DE10352196A1 - Computer-aided music generation method e.g. for entertainment music, speed of reproduction of digital tone signal is matched to tempo - Google Patents

Abstract

A method for generating music by computer, in which a tone or sound sequence is divided into bars and in which is reproduced by a specified tempo value according to the value of a command sequence stored in the data store of the computer, which at the same time at least one digital tone signal likewise stored in the computer is reproduced. For matching the speed of the reproduction of the digital tone signal to the tempo, initially the digital tone signal is divided into bars (7,8) and then the reproduction speed of the digital signal is selected so that the resulting reproduction duration of one bar of the digital tone signal (6) is equal to the resulting duration from the value of the tempo of one bar (2-5) of the sound/tone sequence (1). Independent claims are included for the following: (1) (A) A system for generating music with a computer. (2) (B) A computer program with program code.

Description

The The invention relates to a method for generating music by means of a computer using electronic sound generating means, wherein a sound sequence divided into a plurality of clocks in a tempo determined by a specifiable tempo value Stipulation of a Playback sequence stored in the computer's memory is while at the same time at least one also stored in the data memory of the computer digital audio signal is played back.

Further The invention relates to a working according to such a method System for the production of music, as well as a computer program with a Program code for implementing the method on a computer.

In front All in the field of light music is computerized electronic Production of music widely used. Usually, individual Sounds or sounds using electronic sound generating means, such as for example, synthesizers and computer-integrated sound cards, generated. The production of complete music is possible, by corresponding sequences of sounds or sounds in accordance with stored in the data memory of a computer command sequences be reproduced. The computers used may be for example, equipped with suitable hardware and software commercial PCs or even for special music production purposes computer (so-called "sequencer") act under the Designation "MIDI" (English "Musical Instruments Digital Interface ") a standardized protocol is known, which is for computer aided reproduction and also for recording pieces of music using electronic music Sound generating means of the type mentioned serves. According to the MIDI standard During music playback, a stored command sequence is processed, which comprises a chronological sequence of instructions. According to these Instructions are thereby the electronic sound generating means via a likewise standardized data interface activated. The single ones Instructions of the instruction sequence can represent individual notes of the piece of music in question or otherwise Control commands for controlling the tone generation means used represent.

A alternative approach to the computer-aided generation of music is that in the digital memory of a computer stored digital audio signals (so-called "samples"). A big Number of multimedia computer applications works to music generation after this procedure. The digital audio signals are each as a sequence of digital data values, from which the acoustic Waveform of the piece of music is reproducible. The data values of digital audio signals are, for example, with a given Sampling rate (so-called "sampling rate") sampled sound level values of pieces of music produced by real musical instruments. Usual data formats for digital Sound signals in the PC area are the WAV format or memory-space-optimized MP3 format. The music production by means of digital audio signals has the advantage of realistic sound reproduction. The disadvantage is, that a "programming" of pieces of music according to the above described MIDI standard with digital audio signals not or only possible with considerable effort is.

at the computer-aided In particular, music production also has the option of playing back Combine MIDI sequences with the playback of digital samples. This technique comes frequently when using so-called "drum loops" in pieces of music for Commitment. Drum loops are more or less short Fragments of mostly exclusively with percussive instruments (drums) generated, rhythmic Music passages available as digital audio signals. The peculiarity consists in the fact that the Drum loops can be cyclically repeated during music playback and in this way serve as rhythm accompaniment of the entire piece of music. However, the prerequisite is that the meter of the reproduced piece of music exactly matches that of the used drum loop. The drum loops usually include this a certain number of music files, taking for cyclic repeatability It is crucial that the digital sound signal of the respective drum loops precisely at the beginning of a measure used and just as precise stops at the end of a bar.

Drum Loops are usually the producers or composers of electronic music on suitable data carriers, such as floppy disk or CD-ROM, stored as a kind of "raw material" available this way the composer or producer can be programming a piece of music from a number of different by genre, style, tempo and sound Select rhythm accompaniments.

There is the problem that each drum loop is present at a certain predetermined tempo, namely at that tempo at which the rhythm in question was recorded during the production of the digital audio signal. The tempo is usually given in units of beats per minute or also briefly in "bpm" (English "beats per mi For a variety of different preset tempo values (60 bpm, 80 bpm, 100 bpm, 120 bpm, 160 bpm, etc.) the composer will usually have suitable drum loops available, but this is in view of The flexibility and creativity of composing an electronic piece of music is often unsatisfactory, but it is often necessary to modify the tempo of the selected drum loop, such as a 120 bpm drum loop for a composition that has a tempo of 124 The adjustment of the tempo is most easily made by a suitable choice of the so-called "pitch" value, ie the speed of playback of the relevant digital audio signal is adjusted so that the desired tempo results. This inevitably results in a change in the pitch, ie the frequency spectrum of the digital audio signal, since the playback speed is no longer consistent with the original input speed of the drum loop. However, a change in pitch does not play a significant role in the percussive, ie non-tonal sounds of the drum loops. However, there are also so-called "timestretching" algorithms which, based on an analysis of the sound spectrum of the digital audio signal, make it possible to change the playback speed even without changing the pitch, but such algorithms are very computation-intensive.

adversely is in the previously outlined known methods for computer aided music production, that the Adjusting the playback speed of the drum loop to be used to the tempo of each piece of music always with a considerable Effort is connected. Often It takes a long time to try and manual tuning the rhythm accompaniment with the sound sequence of the piece of music in accordance bring to. this leads to often with composers too Frustration, as it makes it impossible in particular, in a short time different drum loops during the creation of a piece of music to try out the right rhythm accompaniment. Known Software products allow it as well disadvantageously often not, the playback speed of the drum loop at all flexible to vary without losing the stored data of the digital To modify the sound signal itself.

From that The present invention is based on the object, a method of computer-aided To provide music production in which the above disadvantages be avoided. In particular, the comfortable and automatic Adjustment of the playback speed of the digital audio signal be possible at the pace of the sound sequence of the piece of music.

These Task solves the invention starting from a method of the aforementioned Kind in that the Adjustment of the speed of the reproduction of the digital audio signal to the pace first the digital audio signal is divided into bars and that then the Playback speed of the digital audio signal is chosen such that the resulting playback time a clock of the digital audio signal equal to the tempo value resulting duration of a clock of the sound sequence.

The invention is based on the finding that a synchronization of the reproduction of the digital audio signal with the reproduced according to the command sequence sound sequence, ie the MIDI sequence, is only possible if the clock division of the digital audio signal is previously determined. Usually, drum loops contain the digital audio signals 1 . 2 . 4 . 8th , less common 16 or more clocks, each clock having the same length of time and, for example 4 Assuming that the number of clocks of the digital audio signal is first determined with a suitable algorithm, the clock division of the digital audio signal automatically results from the number of clocks desired playback speed of the digital audio signal, ie, for example, the pitch value, be calculated easily, so that the duration of a clock of the MIDI sequence is equal to the duration of a clock of the digital drum loop.For adjusting the playback speed based on the invention inventively clock division can also a suitable time-stretching algorithm may be used which, as mentioned above, has the advantage that the pitch remains unchanged during the reproduction of the digital audio signal.

Consequently is according to the invention advantageously a fully automatic synchronization of the cyclically repeated Playing drum loops with the MIDI sequence of an electronic produced piece of music guaranteed.

Conveniently, the subdivision of the digital audio signal in cycles according to the following steps: First, the estimated playback time of the entire digital audio signal is calculated. The estimated playback time results from the normal playback speed of the digital audio signal, ie without modifying the pitch or without the time stretch. From this, a cycle number value is then determined by comparing the estimated reproduction time with typical time values. In fact, assuming that the playback speed of the drum loop for synchronization with the MIDI sequence only has to be slightly adjusted, then from the estimated playback time on the Number of bars of the drum loop to be closed. However, the default tempo value should also be considered. For example, if the tempo value is 120 bpm, the playing time of a drum loop recorded at a non-120 bpm tempo must be approximately 4,000 milliseconds (4/4) when the drum loop 2 Bars included. In case he does 4 Clocks is expected to be about 8000 ms. at 8th It measures 16000 ms, etc. Because of the significant differences between these time values, which at a given tempo value to the usual number of cycles of, for example 2 . 4 . 8th or 16 correspond, can be easily concluded by a simple comparison on the number of bars. It is advantageous if, for this purpose, a table with typical time values is stored in the data memory of the computer, to each of which cycle number values are assigned. As soon as the clock number is known, the clock division of the digital audio signal can be carried out according to the invention.

In addition to this or alternatively, the subdivision of the digital audio signal in Clocks occur by periodically occurring signal peaks in the digital audio signal can be found. This is done by means of a appropriate algorithm performs an analysis of the digital audio signal, which occurring periodicities automatically determined. From this, it is then possible to deduce the number of cycles. By combining the method of clock division described above based on the estimated Playback time of the sound signal with the signal peak detection is an overall very reliable and precise Clock division guaranteed.

Especially It is advantageous if in the data memory of the computer a Plurality of digital audio signals in the form of an electronic Library is stored such that the user side of one or several of the stored digital audio signals for simultaneous Playback with the sound sequence are selectable. When composing a electronic piece of music On the part of the composer, there is often a desire to have different ones To try drum loops, to determine which of a variety of available rhythm accompaniments best fits the edited piece of music. For this purpose serves the electronic library, from which the composer a drum loop select freely can. Upon selection, the tempo of the drump loop becomes instant and automatically according to the invention adapted to the tempo of the MIDI sequence of the piece of music. The composer can even while the playback of the piece of music between the drum loops stored in the electronic library switch to directly and without delay based on the acoustic Impression of the rhythm and rhythm best suited to style and sound to investigate. From the point of view of the composer, the synchronization according to the invention runs unnoticed, so that he can concentrate fully on the actual creative work.

Sinnvollerweiswe should in the inventive music production the possibility consist of subjecting the digital audio signal to a sound filtering. This can also be implemented on the computer digital Filtering be used by which, for example, a low-pass, high-pass, Bandpaß-, or Tape stop filtering is realized. Sound effects, such as distortion, Bit reduction and the like are also possible. In particular, when according to the invention, the reproduction the MIDI sequence simultaneously with playing multiple drum loops is done, is the individual and independent tonal filter option every single drum loop is an advantage.

A useful development of the method according to the invention consists in that the digital audio signal is automatically divided into audio signal subsections in accordance with the subdivision into cycles, such that each audio signal subsection is individually reproducible. Drum loops typically contain different percussive sounds on individual beats. It can be done on the basis of the clock division according to the invention, a division of the respective drum loops in sound signal subsections, in which case each subsection, for example 1 / 4 . 1 / 8th or 1 / 16 of a bar. Each of these sound signal subsections is then assigned a percussive sound (eg "base drum", "snare drum", "hi-hat", "tom" etc.). Each of these sounds can be played by the user individually, for example to create an individual rhythm accompaniment. It makes sense if each of the audio signal subsections is linked to a key of a piano keyboard connected to the computer, whereby the user is given the opportunity to play the rhythm accompaniment to his composition during the playback of the edited piece of music. It is particularly advantageous if each of the audio signal subsections can be subjected to independent sound filtering in the manner described above, in order to have particularly diverse possibilities of sound manipulation. In this case, an individual adaptation of the pitch value for each sound signal subsection is conceivable.

The method according to the invention can advantageously be used without problems by means of software on a conventional system for the production of music, which consists of a computer and associated electronic sound generating means. An appropriate computer program can be used by users of such system on suitable data carriers, such as CD-ROM or Floppy disk, or be made available for download via the Internet. Modern MIDI-based software, such as the program "Cubase" from Steinberg, has a so-called VST interface (English: "virtual studio technology") as a standardized data interface, by means of which the inventive method in the form of an independent module as "Plug -In "can be used.

embodiments The invention will be explained below with reference to the figures. It demonstrate:

1 Flowchart of the method according to the invention;

2 Dividing a digital audio signal according to the invention;

3 Control elements of the computer program according to the invention.

The 1 shows a section of a piece of music 1 in the form of a standard musical notation. The piece of music 1 is in a plurality of bars 2 . 3 . 4 and 5 divided. Electronic music production is the piece of music 1 as a MIDI sequence, that is, as a stored in the data memory of a computer instruction before, each note of the piece of music 1 each represented by at least one MIDI command. In accordance with these commands, a sound generating means, such as a synthesizer, connected to the computer via a MIDI interface is controlled to control the individual tones of the music piece 1 to sound in succession. The commands are processed according to a given tempo value of eg 90 bpm.

Simultaneously with the playback of the piece of music 1 should now be played a rhythm accompaniment, as a drum loop 6 that is, as stored in the data memory of the computer digital audio signal is present. In the 1 is the drum loop 6 shown as a diagram showing the sound signal amplitude as a function of time.

To adjust the speed of the drum loop playback 6 to the tempo of the piece of music 1 First, the digital audio signal 6 in two bars 7 and 8th divided. This is done by first estimating the playback time of the entire digital audio signal 6 is calculated. Thereafter, in the case shown, the clock number value two is determined, including the estimated playback time with the time duration of a bar of the piece of music 1 is compared with the tempo value of 90 bpm. Since the comparison assumes that the tempo of the drum loop 6 not too much of the tempo of the piece of music 1 and that either 1 . 2 . 4 or 8th Bars from the drum loop 6 are included, the comparison shows that the digital audio signal two bars, namely the clocks 7 and 8th includes. At the same time it can be determined by comparison that the original tempo, ie the tempo with which the rhythm accompaniment according to the drum loop 6 less than the default tempo value of 90 bpm. On the basis of the found bar division, it can even be calculated that the original tempo of the drum loop 6 68 bpm.

Next will be the digital audio signal 6 and the piece of music 1 played simultaneously, with the playback speed (pitch) of the drum loop 6 is chosen so that the resulting playback time of a clock 7 respectively. 8th of the drum loop 6 exactly with the playback time of a bar 2 . 3 . 4 . 5 matches the piece of music. In the present case, there is an increase in the speed of playback of the drum loop by a factor of 1,323 compared to the recording speed of 68 bpm. According to the MIDI standard, this corresponds to a pitch value of 13230.

Like in the 1 Furthermore, it can be seen, the playback of the drum loop takes place 6 cyclically repeated, creating a continuous rhythm accompaniment of the piece of music 1 is achieved.

The 2 shows the digital audio signal 6 , according to the invention in two bars 7 and 8th is divided. Each of these bars is in turn divided into eight audio subsections 9 divided, each subsection corresponds to an eighth note. Each of these eighth notes corresponds to a percussive sound within the drum loop 6 , The subsections of the first clock are according to the invention individually reproducible, including the individual subsections the keys C1, C # 1, D1, D # 1, E1, F1, F # 1 and G1 connected to the computer used via the MIDI interface Piano keyboard are assigned. Upon pressing one of the keys on the piano keyboard, the corresponding percussive sound will sound. The user of a software used to carry out the method according to the invention can, at his option, the subsections 9 the first bar 7 or the second bar 8th place it on the corresponding keys on his piano keyboard.

In the 3 are two control elements 10 and 11 shown schematically for the computer program according to the invention. Such control elements are components of graphical user interfaces that are common in modern software.

The control element 10 includes a text entry field 12 which is used to enter a file mens or to select a filename from a list of filenames. The file name indicates the digital audio signal stored on the computer 6 , Among them are a plurality of display panels 13 and 14 provided, wherein in the display fields 14 the starting points of the audio signal subsections 9 of the drum loop 6 are given in units of ms. These values can be manually changed by the user if the individual sounds of the drum loop 6 do not lie precisely on the corresponding beats. The fields 13 indicate on which keys of the piano keyboard the respective sound signal subsections 9 are laid. Two input fields 15 and 16 are, for example, clickable with a mouse belonging to the computer. The field 15 is with a plus sign and the field 16 provided with a minus sign. Clicking on plus or minus can be comfortable while playing the piece of music 1 be alternated in turn between different drum loops stored in an electronic library. The inventive synchronization between piece of music 1 and drum loop 6 takes place during a drum loop change automatically and unnoticed by the user. In a field 17 the pitch value determined according to the invention is displayed and can be changed manually by the user. By clicking on the field 18 the automatic synchronization according to the invention is switched on and off. A field 19 is provided, which determines the original tempo of the drum loops 6 displays. Other fields, not shown, for example, to display and the user-side manual input required for the inventive clock division number of bars of the drum loop 6 be provided.

The control element 11 is used to control the digital filtering of the drum loop 6 , The exemplified control element 11 Used to enter user-defined parameters for a bandstop filter.

On the graphical user interface, a plurality of control elements 10 and 11 be shown if more than one drum loop simultaneously with the piece of music 1 should be reproduced.

Claims (19)

Method for generating music by means of a computer using electronic sound generating means, one of a plurality of bars ( 2 . 3 . 4 . 5 ) subdivided sound sequence ( 1 ) is reproduced in a tempo determined by a predeterminable tempo value in accordance with a sequence of instructions stored in the data memory of the computer, while at the same time at least one digital audio signal (also stored in the data memory of the computer) ( 6 ), characterized in that in order to adjust the speed of the reproduction of the digital audio signal ( 6 ) to the tempo first the digital audio signal ( 6 ) in bars ( 7 . 8th ) and then that the playback speed of the digital audio signal ( 6 ) is selected such that the resulting playback duration of a clock ( 7 . 8th ) of the digital audio signal ( 6 ) equal to the duration of a bar resulting from the tempo value ( 2 . 3 . 4 . 5 ) of the sound sequence ( 1 ). Method according to Claim 1, characterized in that the digital audio signal ( 6 ) is repeated cyclically. Method according to Claim 1 or 2, characterized in that the subdivision of the digital audio signal ( 6 ) in bars ( 7 . 8th ) according to the following method steps a) calculation of the estimated playback time of the entire digital audio signal ( 6 b) determination of a cycle number value by comparison of the estimated reproduction time with typical time values taking into account the tempo value, c) subdivision of the digital audio signal ( 6 ) in a number of clocks corresponding to the determined number of cycles ( 7 . 8th ). Method according to claim 3, characterized that in The computer's datastore has a table of typical time values is stored, each of which clock number values are assigned. Method according to one of Claims 1 to 4, characterized in that the subdivision of the digital audio signal ( 6 ) in cycles by periodically occurring signal peaks in the digital audio signal ( 6 ) can be found. Method according to one of Claims 1 to 5, characterized in that a plurality of digital audio signals ( 6 ) is stored in the form of an electronic library, such that the user side one or more of the stored digital audio signals ( 6 ) for simultaneous playback with the sound sequence ( 1 ) are selectable. Method according to one of Claims 1 to 6, characterized in that the digital audio signal ( 6 ) is subjected to a tonal filtering. Method according to one of Claims 1 to 7, characterized in that the digital audio signal ( 6 ) according to the division into bars ( 7 . 8th ) automatically into sound signal subsections ( 9 ), such that each audio signal subsection ( 9 ) is reproduced individually. Method according to Claims 7 and 8, characterized in that the audio signal subsections ( 9 ) are subjected to independent sound filtering and / or pitch adjustment. System for the production of music, with a computer and with electronic sound generating means, characterized that the Computer has a program control, which according to the method according to one of the claims 1 to 8 works. Computer program with a program code, by means of which on a computer a method for playing back a digital audio signal stored in the data memory of the computer ( 6 ), characterized in that in order to adjust the speed of the reproduction of the digital audio signal ( 6 ) to a predeterminable tempo value, first the digital audio signal ( 6 ) in bars ( 7 . 8th ) and then that the playback speed of the digital audio signal ( 6 ) is selected such that the resulting playback duration of a clock ( 7 . 8th ) of the digital audio signal equal to the duration of a clock resulting from the tempo value ( 2 . 3 . 4 . 5 ). Computer program according to claim 11, characterized in that the digital audio signal ( 6 ) is repeated cyclically. Computer program according to claim 11 or 12, characterized in that the subdivision of the digital audio signal ( 6 ) in cycles according to the following method steps a) calculation of the estimated playback time of the entire digital audio signal ( 6 b) determining a cycle number value by comparing the estimated reproduction time with typical time values taking into account the tempo value, c) subdividing the digital audio signal into a number of cycles corresponding to the determined cycle number value ( 7 . 8th ). Computer program according to claim 13, characterized that in The computer's datastore stores a table of typical time values is, to each of which clock number values are assigned. Computer program according to one of Claims 11 to 14, characterized in that the subdivision of the digital audio signal ( 6 ) is performed in cycles by periodically occurring signal peaks are found in the digital audio signal. Computer program according to one of claims 11 to 15, characterized in that in the data memory of the computer a plurality of digital audio signals ( 6 ) is stored in the form of an electronic library, such that the user side one or more of the stored digital audio signals ( 6 ) are selectable for playback. Computer program according to one of Claims 11 to 16, characterized in that the digital audio signal ( 6 ) is subjected to a tonal filtering. Computer program according to one of Claims 11 to 17, characterized in that the digital audio signal ( 6 ) according to the division into bars ( 7 . 8th ) automatically into sound signal subsections ( 9 ), such that each audio signal subsection ( 9 ) is reproduced individually. Computer program according to one of claims 11 to 18, characterized in that it as independent Module with a data interface to one for playing a piece of music using electronic sound generating means further computer program is formed.