JPH0787384B2 - Music signal compression method - Google Patents
Music signal compression methodInfo
- Publication number
- JPH0787384B2 JPH0787384B2 JP1024976A JP2497689A JPH0787384B2 JP H0787384 B2 JPH0787384 B2 JP H0787384B2 JP 1024976 A JP1024976 A JP 1024976A JP 2497689 A JP2497689 A JP 2497689A JP H0787384 B2 JPH0787384 B2 JP H0787384B2
- Authority
- JP
- Japan
- Prior art keywords
- samples
- sample
- music signal
- encoded
- compression method
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title claims description 16
- 230000006835 compression Effects 0.000 title claims description 12
- 238000007906 compression Methods 0.000 title claims description 12
- 238000010586 diagram Methods 0.000 description 8
- 230000005540 biological transmission Effects 0.000 description 3
- 230000006866 deterioration Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000013139 quantization Methods 0.000 description 2
- 230000005236 sound signal Effects 0.000 description 1
Landscapes
- Electrophonic Musical Instruments (AREA)
- Compression, Expansion, Code Conversion, And Decoders (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、A/D変換された音声信号のサンプル系列を直
線近似する音楽信号圧縮方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a music signal compression method for linearly approximating a sample sequence of an A / D converted audio signal.
従来の技術 従来の音声符号化方式においては、音声信号は複数の帯
域に分割され、各々について予測係数が求められ、この
予測係数を用いて、各々の帯域の信号は予測符号化され
る。その際に量子化レベル数を時間的に不均一に割り当
て、符号化前後の量子化誤差が小さくなるようにする。
（例えば、特願昭54−42858号参照）。2. Description of the Related Art In the conventional speech coding system, a speech signal is divided into a plurality of bands, a prediction coefficient is obtained for each band, and signals in each band are predictively coded using this prediction coefficient. At this time, the number of quantization levels is non-uniformly assigned in time so that the quantization error before and after encoding is reduced.
(For example, see Japanese Patent Application No. 54-42858).
発明が解決しようとする課題 従来の音声符号化方法では、分割された各周波数帯域に
ついて予測残差信号を送っており、この予測残差信号の
情報量が比較的多く、全体としての伝送情報量が多くな
るという問題点があった。DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the conventional speech coding method, a prediction residual signal is transmitted for each divided frequency band, and the information amount of this prediction residual signal is relatively large, and the transmission information amount as a whole is large. There was a problem that there were many.
本発明は、少ない伝送情報量で品質がよい音楽信号圧縮
方法を提供することを目的としている。It is an object of the present invention to provide a music signal compression method with a small amount of transmitted information and high quality.
課題を解決するための手段 上記目的を達成するために、本発明の音楽信号圧縮方法
は、A/D変換された音楽信号のサンプル系列を直線近似
するもので、最初の３サンプルを近似する直線を最小２
乗法を用いて求め、最小２乗誤差があらかじめ定めてお
いたしきい値を超えていなければ、サンプル数を１個ず
つ増やしながら、逐次最小２乗誤差を算出し、最小２乗
誤差がしきい値を超えたとすれば、しきい値を超えるま
でのサンプルを近似する直線を定める係数２個と、直線
近似されたサンプル個数を符号化することとし、次の３
サンプルから新たな直線近似を行うようにする。最初の
３サンプルの直線近似の最小２乗誤差がしきい値を超え
てしまった場合は、最初の２サンプルの値と２サンプル
が直線近似されていないことのフラグを符号化すること
とし、３個目のサンプルから新たな直線近似を行うよう
にする。Means for Solving the Problems In order to achieve the above object, the music signal compression method of the present invention linearly approximates a sample sequence of an A / D converted music signal, and a straight line approximating the first three samples. A minimum of 2
If the least-squares error does not exceed a predetermined threshold value by using the multiplicative method, the least-squares error is calculated by sequentially increasing the number of samples one by one. If it exceeds, the two coefficients that determine the straight line that approximates the samples until the threshold is exceeded and the number of samples that are linearly approximated are coded.
Perform a new linear approximation from the sample. If the least squares error of the linear approximation of the first three samples exceeds the threshold value, the value of the first two samples and the flag indicating that the two samples are not linearly approximated are coded. A new linear approximation is performed from the th sample.
また、直線近似されないで符号化されるサンプルがある
き、そのサンプルを対数圧縮して符号化することもでき
る。Further, when there is a sample that is encoded without being linearly approximated, the sample can be logarithmically compressed and encoded.
作用 上記のような音楽信号圧縮方法を用いてサンプル系列を
符号化すると、最小２乗誤差があらかじめ定めたしきい
値を超えないサンプル系列が一つの直線として扱われ、
サンプル系列は圧縮されて符号化されることとなる。ま
た、３サンプルですでにしきい値を超えるような、サン
プルの値の変化が激しい場合はサンプルの値をそのまま
符号化することにより、音質の劣化が少なくなる。Action When a sample sequence is encoded using the music signal compression method as described above, a sample sequence whose least square error does not exceed a predetermined threshold value is treated as one straight line,
The sample sequence will be compressed and encoded. Further, when the sample value changes drastically such that the threshold value is already exceeded in 3 samples, the deterioration of the sound quality is reduced by encoding the sample value as it is.
実施例 以下本発明の音楽信号圧縮方法の一実施例について、図
面を参照しながら説明する。第１図は音楽信号の模式図
である。第１図において１は音楽信号を表わし、s1,s2,
s3,s4,s5,……はA/D変換された音楽信号のサンプル系列
である。2,3,4,5は音楽信号を近似する直線である。
s1′,s2′,s3′,s4′,s5′……はサンプルs1,s2,s3,s4,
s5の近似値である。直線2,3,4,5,は最小２乗誤差があら
かじめ定めたしきい値を超えないような直線として求め
られる。Embodiment An embodiment of the music signal compression method of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a music signal. In FIG. 1, 1 represents a music signal, and s 1 , s 2 ,
s 3 , s 4 , s 5 , ... Are sample sequences of A / D converted music signals. 2,3,4,5 are straight lines that approximate the music signal.
s 1 ′, s 2 ′, s 3 ′, s 4 ′, s 5 ′ …… are the samples s 1 , s 2 , s 3 , s 4 ,
It is an approximation of s 5 . The straight lines 2, 3, 4, 5 are obtained as straight lines such that the least square error does not exceed a predetermined threshold value.
第２図は第１図の直線の係数２個、サンプル個数を符号
化した図である。6,7,8,9は各々第１図の直線2,3,4,5を
符号化したもので、a1,a2,a3,a4およびb1,b2,b3,b4は直
線を定める係数、n1,n2,n3,n4はサンプル個数である。FIG. 2 is a diagram in which two coefficients of the straight line in FIG. 1 and the number of samples are encoded. 6,7,8,9 are the codes of the straight lines 2,3,4,5 of FIG. 1, respectively, and are a 1 , a 2 , a 3 , a 4 and b 1 , b 2 , b 3 , b. 4 is a coefficient that defines a straight line, and n 1 , n 2 , n 3 and n 4 are sample numbers.
第１図において１サンプル当たり16ビットで符号化され
ているとすると、図中には18サンプルあるので、全サン
プルで288ビット必要である。しかし、本方法を用い
て、第２図のように符号化した場合、直線の係数２個、
サンプル個数を各々８ビットで符号化すると、４直線あ
るので、全サンプルで96ビット必要となり、情報圧縮が
可能となる。Assuming that each sample is encoded with 16 bits in FIG. 1, there are 18 samples in the figure, so that 288 bits are required for all samples. However, when the present method is used for encoding as shown in FIG. 2, two linear coefficients,
If the number of samples is encoded with 8 bits each, there are 4 straight lines, so 96 bits are required for all samples, and information compression is possible.
第３図は第１図と同様に音楽信号の模式図である。第３
図において10は音楽信号を表わし、s1,s2,s3,s4,s5,s6,
……はA/D変換された音楽信号のサンプル系列である。1
1,12,13,14は音楽信号を近似する直線である。直接11,1
2,13,14は最小２乗誤差があらかじめ定めたしきい値を
超えないような直線として求められる。FIG. 3 is a schematic diagram of a music signal similarly to FIG. Third
In the figure, 10 represents a music signal, which is s 1 , s 2 , s 3 , s 4 , s 5 , s 6 ,
…… is a sample sequence of A / D converted music signals. 1
1, 12, 13, and 14 are straight lines that approximate the music signal. Direct 11,1
2,13,14 are obtained as straight lines such that the least square error does not exceed a predetermined threshold value.
第４図は第３図の直線の係数２個、サンプル個数を符号
化した図である。15,16,17は各々第３図のサンプルs1,s
2とフラグF1、サンプルs3,s4とフラグF2,サンプルs5,s6
とフラグF3を符号化したものである。18,19,20,21は各
々第３図の直線11,12,13,14を符号化したもので、a1,
a2,a3,a4及びb1,b2,b3,b4は直線を定める係数、n1,n2,n
3,n4はサンプル個数である。FIG. 4 is a diagram in which two coefficients of the straight line in FIG. 3 and the number of samples are encoded. 15, 16 and 17 are samples s 1 and s of Fig. 3, respectively.
2 and flag F 1 , sample s 3 , s 4 and flag F 2 , sample s 5 , s 6
And the flag F 3 is encoded. 18, 19, 20, 21 intended to respectively have a linear 11, 12, 13, 14 of FIG. 3 encodes, a 1,
a 2, a 3, a 4 and b 1, b 2, b 3 , b 4 is a coefficient defining a straight line, n 1, n 2, n
3 and n 4 are the number of samples.
第３図において１サンプル当たり16ビットで符号化され
ているとすると、図中には18サンプルあるので、全サン
プルで288ビット必要である。しかし、本方式を用い
て、第４図のように符号化した場合、直線の係数２個、
サンプル個数、フラグを各々８ビットで符号化すると、
全サンプルで216ビット必要となり、情報圧縮が可能と
なる。Assuming that each sample is encoded with 16 bits in FIG. 3, there are 18 samples in the figure, so that 288 bits are required for all samples. However, when the present method is used for encoding as shown in FIG. 4, two linear coefficients,
If the number of samples and the flag are encoded with 8 bits each,
All samples require 216 bits, which enables information compression.
発明の効果 本発明は、以上説明したような音楽信号圧縮方法なの
で、以下に記載されるような効果を奏する。EFFECTS OF THE INVENTION Since the present invention is the music signal compression method as described above, the following effects can be obtained.
あらかじめA/D変換された音楽信号のサンプル系列を直
線近似するので、情報伝送量が少なくなる。また、最小
２乗法を用いて直線を求めるので、サンプル系列をより
良く近似する直線が得られる。さらに、３サンプルを近
似する直線を求めた際に、最小２乗誤差があらかじめ定
めたしきい値を超える場合は、最初の２サンプルをその
まま符号化するので、サンプルの値の変化が急激であっ
ても、音質の劣化が少なくなる。Since the sample sequence of the music signal that has been A / D converted in advance is approximated by a straight line, the amount of information transmission is reduced. Further, since the straight line is obtained by using the least squares method, a straight line that better approximates the sample series can be obtained. Furthermore, when a straight line that approximates three samples is obtained and the least squares error exceeds a predetermined threshold value, the first two samples are coded as they are, and the change in the sample value is rapid. However, the sound quality is less deteriorated.
また、サンプル値を直線近似しないでそのまま符号化す
る際に、対数圧縮して符号化することもできるので、音
質の劣化を押えて、より情報伝送量を少なくすることが
可能である。Further, when the sample value is encoded without being linearly approximated, it can be logarithmically compressed and encoded, so that it is possible to suppress deterioration of sound quality and further reduce the amount of information transmission.
第１図は本発明を説明するための音楽信号の模式図、第
２図は第１図の音楽信号を符号化した説明図、第３図は
本発明を説明するための音楽信号の模式図、第４図は第
３図の音楽信号を符号化した説明図である。 １……音楽信号、2,3,4,5……音楽信号を近似する直
線、6,7,8,9……符号化された音楽信号、10……音楽信
号、11,12,13,14……音楽信号を近似する直線、15,16,1
7,18,19,20,21……符号化された音楽信号。FIG. 1 is a schematic diagram of a music signal for explaining the present invention, FIG. 2 is an explanatory diagram encoding the music signal of FIG. 1, and FIG. 3 is a schematic diagram of a music signal for explaining the present invention. , FIG. 4 is an explanatory diagram in which the music signal of FIG. 3 is encoded. 1 ... Music signal, 2,3,4,5 ... Straight line approximating music signal, 6,7,8,9 ... Encoded music signal, 10 ... Music signal, 11,12,13, 14: a straight line approximating a music signal, 15,16,1
7,18,19,20,21 …… Encoded music signal.
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 昭63−217731（ＪＰ，Ａ) 特開 昭59−96513（ＪＰ，Ａ) 特開 昭53−52045（ＪＰ，Ａ) 特開 昭53−101968（ＪＰ，Ａ) 特開 平１−82711（ＪＰ，Ａ) 特開 平１−105617（ＪＰ，Ａ) 特開 平３−66225（ＪＰ，Ａ) 特公 昭40−10178（ＪＰ，Ｂ１) 特公 平６−31989（ＪＰ，Ｂ２) ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A 63-217731 (JP, A) JP-A 59-96513 (JP, A) JP-A 53-52045 (JP, A) JP-A 53- 101968 (JP, A) JP-A-1-82711 (JP, A) JP-A-1-105617 (JP, A) JP-A-3-66225 (JP, A) JP-B-40-10178 (JP, B1) Japanese Patent Publication 6-31989 (JP, B2)
Claims (2)
プル系列を直線近似する音楽信号圧縮方法であって、時
刻t1,t2,t3,……におけるサンプル値をs1,s2,s3……と
すると、最初の３サンプルs1,s2,s3を近似する直線を最
小２乗法を用いて求め、最小２乗誤差があらかじめ定め
ておいたしきい値を超えていなければ、s4,s5,……とサ
ンプル数を１個ずつ増やしながら、逐次最小２乗誤差を
算出し、上記最小２乗誤差がサンプルsn+1のとき上記し
きい値を超えたとすれば、サンプルs1……snを近似する
直線を定める係数２個と、直線近似されたサンプル個数
ｎを符号化することとし、サンプルsn+1から新たな直線
近似を行うようにし、s1,s2,s3の３サンプルの直線近似
の最小２乗誤差がすでに上記しきい値を超えた場合は、
サンプルs1,s2の値とs1,s2が直線近似されていないこと
のフラグを符号化することとし、サンプルs3から新たな
直線近似を行うようにしたことを特徴とする音楽信号圧
縮方法。1. A pre-sample sequence of the A / D converted music signals a music signal compression method of linear approximation, the time t 1, t 2, t 3 , s 1 sample values in ......, s 2 , s 3 ......, the straight line approximating the first three samples s 1 , s 2 , and s 3 is obtained by using the least squares method, and if the least squares error does not exceed the predetermined threshold value, , S 4 , s 5 , ..., While increasing the number of samples one by one, the least square error is successively calculated, and if the above least square error is sample s n + 1 , the above threshold value is exceeded. , S 1 ...... sn 2 coefficients that define a straight line that approximates s n and the number n of samples that have been linearly approximated are encoded, and a new linear approximation is performed from sample s n + 1. If the least-squares error of the three-sample linear approximation of, s 2 , s 3 has already exceeded the above threshold,
Music signal characterized in that the values of samples s 1 and s 2 and the flag that s 1 and s 2 are not linearly approximated are coded, and new linear approximation is performed from sample s 3. Compression method.
si,si+1があるとき、上記si,si+1を対数圧縮して符号化
するようにした請求項（１）記載の音楽信号圧縮方法。2. Samples encoded without linear approximation
The music signal compression method according to claim 1 , wherein when s i , s i + 1 are present, the s i , s i + 1 are logarithmically compressed and encoded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1024976A JPH0787384B2 (en) | 1989-02-03 | 1989-02-03 | Music signal compression method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1024976A JPH0787384B2 (en) | 1989-02-03 | 1989-02-03 | Music signal compression method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02205117A JPH02205117A (en) | 1990-08-15 |
| JPH0787384B2 true JPH0787384B2 (en) | 1995-09-20 |
Family
ID=12153007
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1024976A Expired - Lifetime JPH0787384B2 (en) | 1989-02-03 | 1989-02-03 | Music signal compression method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0787384B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0787385B2 (en) * | 1989-08-05 | 1995-09-20 | 松下電器産業株式会社 | Music signal compression method |
| JP2002368624A (en) | 2001-06-08 | 2002-12-20 | Sakai Yasue | Compressor and compressing method, expander and expanding method, companding system, program and recording medium |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5352045A (en) * | 1976-10-22 | 1978-05-12 | Fujitsu Ltd | Modulating converter for pcm-forecasting code |
| JPS53101968A (en) * | 1977-02-17 | 1978-09-05 | Fujitsu Ltd | Modulating converter for pcm-forecast code |
| JPS5996513A (en) * | 1982-11-24 | 1984-06-04 | Nippon Gakki Seizo Kk | Method for recording and reproducing waveform |
| JPS63217731A (en) * | 1987-03-05 | 1988-09-09 | Yuuseishiyou Tsushin Sogo Kenkyusho | Method for saving memory quantity for vector quantized code directory |
| JPH0793584B2 (en) * | 1987-09-25 | 1995-10-09 | 株式会社日立製作所 | Encoder |
| JP2542864B2 (en) * | 1987-10-19 | 1996-10-09 | 三洋電機株式会社 | Digital correction circuit |
-
1989
- 1989-02-03 JP JP1024976A patent/JPH0787384B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02205117A (en) | 1990-08-15 |
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