiment, the management system is used to manage a signal processing module that provides psychoacoustic audio processing to create a wider soundstage, an acoustic correction process to increase the perceived height and clarity of the audio image, and bass enhancement processing to create the perception of low bass from the small speakers or headphones typically used with multi-media systems and portable audio players.

1 . An audio enhancement system comprising:
 a vertical image adjustment module configured to adjust a vertical image of input audio;   a bass enhancement module configured to enhance a bass response of the input audio to produce bass-enhanced input audio; and   a horizontal image enhancement module configured to enhance a horizontal image of the input audio by at least equalizing difference information present in the input audio to produce image-enhanced input audio;   wherein the vertically-adjusted, bass-enhanced, and image enhanced input audio is combined to produce output audio.   
     
     
         2 . The audio enhancement system of  claim 1 , wherein the vertical image adjustment module comprising one or more high pass filters configured to modify the input audio to create vertically-adjusted input audio. 
     
     
         3 . The audio enhancement system of  claim 1 , wherein the horizontal image enhancement module comprises a left-channel filter configured to filter sounds in a left signal channel of the input audio and a right-channel filter configured to filter sounds in a right signal channel of the input audio, and wherein the left-channel filter and the right-channel filter are configured to emphasize lower frequencies relative to higher frequencies. 
     
     
         4 . The audio enhancement system of  claim 3 , wherein the left-channel filter and the right-channel filter are configured to filter the left and right channels in accordance with a variation in frequency response of a human auditory system as a function of vertical position of a sound source. 
     
     
         5 . The audio enhancement system of  claim 1 , wherein the bass enhancement module is configured to emphasize portions of lower frequencies relative to higher frequencies. 
     
     
         6 . The audio enhancement system of  claim 1 , wherein the bass enhancement module comprises:
 a first combiner configured to combine a least a portion of a left channel signal of the input audio with at least a portion of a right channel signal of the input audio to produce a combined signal;   a filter configured to select a portion of the combined signal to produce a filtered signal;   a variable gain module configured to adjust the filtered signal in response to an envelope of the filtered signal to produce a bass enhancement signal;   a second combiner configured to combine at least a portion of the bass enhancement signal with the left channel signal; and   a third combiner configured to combine at least a portion of the bass enhancement signal with the right channel signal.   
     
     
         7 . The audio enhancement system of  claim 1 , wherein the image enhancement module is configured to provide a common-mode transfer function and a differential-mode transfer function. 
     
     
         8 . The audio enhancement system of  claim 7 , wherein the differential-mode transfer function is configured to emphasize lower frequencies relative to higher frequencies. 
     
     
         9 . A method for enhancing audio, the method comprising:
 height-adjusting input audio to adjust a vertical image of the input audio;   bass-enhancing the input audio to enhance a bass response of the input audio, wherein bass-enhancing produces bass-enhanced input audio;   width-adjusting the input audio to enhance a width of an apparent sound stage associated with the input audio to produce width-adjusted input audio, wherein width-adjusting equalizes difference information present in the input audio; and   providing the height-adjusted, bass-enhanced, and width-adjusted input audio as an output audio signal.   
     
     
         10 . The method of  claim 9 , wherein height adjusting comprises using one or more high pass filters to modify the input audio to produce height-adjusted input audio. 
     
     
         11 . The method of  claim 9 , wherein said height-adjusting comprises filtering signals in a left signal channel of the input audio and filtering signals in a right signal channel of the input audio to change a perceived vertical location of the apparent sound stage as heard by a listener. 
     
     
         12 . The method of  claim 11 , wherein said filtering comprises emphasizing lower frequencies relative to higher frequencies. 
     
     
         13 . The method of  claim 9 , wherein said bass-enhancing comprises emphasizing portions of lower frequencies relative to higher frequencies. 
     
     
         14 . The method of  claim 9 , wherein said bass-enhancing comprises:
 combining at least a portion of a left channel signal of the input audio with at least a portion of a right channel signal of the input audio to produce a combined signal;   filtering the combined signal to produce a filtered signal;   amplifying the filtered signal according to an envelope of the filtered signal to produce a bass enhancement signal;   combining at least a portion of the bass enhancement signal with the left channel signal; and   combining at least a portion of the bass enhancement signal with the right channel signal.   
     
     
         15 . The method of  claim 14 , wherein said amplifying comprises compressing the filtered signal during an attack time period. 
     
     
         16 . The method of  claim 14 , wherein said amplifying comprises expanding the filtered signal during a decay time period. 
     
     
         17 . The method of  claim 9 , wherein said width-enhancing comprises applying a common-mode transfer function and applying a differential-mode transfer function to the input audio. 
     
     
         18 . The method of  claim 17 , wherein said applying the differential-mode transfer function comprises:
 de-emphasizing frequency components in a first frequency band of the input audio according to a first de-emphasis value;   de-emphasizing frequency components in a second frequency band of the input audio according to a second de-emphasis value, wherein the second frequency band is higher in frequency than the first frequency band and wherein the second de-emphasis value is relatively less than the first de-emphasis value; and   emphasizing frequency components in a third frequency band of the input audio according to an emphasis value, wherein the third frequency band is higher in frequency than the second frequency band.   
     
     
         19 . An audio enhancement system comprising:
 means for height-adjusting input audio to adjust a vertical image of the input audio;   means for bass-enhancing the input audio to enhance a bass response of the input audio, wherein the means for bass-enhancing is configured to produce bass-enhanced input audio;   means for width-adjusting the input audio to enhance a width of an apparent sound stage associated with the input audio to produce a width-adjusted input audio, wherein the means for width-adjusting is configured to equalize difference information present in the input audio; and   means for providing the height-adjusted, bass-enhanced, and width-adjusted input audio as an output audio signal.   
     
     
         20 . The audio enhancement system of  claim 19 , wherein the means for height adjusting is configured to use one or more high pass filters to modify the input audio to produce a height-adjusted input audio.