Audio signal analysing method and apparatus
AssigneeKoninklijke Philips Electronics N.V.
InventorsChristopher Thorne, Richard Cole
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Abstract
A method for determining the key of an audio signal such as a music track. Portions (106) of the audio signal are analysed (104) to identify (108) a musical note and its associated strength (110) within each portion. Some notes identified in a portion may be ignored (118) to enable notes related to the key to be more readily distinguished. A first note is then determined (124) from the identified musical notes as a function of their respective strengths. From the identified musical notes, at least two further notes are selected (128) as a function of the first note. The key of the audio signal is then determined (130) based on a comparison of the respective strengths of the selected notes.
Claims29
A method for determining the key of an audio signal, the method comprising the steps of:
- for each of a plurality of signal portions, analysing the portion to identify [p v1]a musical note, and where at least one musical note is identified:
- determining a strength associated with the or each musical note;
- and
- generating a data record containing the identity of the or each musical note, the strength associated with the or each musical note and the identity of the portion;
- for each of the data records, ignoring the strength associated with an identified musical note where said strength is less than a predetermined fraction of the maximum strength associated with any identified musical note contained within the data records;
- determining a first note from the identified musical notes as a function of their respective strengths;
- selecting at least a second and a third note from the identified musical notes as a function of the first note;
- and
- determining the key based on a comparison of the respective strengths of the at least second and third notes.
An apparatus for determining the key of an audio signal, the apparatus comprising:
- an input device operable to receive a signal;
- a data processing apparatus operable to:
- for each of a plurality of signal portions, analyse the portion to identify [p v2]a musical note, and where at least one musical note is identified:
- determine a strength associated with the or each musical note;
- and
- generate a data record containing the identity of the or each musical note, the strength associated with the or each musical note and the identity of the portion;
- for each of the data records, ignore the strength associated with an identified musical note where said strength is less than a predetermined fraction of the maximum strength associated with any identified musical note contained within the data records;
- determine a first note from the identified musical notes as a function of their respective strengths;
- select at least a second and a third note from the identified musical notes as a function of the first note;
- and
- determine the key based on a comparison of the respective strengths of the at least second and third notes.
A method for determining the key of an audio signal substantially as hereinbefore described and with reference to the accompanying drawings.
An apparatus for determining the key of an audio signal substantially as hereinbefore described and with reference to the accompanying drawings.
Dependencies are inferred from the claim text.