Method and apparatus for manipulating an input signal to form an output signal having a different length

• US 5,611,002 A
• Filed: 08/03/1992
• Issued: 03/11/1997
• Est. Priority Date: 08/09/1991
• Status: Expired due to Term

• Current Assignee: Nuance Communications, Inc. (Microsoft Corporation)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Vogten, Leonardus L. M., Verhelst, Werner D. E., Eggen, Josephus H., Ma, Chang X.
• Primary Examiner(s): Hafiz, Tariq R.
• Application Number:
  US07/924,726
• Time in Patent Office: 1,681 Days
• Field of Search: 381/36-53, 395/2, 395/2.1-2.87
• US Class Current: 704/267
• CPC Class Codes: G10L 21/04 Time compression or expansion

Abstract

A method and an apparatus for manipulating an input signal (e.g., an audio equivalent signal) having a specific length to form an output signal having a different length. A chain of successive overlapping time windows is positioned with respect to the input signal; segment signals are derived from the input signal and the segment signals; and the output signal is synthesized by chained superposition of a sequence of the segment signals. Each of the windows (except for the first window in the chain) is positioned by incrementing a position of the window from a corresponding position of a preceding window in the chain by a time interval. That time interval is substantially equal to a principal period of periodicity of a portion of the input signal with respect to which the window will be positioned. The sequence of segment signals is derived from the segment signals by performing at least one of repeating and suppressing one or more of the segment signals.

Claims

1. A method for manipulating an input signal having a specific length to form an output signal, said method comprising:

positioning a chain of successive overlapping time windows with respect to the input signal, each of the windows, except for the first window in the chain, being positioned with respect to the input signal by incrementing a position of the window from a corresponding position of a preceding window in the chain positioned with respect to the input signal by a time interval which is substantially equal to a principal period of periodicity of a portion of the input signal with respect to which the window will be positioned, said incrementing thereby determining where the window is positioned with respect to the input signal;

deriving segment signals from the input signal and the windows, each of the segment signals being derived by weighting the input signal as a function of position in a corresponding one of the windows; and

synthesizing the output signal so that it has a predetermined length which differs from the specific length of the input signal by chained superposition of a sequence of the segment signals, the sequence being derived from the segment signals by performing at least one of repeating and suppressing one or more of the segment signals.

2. The method as claimed in claim 1, wherein the input signal is an audio equivalent signal.

3. The method as claimed in claim 1, wherein the predetermined length is equal to a length of an intermission between two non-manipulated signals.

4. The method as claimed in claim 1, wherein the input signal is an audio equivalent signal, the predetermined length is equal to the length of a video signal relating to the audio equivalent signal, and the sequence is derived so that the output signal is synchronized with the video signal.

5. The method as claimed in claim 1, wherein the input signal is an audio equivalent signal, and the principal period of periodicity is a pitch period.

6. A unitary storage medium for storing the output signal formed by the method of claim 1.

7. A method of manipulating a plurality of input signals so as to form respective output signals therefrom having the same lengths, each respective output signal being formed by manipulating a different one of the input signals in accordance with the method of claim 1.

8. The method as claimed in claim 7, wherein the input signals are audio equivalent signals relating to the same matter but having different representations.

9. The method as claimed in claim 7, wherein the input signals are audio equivalent signals which each relate to the same matter but correspond to a different language.

10. A unitary storage medium for storing the output signal formed by the method of claim 7.

12. The apparatus as claimed in claim 1, wherein the input signal is an audio equivalent signal.

11. An apparatus for manipulating an input signal having a specific length to from an output signal, the apparatus comprising:

positioning means for positioning a chain of successive overlapping time windows with respect to the input signal;

incrementing means for determining a position with respect to the input signal with which each of the windows, except for the first window in the chain, is to be positioned by said positioning means by incrementing from a corresponding position of a preceding window in the chain positioned with respect to the input signal by a time interval which is substantially equal to a principal period of periodicity for a portion of the input signal with respect to which the window will be positioned;

segmenting means for deriving a plurality of segment signals from the input signal and the windows, each of the segment signals being derived by weighting the input signal as a function of position in a corresponding one of the windows; and

synthesizing means for synthesizing the output signal so that it has a predetermined length which differs from the specific length of the input signal by chained superposition of a sequence of the segment signals, the sequence being derived from the segment signals by performing at least one of repeating and suppressing one or more of the segment signals.

13. The apparatus as claimed in claim 11, wherein the predetermined length is equal to a length of an intermission between two non-manipulated signals.

14. The apparatus as claimed in claim 11, wherein the input signal is an audio equivalent signal, the predetermined length is equal to the length of a video signal relating to the audio equivalent signal, and the sequence is derived so that the output signal is synchronized with the video signal.

15. The apparatus as claimed in claim 11, wherein the input signal is an audio equivalent signal, and the principal period of periodicity is a pitch period.