KR100296817B1 - Decoder of digital tv receiver - Google Patents

Abstract

PURPOSE: A decoder of a digital TV receiver is provided to perform format conversion in a manner that the vertical direction contains larger amount of information than the horizontal direction when an HD-grade image is received and processed in an SDTV receiver so as to reproduce an image with high picture quality. CONSTITUTION: A decoder of a digital TV receiver includes a down-sampling portion(81) for down-sampling input data in unit of block at a predetermined rate, and a format converter(84) for performing aspect ratio conversion such that the vertical direction contains larger amount of chrominance information than the horizontal direction with respect to the down-sampled data. The decoder further includes encoding portion(85a,85b) for reducing bits of the down-sampled data or data whose format was converted after down-sampling, and a memory(86) for storing the data whose bits were reduced. The decoder also has a decoding portion(87) for decoding the stored data, and an up-sampling portion(88) for converting the data into the final display size data.

Description

Digital TV Receive Decoder Device

The present invention relates to a video decoder device of a digital TV receiver for compressing and transmitting a video signal, and decoding and displaying the transmitted compressed video signal at a decoder of a receiver. The present invention relates to a digital receiving decoder apparatus for converting and processing a video signal into a modified 4: 2: 0 format to improve the quality of a video signal during down converting.

As an embodiment, the present invention provides a digital TV decoder that receives an MPEG video signal and decodes the received video signal, wherein the decoder device is configured to receive an HD video using an SDTV receiver. It is shortened and stored in memory, and data encoded and stored, and when outputted, display is performed by decoding, aspect ratio and format conversion for I and P pictures, and at this time, the resolution of the vertical direction of the video signal. By increasing the resolution and decreasing the horizontal resolution relatively, there is no change in the overall data volume, but by increasing the image quality in the vertical direction due to the human visual sense, it is possible to maintain the best image quality without changing the memory size. A digital TV reception decoder device is provided.

Digital TV receiver decodes video signal compressed and transmitted by MPEG2 in decoder.

Display on the screen. In general, digital TV receivers are classified into HDTV class and SDTV class according to the number of pixels (pel = picture elements) with respect to clarity / reproduction performance (quality), and for HDTV, for example, up to 1920pels / 1080lines Performance and SDTV, for example, has 640pels / 480lines.

Hereinafter, the pixel units shown in FIGS. 1 to 9 are presented as an example for explanation of the present invention and are not limited thereto.

Fig. 1 shows an example of a decoder in a digital TV receiver, and one pixel is represented by 8 bits.

Currently, a macro block has a data structure of 16 * 16 pixels and processes a bit stream of a level corresponding to each class including a DCT coefficient and motion vector information.

In Figure 1, Variable Length Decoder (VLD) 1 variable length decodes the input bit stream data, IDCT 2 decodes the variable length decoded data by Inverse Discrete Cosine Transform, The adder 3 stores the reconstructed image using the motion compensated information of the motion estimation compensator 4 in the decoded data in the frame memory 5 in a 4: 2: 0 image signal format, and the stored data is 4 It is upsampled to the video signal format of 2: 2 and output to the display means.

Since the HDTV receiver receives and decodes HD class data, there is no obstacle in receiving and decoding SD data.

Since the SDTV receiver receives and decodes the SD level data, there is no obstacle in receiving and decoding the SD level data, but from the viewpoint of compatibility, the SDTV receiver should be able to receive and process (decode / display) the HD level data.

To this end, the decoder of the SD TV receiver performs 'data processing' for the SD reception of HD data.

This data processing process is secured by downsampling / or down-converting, ie filtering / decimation.

2 shows a 4: 4: 4 video signal format, b shows a 4: 2: 2 video signal format, and FIG. 3 shows a 4: 2: 2 video signal format.

In Figs. 2 and 3, the cross is the luminance signal, and the circle represents the color signals Cb and Cr.

4 shows an example of a downsampling technique of a decoder device for receiving, decoding and displaying HD data in an SD TV receiver.

4 is a method of decoding 8 * 8 block data by reducing it to 4 * 4.

The 8 * 8 sized data block 41 is inversely cosine transformed and downsampled on the 8 pixels in the IDCT / downsampler 42 horizontally and vertically to reduce the size of the 8 * 8 sized block to 4 * 4 size. Reduce

In FIG. 4, 16 samples of DCT coefficients were selected from the upper end of the data block 41, and 4x4 inverse discrete cosine transform was used to obtain downsampled image data.

The discarded coefficients, except for the selected coefficients, are shown as white spots (blanks).

The number of coefficients selected here and the method of selecting the coefficients are various as well.

The image data downsampled to 4 * 4 is stored in the frame memory 44 via the adder 43 (or may be a field memory).

The image data of the frame memory 44 is upsampled horizontally and vertically up to 8 * 8 by the upsampler 45 for processing motion vectors adapted to the down sampled image data. The upsampled image data is motion compensated by motion vectors in the motion compensation predictor 46, and the compensated information is 8 * 8 in size, so the downsampler 47 is again horizontally 4 * 4 in size. After downsampling in the vertical direction is performed, this 4 * 4 downsampled motion compensated block is applied to the adder 43, whereby -8 * 8 is finally downsampled to 4 * 4. The image block is obtained and stored in the frame memory.

At the time of output, the output value of the frame memory 44 is converted into 4: 2: 0 format by the format converter 48, and this is converted into 4: 2: 2 format by the upsampler 49 and output.

Figure 5 shows another example of a downsampling technique of a decoder device for receiving, decoding and displaying HD data in an SD TV receiver.

5 is a technique of reducing 8 * 8 size data to 8 * 4.

The size of 8 * 8 is reduced to 8 * 4 by performing inverse discrete cosine transform and downsampling on the 8 * 8 data block 51 horizontally in IDCT / downsampler 52.

The discarded coefficients, except for the selected coefficients, are shown as white spots (blanks).

The number of coefficients selected here and the method of selecting the coefficients are various as well.

The image data downsampled to 8 * 4 is stored in the frame memory 54 via the adder 53 (or may be a field memory).

The image data of the frame memory 54 is upsampled to 8 * 8 by the upsampler 55, and upsampled by the upsampler 55 for motion vectors processing to adapt to the down sampled image data. The data is motion compensated by the motion vectors in the motion compensation predictor 56. Since the compensated information is 8 * 8 size, downsampling is performed again in the downsampler 57 to 8 * 4 size. The 8 * 4 downsampling motion processing information is added to the adder 53, so that finally, the desired 8 * 8 downsampled to 8 * 4 -image block is stored in the frame memory.

At the time of output, the output value of the frame memory 54 is converted into 4: 2: 0 format by the format converter 58, and this is converted into 4: 2: 2 format by the upsampler 59 and output. FIG. 6 is another embodiment of a digital TV reception decoder device, and is a content of Patent No. 98-5292 filed by the present applicant, and decoded I, P, and B pictures by 8 * 4, and then B pictures are 720pels / A frame conversion and data encoding of 480 lines are stored and stored in a memory, and the I and P pictures are converted to frames of 720pels / 480 lines after data decoding and output together with the data decoded B picture.

The IDCT / down sampling unit 61 inverses discrete DC cosine conversion of the input DCT coefficient and performs filtering / down sampling in the horizontal direction to reduce the size of 8 * 8 to 8 * 4.

Here, downsampling is performed on all I, P, and B pictures, and this 8 * 4 data is input to the adder 62.

The output of the adder 62 is processed differently according to the I, P picture and the B picture.

The B picture is converted into a 4: 2: 0 format while passing through the display size converting unit 64.

The B-picture information with format conversion is stored in the B-frame memory 66b of the memory unit 66 after data reduction is performed via the data encoding unit 65b.

The operation of bit reduction by the data encoding unit 65b is shown in Fig. 7, which also applies to the data encoding unit 65a for I and P pictures, and data decoding corresponds to the reverse process of encoding.

As shown in Fig. 7, correlation of adjacent pixels in consideration of memory capacity limitation

Reduce the bit rate by using.

That is, the bit amount is reduced to 14 bits based on 8 * 4 in consideration of the correlation of adjacent pixels in the horizontal (or vertical) direction.

An example of a method of reducing the number of bits is DPCM.

P1 (original value), p2-p1 (adjacent pixel difference value) and p3 (original value) for horizontal (or vertical) pixels p1, p2.p3, p4 701 of the decoded image pels 700 p4-p3 (adjacent pixel difference value) 702, wherein p1 is an 8-bit value, p2-p1 is a 6-bit value, p3 is an 8-bit value, p4-p3 The 6-bit value is encoded by using a non-uniform quant izat ion method (703).

The signed result 704 is stored in the corresponding memory 705, which may be an anchor frame memory or a B frame memory in FIG.

The bit-reduced data as described above is stored in the B-frame memory 66b and decoded by the data decoding unit 71 through the reverse process of the decoding for image restoration (reproduction).

In addition, by selecting the switching unit 63, the I and P pictures are also bit-reduced through the data encoding unit 65a, which is stored in the anchor frame memory 66a, and decoded by the data decoding unit 67 to restore the image. do.

The decoded 8 * 4 data is upsampled in the horizontal direction by a horizontal upsampler 68 that receives motion vector information for motion compensation and output as 8 * 8 data.

This upsampled 8 * 8 data is input to the motion compensation predictor 69 and motion compensated by the motion vector information, and the motion compensated information is input to the horizontal downsampler 70 in 8 * 8 size.

The horizontal downsampler 70 horizontally downsamples the input 8 * 8 motion compensation information to 8 * 4 and supplies it to the adder 62, thereby downsampling to 8 * 4 by the IDCT / downsampling unit 61. Outputs motion-compensated I, P, B picture signals corresponding to the I, P, B picture data 74 obtained.

By repeating the above process, data processing of I, P, and B frames is performed, and 8 * 4 data output from the anchor frame memory 66a and decoded by the data decoder 72 by the frame size converter 73. After converting to 4: 2: 0 format (consistent with B frame format), the upsampling unit 74 converts to 4: 2: 2 format and outputs the final image signal together with the B picture information. (Video Out).

The conventional digital TV receiver decoder as described above stores video signals in a 4: 2: 0 format in consideration of memory size.

However, due to the human visual sense, the change in the vertical direction is more than the change in the horizontal direction.

Not sensitive.

In other words, as shown in Fig. 3, the conversion to the 4: 2: 0 format takes the form of a lack of color signals in the vertical direction and a relatively large amount of data in the horizontal direction in consideration of human visual sense characteristics. When the video signal is converted into a format, the visual and visual quality felt by a human cannot help but deteriorate.

In the present invention, the total amount of data is the same in the downsampling, data encoding and decoding, and the conversion to the display size in the case of B picture by dividing I, P picture and B picture. The present invention provides a digital TV receiver decoder device capable of securing a high-definition and a high color sense of image quality that is visually sensed by having a large amount of color information.

1 is a block diagram of a digital TV receiver decoder.

2, 3 and 3 show conventional video signal storage in a digital TV receiver decoder.

Figure showing the format.

4 is a block diagram of a conventional downconverter first embodiment;

Fig. 5 is a block diagram of a conventional downconverter second embodiment;

6 is a block diagram of a conventional downconverter third embodiment;

7 illustrates a data encoding / decoding method.

8 is a block diagram of a digital TV receiver decoder device of the present invention.

9 a and b show the video signal growth format of the present invention;

FIG. 8 illustrates an embodiment of the digital TV receiver decoder of the present invention, in which I, P, and B pictures are downsampled to 8 * 4, and B pictures have the same total data amount as the conventional 4: 2: 0 format. Convert to 720pels / 480lines in a format defined as including more image information in the vertical direction relative to the horizontal direction (Modified 4: 2: 0 Format), perform data encoding, and store in memory, I, P The picture performs data encoding and stores it in memory as a permanent frame, the B picture decodes the data, and the I and P pictures decode the data into a modified 4: 2: 0 format of 720pels / 480lines after decoding the data. The embodiment outputs together with the B picture.

The downsampling ratio and the number of pixels (pels) presented in this embodiment are provided as an example and the present invention is not limited thereto.

Hereinafter, the configuration and operation of the digital TV reception decoder device according to the present invention will be described.

IDCT / Down outputting 8 * 4 size data by performing DCT coefficients for 8 * 8 size input data (I, P, B picture), performing inverse discrete cosine transform (IDCT), filtering, and horizontal downsampling. A sampling means 81, an adding means 82 for adding and outputting the 8 * 4 data and motion compensation information, and a B picture of 8 * 4 data output from the adding means 82 with respect to the horizontal direction. In the format converting means 84 for converting the display size into a form further comprising relatively vertical image information, the I, P picture output from the adding means 82 and the format converting means 84 Data encoding means 85a and 85b for performing data encoding on the output B picture, anchor frame memory 86a for storing the data encoded I and P picture information, and B frame for storing B picture information. Storage means 86 comprising a memory 86b and . Data decoding means (87) for data decoding the output of the anchor frame memory (86a), horizontal upsampling means (88) for upsampling the data decoded information in a horizontal direction and converting it into an 8 * 8 size; Motion compensation predicting means 89 which receives the output of upsampling means 88 and performs motion compensation and prediction from the motion vector information, and downsamples the output of the motion compensation predicting means 89 in a horizontal direction to 8 *. Horizontal downsampling means (90) for converting into four sizes and supplying to the adding means (82), data decoding means (91) for outputting B frame information by data decoding the output of the B frame memory (86b); Data decoding means 92 for data decoding the output of the anchor frame memory 86a, and to correspond the output of the data decoding means 92 to the same format as the format converting means 84; A format converting means 93 for containing more information in a vertical direction relative to a horizontal direction, and converting an output of the decoding means 91 and an output of the format converting means 93 into a 4: 2: 2 format And upsampling means 94 for outputting the final video signal. 8 and 9, the operation of the present invention will be described.

The IDCT / downsampling means 81 inverts the input DCT coefficients by inverse discrete cosine transform and performs downsampling in the horizontal direction to reduce the size of 8 * 8 to 8 * 4.

Here downsampling is performed on all I, P, and B pictures and this 8 * 4 data is added.

Input to mountain means 82.

In the present invention, the down sampling method (upsampling is also the same) is performed through various known methods.

The result of performing 8 * 4 horizontal downsampling on 8 * 8 I, P, and B pictures as described above is added to the adding means 82.

The output of the adding means 82 is selected by I, P picture and B picture by the switching means 83.

All.

For the B picture, the frame size conversion is performed according to the display size while passing through the format converting means 84.

That is, the B picture composed of 8 * 8 blocks is downsampled in the vertical and horizontal directions to reduce the size to 720pels / 480lines, which is again reduced by bit through the data encoding means 85b. Is stored in the B frame memory 86b.

The Modified 4: 2: 0 format for the storage format of B frames is shown in Figs. 9A and 9B.

720pels, which includes 1920pels / 1080lines of B frame signal input in the original 4: 2: 0 format as shown in FIG. 9, to include more information in the vertical direction relative to the horizontal direction as shown in FIG. Converts it to the Modified 4: 2: 0 format of size / 480lines.

In this case, the total data amount of the existing 4: 2: 0 format (a in FIG. 9) and the modified 4: 2: 0 format (b in FIG. 9) is the same.

In other words, instead of reducing the sensitivity in the horizontal direction is to increase the sensitivity in the vertical direction, which deeply affects the human visual sense characteristics.

In Fig. 9, the scissors table is the luminance signal, and the original display indicates the color difference signals Cb and Cr.

In the present invention, four color signals are arranged in the horizontal direction, but in the present invention, two color signals are arranged. In the prior art, four color signals are arranged in the vertical direction. However, in the present invention, eight color signals are arranged. Was arranged.

Therefore, there is no change in the total amount of data, but the vertical direction includes an increased amount of information relative to the horizontal direction.

In this way, the format-converted data for the B frame is stored in the B frame memory 86b via the encoding means 85b, and the I and P frames selected by the switching means 83 are also anchored via the encoding means 85a. It is stored in the frame memory 86a.

The effect of bit reduction by the data encoding means is shown in FIG. Data output from the anchor frame memory 86a is decoded by the decoding means 87, and the decoded 8 * 4 data is horizontal upsampling means 88 which inputs motion vector information for motion compensation. Up-sampled in the horizontal direction at, output as 8 * 8 data.

This upsampled 8 * 8 data is input to the motion compensation predicting means 89 and motion compensated by the motion vector information, and the motion compensated information is input to the horizontal downsampling means 90 with 8 * 8 size.

The horizontal downsampling means 90 horizontally downsamples the input 8 * 8 motion compensation information into 8 * 4 and supplies it to the adding means 82, whereby the IDCT / downsampling means 81

Outputs motion-compensated I, P, B picture signals suitable for 8 * 4 downsampled I, P, B picture data (size).

By repeating the above process, I, P, B frame data processing is performed, and I, P picture data output from the anchor frame memory 86a is decoded by the data decoding means 92, and the decoded 8 * 4 data is converted into a format of 720pels / 480lines (Modified 4: 2: 0) to match the format of the B frame while passing through a format converting means 93.

Thus, the output of the B frame memory 86b is decoded by the decoding means 91 and the value obtained by the format conversion of the I and P pictures is input from the upsampling means 94 to finally receive the value.

In-display size conversion is performed and output as a video signal (Video Out).

According to the present invention, when the HDTV image is received and processed by the SDTV receiver using MPEG2, the format conversion is performed so that the vertical direction includes more information than the horizontal direction, thereby reproducing high quality images.

Claims (4)

(Single correction) An apparatus for receiving data in units of blocks and converting the data format into a format considering the display size, and processing and displaying the stored data, wherein the predetermined data is input to the input data in units of blocks. Means for performing downsampling at a rate, format conversion means for performing aspect ratio conversion so that the downsampled data includes more chromaticity information in a vertical direction relative to the horizontal direction, and after downsampling data or downsampling Data encoding means for bit-reducing the format-converted data, storage means for storing the bit-reduced data, data decoding means for decoding the stored data, and converting and outputting the format-converted data to a final display size. Characterized in that it further comprises a sampling means Jital TV receiver decoder device. A device that receives data in units of blocks and converts the data format into a format that considers display size and processes and displays the stored data. Downsampling is performed at a predetermined rate with respect to input data in units of blocks. The downsampled result is divided into a first group of data and a second group of data, and further downsampling is performed on the first group of data, and then more information is performed in the vertical direction than the horizontal direction. Means for performing screen aspect ratio conversion suitable for a display size in a format including; means for storing a second group of data together with the converted first group of data; and the stored second group of data at the time of reproduction Further performing format conversion conversion to correspond to the format-converted data of the first group so that the data of the first group and the second group can be used. The digital television decoder receiving device, characterized by comprising means adapted for displaying. The display size of claim 2, wherein data input in units of blocks is 8 * 8, downsampled to 8 * 4, and a display size including more information in a vertical direction than a horizontal direction for the first group of data. Aspect ratio conversion and storage and playback are performed in 4: 2: 0 format (Modified Format). A digital TV receiver decoder, characterized in that for conversion to: 0 (Modified Format). 3. The digital receive decoder device according to claim 2, wherein the block unit input data is an I, P, B picture, the first group of data is a B picture, and the second group of data is an I, P picture.