CN102457723A

CN102457723A - MPEG-4 filtering VLSI (Very Large Scale Integration) with decoder for deblocking effect

Info

Publication number: CN102457723A
Application number: CN 201010519550
Authority: CN
Inventors: 王佳
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-10-26
Filing date: 2010-10-26
Publication date: 2012-05-16

Abstract

The invention relates to a MPEG-4 (Moving Picture Experts Group-4) filtering VLSI (Very Large Scale Integration) device with a decoder for deblocking effect. In order to eliminate block effect, the MPEG-4 is introduced to a post-processing filter, and the post-processing filter is used for carrying smooth processing on a decoded image so as to eliminate false edges; the MPEG-4 post-processing filter belongs to a ring outer filter; the filter takes effects after decoding and carries out filtering by using parameters obtained during decoding; and therefore, the filter must be placed in a decoder, thereby obtaining decoding real-time parameters. The device is mainly used for increasing the efficiency of a filtering system for deblocking effect and the real-time performance of the video decoder with a low code rate for the post-processing filtering.

Description

MPEG_4 decoder block-eliminating effect filtering VLSI device

Technical field:

A kind of hardware implementation structure system to the low bit rate video coding post processing and filtering.

Background technology:

Along with the fast development of information industry, extensive uses such as DTV, video conferencing, video telephone, digital high-definition television (HDTV), video request program, electronic publication and network multimedia impel image coding technique to be developed rapidly.MPEG_4 is as one of video compression coding standard, formally issued in November, 1998 by Motion Picture Experts Group and launches.MPEG_4 video compression coding standard can either be supported the Video Applications of low code check; Also can support the Video Applications of broadcast level; It utilizes the visual characteristic of human eye, catches the essence of image information transmission, from the thinking of profile texture; Take content-based video coding, thereby support content-based interactive function.At present, this standard has been widely used in the various information industries fields such as IP network, interactive video, mobile communication, professional video.MPEG-4 adopts dct transform to remove the spatial redundancy in the view data, is divided into the identical 8x8 piece of many mutual nonoverlapping sizes to image, then each piece is carried out dct transform, quantification, coding and transmission independently.Blocking effect is caused by block-based conversion, quantification and motion compensation.Blocking effect just is created in the independent process and the infringement of quantization operation to the high frequency coefficient of dct transform of each image block.Blocking effect is the topmost shortcoming of branch block transform coding, is the topmost restriction to the low bit rate video coding performance.Blocking effect mainly is that the independent quantification owing to each transform block causes, and quantization step is big more, and blocking effect is obvious more, and the visual effect of image is also just poor more.It is this because the error that interpolation arithmetic is introduced in quantification and the motion compensation makes the image after the coder/decoder anti-change blocking effect can occur; And this blocking effect can accumulate down along with previous reconstructed frame, thereby greatly has influence on the quality and the compression efficiency of image.Blocking effect has become in the piece conversion compression algorithm picture quality has been impacted one of distinct issues.Along with the continuous expansion of multimedia technology application scope, the important function of Image Communication is obvious day by day, for the recipient of most of video coding final images, and the subjective quality important that seems.How effectively to address this problem, reduce as much as possible or eliminate piece and handle the blocking effect of bringing and in fact will surpass the importance that only improves the image objective quality, for this reason, solving blocking effect has become a part important in the piecemeal Processing Algorithm.

Summary of the invention:

The present invention is exactly to the problems referred to above, and a kind of correct completion filter function is provided, and improves the system of picture visual quality.

For realizing above-mentioned purpose, the present invention adopts following technical scheme, and in order to eliminate blocking effect, MPEG-4 introduces post-processing filter, and this filter is that decoded image is carried out smoothing processing, to eliminate false edge; The MPEG-4 post-processing filter belongs to the ring outer filter; This type filter is had an effect after decoding, and resulting parameter is carried out filtering when utilizing decoding; Filter must be placed in the decoder, thereby obtains the real-time parameter of decoding.

Beneficial effect of the present invention:

The present invention improves reading and writing data speed with the intermediate data buffer memory with the recycling data; And the recycling buffer reduces hardware spending; Improve memory space, in filtering algorithm, take The pipeline design simultaneously, realize data flow con-trol and filtering calculating executed in parallel; This system's ratio block-eliminating effect filtering system in the past has characteristics such as high efficiency low complex degree, has improved the real-time performance of low bit-rate video decoder post processing and filtering.

Description of drawings

Below in conjunction with accompanying drawing the present invention is further specified.

Fig. 1 MPEG-4 post-processing filter location drawing in decoder.

The improved MPEG-4 block-eliminating effect filtering of Fig. 2 precedence diagram.

Embodiment

In order to eliminate blocking effect, MPEG-4 introduces post-processing filter, and this filter is that decoded image is carried out smoothing processing, to eliminate false edge; The MPEG-4 post-processing filter belongs to the ring outer filter; This type filter is had an effect after decoding, and resulting parameter is carried out filtering when utilizing decoding; Filter must be placed in the decoder, thereby obtains the real-time parameter of decoding.

In order better to carry out post processing and filtering, obtain good video quality, the MPEG-4 post-processing filter is judged the pixel condition of filtering boundary two sampling edges according to filtering parameter, has taked two kinds of filter patterns: Defaultmode and DC offset mode.The MPEG-4 post processing and filtering comprises following components: (1) computation bound filtering condition eq_cnt.According to the difference of filtering strength, be basis for estimation with the filtering threshold, which kind of filter patterns decision takes: general filtering and strong filtering.(2) carry out filtering according to filter patterns, the v4 and the v5 pixel value of each block boundary interface only need recomputated and upgrade to general filtering; The pixel value of v1, v2, v3, v4, v5, v6, v7, v8 just need recomputated and upgrade to strong filtering.

Adopt MPEG-4 block-eliminating effect filtering algorithm in the present invention, the concrete implementation procedure of its filtering algorithm is (chrominance block has the similar algorithms implementation procedure) as follows:

(1) from external memory storage, read A, C piece, and buffer memory; (2) from external memory storage, read the B piece, filtering boundary 1, the intermediate object program of buffer memory A, the filtering of B piece; (3) from external memory storage, read the D piece, filtering boundary 2, the intermediate object program of buffer memory C, the filtering of D piece; (4) T inversion A, C piece, filtering boundary 3, the final result of buffer memory A piece filtering and the intermediate object program of C piece filtering, and read the A piece; (5) the A piece is write back external memory storage, filtering boundary 4, the intermediate object program of buffer memory B, the filtering of A piece; (6) from external memory storage, read the C` piece, filtering boundary 5, the intermediate object program of buffer memory D, the filtering of C piece; (7) T is inverted B, D piece, filtering boundary 6, and the final result of buffer memory B piece filtering and the intermediate object program of D piece filtering, and read the E piece; (8) the B piece is write back external memory storage.(9) from external memory storage, read the F piece, filtering boundary 7, the intermediate object program of buffer memory E, the filtering of F piece; (10) T is inverted C, E piece, filtering boundary 8, and the final result of buffer memory C piece filtering and the intermediate object program of E piece filtering, and read the E piece; (11) the C piece is write back external memory storage, filtering boundary 9, the intermediate object program of buffer memory F, the filtering of E` piece; (12) T is inverted D, F piece, filtering boundary 10, and the final result of buffer memory D piece filtering and the intermediate object program of F piece filtering, and read the G piece; (13) the D piece is write back external memory storage.

Claims

1. a MPEG_4 decoder block-eliminating effect filtering VLSI device is characterized in that MPEG-4 introduces post-processing filter in order to eliminate blocking effect, and this filter is that decoded image is carried out smoothing processing, to eliminate false edge; The MPEG-4 post-processing filter belongs to the ring outer filter; This type filter is had an effect after decoding, and resulting parameter is carried out filtering when utilizing decoding; Therefore, this type filter must be placed in the decoder, thereby obtains the real-time parameter of decoding.

2. MPEG_4 decoder block-eliminating effect filtering VLSI device according to claim 1; It is characterized in that obtaining good video quality in order better to carry out post processing and filtering, the MPEG-4 post-processing filter is according to filtering parameter; Judge the pixel condition of filtering boundary two sampling edges; Taked two kinds of filter patterns: Defaultmode and DC offset mode, the MPEG-4 post processing and filtering comprises following components: (1) computation bound filtering condition eq_cnt, according to the difference of filtering strength; With the filtering threshold is basis for estimation, and which kind of filter patterns decision takes: general filtering and strong filtering; (2) carry out filtering according to filter patterns, the v4 and the v5 pixel value of each block boundary interface only need recomputated and upgrade to general filtering; The pixel value of v1, v2, v3, v4, v5, v6, v7, v8 just need recomputated and upgrade to strong filtering.

3. MPEG_4 decoder block-eliminating effect filtering VLSI device according to claim 1; It is characterized in that adopting among the present invention MPEG-4 block-eliminating effect filtering algorithm; The concrete implementation procedure of its filtering algorithm is (chrominance block has the similar algorithms implementation procedure) as follows: A, C piece are read in (1) from external memory storage, and buffer memory; (2) from external memory storage, read the B piece, filtering boundary 1, the intermediate object program of buffer memory A, the filtering of B piece; (3) from external memory storage, read the D piece, filtering boundary 2, the intermediate object program of buffer memory C, the filtering of D piece; (4) T inversion A, C piece, filtering boundary 3, the final result of buffer memory A piece filtering and the intermediate object program of C piece filtering, and read the A piece; (5) the A piece is write back external memory storage, filtering boundary 4, the intermediate object program of buffer memory B, the filtering of A` piece; (6) from external memory storage, read the C piece, filtering boundary 5, the intermediate object program of buffer memory D, the filtering of C piece; (7) T is inverted B, D piece, filtering boundary 6, and the final result of buffer memory B piece filtering and the intermediate object program of D piece filtering, and read the E piece; (8) the B piece is write back external memory storage, the F piece is read in (9) from external memory storage, filtering boundary 7, the intermediate object program of buffer memory E, the filtering of F piece; (10) T is inverted C, E piece, filtering boundary 8, and the final result of buffer memory C piece filtering and the intermediate object program of E piece filtering, and read the E piece; (11) the C piece is write back external memory storage, filtering boundary 9, the intermediate object program of buffer memory F, the filtering of E piece; (12) T is inverted D, F piece, filtering boundary 10, and the final result of buffer memory D piece filtering and the intermediate object program of F piece filtering, and read the G piece; (13) the D piece is write back external memory storage.