JP4523885B2 - Signal encoding apparatus, method, program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform separation into an integer and an error so that the amount of codes becomes a minimum. <P>SOLUTION: A shift amount determination calculates a candidate for the amount of shift so that an amplitude value in a frame becomes the largest one capable of expressing the largest sample value in the integer; and determines the shift amount of the frame from the candidate for the shift amount by correcting, according to a predetermined reference, by using the frequency of 0 of 1 of a bit plane in a predetermined range of the lower order of the integer determined according to the candidate for the shift amount. A dividing portion divides a digital signal into an integer signal and an error signal according to the shift amount determined by the shift amount determination portion, codes the integer signal by an integer signal coding portion, and codes the error signal by an error signal coding portion. A multiplexer multiplexes the output of the integer signal coding portion and the output of the error signal coding portion. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to an information encoding apparatus, method, program, and recording medium for encoding information on a plurality of sample values.

  2. Description of the Related Art In recent years, information compression coding techniques have been used when acoustic signal data and image information data are transmitted through a communication channel or recorded on an information recording medium. In addition, lossless compression of floating-point format data that is easy to edit is also important. In these encoding methods, a data sample sequence in a floating-point format is composed of a plurality of samples to form a frame. Then, for each frame, the bit shift amount is determined so that the maximum amplitude value in the frame becomes an integer maximum value. Using the determined bit shift amount, each sample is separated into an integer signal and an error signal, and each is encoded for each frame.

FIG. 1 shows a functional configuration of an encoding processing unit in the prior art. The encoding processing unit 800 includes a frame buffer 810, a shift amount calculation unit 820, an integer signal / error signal separation unit 830, an integer signal encoding unit 840, an error signal encoding unit 850, and an integration unit (Multiplexer) 860. .
An image of this encoding process is shown in FIG. The frame is composed of a plurality of sample values, and each sample value is composed of a finite bit string. FIG. 2 shows a floating point representation in which the integer part is represented by 23 bits. In FIG. 2, the shaded bits contain 0 or 1, but all other bits are 0. When encoding in units of frames, the sample values in the frame are separated into an integer part and an error part (all or a part of the remainder obtained by subtracting the integer part from the input signal). A portion surrounded by a dotted line in FIG. 2 is an integer portion. The integer part is determined by performing mapping so that the maximum amplitude value in the frame becomes the maximum value of the integer. The separated integer part and error part are encoded separately and then integrated into encoded data.

  Note that the image shown in FIG. 2 can be applied not only to the floating-point representation but also to the integer representation. In any representation, only a bit string from a maximum bit (MSB: Most Significant Bit) expressing the amplitude to a minimum bit (LSB: Least Significant Bit) that is a finite number of bits can have 0 or 1 If all other bits are 0, the same method can be applied. For example, in the case of a 32-bit or 64-bit integer expression, there may be a case where there are 0 or 1 bits in only specific 24 bits for each sample, and the other bits are 0.

  In the conventional encoding method shown in FIG. 2, for example, when the dynamic range of the input signal is narrower than the number of quantization bits in the integer part, it belongs to the same digit in the frame on the LSB side of the integer after mapping. There are cases where all the bits (hereinafter referred to as “bit plane”) are 0 or almost all. For example, when the dynamic range of the input signal is only about 16 bits, when such a signal is expressed with a quantization bit number of 24 bits, a bit plane in which all the samples have 0 bits is generated on the LSB side of the integer signal. . Here, as shown in FIG. 2, when the time axis of the input signal is taken on the vertical axis and the binary represented bits constituting each sample are taken on the horizontal axis, the signal of each sample is represented in binary, A group of bits corresponding to the same digit is called a bit plane or a bit digit when the constituent bits are arranged so that the relative relationship of the amplitudes of the samples is maintained. For integer signal encoding, linear prediction is performed, and if the encoding is based on the assumption that samples with small prediction coefficients and residual signal amplitudes are larger than samples with large amplitudes, integer signals are efficiently compressed. Can be encoded. As the compression coding method of the error part, the error signal can be efficiently processed by using a compression coding method that uses a dictionary of several bits or by using run length coding for each bit plane. Compression encoding can be performed efficiently.

  As a representative floating point display, there is IEEE754 32-bit floating point. This floating point is

と表現される。ここで、Ｓは符号部、Ｍは仮数部、Ｅは指数部である。また、IEEE754では、Ｅ_０＝２^７−１＝１２７と決められている。上記式中のＥ−Ｅ_０は−１２７≦Ｅ−Ｅ_０≦１２８の範囲の値である。仮数部Ｍは、２進表現で値が１となるビットがＭＳＢに来るように、かつ、ＭＳＢビットと次のビットの間に小数点の位置がくるように正規化され、１となるＭＳＢビットを除いた小数点以下のビットである２３ビットで構成されている。以下の説明では、整数部の信号（以下、「整数信号」という。また、誤差部の信号を「誤差信号」という。）の量子化ビット数Ｑを２４とする。

It is expressed. Here, S is a sign part, M is a mantissa part, and E is an exponent part. In IEEE754, E ₀ = 2 ⁷ −1 = 127 is determined. EE ₀ in the above formula is a value in the range of −127 ≦ E−E ₀ ≦ 128. The mantissa M is normalized so that the bit whose value is 1 in the binary representation comes to the MSB, and the position of the decimal point is between the MSB bit and the next bit, and the MSB bit that becomes 1 is It consists of 23 bits that are bits after the decimal point. In the following description, the quantization bit number Q of the integer part signal (hereinafter referred to as “integer signal” and the error part signal is referred to as “error signal”) is 24.

FIG. 3 is a processing flow of the encoding processing unit 800 shown in FIG. Frame buffer 810, a digital input signal x (i) is temporarily stored, forming a frame with the _{N F} sample values x (i) (i = 1~N F) (S810). The shift amount calculation unit 820 determines the shift amount S _j for each frame by the method described with reference to FIG. 2 (S820). The integer signal / error signal separation unit 830 uses the shift amount S _j to separate each of the N _F samples of the frame input signal into an integer part and an error part (S830). The integer signal encoding unit 840 encodes the integer signal separated by the integer signal / error signal separation unit 830 (S840). The error signal encoding unit 850 encodes the error signal separated by the integer signal / error signal separation unit 830 (S850). The integration unit (Multiplexer) 860 integrates the encoded integer signal, error signal, and shift amount, and outputs encoded data (S860).

FIG. 4 shows a detailed processing flow example of the processing of the shift amount calculation unit 820 (step S820). However, this processing example is a processing example in the case of a sample value expressed in IEEE754 32-bit floating point. The shift amount calculating unit 820 first reads the entire sample _{(N F} number) in the frame input signal (S8201). Next, 1 is set to the variable i, and −127 (E ₀ ) is set to ΔE _max (S8202). The exponent part E _i -E ₀ of the i-th sample of the current frame, that is, E _i -127 is calculated and substituted for the variable ΔE _i (S8203). It is determined whether ΔE _i > ΔE _max is satisfied (S8204). If true, ΔE _i is set to ΔE _max (S8205). It is confirmed whether i <N _F (S8206). If i _{<N F,} substitutes i + 1 in i (S8207), the flow returns to step S8203. <If not _{N F, ΔE max>} i to check whether it is a -127 (S8208). If ΔE _max > −127, ΔE _max is substituted for the shift amount S _j (S8209), and the process is terminated. If ΔE _max ≦ −127, it means that all the samples in the frame are 0, so the shift amount S _j is set to 0 (S8210). This processing is equivalent to determining the shift value so that the maximum amplitude is assigned to the maximum amplitude within a range in which the maximum amplitude and the minimum value that can be expressed by the integer part do not exceed the range.

FIG. 5 shows a modification of the processing flow of the shift amount calculation unit 820 (step S820 ′). In the sample expressed in IEEE 754 32-bit floating point, when E-E ₀ is 128 or -127, it is a special value such as NaN or a denormalized number. 4 is different from FIG. 4 in that, when determining the maximum amplitude, the shift amount is calculated using only numerical values in the range of −127 <E−E ₀ <128 among the samples in the frame. Also, when analyzing the i-th sample, the decimal point position of the i-th sample can be moved using the ΔE _max obtained so far, and the value after digit adjustment can be expressed by the number of quantized bits assumed Whether it is within the range of values. At this time, if the range of values that can be expressed by a predetermined number of quantization bits is exceeded as a result of digit adjustment, ΔE _max is increased by 1 so as not to exceed the range. Different.

The specific difference in processing flow is as follows. Step S8221 is added between step S8202 and step S8203, and it is confirmed whether -127 <E _i -127 <128 (S8221). If S8221 is true, the process proceeds to step S8203, and if not true, the process proceeds to step S8206. Further, step S8220 is added between step S8205 and step S8206. In step S8220, first, the product of X _i and 2 to the power of (−ΔE + (Q−1)) is substituted for X ′ _i (S8222). X ′ _i > 2 ^Q−1 −1 or X ′ _i <−2 ^Q−1 is confirmed (S8223). Step S8223 is the case of true, adds 1 to ΔE _max (S8224). If step 8223 is not true, go to step 8206.

FIG. 6 shows in detail the procedure for separating the input signal X _i into the integer signal Y _i and the error signal Z _i using the shift amount S _j in step S830. Performing sequentially the following processing on the N _F of each sample X _i. In an internal memory, it captures the _{N F} samples from the frame buffer (S8301). 1 is substituted into i indicating the sample number (S8302). It is determined whether or not the exponent (E _i -127) of the input sample X _i is greater than −127 and less than 128 (S8303). If it is determined in step S8303 that the exponent part is outside the above range, the i-th sample has a value of 0, a denormalized number, or a special number such as NaN. Therefore, the sample Y _i after digit alignment is set to 0, and X ′ _{i is set} to the error part Z _i (S8309). If exponent is within the range of the in step S8303, the 2 _{X i (-S j + (Q} -1)) squared multiplied by obtaining and X _'i (S8304). Or, 'by _{= E i -S j + (Q} -1), X' samples _{X i} exponent value _{E i} from _{E i} of obtaining the _i 'E of _(i -127 exponent value of _i E)'. Here, Q is the number of quantization bits 24 in the integer part. In this process, all samples in the frame are multiplied by a common power of 2 (−S _j + (Q−1)), and the sample having the maximum amplitude in the frame is represented by the number of quantization bits in the integer part. This corresponds to aligning the position of the decimal point using the shift amount S _j so as not to exceed the maximum possible amplitude. It is checked whether or not the obtained exponent value of X ′ _i (E ′ _i −127) is included in a range larger than −127 and smaller than 128 (S8305). When the exponent part is outside the above range, the sashiple Y _i is set to 0 (S8309). If the exponent is within the above range, it is confirmed whether X ′ _i is positive (S8306). When X ′ _i is positive, an integer part Y _i is obtained by rounding down the decimal point of X ′ _i (S8307). When X ′ _i is negative, an integer part Y _i is obtained by rounding up the decimal point of X ′ _i (S8308). If Y _i is not 0, the portion after the decimal point of X ′ _i is set as the error part Z _i (S8307, S8308). i have to check whether _{N F} smaller than the (S8310). i is if _{N F} is smaller than substitutes i + 1 in i (S8311). i is equal to or larger than _{N F,} to the end. The separation of the integer signal and the error signal is not necessarily limited to the above procedure, and Patent Document 1 discloses several separation methods.

FIG. 7 shows a functional configuration of the decryption processing unit. The decoding processing unit 900 includes a demultiplexer 910 that divides encoded data, an integer signal decoding unit 920 that decodes an integer signal, an error signal decoding unit 930 that decodes an error signal, and an integer / error signal. The integer / error signal combination processing unit 940 is combined.
Dai Yang, and Takehiro Moriya, `` Lossless Compression for Audio Data in the IEEE Floating-Point Format, AES Convention Paper 5987, AES 115th Convention, New York, NY, USA, 2003 0 CTOBER 10-13. International Publication No. 2004/114527 Pamphlet

In the conventional integer signal encoding method, the number of bits required for encoding increases as the residual amplitude increases. However, the conventional error signal encoding method may reduce the number of bits required for encoding. In particular, in the encoding method of the error part, in a special case where the constituent bits are all 0, the encoding can be performed with a 1-bit flag in which all the constituent bits are 0. The compression efficiency is very good compared to the case of applying.
In this way, when all the bits constituting the bit plane or most of the bits are 0, the amount assigned to the error portion is smaller than the amount assigned to the integer portion for encoding. It may be necessary. However, in the conventional method in which the maximum value is used as a reference and assigned to the integer part and the error part, the shift value for separating the integer part and the error part is determined without considering the above-described properties. In other words, depending on the configuration in the lower bit plane of the integer signal part, there has been a problem that the overall compression ratio of the integer part and the error part has deteriorated.

In the present invention, the shift amount determination unit calculates the shift amount candidate so that the sample value having the maximum amplitude value in the frame can be represented by the integer part, and the integer part determined according to the shift amount candidate. The frame shift amount is corrected from the shift amount candidates and determined in accordance with a predetermined criterion using the frequency of 0 or 1 of the bit group in the predetermined range lower than.
FIG. 8 shows an image of the encoding process for determining the amplitude range of the signal to be encoded as the integer part of the present invention. In the conventional method, the shift amount is determined so that the maximum amplitude that can represent the sample value with the maximum amplitude value in the frame can be expressed by the integer part. However, the first method of the present invention is an n-digit range (n is an integer equal to or greater than 1) including the least significant part of the integer part (integer part 1 in the conventional method) determined according to the shift amount candidates. ) Is 0, the shift amount is the number obtained by adding n to the shift amount candidates. In the case of FIG. 8, since all the bits in the two-digit range from the least significant including the least significant are 0, the first integer part 2 in the present invention in the figure is an integer part. The second method of the present invention is such that 1 is predetermined for all bits in the range from the least significant to the n-digit range including the least significant of the integer part (integer part 1 in the conventional method) determined according to the shift amount candidates. If the ratio is less than or equal to (or 0 is greater than or equal to a predetermined ratio), the shift amount is the number obtained by adding n to the shift amount candidates. In the case of FIG. 8, if the predetermined ratio is ½, the second integer part 3 in the present invention in the figure is an integer part. In addition to these, when all bits in the range from the lowest to the nth digit including the lowest of the integer part determined according to the shift amount candidates are 1 or less (or 0 is a predetermined ratio) In the above case), the shift amount is a number obtained by adding n to the shift amount candidate, and the code according to the shift amount while increasing the shift amount one by one from the shift amount determined according to the shift amount candidate. For example, there is a method of calculating the code amount when the conversion is performed and using the previous shift amount as the shift amount of the frame when the code amount is larger than the code amount at the previous shift amount. However, it is not necessary to limit to these methods.

  According to the present invention, since the frame shift amount is determined in consideration of the configuration in the lower bit plane of the integer signal portion, the code amount can be further reduced.

Below, in order to avoid duplication of description, the same number is given to the structural part which has the same function, and the process step which performs the same process, and description is abbreviate | omitted.
[First Embodiment]
FIG. 9 shows a functional configuration example of the encoding processing unit of this embodiment. The encoding processing unit 200 includes a frame buffer 810, a shift amount calculation unit 210 having a lower digit check unit 230, an integer signal / error signal separation unit 830, an integer signal encoding unit 840, an error signal encoding unit 850, an integration unit ( Multiplexer) 860. The difference from the conventional encoding processing unit 800 of FIG. 1 is that the shift amount calculation unit 210 has a lower digit check unit 230.

The processing flow of the encoding processing unit 200 is obtained by replacing step S820 in FIG. 3 with step S210 in FIG. In step S210, the shift amount calculation unit 210 maps the maximum amplitude of the sample value in the frame to the maximum amplitude that can be expressed by the number of quantization bits in the integer part to obtain a shift amount candidate ΔE (S120). The processing content of step S120 is substantially the same as step S820 (FIG. 4) or step S820 ′ (FIG. 5). The difference is that in step S820 (S820 ′) in which the result is treated as a determined value of the shift amount, the result in step S120 is only treated as a candidate for the shift amount. The lower digit check unit 230 of the shift amount calculation unit 210 is a bit plane in the n-digit range (n is an integer of 1 or more) from the lowest order including the lowest part of the integer part determined according to the shift amount candidate ΔE. If the ratio is equal to or less than a predetermined ratio, the shift amount is set to the number obtained by adding n to the shift amount candidates (S230). Here, the predetermined ratio includes 0 (all bits are 0). The shift amount calculation unit 210 sets the shift amount candidate ΔE as the shift amount S _j (S240).

FIG. 11 shows a detailed processing flow of the processing (step S230) of the lower digit check unit 230 of the shift amount calculation unit 210. Lower digit check unit 230 takes in the _{N F} sample values (S2301). The number m of 1s in the bit plane of the least significant digit of the integer part when the integer part and the error part are separated by the shift amount candidate ΔE is acquired (S2302). It is confirmed whether the number m of 1 is equal to or less than a predetermined threshold (S2303). If step S2303 is true, 1 is added to the shift amount candidate ΔE (S2304), and the process returns to step S2302. If step S2303 is not true, step S230 is terminated. When step S230 ends, the process proceeds to step S240 as shown in FIG. 10, and the shift amount _Sj is set to the shift amount candidate ΔE. By processing in this way, each bit plane in the range from the least significant digit to the least significant digit (n is an integer of 1 or more) including the least significant digit of the integer part determined according to the shift amount candidate obtained in step S120. Is equal to or less than a predetermined ratio, the shift amount can be corrected to the number obtained by adding n to the shift amount candidates obtained in step S120. When the threshold is set to 0, the shift amount candidate ΔE is increased by 1 when all the bits of the bit plane are 0.

By determining the shift amount S _j in this way, a bit plane that can be reduced in code amount when included in the error part can be included in the error part, and the compression rate can be improved.
In the present embodiment, it is confirmed that the ratio of the number of 1 is equal to or less than the threshold value, but it may be confirmed that the ratio of 0 is equal to or more than the threshold value.
[Second Embodiment]
In the first embodiment, the lower digit check unit 230 of the shift amount calculation unit 210 compares the number (or ratio) of 1 in each bit plane with a threshold value. In the present embodiment, when 1 in all bits in the range from the least significant digit including the least significant digit of the integer part determined according to the shift amount candidate (n is an integer of 1 or more) is equal to or less than a predetermined ratio. The shift amount S _j is the number obtained by adding n to the shift amount candidates. In the present embodiment, the processing flow (step S230 ′) shown in FIG. 12 is performed instead of step S230 shown in FIG. 11 of the first embodiment.

Lower digit check unit 230 takes in the _{N F} sample values (S2301). 1 is substituted for i (S2311). The number m of 1 bits from the least significant digit of the integer part to the i-th digit including the least significant digit when the integer part and the error part are separated by the shift amount candidate ΔE is acquired (S2312). It is checked whether m / (i · N _F ) is equal to or smaller than a predetermined threshold value (S2313). If step S2313 is true, 1 is added to i (S2314), and the process returns to step S2312. If step S2313 is not true, i-1 is added to the shift amount candidate ΔE (S2315), and step S230 ′ is terminated. When step S230 ′ ends, the process proceeds to step S240 as shown in FIG. 10, and the shift amount _Sj is set to the shift amount candidate ΔE.

In this embodiment, it is confirmed that the ratio of the number of 1 is equal to or smaller than the threshold value, but it may be confirmed that the ratio of 0 is equal to or larger than the threshold value.
[Third Embodiment]
In the present embodiment, the lower digit check unit 230 of the shift amount calculation unit 210 increases the shift amount one by one from the shift amount determined according to the shift amount candidate, and performs encoding according to the shift amount. When the code amount is calculated and the code amount is larger than the code amount at the previous shift amount, the previous shift amount is set as the shift amount S _{j of the} frame. In the present embodiment, the processing flow (step S230 ″) shown in FIG. 13 is performed instead of step S230 shown in FIG. 11 of the first embodiment.

Lower digit check unit 230 takes in the _{N F} sample values (S2301). D _{min is set} to infinity (S2321). Actually, D _min may be the maximum value that can be taken as the code amount. The code amount D when the integer part and the error part are separated by the shift amount candidate ΔE is calculated (S2322). It is confirmed whether D ≦ D _min (S2323). If step S2323 is true, D _{min is set} to D (S2324), 1 is added to the shift amount candidate ΔE (S2304), and the process returns to step S2322. If step S2323 is not true, the shift amount candidate ΔE subtract 1 (S2325), step S230 "is terminated. Step S230" When completed, the process proceeds to step S240 as shown in FIG. 10, the shift amount _{S j} Is set as the shift amount candidate ΔE.
[Fourth Embodiment]
In the present embodiment, the lower-order digit check unit 230 of the shift amount calculation unit 210 includes all the ranges from the lowest order n digits (where n is an integer of 1 or more) including the least significant digit of the integer part determined according to the shift amount candidates. The ratio of 1 of bits is calculated while increasing n by 1 from 1 to obtain n when the ratio of 1 increases from the ratio of the previous shift amount, and the shift amount S _j is determined as the shift amount candidate. And n-1 is added. In the present embodiment, a processing flow (step S230 ′ ″) shown in FIG. 14 is performed instead of step S230 shown in FIG. 11 of the first embodiment.

Lower digit check unit 230 takes in the _{N F} sample values (S2301). Substitute 1 for R _min and 1 for i (S2331). A ratio R of 1 in all the bits from the least significant digit of the integer part to the i-th when the integer part and the error part are separated by the shift amount candidate ΔE is obtained (S2332). It is confirmed whether R ≦ R _min (S2333). If step S2333 is true, R _{min is set} to R, 1 is added to i (S2334), and the process returns to step S2332. If step S2333 is not true, i-2 is added to the shift amount candidate ΔE (S2335), and step S230 ′ ″ is terminated. When step S230 ″ ′ ends, the process proceeds to step S240 as shown in FIG. 10, and the shift amount _Sj is set to the shift amount candidate ΔE.
[Modification]
In the fourth embodiment, the shift amount is obtained using a ratio of 1, but the shift amount may be obtained using a ratio of 0. In this modification, the processing flow (step S230 ″ ″) shown in FIG. 15 is performed instead of step S230 shown in FIG. 11 of the first embodiment.

Lower digit check unit 230 takes in the _{N F} sample values (S2301). 0 is substituted for R _max and 1 is substituted for i (S2331 ′). A ratio R of 0 in all the bits from the least significant digit of the integer part to the i-th when the integer part and the error part are separated by the shift amount candidate ΔE is obtained (S2332 ′). It is confirmed whether R ≧ R _max (S2333 ′). When step S2333 ′ is true, R _{max is set} to R, 1 is added to i (S2334 ′), and the process returns to step S2332 ′. If step S2333 ′ is not true, i−2 is added to the shift amount candidate ΔE (S2335), and step S230 ″ ″ is terminated. When step S230 ″ ″ is completed, the process proceeds to step S240 as shown in FIG. 10, and the shift amount _Sj is set to the shift amount candidate ΔE.
[Fifth Embodiment]
FIG. 16 shows a functional configuration example of the encoding processing unit of this embodiment. The encoding processing unit 100 includes a frame buffer 810, a shift amount candidate calculation unit 210 ′, a shift amount selection unit 130, and a frame shift amount storage buffer 140, a shift amount determination unit 110, an integer signal / error signal separation unit 830, An integer signal encoding unit 840, an error signal encoding unit 850, and a multiplex unit 860 are included. Further, the shift amount candidate calculation unit 210 ′ includes a lower digit check unit 230. Note that the shift amount candidate calculation unit 210 ′ is a configuration unit that calculates a candidate for determining the shift amount by the shift amount determination unit 110, but has exactly the same configuration and processing as the shift amount calculation unit 210 of the first embodiment. It's okay. A difference from the encoding processing unit 200 in FIG. 9 is a shift amount determination unit 110.

The processing flow of the encoding processing unit 100 is obtained by replacing step S820 in FIG. 3 with step S110 in FIG. In step S110, first, the shift amount candidate calculation unit 210 ′ maps the maximum amplitude of the sample value in the frame to the maximum amplitude that can be expressed by the number of quantization bits in the integer part to obtain the shift amount candidate ΔE (S120). The lower digit check unit 230 corrects the shift amount candidate ΔE (S230, S230 ′, S230 ″, S230 ′ ″, or S230 ″ ″). The shift amount selection unit 130 determines whether the current frame is the first frame or random. It is determined whether the frame is an access frame (RA frame: a frame that does not use prediction from a past frame) (S140) In the case of a head frame or a random access frame, the shift amount selection unit 130 sets the shift amount candidate ΔE as the current frame. (S150) If neither the first frame nor the random access frame is selected, the shift amount is selected. 130, _{(the k} 1 or more integer) shift amount S _j-k of one or more past frames from the frame shift amount storing buffer reads, using the shift amount and the shift amount candidate ΔE of past frame present A frame shift amount S _j is determined (S130).

FIG. 18 shows a detailed processing flow example of the processing of the shift amount selection unit 130 (step S130). The shift amount selection unit 130 reads the shift amount S _j−1 of the immediately preceding frame from the frame shift amount holding buffer 140 and the shift amount candidate ΔE from the shift amount candidate calculation unit 120 (S1301). S _j-1 > ΔE is confirmed (S1302). If true, S _j−1 <ΔE + α is confirmed (S1303). Here, α is a predetermined threshold value. A step S1302 and S1303 are both in the case of true, the shift amount _{S j-1} of the previous frame and the shift amount _{S j} of the current frame (S1304). If one of steps S1302 and S1303 is not true, the shift amount candidate ΔE is set as the shift amount S _j of the current frame (S1305).

α is a threshold value for changing the shift amount only when the shift amount fluctuates above a certain level. For example, α is set to 5 in advance. When α = 5, the shift amount compensation ΔE obtained by analyzing the maximum amplitude of the frame is larger than the shift amount S _{j−1 of} the previous frame or S _j−1 −5. This is equivalent to changing the shift amount only when the value becomes smaller than that.
By determining the frame shift amount S _j in this way, frequent shift amount changes are eliminated, and the compression rate in the case of compression encoding using inter-frame prediction can be improved.
[Modification 1]
In the fifth embodiment, the shift amount selection unit 130 of the shift amount determination unit 110 determines a threshold value in advance as shown in FIG. 18, and the difference between the shift amount of the immediately preceding frame and the shift amount candidate of the current frame. If is within the threshold, the shift amount of the current frame is made the same as the previous frame. In this modification, the shift amount selection unit 130 of the shift amount determination unit 110 calculates the data amount after encoding at each shift amount from the shift amount of the previous frame to the shift amount candidate of the current frame, A shift amount with a small amount of data is set as a shift amount of the current frame.

FIG. 19 shows a processing flow (step S130 ′) of the shift amount selecting unit 130, which is an alternative to step S130. The shift amount selection unit 130 reads the shift amount S _j−1 of the immediately preceding frame from the frame shift amount holding buffer 140 and the shift amount candidate ΔE from the shift amount candidate calculation unit 120 (S1301). S _j-1 > ΔE is confirmed (S1302). If step S1302 is true, _{Dmin is set} to infinity, and i is set to the shift amount _Sj-1 of the immediately preceding frame (S1311). However, the infinite value may be a maximum value that can be taken as a code amount. It obtains a code amount of the code amount and the error signal of the integral signal when the shift amount was i, obtaining the code amount D _i of the coded data when integrated (S1312). D _min is to confirm whether greater than _{D i} (S1313). If D _min is greater than D _i , D _{i is set} to D _min (S1314). If D _min is less than _{D i,} the process proceeds to step S1315. It is confirmed that i> ΔE (S1315). If step S1315 is true, i-1 is substituted for i (S1316). If step S1315 is not true, the shift amount S _{j is set} to D _min (S1317).
If step S1302 is not true, the shift amount _Sj is set as a shift amount candidate ΔE (S1305).

If processing is performed in this way, processing time is required, but a shift amount with a small code amount can be selected with certainty.
[Modification 2]
In this modification, the shift amount selection unit 130 of the shift amount determination unit 110 records the shift amounts of the past N frames (N is an integer of 2 or more). The shift amount candidate is larger than the shift amount smaller than the nth (n is an integer of 1 or more and less than N) among the shift amounts of the past N frames, and smaller than the shift amount of the immediately preceding frame. The shift amount of the immediately preceding frame is set as the shift amount of the current frame. In the case where the shift amount candidate is the nth (n is an integer of 1 or more and less than N) shift amount less than or equal to or greater than the shift amount of the immediately preceding frame among the shift amounts of the past N frames, The shift amount candidate is set as the shift amount of the current frame.

20 shows a processing flow (step S130 ″) of the shift amount selecting unit 130 in place of step S130. The shift amount selecting unit 130 shifts the past frame shift amount S _j−k ( k = 1 to N), the shift amount candidate ΔE is read from the shift amount candidate calculation unit 120 (S1301), where N is an integer equal to or greater than 2. The threshold α is the N past shift amounts, The shift amount is set to the nth smallest shift amount (S1322) The processing after step S1302 is the same as that of FIG.
In the present embodiment, the threshold is not determined in advance, but is obtained from the past shift value. Therefore, the threshold value can be changed in consideration of the characteristics of the input signal.
[Modification 3]
In this modification, the shift amount selection unit 130 of the shift amount determination unit 110 sets the shift amount of the immediately preceding frame as the shift amount of the current frame when the shift amount candidate is equal to or smaller than the shift amount of the immediately preceding frame. When the shift amount candidate is larger than the shift amount of the immediately preceding frame, the shift amount candidate is set as the shift amount of the current frame.

FIG. 21 shows a processing flow (step S130 ′ ″) of the shift amount selecting unit 130, which is an alternative to step S130. The difference from the flow of FIG. 18 is that step S1303 is deleted. Accordingly, in the present embodiment, the shift amount may increase but not decrease. However, the content of the process is the simplest.
In addition, said embodiment can also read and implement the program which makes a computer perform each step of the said method. Also, as a method for reading into the computer, the program is recorded on a computer-readable recording medium, and the program is read from the recording medium into the computer, or the program recorded in the server or the like is read into the computer through an electric communication line or the like. There are methods.

The figure which shows the function structure of the encoding process part in a prior art. The figure which shows the image of the encoding process in a prior art. The figure which shows the processing flow of the conventional encoding process part. The figure which shows the detailed processing flow of a process of a shift amount calculation part. The figure which shows the modification of the processing flow of a shift amount calculation part. It illustrates a procedure for separating an input signal X _i into an integer signal Y _i and the error signal Z _i using the shift amount S _j. The figure which shows the function structure of a decoding process part. The figure which shows the image of the encoding process which determines the shift amount of this invention. The figure which shows the function structural example of the encoding process part of this invention. The figure which shows the processing flow which minimizes the code amount of 1st Embodiment of this invention. The figure which shows the detailed process flow of the process (step S230) of the low-order digit check part 230 of the shift amount calculation part 210. FIG. The figure which shows the detailed processing flow of a process (step S230 ') of the low-order digit check part 230 of the shift amount calculation part 210. FIG. The figure which shows the detailed process flow of a process (step S230 ") of the low-order digit check part 230 of the shift amount calculation part 210. FIG. The figure which shows the detailed processing flow of the process (step S230 '') of the low-order digit check part 230 of the shift amount calculation part 210. FIG. The figure which shows the detailed processing flow of the process (step S230 "'") of the low-order digit check part 230 of the shift amount calculation part 210. FIG. The figure which shows the function structural example of the encoding process part of 5th Embodiment. The figure which shows the processing flow of the shift amount determination part 110. FIG. The figure which shows the example of a detailed process flow of the process (step S130) of the shift amount selection part 130. FIG. The figure which shows the processing flow of the shift amount selection part 130 of the modification 1 of 5th Embodiment. The figure which shows the processing flow of the shift amount selection part 130 of the modification 2 of 5th Embodiment. The figure which shows the processing flow of the shift amount selection part 130 of the modification 3 of 5th Embodiment.

Claims (26)

A frame buffer that divides the digital signal into a plurality of sample values (hereinafter referred to as “frames”);
A shift amount determination unit that determines the amplitude range of a signal to be encoded as an integer part;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoder for encoding an integer signal;
An error signal encoder for encoding the error signal;
An integration unit that integrates the output of the integer signal encoding unit and the output of the error signal encoding unit;
A signal encoding device comprising:
The shift amount determination unit
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
When all the bits in the n-digit range (n is an integer of 1 or more) including the least significant part of the integer part determined according to the shift amount candidate are 0, the shift amount is set to the shift amount candidate n , The number plus
A signal encoding device. A frame buffer that divides the digital signal into a plurality of sample values (hereinafter referred to as “frames”);
A shift amount determination unit that determines the amplitude range of a signal to be encoded as an integer part;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoder for encoding an integer signal;
An error signal encoder for encoding the error signal;
An integration unit that integrates the output of the integer signal encoding unit and the output of the error signal encoding unit;
A signal encoding device comprising:
The shift amount determination unit
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
Each bit plane (bit indicating the same digit of each sample value sequence in the same frame) in the n-digit range (n is an integer of 1 or more) from the lowest including the lowest of the integer part determined according to the shift amount candidate. The same shall apply hereinafter.) In the case where 1 is equal to or less than a predetermined ratio or 0 is equal to or greater than a predetermined ratio, the shift amount is a number obtained by adding n to the shift amount candidates.
A signal encoding device. A frame buffer that divides the digital signal into a plurality of sample values (hereinafter referred to as “frames”);
A shift amount determination unit that determines the amplitude range of a signal to be encoded as an integer part;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoder for encoding an integer signal;
An error signal encoder for encoding the error signal;
An integration unit that integrates the output of the integer signal encoding unit and the output of the error signal encoding unit;
A signal encoding device comprising:
The shift amount determination unit
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
Of all bits in the n-digit range (n is an integer of 1 or more) including the lowest part of the integer part determined according to the shift amount candidates, 1 is less than a predetermined ratio or 0 is predetermined If the ratio is greater than or equal to the ratio, the shift amount is the number obtained by adding n to the shift amount candidates.
A signal encoding device. A frame buffer that divides the digital signal into a plurality of sample values (hereinafter referred to as “frames”);
A shift amount determination unit that determines the amplitude range of a signal to be encoded as an integer part;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoder for encoding an integer signal;
An error signal encoder for encoding the error signal;
An integration unit that integrates the output of the integer signal encoding unit and the output of the error signal encoding unit;
A signal encoding device comprising:
The shift amount determination unit
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
While increasing the shift amount one by one from the shift amount determined according to the shift amount candidate, the code amount when encoding according to the shift amount is calculated, and the code amount is more than the code amount at the previous shift amount. When the amount increases, the previous shift amount is set as the shift amount of the frame,
A signal encoding device. A frame buffer that divides the digital signal into a plurality of sample values (hereinafter referred to as “frames”);
A shift amount determination unit that determines the amplitude range of a signal to be encoded as an integer part;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoder for encoding an integer signal;
An error signal encoder for encoding the error signal;
An integration unit that integrates the output of the integer signal encoding unit and the output of the error signal encoding unit;
A signal encoding device comprising:
The shift amount determination unit
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
Calculate the ratio of 1 in all bits in the n-digit range (n is an integer of 1 or more) from the lowest including the lowest of the integer part determined according to the shift amount candidates while increasing n from 1 by 1 N for which the ratio of 1 is larger than the ratio of 1 in the previous calculation is obtained, and the shift amount is determined as the shift amount parameter.
It shall be a number obtained by adding n-1 to the complement,
A signal encoding device. A frame buffer that divides the digital signal into a plurality of sample values (hereinafter referred to as “frames”);
A shift amount determination unit that determines the amplitude range of a signal to be encoded as an integer part;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoder for encoding an integer signal;
An error signal encoder for encoding the error signal;
An integration unit that integrates the output of the integer signal encoding unit and the output of the error signal encoding unit;
A signal encoding device comprising:
The shift amount determination unit
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
Calculate the ratio of 0 in all bits in the n-digit range (n is an integer of 1 or more) from the lowest including the lowest of the integer part determined according to the shift amount candidates while increasing n from 1 by 1 N for which the ratio of 0 is smaller than the ratio of 0 in the previous calculation is obtained, and the shift amount is the number obtained by adding n-1 to the shift amount candidates.
A signal encoding device. A frame buffer that divides the digital signal into a plurality of sample values (hereinafter referred to as “frames”);
A shift amount determination unit that determines the amplitude range of a signal to be encoded as an integer part;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoder for encoding an integer signal;
An error signal encoder for encoding the error signal;
An integration unit that integrates the output of the integer signal encoding unit and the output of the error signal encoding unit;
A signal encoding device comprising:
The shift amount determination unit
Record the shift amount of at least one past frame in the frame shift amount holding buffer,
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
When all the bits in the n-digit range (n is an integer of 1 or more) including the lowest part of the integer part determined according to the shift amount candidate are 0, n is added to the shift amount candidate Let the number be the shift amount candidate,
Using the shift amount candidate and the shift amount recorded in the frame shift amount holding buffer to determine the shift amount of the current frame according to a predetermined criterion;
A signal encoding device. A frame buffer that divides the digital signal into a plurality of sample values (hereinafter referred to as “frames”);
A shift amount determination unit that determines the amplitude range of a signal to be encoded as an integer part;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoder for encoding an integer signal;
An error signal encoder for encoding the error signal;
An integration unit that integrates the output of the integer signal encoding unit and the output of the error signal encoding unit;
A signal encoding device comprising:
The shift amount determination unit
Record the shift amount of at least one past frame in the frame shift amount holding buffer,
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
In each bit plane in the n-digit range (n is an integer of 1 or more) including the lowest part of the integer part determined according to the shift amount candidate, 1 is less than a predetermined ratio or 0 is predetermined. If the ratio is greater than or equal to the ratio, the number obtained by adding n to the shift amount candidates is defined as a shift amount candidate,
Using the shift amount candidate and the shift amount recorded in the frame shift amount holding buffer to determine the shift amount of the current frame according to a predetermined criterion;
A signal encoding device. A frame buffer that divides the digital signal into a plurality of sample values (hereinafter referred to as “frames”);
A shift amount determination unit that determines the amplitude range of a signal to be encoded as an integer part;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoder for encoding an integer signal;
An error signal encoder for encoding the error signal;
An integration unit that integrates the output of the integer signal encoding unit and the output of the error signal encoding unit;
A signal encoding device comprising:
The shift amount determination unit
Record the shift amount of at least one past frame in the frame shift amount holding buffer,
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
Of all bits in the n-digit range (n is an integer of 1 or more) including the lowest part of the integer part determined according to the shift amount candidates, 1 is less than a predetermined ratio or 0 is predetermined If the ratio is greater than or equal to the ratio, the number obtained by adding n to the shift amount candidates is defined as a shift amount candidate,
Using the shift amount candidate and the shift amount recorded in the frame shift amount holding buffer to determine the shift amount of the current frame according to a predetermined criterion;
A signal encoding device. A frame buffer that divides the digital signal into a plurality of sample values (hereinafter referred to as “frames”);
A shift amount determination unit that determines the amplitude range of a signal to be encoded as an integer part;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoder for encoding an integer signal;
An error signal encoder for encoding the error signal;
An integration unit that integrates the output of the integer signal encoding unit and the output of the error signal encoding unit;
A signal encoding device comprising:
The shift amount determination unit
Record the shift amount of at least one past frame in the frame shift amount holding buffer,
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
While increasing the shift amount one by one from the shift amount determined according to the shift amount candidate, the code amount when encoding according to the shift amount is calculated, and the code amount is more than the code amount at the previous shift amount. When the amount increases, the previous shift amount is set as a shift amount candidate of the frame,
Using the shift amount candidate and the shift amount recorded in the frame shift amount holding buffer to determine the shift amount of the current frame according to a predetermined criterion;
A signal encoding device.   A frame buffer that divides the digital signal into a plurality of sample values (hereinafter referred to as “frames”);
  A shift amount determination unit that determines the amplitude range of a signal to be encoded as an integer part;
  A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
  An integer signal encoder for encoding an integer signal;
  An error signal encoder for encoding the error signal;
  An integration unit that integrates the output of the integer signal encoding unit and the output of the error signal encoding unit;
  A signal encoding device comprising:
  The shift amount determination unit
  Record the shift amount of at least one past frame in the frame shift amount holding buffer,
  The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
  Calculate the ratio of 1 in all bits in the n-digit range (n is an integer of 1 or more) from the lowest including the lowest of the integer part determined according to the shift amount candidates while increasing n by 1 from 1 Then, n is obtained in which the ratio of 1 is larger than the ratio of 1 in the previous calculation, and the shift amount is the number obtained by adding n-1 to the shift amount candidates.
  Using the shift amount candidate and the shift amount recorded in the frame shift amount holding buffer to determine the shift amount of the current frame according to a predetermined criterion;
  A signal encoding device.   A frame buffer that divides the digital signal into a plurality of sample values (hereinafter referred to as “frames”);
  A shift amount determination unit that determines the amplitude range of a signal to be encoded as an integer part;
  A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
  An integer signal encoder for encoding an integer signal;
  An error signal encoder for encoding the error signal;
  An integration unit that integrates the output of the integer signal encoding unit and the output of the error signal encoding unit;
  A signal encoding device comprising:
  The shift amount determination unit
  Record the shift amount of at least one past frame in the frame shift amount holding buffer,
  The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
  Calculate the ratio of 0 in all bits in the n-digit range (n is an integer of 1 or more) including the lowest part of the integer part determined according to the shift amount candidates while increasing n from 1 by 1 N for which the ratio of 0 is less than the ratio of 0 in the previous calculation is obtained, and the shift amount is the number obtained by adding n-1 to the shift amount candidates,
  Using the shift amount candidate and the shift amount recorded in the frame shift amount holding buffer to determine the shift amount of the current frame according to a predetermined criterion;
  A signal encoding device. A frame buffer step for dividing the digital signal into a plurality of sample values (hereinafter referred to as “frames”) in the frame buffer;
A shift amount determination unit that determines a range of amplitudes of signals to be encoded as an integer part in the shift amount determination unit;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoding step for encoding the integer signal in the integer signal encoding unit;
An error signal encoding step of encoding an error signal in an error signal encoding unit;
An integration step of integrating the output of the integer signal encoding unit and the output of the error signal encoding unit in an integration unit;
A signal encoding method comprising:
The shift amount determining step includes:
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
When all the bits in the n-digit range (n is an integer of 1 or more) including the least significant part of the integer part determined according to the shift amount candidate are 0, the shift amount is set to the shift amount candidate n To the number plus
A signal encoding method characterized by the above. A frame buffer step for dividing the digital signal into a plurality of sample values (hereinafter referred to as “frames”) in the frame buffer;
A shift amount determination unit that determines a range of amplitudes of signals to be encoded as an integer part in the shift amount determination unit;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoding step for encoding the integer signal in the integer signal encoding unit;
An error signal encoding step of encoding an error signal in an error signal encoding unit;
An integration step of integrating the output of the integer signal encoding unit and the output of the error signal encoding unit in an integration unit;
A signal encoding method comprising:
The shift amount determining step includes:
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
In each bit plane in the n-digit range (n is an integer of 1 or more) including the lowest part of the integer part determined according to the shift amount candidate, 1 is less than a predetermined ratio or 0 is predetermined. If the ratio is greater than or equal to the ratio, the shift amount is the number obtained by adding n to the shift amount candidates.
A signal encoding method characterized by the above. A frame buffer step for dividing the digital signal into a plurality of sample values (hereinafter referred to as “frames”) in the frame buffer;
A shift amount determination unit that determines a range of amplitudes of signals to be encoded as an integer part in the shift amount determination unit;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoding step for encoding the integer signal in the integer signal encoding unit;
An error signal encoding step of encoding an error signal in an error signal encoding unit;
An integration step of integrating the output of the integer signal encoding unit and the output of the error signal encoding unit in an integration unit;
A signal encoding method comprising:
The shift amount determining step includes:
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
Of all bits in the n-digit range (n is an integer of 1 or more) including the lowest part of the integer part determined according to the shift amount candidates, 1 is less than a predetermined ratio or 0 is predetermined If the ratio is greater than or equal to the ratio, the shift amount is the number obtained by adding n to the shift amount candidates.
A signal encoding method characterized by the above. A frame buffer step for dividing the digital signal into a plurality of sample values (hereinafter referred to as “frames”) in the frame buffer;
A shift amount determination unit that determines a range of amplitudes of signals to be encoded as an integer part in the shift amount determination unit;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoding step for encoding the integer signal in the integer signal encoding unit;
An error signal encoding step of encoding an error signal in an error signal encoding unit;
An integration step of integrating the output of the integer signal encoding unit and the output of the error signal encoding unit in an integration unit;
A signal encoding method comprising:
The shift amount determining step includes:
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
While increasing the shift amount one by one from the shift amount determined according to the shift amount candidate, the code amount when encoding according to the shift amount is calculated, and the code amount is more than the code amount at the previous shift amount. When the amount increases, the previous shift amount is set as the shift amount of the frame,
A signal encoding method characterized by the above. A frame buffer step for dividing the digital signal into a plurality of sample values (hereinafter referred to as “frames”) in the frame buffer;
A shift amount determination unit that determines a range of amplitudes of signals to be encoded as an integer part in the shift amount determination unit;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoding step for encoding the integer signal in the integer signal encoding unit;
An error signal encoding step of encoding an error signal in an error signal encoding unit;
An integration step of integrating the output of the integer signal encoding unit and the output of the error signal encoding unit in an integration unit;
A signal encoding method comprising:
The shift amount determining step includes:
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
Calculate the ratio of 1 in all bits in the n-digit range (n is an integer of 1 or more) from the lowest including the lowest of the integer part determined according to the shift amount candidates while increasing n from 1 by 1 Determining n which is larger than the ratio of the previous shift amount of 1, and setting the shift amount as a number obtained by adding n-1 to the shift amount candidates;
A signal encoding method characterized by the above. A frame buffer step for dividing the digital signal into a plurality of sample values (hereinafter referred to as “frames”) in the frame buffer;
A shift amount determination unit that determines a range of amplitudes of signals to be encoded as an integer part in the shift amount determination unit;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoding step for encoding the integer signal in the integer signal encoding unit;
An error signal encoding step of encoding an error signal in an error signal encoding unit;
An integration step of integrating the output of the integer signal encoding unit and the output of the error signal encoding unit in an integration unit;
A signal encoding method comprising:
The shift amount determining step includes:
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
Calculate the ratio of 0 in all bits in the n-digit range (n is an integer of 1 or more) from the lowest including the lowest of the integer part determined according to the shift amount candidates while increasing n from 1 by 1 Then, n which is smaller than the ratio of the shift amount before 1 is obtained, and the shift amount is the number obtained by adding n-1 to the shift amount candidates.
A signal encoding method characterized by the above. A frame buffer step for dividing the digital signal into a plurality of sample values (hereinafter referred to as “frames”) in the frame buffer;
A shift amount determination unit that determines a range of amplitudes of signals to be encoded as an integer part in the shift amount determination unit;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoding step for encoding the integer signal in the integer signal encoding unit;
An error signal encoding step of encoding an error signal in an error signal encoding unit;
An integration step of integrating the output of the integer signal encoding unit and the output of the error signal encoding unit in an integration unit;
A signal encoding method comprising:
The shift amount determining step includes:
Record the shift amount of at least one past frame in the frame shift amount holding buffer,
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
When all the bits in the n-digit range (n is an integer of 1 or more) including the lowest part of the integer part determined according to the shift amount candidate are 0, n is added to the shift amount candidate Let the number be the shift amount candidate,
Using pre carboxymethyl shift amount candidate shift amount recorded in the frame shift amount holding buffer, according to the criteria predetermined by determining the shift amount of the current frame,
A signal encoding method characterized by the above. A frame buffer step for dividing the digital signal into a plurality of sample values (hereinafter referred to as “frames”) in the frame buffer;
A shift amount determination unit that determines a range of amplitudes of signals to be encoded as an integer part in the shift amount determination unit;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoding step for encoding the integer signal in the integer signal encoding unit;
An error signal encoding step of encoding an error signal in an error signal encoding unit;
An integration step of integrating the output of the integer signal encoding unit and the output of the error signal encoding unit in an integration unit;
A signal encoding method comprising:
The shift amount determining step includes:
Record the shift amount of at least one past frame in the frame shift amount holding buffer,
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
In each bit plane in the n-digit range (n is an integer of 1 or more) including the lowest part of the integer part determined according to the shift amount candidate, 1 is less than a predetermined ratio or 0 is predetermined. If the ratio is greater than or equal to the ratio, the number obtained by adding n to the shift amount candidates is defined as a shift amount candidate,
Determining a shift amount of the current frame according to a predetermined criterion using the shift amount candidates and the shift amount recorded in the frame shift amount holding buffer;
A signal encoding method characterized by the above. A frame buffer step for dividing the digital signal into a plurality of sample values (hereinafter referred to as “frames”) in the frame buffer;
A shift amount determination unit that determines a range of amplitudes of signals to be encoded as an integer part in the shift amount determination unit;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoding step for encoding the integer signal in the integer signal encoding unit;
An error signal encoding step of encoding an error signal in an error signal encoding unit;
An integration step of integrating the output of the integer signal encoding unit and the output of the error signal encoding unit in an integration unit;
A signal encoding method comprising:
The shift amount determining step includes:
Record the shift amount of at least one past frame in the frame shift amount holding buffer,
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
Of all bits in the n-digit range (n is an integer of 1 or more) including the lowest part of the integer part determined according to the shift amount candidates, 1 is less than a predetermined ratio or 0 is predetermined If the ratio is greater than or equal to the ratio, the number obtained by adding n to the shift amount candidates is defined as a shift amount candidate,
Determining a shift amount of the current frame according to a predetermined criterion using the shift amount candidates and the shift amount recorded in the frame shift amount holding buffer;
A signal encoding method characterized by the above. A frame buffer step for dividing the digital signal into a plurality of sample values (hereinafter referred to as “frames”) in the frame buffer;
A shift amount determination unit that determines a range of amplitudes of signals to be encoded as an integer part in the shift amount determination unit;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoding step for encoding the integer signal in the integer signal encoding unit;
An error signal encoding step of encoding an error signal in an error signal encoding unit;
An integration step of integrating the output of the integer signal encoding unit and the output of the error signal encoding unit in an integration unit;
A signal encoding method comprising:
The shift amount determining step includes:
Record the shift amount of at least one past frame in the frame shift amount holding buffer,
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
While increasing the shift amount one by one from the shift amount determined according to the shift amount candidate, the code amount when encoding according to the shift amount is calculated, and the code amount is more than the code amount at the previous shift amount. When the amount increases, the previous shift amount is set as a shift amount candidate of the frame,
Determining a shift amount of the current frame according to a predetermined criterion using the shift amount candidates and the shift amount recorded in the frame shift amount holding buffer;
A signal encoding method characterized by the above. A frame buffer step for dividing the digital signal into a plurality of sample values (hereinafter referred to as “frames”) in the frame buffer;
A shift amount determination unit that determines a range of amplitudes of signals to be encoded as an integer part in the shift amount determination unit;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoding step for encoding the integer signal in the integer signal encoding unit;
An error signal encoding step of encoding an error signal in an error signal encoding unit;
An integration step of integrating the output of the integer signal encoding unit and the output of the error signal encoding unit in an integration unit;
A signal encoding method comprising:
The shift amount determining step includes:
Record the shift amount of at least one past frame in the frame shift amount holding buffer,
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
Calculate the ratio of 1 in all bits in the n-digit range (n is an integer of 1 or more) from the lowest including the lowest of the integer part determined according to the shift amount candidates while increasing n from 1 by 1 Then, n is obtained in which the ratio of 1 is larger than the ratio of 1 in the previous calculation, and the shift amount is the number obtained by adding n-1 to the shift amount candidates.
Determining a shift amount of the current frame according to a predetermined criterion using the shift amount candidates and the shift amount recorded in the frame shift amount holding buffer;
A signal encoding method characterized by the above. A frame buffer step for dividing the digital signal into a plurality of sample values (hereinafter referred to as “frames”) in the frame buffer;
A shift amount determination unit that determines a range of amplitudes of signals to be encoded as an integer part in the shift amount determination unit;
A dividing unit that divides the digital signal into an integer signal and an error signal according to a shift amount determined by the shift amount determining unit;
An integer signal encoding step for encoding the integer signal in the integer signal encoding unit;
An error signal encoding step of encoding an error signal in an error signal encoding unit;
An integration step of integrating the output of the integer signal encoding unit and the output of the error signal encoding unit in an integration unit;
A signal encoding method comprising:
The shift amount determining step includes:
Record the shift amount of at least one past frame in the frame shift amount holding buffer,
The shift amount candidate is calculated so that the sample value with the maximum amplitude value in the frame becomes the maximum amplitude that can be expressed only by changing the shift amount within the range of the maximum value and the minimum value of the integer part,
Calculate the ratio of 0 in all bits in the n-digit range (n is an integer of 1 or more) from the lowest including the lowest of the integer part determined according to the shift amount candidates while increasing n from 1 by 1 N for which the ratio of 0 is less than the ratio of 0 in the previous calculation is obtained, and the shift amount is the number obtained by adding n-1 to the shift amount candidates,
Determining a shift amount of the current frame according to a predetermined criterion using the shift amount candidates and the shift amount recorded in the frame shift amount holding buffer;
A signal encoding method characterized by the above.   A signal encoding program for realizing the signal encoding apparatus according to any one of claims 1 to 12 by a computer.   A computer-readable recording medium on which the signal encoding program according to claim 25 is recorded.

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