JP3209259B2 - Image signal encoding / decoding method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image signal encoding / decoding method for outputting encoded data in accordance with a required condition and decoding the encoded data in encoding / decoding an image signal such as a revision. And its equipment.

[0002]

2. Description of the Related Art Conventionally, image signals are encoded according to requirements such as image quality, encoding delay, special reproduction, etc., according to an encoding algorithm and an encoding mode suitable for one of the requirements. Was.

FIG. 6A shows a conventional image signal encoding apparatus,
FIG. 6B is an explanatory diagram of the decoding device.

This encoding apparatus comprises a lossless encoding unit 703, a special reproduction encoding unit 704, a high compression encoding unit 705, and a low delay encoding unit 70.
And the decoding apparatus has a lossless decoding unit 71 as a decoding unit corresponding to the coding unit.
1, a decoding unit for trick play 712, a decoding unit for high compression 713, and a decoding unit for low delay 714. The image signal input from the input terminal 701 is input to one of the encoding units 703 to 706 according to the required conditions by the switch 702. For example, when an encoding algorithm suitable for special reproduction is used, an image signal is input to a special reproduction encoding unit 704, and after being encoded, is switched by a switch 707 synchronized with a switch 702 and an output terminal 708. Is output to

Next, a decoding device will be described.

[0006] The encoded data inputted from the input terminal 709 is inputted by the switch 710 to the decoding units 711 to 714 corresponding to the encoding algorithm at the time of encoding. For example, the encoding unit for special reproduction 704
Is input to the decoding unit for special reproduction 712, and is decoded. The decoded image is switched by the switch 715 synchronized with the switch 710 and output to the output terminal 716. You. Switching of the switch of the decoding device is automatically performed based on the content of the input encoded data and additional information other than the encoded data.

According to such a method, it is possible to connect to a desired coding algorithm from a plurality of different coding algorithms, and as a result, it is possible to select a coding algorithm according to a required condition.

[0008]

In the conventional image signal encoding / decoding apparatus described above, the user switches the individual encoding algorithm appropriately according to the required conditions. According to this, when there are a plurality of required conditions, there are cases where the required conditions are not partially satisfied.

For example, under the requirement of an algorithm that is suitable for special reproduction and has high compression, algorithm A is an algorithm suitable for special reproduction, and algorithm B is an algorithm that is not suitable for high compression. In the conventional method, only one of the algorithms A and B can be selected. In particular, when both requirements are satisfied to some extent, it is almost impossible to use the AB algorithm in combination as an intermediate encoding algorithm.

As described above, the conventional method has a problem that an encoding algorithm satisfying a plurality of requirements cannot be selected, and the requirements are not partially satisfied.

An object of the present invention is to provide an image signal encoding / decoding method and an apparatus capable of making a plurality of requirements correspond to a plurality of encoding algorithms.

[0012]

According to the present invention, there is provided an image signal encoding / decoding method for encoding an image signal by inputting a priority of a required condition item to a plurality of encoding algorithms . In the encoding method, a step of inputting the priority of a plurality of request condition items determined according to the encoding condition of the image signal, and calculating an appropriateness degree for each of a plurality of encoding algorithms from the priority, Calculating individual usage rates of the plurality of encoding algorithms from the suitability level; and adaptively switching the plurality of encoding algorithms to input image data based on the usage rates to perform encoding. Executing, and adding coding algorithm discrimination information to the coded data, wherein the plurality of coding algorithms are applied based on the usage rate. Receiving the encoded data, determining a decoding algorithm corresponding to the corresponding encoding algorithm for the data; and decoding the determined decoding algorithm corresponding to the corresponding data. Has steps.

An image signal encoding / decoding apparatus according to the present invention comprises:
An image signal encoding / decoding device that inputs a priority of a requirement condition item and encodes an image signal with respect to a plurality of encoding algorithms includes a plurality of requirement condition items determined according to an image signal encoding condition. Means for inputting a priority, from the priority , means for calculating the suitability of the selected plurality of encoding algorithms, and means for calculating the usage rate of the plurality of encoding algorithms from the suitability,
Means for adaptively switching the plurality of encoding algorithms based on the usage rate, means for selectively executing the plurality of encoding algorithms, means for adding encoding algorithm determination information to encoded data, Means for determining an encoding algorithm corresponding to the received encoded data when receiving encoded data to which a plurality of encoding algorithms have been applied based on the usage rate, and applying the determined decoding algorithm. Means for decoding in accordance with the data.

Further, the means for calculating the suitability of the plurality of coding algorithms is calculated from a coding algorithm suitability table set for each coding algorithm and each requirement and a priority for each requirement. desirable.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS When the encoding condition of an image signal is determined,
Calculating a suitability degree of the corresponding coding algorithm from the priority of each item of the corresponding requirements to calculate the usage rate of each coding algorithm from該適resistance degree, the appropriate code Kaa <br/> Rugorizu arm Since coding is performed by adaptively switching according to the calculated usage rate, a plurality of coding algorithms are applied in a state according to application requirements.

Next, the concept of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram for explaining the concept of an encoding device of an image signal encoding / decoding device to which the image signal encoding / decoding method of the present invention is applied, and FIG. 2 is a diagram showing the image shown in FIG. It is a flowchart of a part of encoding operation of the signal encoding / decoding device.

It is assumed that the number of application condition items is M, and the number of implemented encoding algorithms is N. For each requirement individually, the appropriateness 207 of each encoding algorithm is
_mn (m = 1, 2,..., M, n = 1, 2,..., N) and are obtained in advance.
For example, if the suitability of the encoding algorithm 1 for the item 1 of the requirement is set to o , then O _1,1 = o (step 11).

When the priority 206 of a plurality of externally input requirement conditions is R _m (m = 1, 2,..., M), each encoding algorithm in the encoding algorithm suitability degree calculating unit 208 Suitability calculation units 281 to 28N
Each coding algorithm suitability degree P ₁ to P _N from that calculated by the following equation (step 12-14).

P _n = F _n ( O _{1, n} , O _{2, n} ,..., OM _{, n} , R ₁ , R ₂ ,..., R _M ) In section 210, the encoding algorithm suitability degree P _n calculated by the above equation
In step 209, the usage rate _Un 211 of each sub-code algorithm under the plurality of input request conditions is determined (step 15).

[0021] _{U n = G (P 1,} P 2, ···, P N) using a utilization U _n, coding algorithm switching control section 2
At 12, the switches 202 and 204 are switched in a desired unit such as a frame unit or a small block unit.

In addition, the coding algorithm discriminating information adding unit 214 uses the coding algorithm information 213 to discriminate the algorithm coded by the decoding apparatus. Add information.

With such a structure, the image signal input to the image signal input terminal 201 switches the encoding units 231 to 23N in the encoding unit 203 to be used adaptively according to a plurality of requirements. After being encoded, the encoded data is output to the encoded data output terminal 205 after being added with encoding algorithm discrimination information.

Next, the decoding device performs decoding by switching and applying the decoding algorithm based on the encoding algorithm discrimination information included in the encoded data.

According to such a method, a plurality of coding algorithms can be adaptively applied to a plurality of requirement conditions according to the priority of each requirement condition. Is obtained.

[0026]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 shows a first embodiment of the video signal encoding apparatus according to the present invention.
FIG. 4 is a block diagram of an embodiment of FIG. This video signal encoding algorithm is of two types, a fixed code length encoding algorithm and a variable length encoding algorithm, and it is assumed that switching is possible in frame units. The items of the required conditions are transmission error strength and compression efficiency.

The characteristics of both encoding algorithms are as follows.
The fixed code length coding algorithm outputs coded data using a code of a fixed length, and thus is resistant to transmission errors, but does not perform code assignment based on the occurrence probability, resulting in low compression efficiency. Conversely, in the variable code length coding algorithm, codes are assigned based on the appearance probability, and although the compression efficiency is high, it is weak against transmission errors. The suitability of both coding algorithms for transmission error strength and compression efficiency is assumed as a coding algorithm suitability table 409 as shown in the table below.

[0029]

[Table 1] The encoding device will be described. Transmission error strength input terminal 4
07 and the compression efficiency input terminal 408, the transmission error strength priority R _r and the compression efficiency priority R _c are input, respectively. However, it is assumed that _Rr + _Rc = 1. Priority R _c in compression efficiency and priority R _r of the input transmission error intensity, and, from the coding algorithm aptitude table 409, calculates the suitability degree P _f of both coding algorithms.

The variable code length coding suitability degree calculation unit 4
At 10, the appropriateness P of the variable code length encoding algorithm
_v 411 is calculated, and the fixed code length coding suitability calculating unit 412 calculates the suitability P _f 413 of the fixed code length coding algorithm.

P _V = 0.3 · R _{r +} 0.8 · R _c P _f = 0.9 · R _{r +} 0.4 · R _{c For} both coding algorithms calculated by the coding algorithm usage rate calculation unit 414, Suitability _Pv 411 and P _f 4
13, the usage rates U _v and U _f 415 of both encoding algorithms
Is calculated.

U _v = P _v / (Pv + P _f ) U _f = 1−U _{v In the} coding algorithm switching control unit 416, the switches 402 and 4 are switched by using the usage rate 415 of the variable length algorithm.
Switch 05. Switching is performed in frame units.
For example, when the usage rate U _v of the variable code length algorithm is 10
Two frames in the frame variable code length coding unit 40
3 and the remaining 8 frames are encoded using the fixed code length encoding unit 404. This example is shown in FIG.
Shown in Next, the operation of the present embodiment will be described.

The image signal input to the image signal input terminal 401 is connected to the input coding unit by the switches 402 and 405 controlled by the coding algorithm switching control unit 416, and is coded by the switch. The coded data passes through a switch 405, is added with coding algorithm information 417 for determining the algorithm coded by the decoding device in a coding algorithm determining information adding unit 418, and is output from an output terminal 406. You.

With such a structure, the encoding algorithm can be adaptively switched for a plurality of requirements.

Next, the decoding apparatus will be described.

FIG . 5 is a block diagram of the decoding device of the first embodiment of the image signal coding / decoding device of the present invention.

The coded data input to the coded data input terminal 601 is subjected to a decoding algorithm judgment by a decoding algorithm discriminating section 602, and a switch 603 switched by the decoding algorithm determining section 602 determines whether the variable code length decoding unit 604 It is connected to the fixed code length decoding unit 605. The image signal decoded by the corresponding decoding unit is selected by the switch 606 linked with the switch 603 and output to the image signal output terminal 607.

In the above-described embodiment, the switching of the encoding algorithm is performed on a frame basis, the required condition is 2, and the type of the encoding algorithm is 2. However, the present invention is not limited to this. Furthermore, the method of calculating the appropriateness of the encoding algorithm and the method of calculating the usage rate are arbitrary.

[0039]

As described above, according to the present invention, the encoding algorithm can be adaptively switched in accordance with the requirement of the inverse number, so that encoding / decoding satisfying a plurality of requirements is possible. There is an effect that there is.

[Brief description of the drawings]

FIG. 1 is a block diagram of an encoding device for explaining the concept of an image signal encoding / decoding device according to the present invention.

FIG. 2 is a flowchart of the operation of the apparatus shown in FIG.

FIG. 3 is a block diagram of an encoding device of the first embodiment of the image signal encoding / decoding device of the present invention.

FIG. 4 is a diagram illustrating an example of switching of an encoding algorithm according to the first embodiment illustrated in FIG. 3;

FIG. 5 is a block diagram of a decoding device part of the first embodiment.

FIG. 6A is a block diagram of an encoding device portion of a conventional image signal encoding / decoding device A, and FIG. 6B is a block diagram of a stiffening device portion thereof.

[Explanation of symbols]

201 the image signal input terminal 202 switch 203 coding unit 204 switch 205 the coded data output terminal 206 requirements priority R ₁ to R _M 207 coding algorithm suitability table 208 coding aptitude degree calculation unit 209 coding suitability degree P ₁ ~ P _N 210 utilization coding algorithm usage rate calculation unit 211 coding algorithm U ₁ ~U _N 212 coding algorithm switching control section 213 encoding algorithm information 214 coding algorithm discrimination information adding unit 231~23N coding unit 281 to 28N coding algorithm suitability degree calculation unit 401 image signal input terminal 402 switch 403 variable code length coding unit 404 priority R _r of a fixed code length coding unit 405 switches 406 encoded data output terminal 407 transmission error intensity Input terminal 409 encoding the encoding algorithm suitability table 410 variable code length coding suitability degree calculation unit 411 variable code length coding suitability degree P _v 412 fixed code length coding suitability degree of priority R _c input terminal 408 compression efficiency Calculation unit 413 Fixed code length coding suitability degree P _f 414 Coding algorithm usage rate calculation unit 415 Both coding algorithm information 416 Coding algorithm switching control unit 417 Coding algorithm information 418 Coding algorithm discrimination information addition unit 601 Coded data Input terminal 602 Switch 603 Decoding algorithm determination unit 604 Variable code length decoding unit 605 Fixed code length decoding unit 606 Switch 607 Image signal output terminal

Claims (3)

(57) [Claims] 1. A picture signal coding and decoding method for encoding and the input image signal a priority requirement items against the plurality of coding algorithms, more defined depending on the encoding condition of image signal Inputting the priority of the required condition item, calculating the suitability for each of the plurality of encoding algorithms from the priority, and calculating the individual usage rates of the plurality of coding algorithms from the suitability Performing coding by adaptively switching the plurality of coding algorithms to the input image data based on the usage rate, and adding coding algorithm determination information to the coded data. When encoded data to which the plurality of encoding algorithms are applied based on the usage rate is input, the Steps and, the image signal coding and decoding method characterized by comprising the step of decoding so as to correspond to data corresponding to the discriminated decoding algorithm to determine the decoding algorithm corresponding to the encoding algorithm to. 2. An image signal encoding / decoding apparatus for encoding an image signal by inputting a priority of a requirement condition item for a plurality of encoding algorithms, comprising: Means for inputting the priority of the requirement condition item, means for calculating the suitability of the selected plurality of encoding algorithms from the priority , and calculating the usage rates of the plurality of coding algorithms from the suitability Means, means for adaptively switching the plurality of coding algorithms based on the usage rate, means for selectively executing the plurality of coding algorithms, means for adding coding algorithm discrimination information to coded data And, upon receiving encoded data to which the plurality of encoding algorithms are applied based on the usage rate, a code corresponding to the received encoded data. Image, characterized in that it comprises means for determining the algorithm, and means for decoding so as to correspond to data corresponding the discriminated decoding algorithm
Image signal encoding / decoding device . 3. The method according to claim 2, wherein the means for calculating the degree of suitability of the plurality of coding algorithms is calculated from a coding algorithm suitability table set for each coding algorithm and each requirement and a priority for each requirement. Image signal encoding / decoding device.