System for and method of determining the period of recurring events within a recorded signal

• US 7,254,455 B2
• Filed: 04/13/2001
• Issued: 08/07/2007
• Est. Priority Date: 04/13/2001
• Status: Expired due to Term

• Current Assignee: SP Software Acquisition Company
• Original Assignee: Sony Creative Software Incorporated (Sony Group Corp.)
• Inventors: Moulios, Christopher J.
• Primary Examiner(s): Tran; Sinh
• Assistant Examiner(s): Sellers; Daniel R.
• Application Number:
  US09/835,253
• Publication Number:
  US 20030014135A1
• Time in Patent Office: 2,307 Days
• Field of Search: 700/94, 844/84, 715/716
• US Class Current: 700/94
• CPC Class Codes: G10H 1/40 Rhythm
• CPC Class Codes: G10H 2220/086 Beats per minute [BPM] indicator, i.e. displaying a tempo value, e.g. in words or as numerical value in beats per minute
• CPC Class Codes: G10H 2230/015 PDA [personal digital assistant] or palmtop computing devices used for musical purposes, e.g. portable music players, tablet computers, e-readers or smart phones in which mobile telephony functions need not be used
• CPC Class Codes: G11B 27/034 on discs G11B27/036, G11B27/038 take precedence
• CPC Class Codes: G11B 27/10 Indexing; Addressing; Timing or synchronising; Measuring tape travel
• CPC Class Codes: G11B 27/28 by using information signals recorded by the same method as the main recording G11B27/22 takes precedence
• CPC Class Codes: G11B 27/34 Indicating arrangements indicating means incorporated in magazine or cassette G11B23/046 and G11B23/0875; indicating measured values in general G01D

Abstract

The disclosure relates to a method of determining one or more periods of recurring events within a recorded signal, such as, music. This method can include establishing one or more anchor points in the recorded signal where an anchor point is indicative of a beginning point for a period of recurring events in the recorded signal, determining a length for the period of recurring events in the recorded signal where the length starts from the established anchor point and defines a first loop, and refining the length for the period of recurring events by comparing the first loop with subsequent loops. The subsequent loops have the length of the first loop.

Claims

1. A method, comprising:

determining a period of recurring events within a recorded signal, the period of recurring events providing a measurement of a tempo of the recorded signal, said determining comprising;

establishing an anchor point in the recorded signal, the anchor point being indicative of a beginning point for a period of recurring events in the recorded signal;

determining a length for the period of recurring events in the recorded signal by digitally comparing a first portion of the recorded signal starting from the established anchor point with at least one different portion of the recorded signal subsequent to the anchor point, said at least one different portion extrapolated from the first portion; and

refining the length for the period of recurring events by digitally comparing a pattern included by the first portion with patterns included by said at least one different portion subsequent to the anchor point, each subsequent portion having the length of the first portion;

associating the tempo with the recorded signal; and

using the tempo to process the recorded signal with a second recorded signal.

2. The method of claim 1, further comprising determining if the recorded signal is rhythmic.

3. The method of claim 1, wherein establishing an anchor point in the recorded signal comprises

utilizing digital signal processing techniques, including pattern matching and slope detection techniques, to identify where recurring events begin.

4. The method of claim 1, wherein establishing an anchor point in the recorded signal comprises

receiving an indication of a location on the recorded signal from a computer input device.

5. The method of claim 1, wherein determining a length for the period of recurring events in the recorded signal comprises

utilizing digital signal processing techniques.

6. The method of claim 1, wherein determining a length for the period of recurring events in the recorded signal comprises receiving an indication of a length of the period on the recorded signal from a computer input device.

7. The method of claim 1, wherein refining the length for the period of recurring events comprises

utilizing digital signal processing techniques.

8. The method of claim 1, wherein refining the length for the period of recurring events comprises using the distance between multiple anchor points as a guide to estimate an approximate count of time periods from which a tempo can be derived.

9. In a computer system comprising:

means for establishing an anchor point in a recorded signal, the anchor point being indicative of a beginning point for a period of recurring events in the recorded signal;

means for determining a length for the period of recurring events in the recorded signal, the length determined by digital comparison of a portion of the recorded signal starting from the established anchor point with at least one different portion of the recorded signal subsequent to the anchor point, said at least one different portion extrapolated from the first portion;

means for refining the length for the period of recurring events by digitally comparing a pattern included by the first portion with patterns included by said at least one different portion subsequent to the anchor point, each subsequent portion having the length of the first portion;

wherein the period of recurring events provides a measurement of a tempo of the recorded signal;

means for associating the tempo with the recorded signal; and

means for using the tempo to process the recorded signal with a second recorded signal.

10. The system of claim 9, further comprising means for adjusting the length for the period of recurring events.

11. The system of claim 9, wherein the means of establishing the anchor point in the recorded signal comprises means for identifying where recurring events begin.

12. The system of claim 9, wherein the means of establishing the anchor point in the recorded signal comprises means for receiving an indication of a location on the recorded signal from a computer input device.

13. The system of claim 9, further comprising means for combining said recorded signal having said tempo with another recorded signal of an unknown tempo.

14. The system of claim 9, further comprising

means for presenting the recorded signal and portions in the recorded signal, including a graphical user interface.

15. A processing system comprising:

a central processing unit; and

a storage device coupled to said central processing unit and having stored there information for configuring the central processing unit to determine a period of recurring events in a recorded signal, the period of recurring events providing a measurement of a tempo of the recorded signal, wherein the determining comprises;

establishing a loop starting point in the recorded signal, the loop starting point being indicative of a beginning point for a period of recurring events in the recorded signal, the period of recurring events defining a loop;

determining a length for the loop in the recorded signal by digitally comparing a first loop of the recorded signal starting from the established loop starting point with at least one different loop of the recorded signal subsequent to the loop starting point, said at least one different loop extrapolated from the first loop;

adjusting the length of the loop by digitally comparing a pattern included by the first loop with patterns included by said at least one different loop subsequent to the loop starting point, each subsequent loop being defined as a portion of the recorded signal having the length of the first loop and starting at a point in the recorded signal later in time;

associate the tempo with the recorded signal; and

use the tern o to process the recorded signal with a second recorded signal.

16. The system of claim 15, further comprising

a presentation device, wherein the presentation device is configured to provide a graphical user interface which presents portions of the recorded signal.

17. The system of claim 15, further comprising

an interface device configured to connect the central processing unit with a network of computers.

18. A method comprising the acts of:

displaying a graphical representation of a recorded audio signal;

establishing an anchor point in the audio signal, wherein the anchor point identifies where a rhythmic pattern in the audio signal appears to begin;

identifying a first period during which the rhythmic pattern in the audio signal appears to occur, the first period beginning at the anchor point and ending at a repeating point;

identifying a second period during which the rhythmic pattern in the audio signal appears to occur, the second period beginning at the repeating point,

wherein identifying the second period includes a digital comparison of a portion of the audio signal from the first period with a portion of the audio signal starting at the repeating point;

adjusting the rhythmic pattern such that a duration of the first period is substantially the same as a duration of the second period, the durations establishing tempo information for the audio signal;

associating the tempo information with the recorded audio signal; and

using the tempo information to process the recorded audio signal with a second recorded audio signal.