JPH08322050A - Lossless video encoding / decoding method and apparatus - Google Patents

Abstract

(57) [Abstract] [Purpose] To efficiently perform lossless coding of moving images using inter-frame prediction, and to decode and play back almost lossless moving images in real time. [Structure] On the transmitting side, the input image 1 is expanded into bit planes, up to an appropriate bit plane is used for inter-frame prediction, the prediction error is lossless encoded, and the information of the bit plane used for prediction is added to the image header. The data of the non-encoded bit planes is accumulated, and the data of the non-encoded bit planes is transmitted after the end of the moving image sequence. On the receiving side, inter-frame prediction is performed based on the bit plane information, the prediction error is decoded and added, the lossless reproduction image 36 is decoded and reproduced in real time, this image is temporarily recorded, and it is insufficient at the end of the moving image sequence. The data of the existing bit planes is received and decoded, and the lossless moving image data is restored for all the bit planes together with the recorded original data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interframe predictive coding / decoding method in lossless moving picture coding.

[0002]

2. Description of the Related Art In conventional lossless moving image coding, data is compressed on the transmitting side, transmitted to the receiving side, and once stored on the receiving side, it is decoded to reproduce the image. That is,
It was decrypting in non-real time.

Here, the lossless coding is a coding method in which, when the coded data is decoded, the original data is stored without any loss. Lossless moving image coding refers to lossless coding of moving images. However, in the fixed rate channel, lossless coding cannot be performed in real time, which may cause delay.

[0004]

To efficiently perform lossless coding on a moving image, interframe prediction (or motion-compensated interframe prediction) may be performed and the prediction error may be lossless encoded. However, since the prediction error cannot be quantized under the constraint condition of lossless, the amount of information generated per frame cannot be controlled.
As a result, lossless encoding of moving images is possible, but it is impossible to transfer them to a fixed data transfer channel. Here, the fixed data transfer channel is a channel having a constant data transfer rate, and is a CBR (Constant Bitrate Cha
Also called nnel).

An object of the present invention is to efficiently perform lossless coding by using inter-frame prediction of moving images and to decode and reproduce a virtually lossless moving image in real time, and particularly on a receiving side, a reproduced image which is deteriorated during real time decoding. It is an object of the present invention to provide a lossless moving image encoding / decoding method and apparatus that can obtain lossless encoded data of all images at the end of a moving image sequence even though is output.

[0006]

According to the lossless moving picture coding / decoding method of the present invention, a transmitting side expands an input image into bit planes, and an appropriate bit plane is generated so that the bit rate is equal to or lower than a desired data transfer rate. It is used for inter-frame prediction, lossless coding of prediction error, information of bit plane used for prediction is added to the image header, data of uncoded bit plane is stored, and after the end of the moving image sequence. This unencoded bit-plane data is transmitted, the receiving side performs inter-frame prediction based on the bit-plane information specified for each input image, and the prediction error is decoded and added to determine the bits determined by the encoding side. The lossless playback image on the plane is decoded and played back in real time, and this image is temporarily recorded to create a moving image sequence. It receives and decodes for all the image data of the bit planes finally missing,
Lossless moving image data is restored for all bit planes together with the recorded original data.

The lossless moving picture coding / decoding apparatus of the present invention divides an input image into designated bit plane data, outputs all bit plane data and prediction bit plane data, and also performs inter-frame prediction. Bit plane disassociation unit for determining and outputting a bit plane disassociation level using prior knowledge about the number of bit planes used for inter-frame prediction and the amount of generated information, which is obtained by experience and the bit plane disassociation level for prediction A first differencer for calculating a difference between the plane data and the prediction data and outputting inter-frame difference data; an inter-frame encoding processing unit for inputting the inter-frame difference data and outputting inter-frame encoded data; Taking the difference between the prediction bit plane data and all the bit plane data,
A second differencer for outputting auxiliary bit plane data,
The intra-frame encoding processing unit that inputs the auxiliary bit plane data and outputs the auxiliary bit plane encoded data, the frame memory that stores all the bit plane data, and the previous frame image from the frame memory, and the bit plane A designated bit plane data extraction unit that outputs only the necessary bit plane data as the prediction data according to the cutting level, a memory, the auxiliary bit plane encoded data, the interframe encoded data, and the bit plane cutting level. Input, output auxiliary bit plate encoded data for the next inter-frame prediction, and add the number of bit planes of the auxiliary bit plane encoded data for the next inter-frame prediction to the bit plane cut level. Inter-frame prediction bit plane cutting And a lossless restoration data for one frame, stored in the memory, and output inter-frame coded data, and an encoding device including the lossless data, A lossless coded data decoding unit that decodes the restoration data and outputs the decoded data for lossless, and a decoding process of the auxiliary bit plate coded data for the next interframe prediction, and performs intraframe decoding for one frame An intra-frame encoded data decoding unit that outputs data, an inter-frame differential encoded data decoding unit that decodes the inter-frame encoded data, and outputs inter-frame differential decoded data,
The bit plane cut level and the previous frame local decoded image are input, and among the previous frame local decoded image, a designated bit plane data extraction unit that extracts only prediction data of a bit plane necessary for prediction, and the inter-frame difference decoded data A first adder that adds the prediction data and outputs inter-frame coded data; and a second adder that adds the intra-frame decoded data to the inter-frame coded data and outputs a real-time reproduced image. A frame memory for storing the real-time reproduced image for the next inter-frame prediction and outputting it as the previous frame local decoded image, and adding the lossless decoded data to the real-time reproduced image, and outputting it as a lossless restored image Three
And a decoding device including an adder.

[0008]

According to the present invention, the encoding side limits the bit plane of an image used for inter-frame prediction, and adds information indicating from the upper bit to which bit plane is used for prediction in the image header.

FIG. 2 shows an example in which one frame of an 8-bit gradation image is developed into a bit plane. Usually, the most significant bit is the first bit plane. In the present invention, for example, up to the fifth bit plane is used for interframe prediction. Which bit plane is used for prediction can be changed for each image, and is multiplexed and transmitted in the header part of the encoded data. The decoding side reads this information and uses up to how many bits of the locally decoded image (the (n-1) th coded image used to predict the nth image on the coding side and the decoding side). To determine. Note that up to a certain bit plane of the input image corresponds to the locally decoded signal, it is not necessary to perform local decoding on the encoding side, the input image is stored in the memory, and the bit plane cut level (for prediction of the bit plane Bit plane used)
It is enough to retrieve the data up to.

The prediction error in the desired bit plane is directly Huffman coded or arithmetic coded, or DPC
After performing M or Hadamard transformation, lossless coding is performed by Huffman coding or arithmetic coding.

Bit plane data not used for prediction is Huffman coded or arithmetic coded as it is, or DPCM is performed and then Huffman coded or arithmetic coded to lossless code. However, among the coded data of the bit planes not used for this prediction, some bit plane data belonging to the most important bit side is used for prediction of the next frame, and therefore is multiplexed and transmitted at the same time. Which bit plane is transmitted at the same time depends on the data transfer rate. That is, encoded data of as many bit planes as possible is transmitted until the data transfer capacity for one frame is reached.

Since the image is lossless-encoded, it is not necessary for the encoding side to generate a locally decoded image for inter-frame prediction. It is only necessary to input the image memory of the previous frame and record only the information of the cutting level of the bit plane used for prediction, and the local decoding process can be omitted.

On the other hand, among the data of the bit planes not used for the prediction, those that have not been transmitted are once recorded. This data is not transmitted when the encoding / decoding system is operating in real time, and is separately transmitted after the transmission of the moving image sequence is completed.

The bit plane used for prediction on the encoding side is selected so that the encoded data can be suppressed to a desired data transfer rate. Now, the example shown in FIG. 3 is a case where when the P-th frame is encoded, data up to the N-th bit plane is predicted and encoded using the data of the past frames.

At this time, even if the prediction error signal is encoded,
If the transfer capacity still has a margin, the encoded data in the N + 1th to Mth bit planes is intraframe-encoded and transmitted as auxiliary data. The data of the first to Mth bit planes are used for the prediction of the P + 1th frame. However, in this example, when the data of the first to M-th and L-th bit planes are inter-frame predicted to be encoded and transferred, the specified rate is exceeded. So P + 1
The data from the K + 1th to Lth bit planes, which uses the data of the first to Kth (K ≦ M) bit planes for the second inter-frame prediction, are once encoded and stored in the memory, and the encoding of the moving image sequence is performed. -After decoding, it is transmitted for lossless data restoration.

On the contrary, the example shown in FIG. 4 is a case where the number of bit planes used for prediction decreases. When the P-th frame is encoded, the data up to the M-th bit plane is predicted and encoded using the data of the past frames. However, when the prediction error signal is encoded by using all of this data for the prediction of the P + 1th frame, the encoded data amount exceeds the specified value. At this time, the first to Nth (N
<M and N are maximum values in which the data amount does not exceed the specified value.) Bit plane data is used. All of the remaining bit plane data is transmitted for lossless data restoration after encoding / decoding of the moving image sequence.

According to the present invention, a lossless moving image up to the bit plane added to the image header can always be obtained during real-time decoding. In addition, at the end of the moving image sequence, if the deficiency for lossless data for all bit planes of each image is received and decoded, the moving image data on the encoding side is added by adding it to the previous decoded data. It can be completely reproduced.

As described in claim 2, motion-compensated interframe prediction can be used instead of simple interframe prediction. Also at this time, the method of bit plane division described above can be used as it is.

Up to this point, it has been described that all the data for lossless data restoration is separately transmitted after the real-time encoding / decoding of the moving image sequence is completed. However, even during transmission of the moving image sequence, the lossless restoration data can be transmitted as soon as the transmission capacity becomes available. In this case, it is necessary to add information about which frame of the image data corresponds to the header.

In the above series of explanations, an example in which the interframe coding method is used over the entire frame has been shown. However, in some cases, partial intraframe coding may result in better coding efficiency. . Therefore, the coding efficiency can be improved by dividing the frame into small blocks and switching between inter-frame coding and intra-frame coding for each block. At this time, it is necessary to give a flag indicating in block units which mode is used for encoding between frames or within a frame.

[0021]

Embodiments of the present invention will now be described with reference to the drawings.

FIGS. 1A and 1B are block diagrams of an encoding device and a decoding device of a lossless moving image encoding / decoding device of the present invention, respectively.

The encoding device divides the input image 1 into data of a specified bit plane, outputs all bit plane data 3 and prediction bit plane data 4, and also inter-frame prediction bit plane cut level information 19 And a bit plane disassembling unit 2 that determines and outputs a bit plane cutting level 5 using prior knowledge about the number of bit planes used for inter-frame prediction versus the amount of generated information obtained through experience, and the prediction bit plane data 4. A difference unit 7 that takes the difference between the prediction data 6 and outputs inter-frame difference data 8; an inter-frame coding processing unit 9 that inputs the inter-frame difference data 8 and outputs inter-frame coded data 10; The difference between the bit plane data 4 and all bit plane data 3 is calculated, and the auxiliary bit plane data 12 is output. And minute 11, enter the auxiliary bit plane data 12, the auxiliary bit-plane coded data 1
4, an intra-frame encoding processing unit 13 that outputs 4, a frame memory 15 that stores all bit-plane data 3, and a previous frame image 16 from the frame memory 15, and the data of the bit-plane required according to the bit-plane cutting level 5. The specified bit plane data extraction unit 17 that outputs only the prediction data 6, the memory 21, the auxiliary bit plane coded data 14, the inter-frame coded data 10, and the bit plane cut level 5 are input, and the next inter-frame prediction is performed. Of the auxiliary bit plane encoded data 23 is output, and the bit plane disconnection level information 19 is obtained by adding the number of bit planes of the auxiliary bit plane encoded data 23 to the bit plane disconnection level 5.
Is output to the bit plane disassembling unit 2, the lossless data 20 for one frame is output, the data is stored in the memory 21, and the inter-frame coded data 24 is output.

The decoding device decodes the lossless restoration data 22 and outputs a lossless coded data decoding unit 25 for outputting the lossless decoded data 28 and an auxiliary bit plate coded data 23 for the next interframe prediction. An intraframe coded data decoding unit 26 that performs decoding processing and outputs intraframe decoded data 29 for one frame, and an interframe differential code that decodes interframe coded data 24 and outputs interframe differential decoded data 30. Data decoding unit 2
7, a bit plane cut level 5, a previous frame local decoded image 38, and a designated bit plane data extraction unit 34 for extracting only the prediction data 31 of the bit plane necessary for prediction from the previous frame local decoded image 38; The predicted data 31 is added to the inter-difference decoded data 30,
An adder 32 that outputs interframe encoded data 33,
The intraframe decoded data 29 for one frame is added to the interframe coded data 33, and the realtime reproduced image 36
And a frame memory 37 that stores the real-time playback image 36 for the next inter-frame prediction and outputs as the previous frame local decoded image 38, and the lossless decoded data 28 to the real-time playback image 36. , A lossless decoded image 40 is output, and an adder 39 is provided.

Next, the operation of this embodiment will be described.

First, the encoding side (FIG. 1A) will be described.

The input image 1 is divided into data of a designated bit plane in the bit plane decomposition unit 2,
Bit plane cut level 5 is output for decoding processing and prediction. Further, all bit plane data 3 is output as it is, and the prediction bit plane data 4 is used for interframe prediction. In the bit plane decomposition unit 2, inter-frame prediction bit plane disconnection level information 19 input from the data capacity inspection unit 18 and prior knowledge about the number of bit planes used for inter-frame prediction and the generated information amount obtained from experience are provided. Use to determine bitplane cut level 5. When the amount of information generated by the inter-frame predictive coding exceeds the data transfer rate, the bit plane cut level 5 is reduced to reduce the amount of information generated by the inter-frame predictive coding. The entire bit plane data 3 is stored in the frame memory 15 to predict the next frame. Bit plane data for prediction 4
Of the prediction data 6 is calculated by the difference calculator 7, and the obtained inter-frame difference data 8 is input to the inter-frame encoding processing unit 9. Interframe encoded data 10 is output from the interframe encoding processing unit 9 and input to the data capacity calculation unit 18. The difference between the predicted bit plane data 4 and all the bit plane data 3 is calculated by the differentiator 11, and the auxiliary bit plane data 12 is obtained. The auxiliary bit plane data 12 is the intra-frame encoding processing unit 13
And the auxiliary bit plane encoded data 14 is output.

The previous frame image 16 is extracted from the frame memory 15 and the designated bit plane data extraction unit 1
In 7, only the data of the bit plane required according to the bit plane cut level 5 is output as the prediction data 6.

In the data capacity inspection unit 18, the inter-frame prediction bit plane disconnection level information 19 is output to the bit plane decomposition unit 2 for the next inter-frame prediction.
Further, lossless restoration data (for one frame) 20 is output and stored in the memory 21, and auxiliary bit plane encoded data (for the next interframe prediction) 23 and interframe encoded data 24 are output. After the real-time transmission is completed, the memory 21 outputs lossless restoration data (for a moving image sequence) 22.

In the data capacity checking unit 18, when the amount of information generated by inter-frame coding is less than or equal to the data transfer rate, and even if one or more bit planes are intra-coded, the data transfer rate does not exceed the auxiliary bit plane code. The converted data 23 is output, and this data is used for the next inter-frame prediction.

The inter-frame prediction bit plane cut level information 19 is information obtained by adding the number of bit planes of the auxiliary bit plane encoded data (for the next inter frame prediction) 23 to the bit plane cut level 5 and below this level. Interframe prediction is possible in the bit plane. This information is fed back to the bit plane decomposition unit 2 for encoding the next frame.

Next, the decoding side (FIG. 1B) will be described.

The lossless decoding data (for the moving image sequence) 22 is decoded by the lossless encoded data decoding unit 25, and the lossless decoded data 28 is output. The auxiliary bit plane coded data (for the next inter-frame prediction) 23 is decoded by the intra-frame coded data decoding unit 26, and the intra-frame decoded data (one frame) 29 is output. The interframe encoded data 24 is decoded by the interframe differential encoded data decoding unit 27, and the interframe differential decoded data 30 is output.
The bit plane cut level 5 is given to the designated bit plane data extraction unit 34, and the previous frame locally decoded image 38
Of the bit plane prediction data 31 required for prediction
Only is taken out. The interframe difference decoded data 30 is added to the prediction data 41 by the adder 32 to obtain interframe encoded data 33. Interframe coded data 3
In-frame decoded data (for one frame) 29 is further added to 3 by the adder 35, and the real-time reproduced image 36
Is obtained. This image 36 is reproduced when the encoding and decoding are operated in real time. The real-time reproduced image 36 is stored in the frame memory 37 for the next inter-frame prediction. In addition, after the real-time encoding and decoding are finished once, the lossless decoded data 28 is added to each image 36 by the adder 39 to obtain a lossless image, and the lossless restored image 40 is output.

[0034]

As described above, according to the present invention, a moving image is efficiently lossless-encoded using interframe prediction under a fixed data transfer channel, and a substantially lossless moving image is decoded and reproduced in real time. High-compression rate, display function, and data storage because the receiving side outputs lossless coded data of all images at the end of the moving image sequence, even though a reproduced image with deterioration is output during real-time decoding. There is an effect that a moving image lossless encoding / decoding method that satisfies the requirement can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram of a lossless moving image encoding / decoding device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example in which one frame of an image having 8-bit gradation is developed into a bit plane.

[Fig. 3] Fig. 3 is a diagram illustrating an example in which, when the P-th frame is encoded, data up to the N-th bit plane is predicted and encoded using data of past frames.

FIG. 4 is a diagram showing an example in which the number of bit plates used for prediction decreases.

[Explanation of symbols]

1 Input image 2 Bit plane decomposition unit 3 All bit plane data 4 Prediction bit plane data 5 Bit plane cutting level 6 Prediction data 7, 11 Difference unit 8 Interframe difference data 9 Interframe encoding processing unit 10 Interframe encoded data 12 auxiliary bit plane data 13 intra-frame encoding processing unit 14 auxiliary bit plane encoded data 15 frame memory 16 previous frame image 17 designated bit plane data extraction unit 18 data capacity inspection unit 19 inter-frame prediction bit plane cut level information 20 lossless Restoration data (for one frame) 21 Memory 22 Lossless restoration data (moving image sequence) 23 Auxiliary bit plane coded data (for next inter-frame prediction) 24 Inter-frame coded data 25 Lossless coded data Decoding unit 26 Intra-frame encoded data decoding unit 27 Inter-frame differential encoded data decoding unit 28 Lossless decoded data 29 In-frame decoded data (for one frame) 30 Inter-frame differential decoded data 31 Predicted data 32, 35, 39 Adder 33 inter-frame coded data 34 designated bit plane data extraction unit 36 real-time playback image 37 frame memory 38 previous frame locally decoded image 40 lossless restored image

Claims (5)

[Claims] 1. A lossless moving picture coding / decoding method for losslessly coding and transmitting a moving picture using inter-frame prediction and decoding the same, wherein a transmitting side expands an input picture into a bit plane and transfers desired data. Uses up to an appropriate bitplane so that it is less than or equal to the rate for interframe prediction, losslessly encodes the prediction error, adds the information of the bitplane used for prediction to the image header, and the data of the unencoded bitplane Are stored, and the data of this uncoded bit plane is transmitted after the end of the moving image sequence, and the receiving side performs inter-frame prediction using the bit plane information specified for each input image and decodes the prediction error. Then, the lossless playback image on the bit plane determined by the encoding side is decoded and played back in real time. At the same time, this image is temporarily recorded, and the missing bit plane data is received and decoded for all images at the end of the moving image sequence, and all the bit planes are combined with the original data that was recorded. A lossless moving image encoding / decoding method characterized by restoring lossless moving image data. 2. The lossless video encoding / decoding method according to claim 1, wherein motion-compensated interframe prediction is used instead of interframe prediction. 3. The method according to claim 1, wherein even in the middle of the moving image sequence, when the data transfer has a margin, the data of the missing bit planes are sequentially transmitted in the image encoding order of the moving image sequence. 2. The lossless moving image encoding / decoding method described in 2. 4. The lossless according to claim 1, wherein instead of using inter-frame prediction for the entire image, the image is blocked and the modes of intra-frame coding and inter-frame coding are locally switched. Video coding / decoding method. 5. An input image is divided into designated bit plane data, all bit plane data and prediction bit plane data are output, and inter-frame prediction bit plane cutting level information and experience are obtained. The bit plane cutting level is determined using prior knowledge about the number of bit planes used for inter-frame prediction versus the amount of generated information, and the difference between the bit plane decomposition unit for outputting and the prediction bit plane data and the prediction data is calculated, A first difference device that outputs difference data; an interframe encoding processing unit that inputs the interframe difference data and outputs interframe encoded data; a prediction bitplane data and all bitplane data; A second differencer for calculating a difference and outputting auxiliary bit plane data; and the auxiliary bit In-frame encoding processing unit that inputs plane data and outputs auxiliary bit plane encoded data, frame memory that stores all the bit plane data, and a previous frame image is extracted from the frame memory, and the bit plane cut level is set. A designated bit plane data extraction unit that outputs only the required bit plane data as the prediction data according to the above, a memory, the auxiliary bit plane encoded data, the inter frame encoded data, and the bit plane cut level are input.
Output auxiliary bit plane encoded data for the next inter-frame prediction, and add the bit plane cut level to the number of bit planes of the auxiliary bit plane encoded data for the next inter-frame prediction An encoding device including a data capacity calculator that outputs to the bit plane disassembling unit as output bit plane cutting level information, outputs lossless restoration data for one frame, stores the data in the memory, and outputs interframe encoded data. And a lossless encoded data decoding unit that decodes the lossless restoration data and outputs the lossless decoded data, and a decoding process of the auxiliary bit plate encoded data for the next inter-frame prediction, for one frame. Intra-frame encoded data decoding unit that outputs the intra-frame decoded data of And decoding the data, the inter-frame differential coding data decoding section for outputting a differential decoding data between frames, enter the bit plane cutting level and the previous frame local decoded image, of the previous frame local decoded image,
A designated bit plane data extraction unit for extracting only prediction data of a bit plane required for prediction; a first adder for adding the prediction data to the inter-frame difference decoded data and outputting inter-frame encoded data; A second adder for adding the intra-frame decoded data to the inter-coded data and outputting a real-time reproduced image, and the real-time reproduced image is stored for the next inter-frame prediction and output as the previous frame locally decoded image. A lossless moving image coding / decoding device having a frame memory and a decoding device including a third adder that adds the lossless decoded data to the real-time reproduced image and outputs the lossless restored image.