KR0148136B1 - Inter/intramode code method and apparatus - Google Patents

Abstract

The present invention relates to a method of encoding digital image data, and receives inter- or intra-mode data for each block among transmission data having information on one screen, and inter-mode or intra-block unit by block unit or macro block unit. By setting a value of 0 or 1 for a mode, it is configured in the form of a bit map for one screen, and the mode data in the bitmap form is run in consideration of the fact that each of the above modes are located in a cluster. The present invention relates to an inter / intra-mode encoding method and apparatus for further increasing the compression rate of total transmission data by encoding and variable length encoding.

Description

Inter / Intramode Coding Method and Apparatus

1 is a block diagram showing an inter / intra mode encoding apparatus according to the present invention.

2 is a block diagram showing data output from a quantization unit of a general encoding apparatus.

FIG. 3 is a conceptual diagram for describing an operation of a bitmap converter of FIG. 1 apparatus.

* Explanation of symbols for main parts of the drawings

20: mode determination unit 21: bitmap conversion unit

22: run length encoder 23: variable length encoder

The present invention relates to a method of encoding digital image data, and more particularly, to compressing transmission data by bitmaping the overhead data for distinguishing the intra mode and the inter mode among the data transmission formats, and performing run length and variable length encoding. The present invention relates to an intra mode encoding method and apparatus.

Recently, in a system for transmitting and receiving video and audio, a method of encoding and transmitting a video signal and an audio signal as a digital signal, or storing the image signal and a storage unit, and decoding and replaying the same is mainly used. Methods used for encoding such video signals include a conversion encoding method, a differential pulse code modulation (DPCM) method, a vector quantization method, and a variable length coding (VLC) method. These coding methods are used to compress redundancy data included in the digital video signal to compress the total amount of data. In order to perform the encoding scheme, the screen is divided into blocks having a predetermined size, and predetermined conversion is performed on each block or difference signal between the blocks to convert the image data into a conversion coefficient of the frequency domain. Examples of data transformation methods for each block include DCT (Discrete Cosine Transform), WHT (Walsh-Hadamard Transform), DFT (Discrete Fourier TRansform), and DST (Discrete Sine Transform). The transmission data is compressed by appropriately encoding such transform coefficients according to data characteristics. In order to restore the encoded and transmitted video data to the original video signal, it is necessary to transmit the head data including the encoded state information of the video signal together with the transmission of the video data. In general, in the variable length encoding scheme of moving images, information on which mode is encoded is used in intra mode when there is a large change between images and inter mode when there is a small change between images. .

2 is a block diagram showing a format of data after quantization, including overhead data indicating a quantization level of data quantized in units of blocks, mode information indicating whether each block is encoded in an inter mode or an intra mode, And a quantization coefficient representing substantial image data. However, when encoding an image of one field or frame in units of blocks, information on which mode the data is encoded must be transmitted for each block, thereby increasing the amount of total transmission data.

Accordingly, an object of the present invention is to further compress transmission data by constructing a bitmap of head data indicating an inter mode or an intra mode in block units, and performing run length coding and variable length coding in line units in transmitting video signals. An inter / intra mode encoding method can be provided.

Another object of the present invention is to provide an apparatus for implementing the aforementioned inter / intra mode encoding method.

An object of the present invention as described above is a method of encoding an overhead data for determining an inter / intra mode in a block unit or a macroblock unit for a screen, wherein the intermode is performed for each block or macroblock from image data for transmission. Determining whether to encode in the frame or intra mode, and by receiving the mode information generated in the determining step, and assigning a value of 0 or 1 for each mode in units of blocks or macroblocks, A bitmap form, a runlength-encoded data line-by-line, and a variable length-encoded runlength-coded data. Is achieved.

Another object of the present invention is an apparatus for encoding an overhead data for determining an inter / intra mode in a block unit or a macroblock unit for one screen, and receives an image data for transmission to interleave each block or macroblock. Supply a mode decision unit for outputting mode data for determining whether to encode in mode or intra mode, a bitmap converter configured to receive mode data in a bitmap form, and data in bitmap form. It is achieved by an inter / intra-mode encoding apparatus including a run length encoding unit for receiving a line length code and a variable length encoding unit for variable length encoding and outputting data applied from the run length encoding unit.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 shows an embodiment of an inter / intra mode encoding apparatus according to the present invention. In FIG. 1, the image data VS is input to the N × N converter 11 through the first adder A1, and the output terminal of the N × N converter 11 is connected to the input terminal of the quantization unit 12. The output terminal of the quantization unit 12 is connected to the variable length encoding unit 13. On the other hand, the image data VS is also supplied to the mode determination unit 20, and the mode determination unit 20 determines the inter mode or the intra mode according to the degree of change of the image, and then converts the inter / intra mode information into the next bitmap. It is supplied to the converter 21 and the two switches RSW1 and RSW2. The output terminal of the bitmap converter 21 is connected to the run length encoder 22 and the output of the run length encoder 22 is supplied to the variable length encoder 23 so that variable length encoded mode information is applied to the buffer 14. do. The variable length coded signal is transmitted after being delayed in the buffer 14. A signal for determining the quantization level QS according to the buffer 14 state is supplied to the quantization unit 12 and the dequantization unit 15. Meanwhile, the quantization unit 12 outputs a quantized signal to the inverse quantization unit 15, and the inverse quantization unit 15 is connected to an input terminal of the N × N inverse transform unit 16. At this time, the signal output from the N × N inverse transform unit 16 is applied to the frame memory 17 through the second adder A2, and the frame memory 17 is divided into the equalizer 18 and the dynamic compensator 19, respectively. It is configured to apply an output. The output of the compensator 19 is applied to the first adder A1 and the second adder A2, and the equalizer 18 receives the image data VS to the compensator 19 to obtain the motion vector MV. And output together with the encoded video signal VC.

The operation of the present invention configured as described above will be described in more detail. First, the image data VS of the N × N blocks (generally N ₁ × N ₂ blocks, but in the embodiment, assumes N ₁ × N ₂ = N) is the mode decision unit 20 and the first adder A1. ) And the winter weight 18. In the mode determining unit 20, each encoding method is selected as an inter mode when there are many similar parts between the telephone image and the current image, and an intra mode when there is a large change between the telephone image and the current image. Decide The inter / intra mode determined in this manner determines the inter / intra mode of the encoding apparatus by controlling the two switches RSW1 and RSW2.

First, in the intra mode with a large change between the images, the first and second switches RSW1 and RSW2 are turned off by the inter / intra mode, and the image data VS of the input N × N block is converted into an N × N converter. In (11), the data is converted into data in the frequency domain, and the transformed coefficient coefficient energy is mainly concentrated toward the low frequency side. The quantization unit 12 converts the transform coefficients into representative values of a predetermined level through a predetermined quantization process. That is, the quantization unit 12 is supplied with the quantization level (QS) signal fed back from the buffer 14, thereby quantizing the output data of the N × N conversion unit 11 by a predetermined quantization weighting matrix. The variable length encoder 13, which performs zigzag scan, run amplitude encoding, and variable length coding (VLC), utilizes the statistical properties of these representative values for quantized quantization coefficients. Compresses the data being sent by encoding it. The buffer 14 receives the compressed data supplied from the variable length coding unit 13 and transmits the data at a constant speed, and adjusts the input data amount so that overflow or underflow does not occur. Outputs a signal.

In the inter mode with little change between images, since the first and second switches RSW1 and RSW2 are turned on by inter / intra mode information, the video data VS of the N × N block is added to the first adder A1. The error data is calculated by subtracting from the predetermined feedback data. This error data is applied to the N × N converter 11 and encoded by the quantizer 12 and the variable length encoder 13, and the process up to the variable length encoder is the same as that of the above-described intra mode, and thus is omitted. Let's do it. In general, since there are many similar parts between the screen and the screen, in the intra mode, the motion vector is calculated by estimating the motion and the motion vector is compensated using the motion vector. Since the difference signal between them is very small, the transmission data can be further compressed. In order to perform such dynamic compensation, the inverse quantization unit 15 and the N × N inverse transform unit 16 inversely quantize the quantization coefficients output from the quantization unit 12 and inversely transform the image data in the spatial domain. The video data output from the NxN inverse transform unit 16 is added to the predetermined feedback data by the second adder A2 and stored in the frame memory 17 to reconstruct the screen. The tracking unit 18 then finds the block data of the pattern most similar to the image data VS of the N × N block to be inputted from the frame data stored in the frame memory 17, and indicates the motion vector representing the movement between the two blocks. MV) is calculated. This moving vector (MV) is transmitted to the receiving side for use in the decoding system, and also to the compensating unit (19). The compensating unit 19 reads block data corresponding to the motion vector from the frame data of the frame memory 17 and supplies it to the first adder A1. Then, the first adder A1 calculates error data between the block image data VS input and the block data supplied from the compensator 19 as described above, and the error data is encoded again and transmitted to the receiving side. . In addition, in FIG. 1, the two switches RSW1 and RSW2 refresh data in a frame unit or a predetermined block unit in order to prevent the encoded image from being different from the actual image due to accumulation of error data.

As described above, the inter-mode or intra-mode is performed according to the change of the video data between the telephone image and the current image, and the bitmap converter 21 converts the inter / intra-mode information to the third to encode the head data including the mode information. Like a map, it consists of a bitmap. FIG. 3 is a conceptual diagram illustrating the operation of the bitmap converter in the present invention, and portions indicated by 0 and 1 indicate an intra mode and an inter mode in a block unit, respectively. Since the intermode part and the intradom part are usually crowded together on one screen, it is advantageous to compress data by running run encoding. Therefore, the run length encoder 22 performs run length encoding of the bitmap of the inter / intra mode configured as shown in FIG. In order to further increase the data compression, the variable length coder 23 of the next stage performs variable length coded data by line length and transmits the data to the receiving side at a constant speed through the buffer 14.

As described above, the mode data for distinguishing whether each block of one screen is encoded in inter mode or intra mode is concentrated on each other. Reduce the capacity of the head data.

As described above, the inter / intra mode encoding method and apparatus according to the present invention receives the transmission video data having the information on one screen, determines the inter / intra mode information for each block of the screen, and then selects the mode information. Composed of bitmaps, runlength encoding, and variable length encoding can further compress the entire transmitted data.

Claims (3)

An apparatus for encoding overhead data for determining an inter / intra mode on a block-by-block basis for a screen, comprising: receiving an image data for transmission and encoding each block in the inter mode or the intra mode Mode determination means for outputting mode data for determining a; Bitmap means for receiving the mode data and configuring the bitmap in a bitmap form; Run length encoding means for receiving the data configured in the bitmap form and performing run length encoding on a line basis; And variable length encoding means for variable length encoding and outputting data applied from the run length encoding means. The bitmap unit of claim 1, wherein the bitmap unit configures the mode data for distinguishing the inter / intra mode in the form of one screen, and specifies a value of 0 or 1 for each mode in units of blocks or macroblocks. An inter / intra mode encoding apparatus, characterized in that configuration. In a method of encoding overhead data for determining an inter / intra mode in units of blocks or macroblocks for one screen, whether to encode in intra mode for each block or macroblock from image data to be transmitted or intra Determining whether to encode in mode; Receiving the mode information generated in the determining step and designating a value of 0 or 1 for each mode in a block unit or a macroblock unit to form a bitmap form of a screen; Receiving run-length encoding on a line-by-line basis by receiving data in the form of the bitmap; And variable length encoding the run length coded data.