Abstract:
An audio management application includes a recombiner and aggregation rules to manipulate and recombine segments of a musical piece such that the resulting finished composition includes parts (segments) from the decomposed piece, typically a song, adjustable for length by selectively replicating particular parts and combining with other parts such that the finished composition provides a similar audio experience in the predetermined duration. The architecture defines the parts with part variations of independent length, identified as performing a function of starting, middle, (looping) or ending parts. Each of the parts provides a musical segment that is integratable with other parts in a seamless manner that avoids audible artifacts (e.g. “pops” and “crackles”) common with conventional mechanical switching and mixing. Each of the parts further includes attributes indicative of the manner in which the part may be ordered, whether the part may be replicated or “looped,” and modifiers affecting melody and harmony of the rendered finished composition piece.

Description:
BACKGROUND 
   Conventional sound amplification and mixing systems have been employed for processing a musical score from a fixed medium to a rendered audible signal perceptible to a user or audience. The advent of digitally recorded music via CDs coupled with widely available processor systems (i.e. PCs) has made digital processing of music available to even a casual home listener or audiophile. Conventional analog recordings have been replaced by audio information from a magnetic or optical recording device, often in a small personal device such as MP3 and Ipod® devices, for example. In a managed information environment, audio information is stored and rendered as a song, or score, to a user via speaker devices operable to produce the corresponding audible sound to a user. 
   In a similar manner, computer based applications are able to manipulate audio information stored in audio files according to complex, robust mixing and switching techniques formerly available only to professional musicians and recording studios. Novice and recreational users of so-called “multimedia” applications are able to integrate and combine various forms of data such as video, still photographs, music, and text on a conventional PC, and can generate output in the form of audible and visual images that may be played and/or shown to an audience, or transferred to a suitable device for further activity. 
   SUMMARY 
   Digitally recorded audio has greatly enabled the ability of home or novice audiophiles to amplify and mix sound data from a musical source in a manner once only available to professionals. Conventional sound editing applications allow a user to modify perceptible aspects of sound, such as bass and treble, as well as adjust the length by performing stretching or compressing on the information relative to the time over which the conventional information is rendered. 
   Conventional sound applications, however, suffer from the shortcoming that modifying the duration (i.e. time length) of an audio piece changes the tempo because the compression and expansion techniques employed alter the amount of information rendered in a given time, tending to “speed up” or “slow down” the perceived audio (e.g. music). Also, it can be difficult for novice users to combine portions of audio to meet a prescribed desired time duration. Further, conventional applications cannot rearrange discrete portions of the musical score without perceptible inconsistencies or artifacts (i.e. “crackles”, “phase erasement” or “pops”) as the audio information is switched, or transitions, from one portion to another. 
   Accordingly, configurations herein substantially overcome the shortcomings presented by conventional audio mixing and processing applications by defining an architecture and mechanism of storing audio information in a manner operable to be rearranged, or recombined, from discrete parts of the audio information into a finished musical composition piece of a predetermined length without detectable inconsistencies between the integrated audio parts from which it is combined. The example audio rearranger presented herein rearranges an audio piece (song) by concatenating the constituent parts into a finished composition having a predetermined duration (length). The method identifies a decomposed set of audio information in a file format indicative of a time and relative position of parts of the musical score, or piece, and identifies, for each part, a function and position in the recombined finished composition. Each of the stored parts is operable to be recombined into a seamless, continuous composition of a predetermined length providing a consistent user listening experience despite variations in duration. 
   The disclosed configuration provides time specification and limiting while adhering to a general musical experience by using a minimization technique that selects a song structure with least repetition. The minimizing technique further deviates minimally from the structure to achieve the desired length by rearranging the parts in the same or similar structure as the original. Employing such a rearranger allows less skilled users to adjust pre-composed songs to a desired length without involving a composer and thus mitigating resource (time and money) usage in developing a time conformant rendering of a song or other musical score. 
   The example shown herein presents an audio editing application that employs aggregation rules applicable to the parts of a song to produce a logical sequence of musical parts based on the type of the parts. The aggregation rules identify an ordering of the parts in the recombined, finished composition. A set of song structures identifies a mapping of sequential types of song parts that indicate allowable ordering of the types. In concurrence with the aggregation rules, the recombiner selects parts of a particular length to satisfy the desired total duration. Certain parts may be replicated in succession, to produce a duration multiple (e.g. 2 times, 3 times, etc.) of a part. The parts may also have part variations including similarly renderable (i.e. sounding similar) parts with a different duration. The aggregation rules attempt to minimize repetition while maintaining musical structure (i.e. logical part progression) in the finished composition. 
   The disclosed recombination mechanism allows the audio editing application to manipulate and recombine segments of a musical piece such that the resulting finished composition includes parts (segments) from the decomposed piece, typically a song, adjustable for length by selectively replicating particular parts and combining with other parts such that the finished composition provides a similar audio experience in the predetermined duration. The segments define the parts with part variations of independent length, and identified as performing a function of starting, middle, (looping) or ending parts. Each of the parts provides a musical segment that is integratable with other parts in a seamless manner that avoids audible artifacts (e.g. “pops” and “clicks” or “phase erasement”) common with conventional mechanical switching and mixing. Each of the parts further includes attributes indicative of the manner in which the part may be ordered, whether the part may be replicated or “looped” and modifiers affecting melody and harmony of the rendered finished composition piece, for example. 
   In further detail the method of processing and rendering audio information as disclosed herein includes computing a plurality of parts of an audio piece, such that each of the parts has a function and a duration, in which the function is indicative of a recombinable order of the parts, and the duration is indicative of a time length of the part. A file repository organizes each of the parts according to length and function, and a rearranger arranges a sequence of the parts according to an aggregate duration, in which arranging further includes ordering the parts according to the function of the preceding part and the combined duration of the aggregate parts. 
   In an example configuration, arranging the parts further includes gathering, from an audio source, a set of parts of the audio piece, each of the parts having a duration and a function, in which the function is indicative of the ordering of the parts in a renderable audio composition. A recombiner combines the set of parts in a sequence of parts to compute a renderable audio composition of a predetermined length based on the aggregate duration. The sequence of parts may include, for example, a part of a starting function, at least one part of a looping function, and a part of an ending function. Other sequences defined by song structures may be employed. 
   Further, the parts may include part variations, such that each of the part variations has the same type and a particular independent duration of the audio content contained in the part. Arranging the series of parts further includes building a finished composition piece by iteratively selecting a next part for concatenation to the finished composition. Iterating through available parts includes examining the available parts for concatenation, and computing, based on aggregation rules, a type of part adapted for inclusion as the next part. The iteration computes, if the type of part is adapted for inclusion, part variations of the part, each part variation having a different duration, and selects, if a part variations having a corresponding duration is found, the part variation. The selected corresponding duration is operable to provide a predetermined duration to the finished composition from all of the aggregated parts. 
   In an example configuration, the recombiner employs aggregation rules for identifying a song structure, in which the song structure is indicative of a sequence of part types operable to provide an acceptable musical progression. The recombiner selects, for each iteration, a part variation having a type corresponding to the song structure. Particular arrangements determine a resizability attribute for each of the parts, and concatenate, if the part is resizable, multiple iterations of the part to achieve a desired aggregate (total) duration of the rearranged renderable part. If a part is resizable, the recombiner computes an optimal number of iterations based on the duration of available parts, the duration minimizing duplicative rendering of the rearranged parts. 
   Particular configurations determine a recombination mode, in which the recombination mode is operable to automatically arrange types of parts such that the part structure may be modified in the generated renderable sequence of parts. 
   Alternate configurations of the invention include a multiprogramming or multiprocessing computerized device such as a workstation, handheld or laptop computer or dedicated computing device or the like configured with software and/or circuitry (e.g., a processor as summarized above) to process any or all of the method operations disclosed herein as embodiments of the invention. Still other embodiments of the invention include software programs such as a Java Virtual Machine and/or an operating system that can operate alone or in conjunction with each other with a multiprocessing computerized device to perform the method embodiment steps and operations summarized above and disclosed in detail below. One such embodiment comprises a computer program product that has a computer-readable medium including computer program logic encoded thereon that, when performed in a multiprocessing computerized device having a coupling of a memory and a processor, programs the processor to perform the operations disclosed herein as embodiments of the invention to carry out data access requests. Such arrangements of the invention are typically provided as software, code and/or other data (e.g., data structures) arranged or encoded on a computer readable medium such as an optical medium (e.g., CD-ROM), floppy or hard disk or other medium such as firmware or microcode in one or more ROM or RAM or PROM chips, field programmable gate arrays (FPGAs) or as an Application Specific Integrated Circuit (ASIC). The software or firmware or other such configurations can be installed onto the computerized device (e.g., during operating system or execution environment installation) to cause the computerized device to perform the techniques explained herein as embodiments of the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects, features and advantages of the invention will be apparent from the following description of particular embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. 
       FIG. 1  is a context diagram of an exemplary audio development environment suitable for use with the present invention; 
       FIG. 2  is a flowchart of song rearrangement in the environment of  FIG. 1 ; 
       FIGS. 3-4  are exemplary song structures defined in the aggregation rules according to the system in  FIG. 3 ; and 
       FIG. 5  is a block diagram of parts of a song being rearranged for a predetermined duration according to the flowchart of  FIG. 2 ; 
       FIGS. 6-9  are a flowchart of rearrangement of parts of a song according to the aggregation rules in the system in  FIG. 3 . 
   

   DETAILED DESCRIPTION 
   Conventional sound applications suffer from the shortcoming that modifying the duration (i.e. time length) of an audio piece tends to change the tempo because the compression and expansion techniques employed alter the amount of information rendered in a given time, tending to “speed up” or “slow down” the perceived audio (e.g. music). Further, conventional methods employing mechanical switching and mixing tend to introduce perceptible inconsistencies (i.e. “crackles” or “pops”) as the audio information is switched, or transitions, from one portion to another. Configurations discussed below substantially overcome the shortcomings presented by conventional audio mixing and processing applications by defining an architecture and mechanism of storing audio information in a manner operable to be rearranged, or recombined, from discrete parts of the audio information. The resulting finished musical composition has a predetermined length from the constituent parts, rearranged by the rearranger without detectable inconsistencies between the integrated audio parts from which it is combined. Accordingly, configurations herein identify a decomposed set of audio information in a file format indicative of a time and relative position of parts of the musical score, or piece, and identify, for each part, a function and position in the recombined finished composition. Each of the stored parts is operable to be recombined into a seamless, continuous composition of a predetermined length providing a consistent user listening experience despite variations in duration. 
     FIG. 1  is a context diagram of an exemplary audio development environment suitable for use with the present invention. Referring to  FIG. 1 , an audio editing environment  100  includes a decomposer  110  and an audio editing application  120 . In an example configuration, the audio editing application may be the SOUNDBOOTH application, marketed commercially by Adobe Systems Incorporated, of San Jose, Calif. The audio editing application  120  includes a rearranger  130  for rearranging, or recombining, parts of a song, and a renderer  122  for rendering a finished (rearranged) audio composition  166  on a user device  160 . The decomposer  110  is operable to receive a musical piece, or score  102 , and decompose segments  104 - 1  . . .  104 - 3  corresponding to various portions of a song. Such portions include, for example, intro, chorus, verse, refrain, and bridge. The rearranger  130  receives the decomposed song  112  (or song) as a series of parts  114  corresponding to each of the segments  104  in the original score  102 . The resulting rendered audio composition  166  is a rearranged composition having constituent parts  114  processed by the rearranger  130  as discussed further below. Processing by the rearranger  130  includes reordering and replicating parts  114  to suit a particular time constraint, and modifying characteristics of the parts  114  such as melody, harmony, intensity and volume. A graphical user interface  144  receives user input for specifying the rearranging and reordering of the parts  114  in the song. 
   The rearranger  130  further includes a recombiner  132 , aggregation rules  134  and song structures  136 . The recombiner  130  is operable to rearrange and reorder the parts  114  into a composition  138  of reordered segments  144 - 1  . . .  144 - 4  ( 144  generally) corresponding to the parts  114 . Each of the segments  144  is a part variation having a particular duration, discussed further below. Each part variation  144  includes tracks having one or more clips, discussed below. The aggregation rules  134  employ a function of each of the parts  114  that indicates the order in which a particular part  114  may be recombined with other parts  114 . In the example shown herein, the functions include starting, ending, and looping (repeatable) elements. Alternate parts having other functions may be employed; the recombinability specified by the function is granular to the clip and need not be the same for the entire part. The function refers to the manner in which the part, clip, or loop is combinable with other segments, and may be specific to the clip, or applicable to all clips in the part. The song structures  136  specify a structure, or type-based order, of each of the parts  114  used to combine different types of parts in a sequence that meets the desired duration. In the example configuration below, the recombiner  132  computes time durations of a plurality of parts  114  to assemble a composition  138  having a specified time length, or duration, received from the GUI  164 . 
   In such a system, it is desirable to vary the length of a musical score, yet not deviate from the sequence of verses and intervening chorus expected by the listener. The rearranged composition  138  rendered to a user maintains an expected sequence of parts  114  (based on the function and type) to meet a desired time duration without varying the tempo by “stretching” or “compressing” the audio, while also preserving the musical “structure,” or logical progression of the parts. It should be noted that the concept of a “part” as employed herein refers to a time delimited portion of the piece, not to a instrument “part” encompassing a particular single instrument. 
   The rearranger  130  employs the decomposed song  112 , which is stored as a set of files indexed as rearrangable elements  142 - 1  . . .  142 -N ( 142  generally) on a local storage device  140 , such as a local disk drive. The rearrangable elements  142  collectively include parts  114 , part variations  144 , and tracks and clips, discussed further below in  FIG. 3 . In an example arrangement, the rearrangable elements  142  define a set of files named according to a naming convention indicative of the elements, and may include a part  114  or variations of a part  144 , for example. Other suitable file arrangements may be employed for storing the elements  142 . 
   Therefore, in an example arrangement, the rearranger  130  computes for a given song variation (time length variant of a song) the length of the song (rearranged composition)  138  by combining all parts  114  contained in this song variation  138 . For each part  114  all part variations are iteratively attempted in combination with any part variation of the other parts  114  of the song variation. If the resulting song variation duration is smaller than the desired length, the repetition count for all parts is incremented part by part. The rearranger  130  iterates as long as the resulting duration is equal or larger than the desired length. During the iteration part variations  144  are marked to be removed from search if the duration keeps being under the desired length. The  138  rearranger searches for a combination which gives the minimal error towards the desired length. ( 149 ,  FIG. 3 ) In an automatic mode, discussed further below, the result/best fit of each song variation is compared as such that the resulting minimal error and the repetition count over all parts of a song variation is chosen, where both values weighted equally are minimal. 
     FIG. 2  is a flowchart of song rearrangement in the environment of  FIG. 1 . Referring to  FIGS. 1 and 2 , the method of processing audio information as defined herein includes, at step  200 , computing a plurality of parts  114  of an audio piece, such that each of the parts  114  has a function and a duration, in which the function is indicative of a recombinable order of the parts  114 , and the duration is indicative of a time length of the part  114 . The function of a part, discussed further below in  FIG. 3 , is indicative of an ordering sequence of the parts in the finished composition  138 . The duration specifies the time length such that the recombiner  132  orders the recombined parts  114  in the finished composition  138  to have a predetermined aggregate duration. 
   The decomposer  110  organizes each of the parts  114  according to length and function, as depicted at step  201 , and decomposes the song into rearrangeable elements  160  typically stored as individual files of tracks and clips, although any suitable file organization may be employed. The rearrangeable elements  160  therefore form a set of files of parts, responsive to the rearranger  130  for rearranging and reordering the parts  114  into the finished composition  138  according to the aggregation rules  134  and the desired predetermined duration. The rearranger  130  arranges a sequence  112  of the parts  114  according to an aggregate duration, in which arranging further includes ordering the parts according to the function of the preceding part and the combined duration of the aggregate parts, as depicted at step  302 . The function of the part  114  indicates position relative to other parts, such as parts types which may follow or precede another, also referred to as the structure, discussed further below with respect to  FIGS. 3 and 4 . 
     FIGS. 3-4  are exemplary song structures defined in the aggregation rules according to the system in  FIG. 1 . Referring to  FIGS. 3 and 4 ,  FIGS. 3 and 4  show example song structures employable by the aggregation rules. The song structures  520 ,  540  maintain a logical musical progression that, when rendered to a user, provides a musically coherent, flowing composition. The song structure identifies a sequence of part  114  types, such as intro, verse, chorus, refrain and bridge. The structure id depicted as a state diagram showing an example transition to an acceptable “next” part; any suitable song structure may be employed, as long as the element (part, track and clip) structure specified by the rules may be determined. Alternate representations may be employed, such as a graph or matrix. Referring to  FIG. 3 , a simple structure having three parts is shown. An intro part  500  is followed by a bridge  502  and an end part  504 . The bridge part  502  may be replicated, as shown by arrow  505 . Thus, the rearranger begins aggregating the start part  502 , followed by a multiple of the bridge part  502  to occupy most of the desired duration until there is just enough duration for the end part  504 , and finally by the end part  504 . 
     FIG. 4  shows a song structure  540  having 6 nodes indicative of part  114  progression. In  FIG. 4 , a start part  510  may be followed by a refrain  512  or chorus  514 . The refrain  512  and verse  516  may alternate any number of times, and leads into the bridge  518 . The chorus  514  is followed by the verse  516 , and may also alternate between the refrain and verse, until leading to the bridge  518  which is followed by the end. The example song structures  520  and  540  shown are not restrictive, and may demonstrate any suitable sequence or transition of part types that presents a logical musical progression of parts that is renderable into a pleasing musical experience for the listener. 
     FIG. 5  is a block diagram of parts of a song (score)  102  being modified according to the flowchart of  FIG. 2 . Referring to  FIGS. 1 and 3 , the local drive  140  stores the rearrangeable elements  142  as parts  114 - 1  . . .  114 - 3 . The rearranger  130  accesses the elements  142  as files to extract the parts  114 . Each part  114  has one or more part variations  144 - 11  . . .  144 - 31  ( 144 -N generally). The part variations  144 -N are a time varied segment  104  that generally provide a similar rendered experience and have the same part function and part type. The set of rearrangeable elements  142  therefore provides a range of time varied, recombinable elements  142  that may be processed and rearranged by the rearranger  130  to generate a rearranged composition  138  that provides a similar rendered experience with variable total duration. Each part further includes one or more tracks  146 - 1  . . .  146 -N, and each track may include one or more clips  148 - 1  . . .  148 -N. One particular usage is matching a soundtrack to a video segment. The soundtrack can be matched to the length of the video segment without deviating from the song structure of verses separated by a refrain/chorus and having an introductory and a finish segment (part). 
   In  FIG. 5 , the example rearranged composition  138  has four parts  144 - 1  . . .  144 - 4 . A desired time  149  of 60 seconds is sought by the recombiner  132 . The aggregation rules  134  indicate a song structure  136  that identifies part  114 - 1  as having a start function, part  114 - 2  as having a looping function, being of type bridge, and part  114 - 3  as having an ending function. The recombiner  132 , responsible for selecting the various length part variations  144 , selects part  144 - 12 , having a duration of 20, two iterations (loops) of part  144 - 22 , having a duration of 15 each, thus totaling 30 seconds, and part variation  144 - 31 , having a duration of 10, totaling 60 seconds. An alternate composition  138  might include, for example, 5 parts having part types of intro, verse, chorus, verse, outtro, or other combination that preserves the sequence specified by the type, iterations specified by the function, and part variations that aggregate (total) to the desired time. 
   The parts  114  further include attributes  160 , including a function  161 - 1 , a type  161 - 2 , and a resizability  161 - 3 . The function  161 - 1  is indicative of the ordering of the parts in the composition  138 . In the example configuration, the function indicates a starting, ending, or looping part. The type  161 - 2  is a musical designation of the part in a particular song, and may indicate a chorus, verse, refrain, bridge, intro, or outtro, for example. The type indicates the musical flow of one part into another, such as a chorus between verses, or a bridge leasing into a verse, for example. The resizability  161 - 3  indicates whether a part  114  may be replicated, or looped multiple of times, to increase the duration of the resulting aggregate parts  114 . This may be related to the function  161 - 2  (i.e. looping), although not necessarily. 
     FIGS. 6-9  are a flowchart of rearrangement of parts of a song according to the aggregation rules in the system in  FIG. 5 . Referring to FIGS.  5  and  6 - 9 , method of representing audio information as defined herein includes, at step  300 , computing a plurality of parts of an audio piece, each of the parts having a function and a duration, such that the function indicative of a recombinable order of the parts, the duration indicative of a time length of the part. This includes gathering, from an audio source, a set of parts of the audio piece, each of the parts having a duration and a function, the function indicative of the ordering of the parts in a renderable audio composition, and storing the parts in an indexed or enumerated form, as the rearrangeable elements. For example, a script file, such as that defined in copending U.S. patent application entitled “METHODS AND APPARATUS FOR STRUCTURING AUDIO DATA”, incorporated herein by reference, filed concurrently, may be employed. Further details on the rearrangeable elements are discussed below with respect to  FIG. 7 , at step  302 . 
   The rearranger  130  arranging a sequence of the parts according to an aggregate duration, such that arranging further includes ordering the parts according to the function of the preceding part and the combined duration of the aggregate parts, as depicted at step  310 . The aggregation rules, discussed further below with respect to  FIGS. 8 and 9 , perform rearranging with the intent to minimize duplication while satisfying the predetermined duration as closely as feasible with the aggregate parts. The recombiner  132  computes, based on the aggregation rules  134 , a type of part  114  adapted for inclusion as the next part  114  in a sequence  112  accumulated as the finished composition  138 , as shown at step  311 . Accordingly, the recombiner  132  examines available parts  114  for concatenation, as depicted at step  312 , to determine the sequence of part types  161  and durations D according to the aggregation rules  134  and song structures  136  that satisfies the intended duration  149 , discussed further below in  FIGS. 7 and 8 . 
   The recombiner selects, if a part variation  144  having a corresponding duration D is found, the part variation  144 , the corresponding duration operable to provide a predetermined duration to the finished composition  138 , as shown at step  321 . Using the selected part variation  144 , the recombiner builds the finished composition  138  piece by iteratively selecting a next part for concatenation to the finished composition, ass depicted at step  328 . Therefore, a check is performed, at step  329 , to determine if the intended duration  149  is reached, and control reverts to step  311  accordingly. Otherwise, the renderer  122  combines the set of parts selected in the sequence of parts  138  to compute a renderable audio composition  166  of a predetermined length based on the aggregate duration, as shown at step  330 . 
   Referring now to  FIG. 7 , the decomposer  110  computes a plurality of parts of an audio piece  102 , such that each of the parts has a function  161 - 1  and a duration D, in which the function  161 - 1  is indicative of a recombinable order of the parts  114 , and the duration is indicative of a time length of the part  114 . The parts  114 , take the form of rearrangeable elements  142  available to the rearranger  130 , in which the audio score  102  further comprises a plurality of song variations, such that each of the song variations has a predetermined length and includes a set of part variations  144  corresponding to the predetermined length. The song variations are operable to form a decomposition of parts  114 , such that the decomposition is operable to adjust the length of the song to generate a substantially similar audible combination  138  of parts  114  renderable into a similarly perceptible audio reproduction  166 , as disclosed at step  303 . The decomposer generates or obtains the score (song) variations of a musical piece  102 , the musical piece being a composed version of a song, as depicted at step  304 , and demarcates the score variations into parts  114 , each of the parts  114  having a particular function  161 - 1 , as shown at step  305 . The decomposer  110  generates part variations  144  from the score variations, such that each of the score variations has a series of part variations  144  of varying duration D, as disclosed at step  306 . The local storage device  140  stores the part variations  144  as rearrangeable elements  142  in a set of files, in which the files are arranged according to a predetermined set of naming conventions indicative of the type and duration of each of the parts  114 , as shown in step  307 . For example, the rearrangeable elements may each occupy a particular file. Other levels of granularity may be achieved; in the example configuration, the files are named according to the methods in the copending U.S. patent application cited above. The decomposer  110  identifies a type  161 - 1  for each of the parts  114 , as depicted at step  308 , and organizes each of the parts according to length D and function  161 - 1 , such as by the naming conventions, as shown at step  309 . 
   Referring to  FIG. 8 , from step  312 , the recombiner selects, based on the type  161 - 1  of a previous part  114 , a successive part  114  for inclusion in the rearranged composition  138 , such that the successive part has a corresponding type, as depicted at step  313 . Therefore, the recombiner iteratively selects parts variations  144  for concatenation, or aggregation, into the finished composition  138 , based on the aggregation rules  134 . 
   The recombiner determining a recombination mode, in which the recombination mode is operable to automatically arrange types of parts such that the part structure is modified in the generated renderable sequence of parts, as shown at step  314 . A check is performed, at step  315 , to determine if recombination is enabled, meaning that the recombination may rearrange the structure (sequence of types) in the finished composition  138 . If the recombination mode is enabled, then the structure (e.g. part  114  type ordering) is preserved, for example, the sequence of parts  138  includes a part of a starting function  114 - 1 , at least one part of a looping function  114 - 2 , and a part of an ending function  114 - 3 , as depicted at step  316 . In this mode, the recombiner selects, for each iteration, a part variation having a type corresponding to the song structure of the input score  102 , as shown at step  317 . 
   Otherwise If the recombination mode is enabled, the aggregation rules  134  may be employed to identify permissible song structures  136 , or sequences of part types  161 - 1 . The aggregation rules  136  identify a song structure such that the song structure i 136  is indicative of a sequence of part types  161 - 1  operable to provide an acceptable musical progression, as shown at step  318 . The recombiner  132  selects, for each iteration, a part variation  144  having a type  161 - 1  corresponding to the song structure  136  permitted by the aggregation rules  134  (e.g.  520 ,  540 ). Other structures may be specified by the song structures  136 . The corresponding types  161 - 1  are determinable from a mapping of types, the mapping based on a logical musical progression defined by a predetermined song structure ( 520 ,  540 ), as shown at step  319 . The recombiner selects the next part type  161 - 1  by iterating through the sequence defined by the song structure  136 , as shown at step  320 . 
   Referring to  FIG. 9 , while iterating (searching) for part variations corresponding to a duration  149 , the recombiner  132  computes, if the type  161 - 1  of part is adapted for inclusion (based on the type check of step  312 ), part variations  144  of the part  114 , such that each part variation has a different duration, as shown at step  322 . The recombiner determining a resizability attribute for each of the parts, as depicted at step  323 . The resizability indicates if multiple repetitions the part variation may be performed to achieve a desired duration. A check is performed, at step  324 , to identify if a part variation  144  is resizable. If not, then the recombiner looks to part variations  144 , in which each of the part variations has the same type and a particular independent duration of the audio content contained in the part, as shown at step  325 , to identify a part variation of an appropriate length. 
   Otherwise, at step  326 , the recombiner concatenates, if the part is resizable, multiple iterations of the part  114  to achieve a desired aggregate duration of the rearranged renderable piece  138 . In view of minimizing repetition, the aggregation rules specify repetition of the largest part that can be accommodated. Therefore, the recombiner computes, if a part is resizable, an optimal number of iterations based on the duration of available parts  114  (i.e. part variations  144 ), such that the duration minimizes duplicative rendering of the rearranged parts. Thus, 2 multiples of a 10 second part variation  144  are preferred to 4 multiples of a 5 second variation, for example. 
   Those skilled in the art should readily appreciate that the programs and methods for representing and processing audio information as defined herein are deliverable to a processing device in many forms, including but not limited to a) information permanently stored on non-writeable storage media such as ROM devices, b) information alterably stored on writeable storage media such as floppy disks, magnetic tapes, CDs, RAM devices, and other magnetic and optical media, or c) information conveyed to a computer through communication media, for example using baseband signaling or broadband signaling techniques, as in an electronic network such as the Internet or telephone modem lines. The disclosed method may be in the form of an encoded set of processor based instructions for performing the operations and methods discussed above. Such delivery may be in the form of a computer program product having a computer readable medium operable to store computer program logic embodied in computer program code encoded thereon, for example. The operations and methods may be implemented in a software executable object or as a set of instructions embedded in a carrier wave. Alternatively, the operations and methods disclosed herein may be embodied in whole or in part using hardware components, such as Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), state machines, controllers or other hardware components or devices, or a combination of hardware, software, and firmware components. 
   While the system and method for representing and processing audio information has been particularly shown and described with references to embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.