Abstract:
The invention provides apparatus and a method for creating a visual representation of music that conveys the musical form, structure, event surface, orchestration, and sonic framework of the piece being visualized. The representation comprises visual characters/sprites that move in time according to instructions from the metadata synchronized to the actual musical recording. These characters accurately portray the rhythm, pitch, and timbre of the individual elements in the musical surface (individual lines or performers) and have a hierarchy of representation, e.g. thematic elements that are divided into sub-elements (gestures or phrases) that are further divided into individual notes. The visual representation corresponds to the structure of the music as heard, where simultaneous harmonic events are parsed into individual notes which are then tied together into a rhythmic stream of linked events. Two streams of data (the “musical” and the “sonic”) are synchronized to the musical piece to drive the visualization.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Application No. 60/705,023, filed Aug. 3, 2005, herein incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    This invention relates to an interactive tool for creating and displaying visual representations of musical works. 
         [0003]    There are numerous ways to convey musical content in media other than by sound recordings. Sheet music, including musical scores, conveys to a performer musical qualities such as tempo, pitch, duration, volume, and articulation. For example, the tempo and mood is indicated by separating the notes into measures and stating a tempo by phrases such as adagio, andante cantabile, presto, rallendo etc. 
         [0004]    The pitch of individual notes is indicated by their position on a staff of five lines preceded by a clef (e.g. treble, bass, alto, etc.) and a key signature. The duration of a note is indicated by whether it is hollow or solid, by dependent flags and by its font size if it is a grace note. 
         [0005]    Volume is indicated by combining abbreviations for forte (louder) and piano (softer) and by indicating swells (crescendos) and diminuendos by elongated wedges written below the notes. 
         [0006]    Articulation is indicated by dots for staccato, bars for legato, curved lines for slurs, and by comments. In addition there are specialized notations for each instrument such as guitar fingerings written at chord transitions, pedal instructions for keyboard instruments, etc. 
         [0007]    Since score reading requires a long time to learn, there have been attempts to provide information in connection with scores by using visual means. 
         [0008]    The use of colors to indicate notes is the most common: U.S. Pat. No. 1,085,603 (Grant) discloses a method of writing music using different colors to represent the different tones of a vocal scale (this reference, and all others cited in this application are herein incorporated by reference); U.S. Pat. No. 3,680,428 (Buckrucker et al.) discloses a color coded music notation wherein a series of colored disks having different shading characteristics represent different notes; U.S. Pat. No. 5,775,915 (Quinn) discloses a music notation wherein different colors are used to represent the key and also whether the note is a sharp or flat; U.S. Pat. No. 6,127,616 (Yu) discloses a method of representing musical notes using colors and shading; U.S. Pat. No. 6,660,921 (Deverich) discloses a method for teaching a stringed instrument using colored fingering numbers; U.S. patent application no. 2004/0007118 (Holcombe) discloses a method of music notation using colors to represent the notes of a scale. 
         [0009]    In general musical scores are intended to guide a performer, but require much interpretation in order to produce the intended musical content. Although they are a remarkably successful notation scheme, musical scores require long familiarity before being able to be converted into quality musical sound. And, even sophisticated musicians would have trouble reading a piece of sheet music or a score and getting a sense of the ultimate musical experience the way one can read words on a page and get the sense, without hearing them, of what they would sound like aloud. Thus, with some notable exceptions, composers usually work on an instrument and not by writing out what one expects to hear. 
         [0010]    With the advent of computer displays there have been several attempts to convey graphically certain aspects of music. The web page http://www.kunstderfuge.com/theory/malinowski.htm, downloaded Jul. 26, 2006, discusses a Musical Animation Machine (MAM) providing a visual display that represents a musical performance. It is intended to be a musical score for listeners rather than a musical notation to serve the needs of composers, performers, and conductors. It uses colored bars to represent the notes of a piece. The vertical placement of each bar indicates the pitch of its note. The horizontal placement indicates its timing relative to the other notes of the piece, and the length of the bar shows its duration. These bars scroll across the screen as the piece plays. When a bar reaches the center of the screen, it brightens as its corresponding note sounds. The center of the screen is always the “now” point. The notes for different instruments are alt on the same “staff”, with the different instruments indicated by color. The MAM notation can be colored to highlight thematic units, instrumentation, harmony, or dynamics. Despite its use of colors and graphics, the MAM adheres closely to the standard layout of a musical score. The graphics convey little feel for the music for someone unaccustomed to interpreting standard scores. 
         [0011]    PCT publication WO 97/46991, entitled “Method and System for Providing Visual Representation of Music” displays graphic representations of the chords, notes and lyrics of a song correlated with the time of performance to facilitate a musician&#39;s ability to learn to play it on an instrument. U.S. Pat. No. 6,717,042 entitled “Dance Visualization of Music” discloses apparatus to analyze samples of a received stream of music and determine a music type. It then displays dance movements for the stream of music in accord with the type. U.S. Pat. No. 6,686,529 entitled “Method and Apparatus for Selecting Harmonic Color Using Harmonics, and Method and Apparatus for Converting Sound to Color or Color to Sound”, discloses an apparatus to convert sound into a color image by selecting a color based on the harmonics. U.S. Pat. No. 6,353,170 entitled “Method and System for Composing Electronic Music and Generating Graphical Information” discloses a system to allow a user to interactively arrange music samples that are looped to create a musical work. The user creates a video of an animated character that dances to the rhythm and beat by selection from several video clips, which may then be edited. In the same vein is U.S. Pat. No. 5,801,694. 
         [0012]    U.S. Pat. No. 6,225,545 entitled “Musical Image Display Apparatus and Method Storage Medium Therefor” discloses a display where a drawing pattern is read from a data base corresponding to musical instruments. The drawing pattern is modified according to performance information. U.S. Pat. No. 6,140,565 entitled “Method of Visualizing Music System by Combination of Scenery Picture and Player Icons” discloses a method for displaying a scenery setting matching an environment in which the music should be played. It provides an icon corresponding to the timbre of the performance. U.S. Pat. No. 5,646,361 entitled “Laser Emitting Visual Display for a Music System” describes a visual display formed by lasers responding to the frequency and volumes of music. In the same vein is U.S. Pat. No. 6,361,188. 
         [0013]    U.S. Pat. No. 5,286,908 entitled “Multi-Media System Including Bi-Directional Music-To-Graphic Display Interface” describes a music controlled graphic interface having a lookup table of video/graphic data and using digital musical information as an index into the table. Alternatively an algorithm can calculate video data in real time corresponding to the digital musical information. U.S. Pat. No. 5,275,082 entitled “Visual Music Conducting Device” displays a simulation of the movement of a conductor&#39;s baton in response to electronic timing signals representative of the tempo of a piece of music. 
         [0014]    U.S. Pat. No. 5,191,319 entitled “Method and Apparatus for Visual Portrayal of Music” discloses a visual color display that portrays music. The audio signal amplitude causes the display brightness to vary. The audio signal frequency content causes the color of the display to vary. Preselected light colors are assigned to frequency bands. A display using two adjacent light sources is presented on a globe to produce attractive color blending. U.S. Pat. No. 5,048,390 entitled “Tone Visualizing Apparatus” discloses a detector for characteristics of an audio signal such as envelope, chord, spectrum components, number of zero-cross points and energy. These are turned into display parameters such as size, brightness or color so that the impression of the image is matched with that of the audio tone. 
         [0015]    U.S. Pat. No. 5,005,459 entitled “Musical tone Visualizing Apparatus Which Displays an Image of an Animated Object in Accordance With a Musical Performance” discloses an apparatus that stores images of players or musical instruments. These are moved in response to performance of an electronic musical instrument. That image may be selectively enlarged whose tone volume is largest during the performance. U.S. Pat. No. 4,713,658 entitled “Apparatus for Providing a Visual Interpretation of an Audio Signal” describes an apparatus for analyzing a musical signal electronically into frequency or amplitude characteristics. Each characteristic controls a motor operating a rotatable indicator. The amplitude component rotates the whole indicator display comprising three indicator sets for bass, treble and mid-range. The indicator sets may be subdivided within further frequency limits. 
         [0016]    U.S. Pat. No. 4,081,829 entitled “Audio Activated Video Display” assigned to Atari, Inc. discloses an apparatus that presents images associated with separate stereo channels, Color is derived based on the zero crossing rate of each channel. Each channel has its own color associated with it. Objects may be solid, or rings, or one may be subtracted from the other. The different arrays may be selected automatically in a random manner. 
         [0017]    Thus there have been many efforts at providing a visual representation of music. They fall into a mainly two categories. First, there are those that adhere closely to the presentation of a musical score. These either use static graphics to make the score more readable, or they use time varying graphics to indicate which notes are being sounded as the piece plays and to provide some information about the volume of the notes. Second, there are those that present images that entertain with pleasing visual patterns responding to the music but with no discernable informative intention regarding the structure of the music. For example, such systems might display the image of a dancer or musician playing instruments. 
         [0018]    Another representation of music, in a non-visual form, is the Musical Instrument Data Interface (MIDI) system, which provides a binary code for transmitting a musical performance. For example, a MIDI code for a piano performance digitizes which key was struck, how hard it was struck, and how long it was sustained, etc. The MIDI code is intended to be converted back into sound by a code interpreter, which for example could produce a piano&#39;s sound emulating the audio effect of the struck key. Typically the corresponding sound is a prestored sampled sound. Thus the MIDI code could be sounded on any instrument whose sound has been sampled. For example, playing on a MIDI keyboard could allow the simulation of an organ, a trumpet, a drum, etc. The reproduced sounds do not have to correspond to any conventional instrument and may be produced electronically as opposed to sampled. Although MIDI code is somewhat successful in digitizing performance information it is not humanly readable and is designed for interpretation throughout the use of some sound production system. 
         [0019]    Yet another successful medium for capturing sound in another medium is the sampling system used in digital recording on tape, CDs or DVDs. Since sound produced on a speaker is merely the result of electrical currents sent to the speaker, the medium records those currents in detail. In digital recording, the music is chopped up into extremely small time intervals and a voltage level is recorded (or sampled) for each interval. Only a finite number of voltage levels are recorded, which gives the recording its digital quality. Although digital recording is only an approximation to the musical sound, if the frequency range is bounded, the sampling rate is high enough, and the number of quantized levels is sufficient, the loss due to the digital approximation cannot be heard. Such digital recording became practical with the development of fast inexpensive electronics and, for the CD and DVD, the development of optical recording techniques employing lasers. Again, this technology is for reproducing sound and not for providing human readable or visual formats. 
         [0020]    There is a huge market for musical performance, and much of its audience is uninterested in or incapable of performing what they hear. Such people have no interest in learning to read sheet music because it is difficult to achieve and is unrelated to listening to the music. Some software programs try to fill this need by offering the user the ability to assemble sound clips into a piece of music. Some of these programs have graphical interfaces in which aspects of sound clips are displayed as .wav files (a standard way of representing digitally sampled files on a computer). In those representations, the amplitude and duration of the sound are represented as a wave. Utilities are provided for attaching those waves to each other to play them in sequence, or attaching them on parallel lines to play several simultaneously, to repeat entire sections, and to modify volumes, pitch and durations. However the formats are not capable of indicating detailed musical characteristics and do not give a pictorial sense of the artistic sonic elements of the musical composition other than perhaps tempo and volume. 
         [0021]    Importantly, it is recognized that music is organized according to a hierarchical structure and can be understood as a hierarchical event. At the lowest level, the music is comprised of individual notes that have a pitch (e.g., middle-C), a duration (e.g., a quarter note), and a timbre (harmonics at varying amplitudes that serve to distinguish, e.g., a violin from a flute). Other lower-level aspects might include the amplitude (volume) envelope or how the harmonic amplitudes vary over time. At a higher level, by way of example, the middle-C can be viewed as the third of an A-flat chord, or it could be serving as a pitch center, tonal center or the like. At an even higher level, the middle-C can be viewed as the second note of a particular motif. These levels can further incorporate higher-level structures as well: a motif within a phrase, and this, within a movement; aspects such as melodies and themes are encompassed at these higher levels. None of the existing notation systems capture the substance hierarchical structure of the music in a comprehensive manner. 
         [0022]    What is needed is a way to create and convey visually to a listener the sense of a musical experience on a number of levels in the hierarchical structure, whether or not accompanied by the sound. What is further needed is a way to enable musical composition or the modification of existing music whether or not accompanied by the sound. Finally, what is needed is a tool that permits an artist to interact with visual display elements in a manner that both respects the form at various levels in the hierarchy while at the same time permitting artistic freedom of expression. 
       SUMMARY 
       [0023]    The invention provides a tool for creating and displaying a visual representation of music that accurately and expressively conveys the musical form on a number of levels in the hierarchical structure of the music, including overall structure, event surface, orchestration, and sonic framework of the piece being visualized. Various embodiments of the invention are discussed below. These entails a novel encoding method and appertaining system for transforming recorded music into: 1) a set of musical metadata; and 2) a set of sonic metadata, that can be transformed into 3) any number of visual mappings and representations that are related to various characteristics of the recorded music. 
         [0024]    The term “event surface” of a piece of music refers to the actual musical events that comprise the piece (i.e., individual notes) as opposed to more global aspects like themes, melodies, etc. This notion could be considered synonymous with “musical events” or an “event stream”. As a musical piece unfolds in some sort of hierarchical manner, a listener is generally only immediately perceiving the musical surface, e.g., the tone color, which is the first thing the listener&#39;s ear is picking up about the piece. The listener may not be consciously aware of all of the superstructure that is underneath. Advantageously, the present invention permits a creation and visualization of not only the event surface, but also of various aspects of the underlying superstructure of the music in a representational form on a visual display. The representation comprises visual characters or sprites made of simple or complex two- or three-dimensional geometric shapes that move in time according to instructions from metadata synchronized to the actual musical recording, where the metadata can be derived from actual audio files, data files, such as MIDI files, and data created by an artist who is interacting, via a user interface, with the music using the inventive tool. 
         [0025]    The characters accurately (i.e., according to some spatial or geometric relationship, consistent use of an attribute, such as color, shape, surface texture, etc.) portray the rhythm, pitch, and timbre of the individual elements in the musical surface (individual lines or performers) that may correspond, e.g., to tracks in a multi-track (or any form of multi-part) recording (that may be stored on any form of media in either digital or analog form), and have a hierarchy of representation, e.g., thematic elements that are divided into sub-elements (gestures or phrases) that are further divided into individual notes. 
         [0026]    Some of the processing may be done automatically. For example, information about individual notes, their volume, duration, and possibly general timbral characteristics could be derived from the data file (e.g., a MIDI file) automatically, whereas higher level divisions, such as themes, melodies, etc. can be done manually via a tagging/annotating the analog or digital data representing the music piece so that it can be visualized synchronously with the sound. Part of the software will allow the user to define how exactly this is visualized (e.g., the user could choose to ignore certain aspects of the analysis or concentrate on ones s/he finds more or less interesting), but as complete an analysis as possible would be pre-computed as metadata for each piece. The tagging/annotating could be done in an off-line manner or in real-time, as the music is playing, using this tool. 
         [0027]    Factors affecting the specific visual form of a character depends on parameters such as pitch (both absolute and relative to the key area of the harmonic surface), dynamic volume, and salience (how prominent a note event is psychoacoustically). This visual representation will therefore correspond to the actual structure of the music as heard, where simultaneous harmonic events are parsed into individual notes which are then tied together into a rhythmic stream of linked events providing themes, melodies, bass figures, and other musical structures. 
         [0028]    To provide the underlying data for the visualization system, the music is analyzed both according to appropriate contemporary music theory (e.g., Piston&#39;s trilogy “Harmony”, “Counterpoint”, and “Orchestration”) as well as hierarchical listening structures derived from formal Gestalt analysis and generative grammar modeling, as are known from, e.g., Schenker, Heinrich. Harmony (ISBN: 0226737349).  Five Graphic Musical Analyses  (ISBN: 0486222942); Lerdahl, Fred, and −Jackendoff, Ray.  A Generative Theory of Tonal Music  (ISBN: 026262107X); Bracewell, Ronald.  The Fourier Transform and Its Applications  (ISBN: 0073039381). 
         [0029]    In addition, the acoustic information from the musical recording (as well as the underlying “multi-track”) is analyzed to provide an accurate sonic “image” of the component timbres being visualized, using a combination of Fourier analysis, Linear Predictive Coding (see; Roads, Curtis.  The Computer Music Tutorial  (ISBN: 0262680823), and equivalent algorithms and technologies to extrapolate meaningful frequency-domain and time-domain data from a sound recording. 
         [0030]    These two streams of data (the “musical” (note and structure-based) and the “sonic” (audiological/waveform-based) are then synchronized by an artist to the digital audio recording of the musical piece to drive the visualization. These streams allow providing a highly configurable system for expressive and complex visual representation that accurately depicts the expressiveness and complexity of the musical piece being listened to. The user (“listener-viewer”) becomes familiar with this relationship between musical content and visual representation and derives from the experience a wide spectrum of intellectual stimulation and aesthetic pleasure. Advantageously, the visual relationships created can serve to introduce, enhance, or reinforce natural patterns and relationships in the music that the user may not have been aware of or focused on previously. 
         [0031]    It should be noted that a first user, the artist, is a part of the creative process for producing the visualization, and his or her input in determining which musical parameters or rules and which part of the musical structure is associated with which displayed attributes is a part of the creative process. A second user, the viewer, is one who observes the finished visualization. 
         [0032]    For works which are intended to be more creative and impose few restrictive constraints on the artist, a minimal set of fixed parameters or rules may be specified. For example, perhaps the only constraints imposed would be that note pitch corresponds with a vertical y-axis position on the display, and that the number of characters reflects the number of voices on the display, and all other parameters are assignable by the user: for example, the artist may assign the texture of a sprite to correspond to timbral characteristics of the note . . . a smooth texture for notes having few harmonics and a rough texture for notes having many, etc. 
         [0033]    For works which are intended to be used as a teaching tool and to help viewers appreciate the underlying structure, more of the parameters or rules may be fixed so that the viewer can learn corresponding relationships. For example, one could always define string section portions to be represented by the color red, whereas the brass section portions could be defined to be represented by the color yellow. The idea being that at some level there is a constancy of the elements (shape, size, position, degree of opacity, movement, surface texture and surface motion, color, etc.)—minimal when great artistic expression is desired, and moderate to maximal when communication of consistent parameters is desired—but in any case defining a visual language for the underlying music. 
         [0034]    The system can be designed to be extremely flexible in associating various aspects in the hierarchy of a musical piece and can define the constraints of the artist as freely or rigorously as desired. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0035]    The invention is described with reference to various preferred embodiments in more detail below that are illustrated in the drawing figures. 
           [0036]      FIG. 1  is a block flow diagram illustrating a conversion of musical source data into a musical meta-score; 
           [0037]      FIG. 2  is a block flow diagram illustrating a conversion of multi-track audio recording data into a sonic meta-score; 
           [0038]      FIG. 3  is a block flow diagram illustrating the integration of the sound recording, the musical meta-score, and the sonic meta score using a configuration file into an audio output and a visual output; 
           [0039]      FIGS. 4A-M  are exemplary screen shots of frames for the visual output; 
           [0040]      FIGS. 5 &amp; 6  are hierarchical illustrations of the graphic interface generators of the code using the Max visual development environment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0041]    Conversion of Musical Source Material/Data into the Musical Meta-Score 
         [0042]    From a high-level perspective,  FIGS. 1 and 2  illustrate the breakdown and output of the system for the musical piece in terms of non-audio musical source material ( FIG. 1 ), audio data ( FIG. 2 ). The output of these breakdowns are then combined with the actual sound recording to produce a synchronized video and audio output that can be displayed to a viewer ( FIG. 3 ) 
         [0043]    In more detail,  FIG. 1  shows the breakdown, analysis, processing and output of the non-audio data related to a musical piece. The raw data of musical source material  1  for a piece, which could include musical scores, MIDI realizations of a piece, transcriptions of the recording, and any other representational forms for a piece of music are subjected to a preparatory Gestalt (overall structural and holistic) analysis  5  according to three main encoding systems. The analysis  5  comprises harmonic  7 , melodic  9 , and rhythmic  11  sections. The harmonic section  7  analyzes and records information such as duration, key areas, and chord vocabulary  13 . The melodic section  9  analyzes and records specific points of interest and repetition such as major themes, motifs, orchestration shifts, etc.  15 . The rhythmic section  11  analyzes and records meters, tactus (beat, measure division), patterns, etc.  17 . 
         [0044]    It should be noted that these analyses can be performed either manually or, when computer-based analytical technology exists, automatically. For example, an automated computer-based analysis of key and chord structure as well as meter would be possible from an interpretation of a MIDI file. However, higher level structures, at present, do not lend themselves well to an automated analysis, for example, the identification of relevant themes or motifs. Nonetheless, additional techniques may be subsequently developed, and nothing in the invention is intended to limit any particular form of analysis to either a manual or an automatic mode. Furthermore, known score recognition technologies could be utilized to assist. 
         [0045]    The musical source material is further subject to a hierarchical analysis  19  and a surface analysis  25 . At present, these analyses would utilize some degree of manual analyses, although various computer tools could be used to assist in such an analysis. 
         [0046]    The hierarchical analysis  19  can incorporate a prolongational analysis  21  and/or a time-span reduction analysis  23 , and is performed to extrapolate thematic and structural elements that are required for the visualization but may not be immediately apparent from the musical surface or easily computable in real-time by the visualization system itself. This includes performing standard harmonic analysis, agreement on the metrical tactus, prolongational analysis  21 , and time-span reduction  23  as discussed above. Finally, the musical surface is analyzed  25  to correctly encode the pitches, durations, articulations, dynamics, and other appropriate metrics  27  for all the individual musical events in the piece. See Schenker, Lerdahl &amp; Jackendoff, cited above, as well as Lerdahl, Fred. Musical Pitch Space (ISBN: 0195178297)). 
         [0047]    A musical meta-score  3  is produced from the output of the Gestalt  5 , hirerarchical  19 , and surface  25  analyses. The term “meta-score” generally refers to a description or elaboration of the content of a score. (The prefix “meta” is used to describe a language descriptive of a subject rather than being in the language of the subject.) The musical meta-score  3  contains digital encodings of the pitches, rhythms, dynamics, and arrangement at a sophistication comparable to common practice Western musical notation, but with a higher degree of precision vis-à-vis pitch and the temporal event stream as necessary. The musical event stream represented in the musical meta-score  3  is synchronized to the recording, and then annotated with whatever other analysis are to be provided (e.g., to identify themes, melodies, formal boundaries, etc.). 
         [0048]    This meta-score  3 , while created descriptively (after the recording of the piece is made), may or may not rely on pre-existing proscriptive notations as a starting point, e.g., a conductor&#39;s score for a 19 th  Century symphonic work. Primarily, however, the score is derived from a transcriptional markup of the recording to be visualized. 
         [0049]    The three analyses  5 , 19 ,  25  may be combined into a single meta-file  3  with time-stamps accurate to the speed of the rendered visualization (e.g., 30 frames/second). The following table illustrates an extremely simplified example of the opening of Beethoven&#39;s Fifth Symphony. Additional tags could be added as necessary on a per-instrument basis (for example, if the violins are playing a down-bow or up-bow, if the brass is muted, etc.) 
         [0000]                                                  TABLE 1                   Meta-Score for       Opening to Beethoven&#39;s 5 th  Symphony                                Orchestra-           Time   Pitch   Volume   Duration   Harmony   tion   Theme               0:0:0:0   Eb3   ff   1   Cminor   (list all)   1A       0:0:1:0   Eb3   ff   1   Cminor   (list all)   1A       0:0:2:0   Eb3   ff   1   Cminor   (list all)   1A       0:0:3:0   C3   ff   5   Cminor   (list all)   1A                    
Conversion of Multi-Track Audio Recording Data into the Sonic Meta-Score
 
         [0050]    As shown in  FIG. 2 , a second set of meta-data is also generated (sonic meta-data  29 ) to describe the “sound” (i.e., pitch, timbre, volume, etc.) (as opposed to the “music”, i.e., tonal relationships, etc.) in the recording, at a level of specificity to be determined by the type of musical piece. 
         [0051]    In the most common case, and as illustrated for the embodiment discussed below, the musical work is provided on a multi-track audio recording  31 , although nothing precludes the application of this technique for a single-track recording. A single-track recording comprising multiple instruments, voices, etc., (such as an old preexisting 78 RPM record) could still be musically “tagged” (i.e., pitches, rhythms, etc., could still be notated) but such a recording could not be acoustically analyzed on a per-instrument basis (and therefore, the resultant visualization would lose some complexity, e.g., one would not be able to have the symbols representing the first violin shimmer in response to violin vibrato). 
         [0052]    For each track  33 ,  35 ,  37 , which typically represents an individual instrument or voice, the recording allows the extraction of several envelopes, including the amplitude envelope  39 , pitch envelope  41 , timbral envelope  43 , noise envelope  45 , and pitch and amplitude stability envelope  47 . For a musical work with only one instrument (e.g., a solo piano recital) a single track of timbral information would suffice, providing information about the tone of the piano used in the recording (including the unique timbral characteristics of the instrument) as well as a fine degree of detail about the performance that would be difficult to encode using musical descriptors (e.g., the spatial layout of the piano sound in the stereo field because of room ambience, the specific nuances of left-hand versus right-hand playing, etc.). 
         [0053]    The “noise envelope”  45  is the volume of noisy sound in an instrumental note. For example, when a violinist draws a bow across a string, the first 20 ms or so of the note consist of colored noise (if one isolated this part, the actual pitch of the sound cannot be determined), until the bow attains enough momentum for the string to start vibrating periodically. Pitch and amplitude “stability” are ways of describing vibrato and tremolo (fluttering of the pitch and the volume, respectively, within a single note). 
         [0054]    The information from the appertaining tracks  33 ,  35 ,  37 , are combined in the sonic meta-score  29 , that may be structured with time stamps, e.g., per frame, similar to that of the musical meta-score  3 , and with a similar structure to that illustrated in Table 1 above, but with the appertaining information relevant to the audio information. 
       Production of the Final Audio and Visual Output 
       [0055]    The musical meta-score  3  and the sonic meta-score  29  are brought together with the original recording  31  to form the final audio  63  and visual  55  output. As shown in  FIG. 3 , the system comprises a mapping system  51  that maps these two types of metadata  3  and  29  to a real-time visualization  53 ,  55  in perfect synchronization with the playback of the recording  31  by use of an event queue  61 , which is able to correlate the data based on the timing information contained within the musical meta-score  3  and the sonic meta-score  29 . The information in the event queue  61  may be represented per frame, although any other time-based mechanism may be used. 
         [0056]    The mapping scheme itself  51  is designed to be highly malleable based on settings stored on the data medium (e.g., a configuration file  57 ) as well as configurable by the user based on specific settings or interactions which the viewer-listener can perform  59  to adjust the visualization to her/his taste, much as s/he would adjust the tone controls on a stereo receiver. The configuration file  57  could be used to make any assignment between a property related to the music and its corresponding visual display attribute, e.g., volume to size, vibrato to shimmering, harmonic components to surface texture, position to pitch, etc. The configuration file could be something as simple as a text-based file that could be edited with a simplistic text editor, or could be implemented with a much more complex program that permits specific types of tagging to be done at a high level. 
         [0057]    The user controls  59  could be used to perform operations in either an off-line manner or in real time, as the scores and sound recording are being produced. Any known form of user interface could be utilized for the user controls—these could be done strictly on a computer with the use of a keyboard and mouse using standard drop-down menus, toolbars with symbols, or any other standards mechanism for interacting with a program. The user controls  59  could also comprise custom designed physical hardware controls, such as sliders, knobs, touch-pads, etc. that are capable of entering data values in a simplified manner, or could combine both physical and computer-based controls. 
         [0058]    The user controls  59  and data from the configuration file  57  provide inputs to the mapping system  51 , which maps input events and data to visual descriptors related to, e.g., the sprites of the visual display. The mapping data thus produced is fed into the real-time visualization system  53  that also accepts inputs from the configuration file  57  and the user controls  59 . 
         [0059]    The details of the preferred scheme for deriving information from the two meta-data files  3 ,  29  and visualizing it on a per-frame basis is contained in the exemplary pseudo code listing in Appendix A. 
       Maxcode Implementation Embodiment 
       [0060]    An explicit code implementation according to an embodiment of the invention in MaxCode is presented in Appendix B. Max is a visual programming language developed and maintained by San Francisco-based software company Cycling&#39;74 (www.cycling74.com). It has its origins in a program called “patcher” written by Miller Puckette at IRCAM/Paris in 1987. A complete description of the Max language can be found in the Max Reference Manual by Chris Dobrian and David Zicarelli, Cycling &#39;74 (2000-2005). 
         [0061]    The textual representations of the program (#X, #P, etc.) are difficult to interpret in raw form, and the only practical way to understand a Max program is to look at the visual function graph ( FIGS. 5 and 6 ); his is what differentiates Max from a procedural programming language (C or Java); the visual layout of the program defines its function. 
       Visualization System and Display 
       [0062]      FIGS. 4A-4M  illustrate exemplary types of visual outputs  55  that can be achieved using the visualization system  53 . Although the following discussion relates to what is shown in these figures, the visualization is best experienced according to the multimedia demonstration submitted as an Exhibit with this application, which illustrates the color, motion, and synchronization that is impossible to illustrate in the Figures. 
         [0063]      FIG. 4A  illustrates a display  100  showing how a mapping scheme for a typical embodiment of a musical work could map specific musical lines (e.g., different instruments in an orchestral work, different voices in polyphonic texture, such as a piano work, or different tracks of a multi-track recording) to a series of two- or three-dimensional objects or sprites  110 . 1  to  110 . 7  in a virtual scene (or “world”) on the screen display  100 . 
         [0064]      FIGS. 4B and 4C  illustrate, by way of example, how the shapes of these “voice objects”  120 . 1  to  120 . 3  could morph among a set of fixed geometric shapes according to, e.g., the pitch classes they play, in such a way that, for example, two instruments playing the same pitch class an octave apart (or integer numbers of octaves apart) would be immediately recognizable by a shared shape  120 . 2 ,  120 . 3  for their voice object. This assists the user in more fully appreciating the underlying structure of the music. 
         [0065]    As the musical composition progresses, one of the objects  120 . 1  has moved downward, rotated about an axis parallel with the display surface, and changed its shape slightly. The objects representing the same pitch class  120 . 2 ,  120 . 3  have also experienced a similar transformation. New musical lines have entered, as are illustrated by the introduction of additional objects  120 . 4  and  120 . 5 . 
         [0066]    To illustrate various mappings that could be performed, volume of the individual pitches could be mapped to the size of the object, and color could be implemented to cue the viewer-listener into a number of shared parameters by, for example, grouping instruments of the same family to a shared color space. 
         [0067]    The spatial layout of these shapes in relationship to each other and in relationship to the viewpoint of the virtual camera into the world could be determined by various factors including the predominant harmony of the musical surface at that time or the salience of a particular voice in the musical structure, where the camera would pivot toward the most prominent melodic line or Haupstimme (the most important polyphonic voice in a passage). As new notes are introduced, previous notes would recede in space or opacity to provide a visual transition equivalent to short-term musical memory. 
         [0068]    More complex graphical elements are introduced to link together the musical hierarchy of the piece as it unfolds. As a result, lines or other trail markings can appear to connect melodic fragments, motifs, themes, etc., with specific visual cues used to mark out formal points in the musical structure according to the analysis undertaken on the musical meta-score prior to the visualization. The result is that the viewer-listener can experience a geo-spatial “history” of the performance as it unfolds and will be graphically informed of recurring patterns in the music through recurring visualized events.  FIGS. 4D-4M  provide exemplary illustrations of various visual representations that can be achieved. 
         [0069]    Referring back to  FIG. 3 , the sonic meta-data  29  encoded off of the components of the recording itself  31  can be applied to add nuance and character to the generated graphics. For example, the specific contour and shape of a solo violinist&#39;s vibrato, easily encoded into the sonic meta-data  29 , can be applied to the violinist&#39;s voice object  120 . 1  as a shimmering texture on the surface of the object in perfect synchronization, providing important visual cues as to the performance practice and technique used in the recording. In this manner, a great deal of information can be imparted to a viewer regarding the underlying musical structure without even hearing the accompanying music. 
         [0070]    Via the user controls  59 , the user can, e.g., selectively isolate voices, freeze, zoom, and pan around the scene in a fluid manner to investigate the visualization or set up a particular vista in three-dimensional space from which to view the rest of the piece. This capacity to view the scene from any angle, as it were, allows for a user to make an informed decision on how best to utilize the system for a particular musical work. 
         [0071]    The specific visualization objects, their shapes, drawing styles, animation actions, and mapping interactions with the score, one another and with the scene overall are implemented in a portable, easily encapsulated algorithm that defines the “look” of the visualization independent of the underlying data supplying it. As a result, a variety of “looks” can be developed and experiments with for different styles of musical content, much as one would approach production design in the performing arts. These values can be stored in the configuration file  57 , e.g., and will depend on the particular visualization used; for the example provided, this could include the location and angle of the camera, the palette of colors used in the sprites, the speed at which the scene rotates (if at all), geometric models of the particular shapes used when drawing the sprites, etc. 
         [0072]    For the purposes of promoting an understanding of the principles of the invention, reference has been made to the preferred embodiments illustrated in the drawings, and specific language has been used to describe these embodiments. However, no limitation of the scope of the invention is intended by this specific language, and the invention should be construed to encompass all embodiments that would normally occur to one of ordinary skill in the art. 
         [0073]    The present invention may be described in terms of functional block components and various processing steps. Such functional blocks may be realized by any number of hardware and/or software components configured to perform the specified functions. For example, the present invention may employ various integrated circuit components, e.g., memory elements, processing elements, logic elements, look-up tables, and the like, which may carry out a variety of functions under the control of one or more microprocessors or other control devices. Similarly, where the elements of the present invention are implemented using software programming or software elements the invention may be implemented with any programming or scripting language such as C, C++, Java, assembler, or the like, with the various algorithms being implemented with any combination of data structures, objects, processes, routines or other programming elements. Furthermore, the present invention could employ any number of conventional techniques for electronics configuration, signal processing and/or control, data processing and the like. 
         [0074]    The particular implementations shown and described herein are illustrative examples of the invention and are not intended to otherwise limit the scope of the invention in any way. For the sake of brevity, conventional electronics, control systems, software development and other functional aspects of the systems (and components of the individual operating components of the systems) may not be described in detail. Furthermore, the connecting lines, or connectors shown in the various figures presented are intended to represent exemplary functional relationships and/or physical or logical couplings between the various elements. It should be noted that many alternative or additional functional relationships, physical connections or logical connections may be present in a practical device. Moreover, no item or component is essential to the practice of the invention unless the element is specifically described as “essential” or “critical”. Numerous modifications and adaptations will be readily apparent to those skilled in this art without departing from the spirit and scope of the present invention.