Data processing: speech signal processing – linguistics – language – Speech signal processing – Synthesis
Reexamination Certificate
1999-07-28
2004-02-03
Dorvil, Richemond (Department: 2654)
Data processing: speech signal processing, linguistics, language
Speech signal processing
Synthesis
C084S604000
Reexamination Certificate
active
06687674
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to devices and methods for forming a waveform of a musical tone, voice or other sound on the basis of waveform data read out from a memory, and more particularly to a waveform forming device and method using loop waveforms read out repeatedly. It will be appreciated that the basic principles of the present invention can be applied extensively to every type of equipment, apparatus and methods having the function of generating musical tones, voices or any other sounds, such as automatic musical performance devices, computers, electronic game devices and multimedia-related devices, not to mention electronic musical instruments. Also, let it be assumed that the terms “tone waveform” in this specification are not necessarily limited to a waveform of a musical tone alone but are used in a much broader sense that may embrace a waveform of a voice or any other type of sound.
The so-called “waveform memory readout” technique has already been well known, which prestores waveform data (i.e., waveform sample data) coded in a given coding scheme, such as the PCM (Pulse Code Modulation), DPCM (Differential Pulse Code Modulation) or ADPCM (Adaptive Differential Pulse Code Modulation), and then reads out the thus-prestored waveform data at a rate corresponding to a desired tone pitch to thereby form a tone waveform. So far, various types of “waveform memory readout” technique have been proposed and known in the art, most of which are directed to forming a waveform covering from the start to end of a tone. As one specific example of the waveform memory readout” technique, there has been known prestoring waveform data of a complete waveform of a tone covering from the start to end thereof. As another example, there has been known an approach of prestoring waveform data of a complete waveform for an attack portion of a tone presenting relatively complex variations and prestoring a predetermined loop waveform for a sustain portion presenting not many variations (e.g., Japanese Patent Laid-open Publication No. SHO-59-l 88697). In the latter approach, the arrangement of storing the loop waveform for the sustain portion can significantly reduce the quantity of the waveform data to be stored, and also the arrangement of repeatedly reading out the stored loop waveform can effectively adjust the sustained time of the tone as desired. In this specification, the terms “loop waveform” are used to refer to a waveform to be read out repeatedly, i.e., in a looped fashion, and the terms “loop-reproduced waveform” are used to refer to a waveform obtained (reproduced) by reading out the loop waveform repeatedly or in a looped fashion.
Also known in the art is a technique using a plurality of loop waveforms to generate a single tone, where the loop waveforms are read out one after another in given sequence and the resultant loop-read-out data of the successive loop waveforms (i.e., loop-reproduced waveforms) are then subjected to cross-fade synthesis for smooth connection between the individual loop-reproduced waveforms (e.g., Japanese Patent Laid-open Publication No. SHO-62-14696). In this case, the cross-fade synthesis is effected in predetermined cross-fading sections; however, unlike the above-discussed technique of repeatedly reading out just a single simple loop waveform, this technique is not arranged to variably adjust the time lengths of the individual cross-fading sections. Further, in this case, it is absolutely necessary that the waveforms to be subjected to the cross-fade synthesis should be in phase with each other (or at least not greatly phase-shifted with each other) and thus the loop waveform data previously matched in phase should be prestored in memory.
However, the conventionally-known tone waveform forming techniques using the loop waveforms are not satisfactory in that, for the purpose of synthesis or connection between the loop waveforms, they would require burdensome operations of prestoring, in the memory, the waveform data having been previously matched in phase. This means that the conventional technique are unable to smoothly synthesize or connect the loop waveforms that have not been matched in phase with each other, and therefore it was not possible, in the past, to freely edit waveforms and create desired sounds by freely combining together desired loop waveforms. Further, although the conventional tone waveform forming techniques using the loop waveforms can suitably reduce the quantity of waveform data to be stored, they are not suitable for use in forming tone waveforms rich in expression and are also irrelevant to formation of tone waveforms taking “articulation” (style of performance or rendition) of sounds into account. Besides, the conventional tone waveform forming techniques using the loop waveforms are only capable of looping in a preset manner and thus lacks controllability and editability.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a device and method for forming a tone waveform using loop waveforms which can smoothly combine (synthesize or connect) the loop waveforms in a simplified manner without a need for prestoring waveform data having been previously matched in phase.
It is another object of the present invention to provide a waveform forming device and method which permit free waveform editing and sound making by freely combining desired loop waveforms.
It is still another object of the present invention to provide a waveform forming device and method which are rich in controllability and editability.
According to a first aspect of the present invention, there is provided a waveform forming device which comprises: a storage section for storing waveform data of a plurality of loop waveforms to be read out repeatedly and also storing phase management information in corresponding relation to the loop waveforms; and a waveform forming section for forming a waveform of at least part of a sound, by selecting at least two of the loop waveforms stored in the storage section, repeatedly reading out the waveform data of the selected loop waveforms to thereby form loop-reproduced waveforms corresponding to the selected loop waveforms and combining together the loop-reproduced waveforms. The waveform forming section performs phase adjustment between the loop-reproduced waveforms to be combined together, using the phase management information corresponding to the selected loop waveforms.
In the present invention, the storage section stores not only waveform data of a plurality of loop waveforms but also phase management information corresponding to the loop waveforms, so that the loop waveforms can be smoothly combined (connected or synthesized) with each other in a simplified manner without a need for prestoring the waveform data in a previously-phase-matched condition. Further, even when the loop waveforms to be combined together are shifted from each other in phase (particularly, in the phase of their start points), their different phases can be controlled to coincide with each other by performing phase adjustment between the loop-reproduced waveforms, to be combined together, with reference to the respective phase management information. As a consequence, free waveform editing and sound making are permitted by freely combining any desired ones of the loop waveforms. In addition, the present invention can significantly reduce the burden involved in the waveform formation, because it can eliminate the need for prestoring in memory the waveform data having been previously matched in phase.
In one implementation, each of the phase management information includes information that is indicative of a phase of the start point or end point of the loop waveform corresponding thereto. When the loop-reproduced waveforms are to be combined through cross-fade synthesis, the loop-reproduced waveforms can be appropriately matched in phase with each other, using the information indicative of the respective start points of the loop waveforms. When the loop-reproduced waveforms
Sakama Masao
Suzuki Hideo
Yasuyuki Umeyama
Azad Abul K.
Dorvil Richemond
Morrison & Foerster / LLP
Yamaha Corporation
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