Abstract: The apparatus for converting an information signal from a time to a variable spectral representation includes a means for windowing the information signal, a means for converting the windowed information signal to a spectral representation, and a means for weighting a set of information signal spectral coefficients with several sets of complex base function coefficients provided from a means for providing the sets of base function coefficients. The sets of base function coefficients are derived from base functions of various frequencies by windowing and transform, wherein several sets of base function coefficients are provided for one and the same base function for base functions of higher frequencies, wherein the windows for providing these sets are related to various time portions of the base function. The variable spectral representation exhibits variable bandwidth of the variable spectral coefficients, which are efficient and accurate to calculate and especially suited for music analysis purposes.

Abstract: An apparatus for determining a type of chord has a means for providing a reference vector for the type of chord, a means for providing a reference vector from a test signal, and a means for comparing the reference vector with the test signal vector. The means for providing a reference vector is configured to provide, for the type of chord, a reference vector from a plurality of different reference vectors. In addition, the means for providing a test signal vector from the test signal is configured to provide the test signal vector having a plurality of test signal vector elements.

Abstract: The apparatus for converting an information signal from a time to a variable spectral representation includes a means for windowing the information signal, a means for converting the windowed information signal to a spectral representation, and a means for weighting a set of information signal spectral coefficients with several sets of complex base function coefficients provided from a means for providing the sets of base function coefficients. The sets of base function coefficients are derived from base functions of various frequencies by windowing and transform, wherein several sets of base function coefficients are provided for one and the same base function for base functions of higher frequencies, wherein the windows for providing these sets are related to various time portions of the base function. The variable spectral representation exhibits variable bandwidth of the variable spectral coefficients, which are efficient and accurate to calculate and especially suited for music analysis purposes.

Abstract: An apparatus for determining a type of chord has a means for providing a reference vector for the type of chord, a means for providing a reference vector from a test signal, and a means for comparing the reference vector with the test signal vector. The means for providing a reference vector is configured to provide, for the type of chord, a reference vector from a plurality of different reference vectors. In addition, the means for providing a test signal vector from the test signal is configured to provide the test signal vector having a plurality of test signal vector elements.

Abstract: In order to implement the melody extraction or the automatic clearly more stable or to improve the transcription result, respectively, at the resulting segments or trajectories, respectively, of a melody line gained from a spectrogram of the audio signal a harmony mapping is performed such that a follower segment directly neighboring a reference segment in time direction is virtually shifted in the frequency direction by stages of octave, fifth and/or third in order to examine whether among the resulting lines of the octave, fifth and/or third there is one that fulfills a predetermined condition, like e.g. that the time/spectral representation along this line comprises a minimum which is larger by a certain factor than a minimum that it comprises along the reference segment line, and, if such a line exists, selects the same and actually performs the shifting of the follower segment. This way, errors in melody line determination may be corrected again.

Abstract: The finding of the present invention is that the melody extraction or automatic transcription may be implemented clearly more stable and if applicable even less expensive when the assumption is considered sufficiently that the main melody is the portion of a piece of music which man perceives the loudest and the most precise. Regarding this, according to the present invention the time/spectral representation or the spectrogram of an interesting audio signal is scaled using the curves of equal volume reflecting human volume perception in order to determine the melody of the audio signal on the basis of the resulting perception-related time/spectral representation.

Abstract: A tone smoothing is performed such that to each time section of a melody line segment a number is associated such that for all groups of directly neighboring time sections, to which the same spectral component is associated by the melody line segment, the numbers associated with the directly neighboring time sections are different numbers from one to the number of the directly neighboring time sections, for each spectral component that is associated with one of the time sections of the melody line segment, the numbers of those groups are added up to which time sections of the same the respective spectral component is associated by the melody line segment, a smoothing spectral component is determined as the spectral component for which the greatest summing-up results, and the melody line segment is changed, by associating the determined smoothing spectral component to each time section of the melody line segment.