Method and system for waveform compression and expansion with time axis

• US 7,010,491 B1
• Filed: 12/09/1999
• Issued: 03/07/2006
• Est. Priority Date: 12/09/1999
• Status: Expired due to Fees

• Current Assignee: Roland Corporation (Taiyo Pacific Partners LP)
• Original Assignee: Roland Corporation (Taiyo Pacific Partners LP)
• Inventors: Kikumoto, Tadao
• Primary Examiner(s): CHAWAN, VIJAY B
• Application Number:
  US09/456,665
• Time in Patent Office: 2,280 Days
• Field of Search: 704/503, 704/211, 704/229, 704/267, 704/278, 704/201, 84604-607, 846/12, 381/106, 381/107
• US Class Current: 704/503
• CPC Class Codes: G10L 21/04 Time compression or expansion

Abstract

With the goal of presenting a waveform compression and expansion apparatus with which the sound quality of such things as musical tones that are expressed by waveforms is satisfactory following the compression and expansion of the waveforms of the musical tones etc., a method and system for waveform compression and expansion is disclosed in which all of the multiple number of band divided waveforms that comprise the original waveform which has been band divided are apportioned to at least two kinds of compression and expansion formats and form a multiple number of compressed and expanded waveforms by compression or expansion an identical amount only in the direction of the temporal axis.

Claims

1. A method for generating a compressed or expanded waveform from original waveform data, said generated compressed or expanded waveform capable of being stored or reproduced, the method comprising the steps of:

frequency band-dividing the original waveform data to produce a plurality of frequency band-divided waveforms;

receiving position data including a plurality of time points indicating when waveform data is to be read out from the plurality of frequency band-divided waveforms, and position information elements indicating a particular location in the plurality of frequency band-divided waveforms corresponding to each time point;

generating at least one processed waveform from each frequency band-divided waveform according to the position data and at least one compression and expansion format; and

superimposing a plurality of processed waveforms generated from all frequency band-divided waveforms to form the compressed or expanded waveform;

wherein in accordance with a first compression and expansion format, the step of generating at least one processed waveform from each frequency band-divided waveform further includes the steps of;

receiving a plurality of opening and starting addresses, each opening and starting address designating a starting point of cycles that comprise the frequency band-divided waveform;

receiving a plurality of position information elements, each position information element designating a particular cycle and address of the frequency band-divided waveform corresponding to each time point;

reading out first waveform data from the frequency band-divided waveform of at least two repeated cycles starting at the opening and starting address associated with the cycle corresponding to every other time point, and waveshaping the first waveform data with an envelope to form a first processed waveform; and

reading out second waveform data from the frequency band-divided waveform of at least two repeated cycles starting at the opening and starting address associated with the cycle corresponding to every other time point that does not coincide with the reading out of the first waveform data, and waveshaping the second waveform data with the envelope to form a second processed waveform.

2. A method as recited in claim 1, further including the step of repetitively reading out cycles within the first and second waveform data when a first interval between addresses designated by the plurality of position information elements is less than a second interval between addresses in the plurality of opening and starting addresses.

3. A method as recited in claim 1, further including the step of jump reading out cycles within the first and second waveform data when a first interval between addresses designated by the plurality of position information elements is greater than a second interval between addresses in the plurality of opening and starting addresses.

4. A method for generating a compressed or expanded waveform from original waveform data, said generated compressed or expanded waveform of being stored or reproduced, the method comprising the steps of:

frequency band-dividing the original waveform data to produce a plurality of frequency band-divided waveforms;

receiving position data including a plurality of time points indicating when waveform data is to be read out from the plurality of frequency band-divided waveforms, and position information elements indicating a particular location in the plurality of frequency band-divided waveforms corresponding to each time point;

generating at least one processed waveform from each frequency band-divided waveform according to the position data and at least one compression and expansion format; and

superimposing a plurality of processed waveforms generated from all frequency band-divided waveforms to form the compressed or expanded waveform;

wherein the step of generating at least one processed waveform from each frequency band-divided waveform further includes the steps of;

receiving a plurality of position information elements, each position information element designating a different address of the frequency band-divided waveform corresponding to each time point;

receiving pitch data indicating a read-out speed of the waveform portions;

reading out successive first waveform portions from the frequency band-divided waveform at the read-out speed at every other time point, each first waveform portion comprising waveform data starting at the address of the position information element corresponding to the time point, the successive first waveform portions comprising first read-out waveform data;

reading out successive second waveform portions from the frequency band-divided waveform at the read-out speed at every other time point that does not coincide with the reading out of successive first waveform portions, each second waveform portion comprising waveform data starting at the address of the position information element corresponding to the time point, the successive second waveform portions comprising second read-out waveform data;

waveshaping the first read-out waveform data with an envelope to form a first processed waveform; and

waveshaping the second read-out waveform data with the envelope to form a second processed waveform.

5. A method as recited in claim 4, further including the step of repetitively reading out first and second waveform portions when each read-out start point associated with each position information element is earlier in time than the time point corresponding to the position information element.

6. A method as recited in claim 4, further including the step of jump reading out first and second waveform portions when each read-out start point associated with each position information element is later in time than the time point corresponding to the position information element.

7. A method for generating a compressed or expanded waveform from original waveform data, said generated compressed or expanded waveform capable of being stored or reproduced, the method comprising the steps of:

frequency band-dividing the original waveform data to produce a plurality of frequency band-divided waveforms;

receiving position data including a plurality of time points indicating when waveform data is to be read out from the plurality of frequency band-divided waveforms, and position information elements indicating a particular location in the plurality of frequency band-divided waveforms corresponding to each time point;

generating at least one processed waveform from each frequency band-divided waveform according to the position data and at least one compression and expansion format; and

superimposing a plurality of processed waveforms generated from all frequency band-divided waveforms to form the compressed or expanded waveform;

wherein the step of generating at least one processed waveform from each frequency band-divided waveform further includes the steps of;

receiving a plurality of mark addresses that designate a starting point at delimiting locations of waveform segments of the frequency band-divided waveform;

receiving a plurality of position information elements indicating a particular waveform segment of the frequency band-divided waveform corresponding to each time point;

receiving pitch data indicating a read-out speed of the waveform portions;

reading out portions of at least one waveform segment at the read-out speed at every time point of the frequency band-divided waveform, the portions of at least one waveform segment comprising waveform data starting at the mark address associated with the waveform segment corresponding to the time point and ending with a mark address corresponding to a subsequent time point; and

sequencing consecutive portions of at least one waveform segment to generate a processed waveform from the frequency band-divided waveform.

8. A method as recited in claim 7, further including the step of repetitively reading out portions of at least one waveform segment when a first interval between addresses designated by the plurality of position information elements is less than a second interval between addresses in the plurality of mark addresses.

9. A method as recited in claim 7, further including the step of jump reading out portions of at least one waveform segment when a first interval between addresses designated by the plurality of position information elements is greater than a second interval between addresses in the plurality of mark addresses.

10. The method of claim 7, wherein the delimiting location is a zero-crossing.

11. The method of claim 7, wherein the delimiting location is an energy peak.

12. A method for generating a compressed or expanded waveform from original waveform data, said generated compressed or expanded waveform capable of being stored or reproduced, the method comprising the steps of:

frequency band-dividing the original waveform data to produce a plurality of frequency band-divided waveforms;

receiving position data including a plurality of time points indicating when waveform data is to be read out from the plurality of frequency band-divided waveforms, and position information elements indicating a particular location in the plurality of frequency band-divided waveforms corresponding to each time point;

generating at least one processed waveform from each frequency band-divided waveform according to the position data and at least one compression and expansion format;

superimposing a plurality of processed waveforms generated from all frequency band-divided waveforms to form the compressed or expanded waveform; and

compressing or expanding each processed waveform by an identical amount of time;

wherein the step of frequency band-dividing the original waveform data further including the steps of;

sampling the original waveform data at a sampling frequency F_S; and

dividing the original waveform data into N frequency band-divided waveforms, wherein the Mth frequency band-divided waveform, where M is an integer varying from one to N, is sampled at a sampling frequency equal to F_S divided by 2<sup>(M−

1)</sup>, and has a frequency band ranging from Fs divided by 2^(M+1) to F_S divided by 2^(M).

13. A method as recited in claim 12, the step of superimposing a plurality of processed waveforms comprising the steps of:

filtering at least one of the N processed waveforms generated from the N frequency band-divided waveforms according to the frequency band of the frequency band-divided waveform associated with each processed waveform; and

summing the N processed waveforms to form the compressed or expanded waveforms.

14. A method as recited in claim 13, the step of frequency band-dividing the original waveform data further including the steps of:

dividing the original waveform data into three frequency band-divided waveforms;

generating at least one processed waveform from the first frequency band-divided waveform in accordance with a second compression and expansion format comprising the steps of

receiving a plurality of position information elements, each position information element designating a different address of the frequency band-divided waveform corresponding to each time point,

receiving pitch data indicating a read-out speed of the waveform portions,

reading out successive first waveform portions from the frequency band-divided waveform at the read-out speed at every other time point, each first waveform portion comprising waveform data starting at the address of the position information element corresponding to the time point, the successive first waveform portions comprising first read-out waveform data,

reading out successive second waveform portions from the frequency band-divided waveform at the read-out speed at every other time point that does not coincide with the reading out of successive first waveform portions, each second waveform portion comprising waveform data starting at the address of the position information element corresponding to the time point, the successive second waveform portions comprising second read-out waveform data, waveshaping the first read-out waveform data with an envelope to form a first processed waveform, and

waveshaping the second read-out waveform data with the envelope to form a second processed waveform; and

generating at least one processed waveform from the second and third frequency band-divided waveforms in accordance with a third compression and expansion format comprising the steps of

receiving a plurality of mark addresses that designate a starting point at zero-crossings of waveform segments of the frequency band-divided waveform,

receiving a plurality of position information elements indicating a particular waveform segment of the frequency band-divided waveform corresponding to each time point,

receiving pitch data indicating a read-out speed of the waveform portions,

reading out portions of at least one waveform segment at the read-out speed at every time point of the frequency band-divided waveform, the portions of at least one waveform segment comprising waveform data starting at the mark address associated with the waveform segment corresponding to the time point, and

sequencing consecutive portions of at least one waveform segment to generate a processed waveform from the frequency band-divided waveform.

15. A method as recited in claim 14, the step of superimposing a plurality of processed waveforms further including the steps of:

sampling and low-pass filtering the processed waveform generated from the third frequency band-divided waveform according to the sampling frequency associated with the second frequency band-divided waveform and frequency band associated with the third frequency band-divided waveform to generate a third intermediate processed waveform;

summing the third intermediate processed waveform with the at least one processed waveform generated from the second frequency band-divided waveform to generate a second intermediate processed waveform;

sampling and low-pass filtering the second intermediate processed waveform according to the sampling frequency associated with the first frequency band-divided waveform and frequency band associated with the second and third frequency band-divided waveforms to generate a first intermediate processed waveform; and

summing the first intermediate processed waveform with the at least one processed waveform generated from the first frequency band-divided waveform to form the compressed or expanded waveform.

16. A method for generating a compressed or expanded waveform from original waveform data, said generated compressed or expanded waveform capable of being stored or reproduced, the method comprising the steps of:

frequency band-dividing the original waveform data to produce a plurality of frequency band-divided waveforms;

receiving position data including a plurality of time points indicating when waveform data is to be read out from the plurality of frequency band-divided waveforms, and position information elements indicating a particular location in the plurality of frequency band-divided waveforms corresponding to each time point;

generating at least one processed waveform from each frequency band-divided waveform according to the position data and at least one compression and expansion format; and

superimposing a plurality of processed waveforms generated from all frequency band-divided waveforms to form the compressed or expanded waveform;

wherein the step of frequency band-dividing the original waveform data further includes the steps of dividing the original waveform data into a plurality of frequency band-divided waveforms, each frequency band-divided waveform having a plurality of frequency band waveform components;

receiving a plurality of mark addresses that designate a starting point at delimiting locations of waveform segments of the frequency band-divided waveform;

receiving a plurality of position information elements indicating a particular waveform segment of the frequency band-divided waveform corresponding to each time point;

receiving pitch data indicating a read-out speed of the waveform portions;

reading out portions of at least one waveform segment at the read-out speed at every time point of the frequency band-divided waveform, the portions of at least one waveform segment comprising waveform data starting at the mark address associated with the waveform segment corresponding to the time point and ending with a mark address corresponding to a subsequent time point; and

sequencing consecutive portions of at least one waveform segment to generate a processed waveform from the frequency band-divided waveform; and

wherein the step of superimposing a plurality of processed waveforms comprising the steps of;

multiplying each processed waveform with a level-controllable time window;

filtering at least one of the plurality of processed waveforms generated from the plurality of frequency band-divided waveforms according to a frequency band of the frequency band-divided waveform associated with each processed waveform; and

summing the processed waveforms to form the compressed or expanded waveforms.

17. The method of claim 16, wherein the delimiting location is a zero-crossing.

18. The method of claim 16, wherein the delimiting location is an energy peak.

19. A method for generating a compressed or expanded waveform from original waveform data, said generated compressed or expanded waveform capable of being stored or reproduced, the method comprising the steps of:

frequency band-dividing the original waveform data to produce a plurality of frequency band-divided waveforms;

receiving position data including a plurality of time points indicating when waveform data is to be read out from the plurality of frequency band-divided waveforms, and position information elements indicating a particular location in the plurality of frequency band-divided waveforms corresponding to each time point;

generating at least one processed waveform from each frequency band-divided waveform according to the position data and at least one compression and expansion format; and

superimposing a plurality of processed waveforms generated from all frequency band-divided waveforms to form the compressed or expanded waveform;

wherein the step of frequency band-dividing the original waveform data further includes the steps of dividing the original waveform data into a plurality of frequency band-divided waveforms, each frequency band-divided waveform having a plurality of frequency band waveform components, the step of frequency band-dividing the original waveform data further including the steps of;

dividing the original waveform data into three frequency band-divided waveforms;

generating at least one processed waveform from the first and second frequency band-divided waveforms in accordance with a compression and expansion format comprising the steps of

receiving a plurality of mark addresses that designate a starting point at zero-crossings of waveform segments of the frequency band-divided waveform,

receiving a plurality of position information elements indicating a particular waveform segment of the frequency band-divided waveform corresponding to each time point,

receiving pitch data indicating a read-out speed of the waveform portions, reading out portions of at least one waveform segment at the read-out speed at every time point of the frequency band-divided waveform, the portions of at least one waveform segment comprising waveform data starting at the mark address associated with the waveform segment corresponding to the time point, and

sequencing consecutive portions of at least one waveform segment to generate a processed waveform from the frequency band-divided waveform; and

generating at least one processed waveform from the third frequency band-divided waveform in accordance with a compression and expansion format comprising the steps of

receiving a plurality of opening and starting addresses, each opening and starting address designating a starting point of cycles that comprise the frequency band-divided waveform,

receiving a plurality of position information elements, each position information element designating a particular cycle and address of the frequency band-divided waveform corresponding to each time point,

reading out first waveform data from the frequency band-divided waveform of at least two repeated cycles starting at the opening and starting address associated with the cycle corresponding to every other time point, and waveshaping the first waveform data with an envelope to form a first processed waveform, and

reading out second waveform data from the frequency band-divided waveform of at least two repeated cycles starting at the opening and starting address associated with the cycle corresponding to every other time point that does not coincide with the reading out of the first waveform data, and waveshaping the second waveform data with the envelope to form a second processed waveform,

wherein the step of superimposing a plurality of processed waveforms comprising the steps of;

multiplying each processed waveform with a level-controllable time window;

filtering at least one of the plurality of processed waveforms generated from the plurality of frequency band-divided waveforms according to a frequency band of the frequency band-divided waveform associated with each processed waveform; and

summing the processed waveforms to form the compressed or expanded waveforms.

20. A method as recited in claim 19, the step of superimposing a plurality of processed waveforms further including the steps of:

sampling and low-pass filtering the processed waveform generated from the third frequency band-divided waveform according to the sampling frequency associated with the second frequency band-divided waveform and frequency band associated with the third frequency band-divided waveform to generate a third intermediate processed waveform;

summing the third intermediate processed waveform with the at least one processed waveform generated from the second frequency band-divided waveform to generate a second intermediate processed waveform;

sampling and low-pass filtering the second intermediate processed waveform according to the sampling frequency associated with the first frequency band-divided waveform and frequency band associated with the second and third frequency band-divided waveforms to generate a first intermediate processed waveform; and

summing the first intermediate processed waveform with the at least one processed waveform generated from the first frequency band-divided waveform to form the compressed or expanded waveform.

21. A method as recited in claim 20, the step of superimposing a plurality of processed waveforms further including the step of establishing the time windows to produce cross-fading.

22. A waveform compression apparatus for compressing a plurality of frequency band-divided waveforms generated from an original waveform, each of the plurality of frequency band-divided waveforms comprising waveform components of a corresponding frequency band of a plurality of frequency bands, the apparatus comprising:

compression means with which each of the plurality of frequency band-divided waveforms is apportioned to a corresponding one of at least two different kinds of compression formats during compression, and each of the plurality of frequency band-divided waveforms is compressed in accordance with the corresponding compression format in a direction of a temporal axis to provide a corresponding compressed frequency band-divided waveform; and

a superimposing means in which, by superimposing the plurality of compressed frequency band-divided waveforms, a resultant waveform that corresponds to the original waveform that has been compressed in the direction of the temporal axis is formed;

wherein said resultant waveform is capable of being stored or reproduced.

23. An apparatus as recited in claim 22,

wherein each of the plurality of frequency band-divided waveform is generated from the original waveform by sampling the original waveform with a corresponding sampling frequency;

and

wherein the compression means executes compression processing for each frequency band-divided waveform of the plurality of frequency band-divided waveforms with a corresponding processing period that is based on the corresponding sampling frequency at which the original waveform was sampled to generate the frequency band-divided waveform.

24. The apparatus as recited in claim 22,

wherein the compression means is configured to compress each of the plurality of frequency band-divided waveforms by an identical amount.

25. A waveform compression apparatus for compressing a plurality of temporally divided waveforms, comprising:

a processing format specification means in which a corresponding compression processing format of a plurality of compression processing formats is specified for each of the plurality of temporally divided waveforms during compression, said plurality of compression processing formats including at least two different compression processing formats, each of the at least two different compression processing formats for compressing waveforms; and

a compression means in which compression processing is performed on each temporally divided waveform of the plurality of temporally divided waveforms to compress the temporally divided waveform in a direction of a temporal axis according to the specified corresponding compression processing format to provide a corresponding resultant temporally divided waveform that is capable of being stored or reproduced.

26. A waveform expansion apparatus for expanding a plurality of frequency band-divided waveforms generated from an original waveform, each of the plurality of frequency band-divided waveforms comprising waveform components of a corresponding frequency band of a plurality of frequency bands, the apparatus comprising:

expansion means with which each of the plurality of frequency band-divided waveforms is apportioned to a corresponding one of at least two different kinds of expansion formats during expansion, and each of the plurality of frequency band-divided waveforms is expanded in accordance with the corresponding expansion format in a direction of a temporal axis to provide a corresponding expanded frequency band-divided waveform; and

a superimposing means in which, by superimposing the plurality of expanded frequency band-divided waveforms, a resultant waveform that corresponds to the original waveform that has been expanded in the direction of the temporal axis is formed;

wherein said resultant waveform is capable of being stored or reproduced.

27. The apparatus as recited in claim 26,

wherein each of the plurality of frequency band-divided waveforms is generated from the original waveform by sampling the original waveform with a corresponding sampling frequency;

and

wherein the expansion means executes expansion processing for each frequency band-divided waveform of the plurality of frequency band-divided waveforms with a corresponding processing period that is based on the corresponding sampling frequency at which the original waveform was sampled to generate the frequency band-divided waveform.

28. The apparatus as recited in claim 26,

wherein the expansion means is configured to expand each of the plurality of frequency band-divided waveforms by an identical amount.

29. A waveform expansion apparatus for expanding a plurality of temporally divided waveforms, comprising:

a processing format specification means in which a corresponding expansion processing format of a plurality of expansion processing formats is specified for each of the plurality of temporally divided waveforms during expansion, said plurality of expansion processing formats including at least two different expansion processing formats, each of the at least two different expansion processing formats for expanding waveforms; and

an expansion means in which expansion processing is performed on each temporally divided waveform of the plurality of temporally divided waveforms to expand the temporally divided waveform in a direction of a temporal axis according to the specified corresponding expansion processing format to provide a corresponding resultant temporally divided waveform that is capable of being stored or reproduced.