KR0123093B1 - Apparatus and method for decoding a code indicating picture starting location - Google Patents

Abstract

In the apparatus for decoding a picture start positional data of a moving picture decoding system in which a variable length decoding is performed when an encoded bit stream data is applied, also an inverse quantization and an inverse discrete cosine transform(IDCT) are executed, and a compensation for a motion and a restoration to an original signal are performed, the apparatus for decoding a picture start positional data in the moving picture decoding system comprises a demultiplexer for demultiplexing and outputting the coded bit stream data applied; a decoder for receiving data within a given area of the bit stream outputted from the demultiplexer, and parsing and outputting the start positional data of a picture or a picture type; a memory for storing the start positional data of the picture or the picture type outputted from the decoder; a controller for reading the start positional data of a corresponding picture from the memory by data of a picture to be currently reproduced by a control signal of a user applied from the outside, and outputting the data by a control signal for selecting the variable length decoded data, to the demultiplexer, whereby enabling to select only a desired picture to reduce it and particularly enabling to provide a specific reproduction.

Description

Picture start position code decoding apparatus and method in a video decoding system

1 is a diagram of a conventional video decoding system.

2 is a block diagram of an Asian image decoding system having a picture start position code decoding apparatus according to the present invention.

3 is a flowchart of a picture start position code decoding method according to the present invention;

* Explanation of symbols for main parts of the drawings

201: multiplexer 202: decoder

203: Memory 204: Control part

205: Moving Picture Expert Group (MPEG) I (One) Decoder

The present invention relates to an apparatus and method for decoding a picture starting position code in a video decoding system. More particularly, the present invention relates to decoding a relative position code between pictures continuously coded and encoded in an extended region in a standardized bit stream during encoding. An apparatus and method are provided.

Conventional Moving Picture Expert Group (MPEG) I (One) does not have a uniformly specified relative position (or starting address) between pictures in the bit stream, so that the bit stream is continuously parsed during decoding and decoded when restored. Since the start position of the picture code is known as the picture start code (0X00000100), the bit stream must be continuously scanned to search for the start position of the picture.

FIG. 1 is a diagram of a conventional video decoding system. When coded (or coded) bit stream data is applied, the video data is temporarily stored through the buffer 101, and the demultiplexer 102 moves in the data transmitted from the buffer 101. FIG. Vector and frame data (information about whether the frame is in I mode, P mode, or B mode), quantization parameters of quantum and step size, and pure image data are selectively output.

The variable length decoding (VLD) unit 103 decodes and outputs the pure picture data output from the demultiplexer 102 to a variable length, and the dequantizer 104 is output from the VLD unit 103. The data is inversely quantized by the quantization parameter output from the demultiplexer 102 and output to the inverse discrete cosine transform (IDCT) unit 105. The inverse DCT unit 105 restores the data of the frequency domain to the original spatial domain and outputs the original spatial domain. The adder 106 and the frame storage and prediction unit 107 inversely predict the prediction image at the time of encoding by using the data output from the inverse DCT unit 105 and the motion vector and picture type data output from the demultiplexer 102. The image data is extracted, added to the inverse DCT data, and output as an original picture, and the frame rearranging unit 108 rearranges the decoded data to enable reproduction.

However, there is a problem in such a video decoding system that it takes a lot of time to detect the starting position of a picture at the time of decoding since there is no part of uniformly specifying the relative position (or starting address) between pictures in the bit stream.

In order to solve this problem, the present inventor has applied for a 'picture start position data coding method and apparatus' (Application No. 94-3282). In the present invention, the relative position between pictures in the wax area or the user area in the GOP layer is applied. Ali has presented a method of inserting and coding a code and picture type.

Accordingly, an object of the present invention is to provide a picture start position code decoding apparatus and method capable of directly accessing a start position of a desired picture in a special playback by decoding and storing relative position codes applied through a predetermined region of a bit stream material. .

In order to achieve the above object, the present invention, when the bit stream including the start position code of the picture is applied, variable length protection, dequantization, inverse discrete cosine transform, motion compensation to restore the original signal to decode In the picture start position code decoding apparatus of the system; A demultiplexer for demultiplexing and outputting the encoded bit stream; A decoder configured to receive data in a predetermined region of the bit stream output from the demultiple and parse and output a picture type and a start position code of the picture; A memory for storing a picture type and a start position code of a picture output from the decoder; A control unit that reads a start position code of a picture corresponding to a picture type code to be reproduced by a user's control signal externally from the memory and outputs the demultiplexer as a control signal to select a picture to be variable-length decoded; Include.

The present invention also provides a picture start position code decoding method for decoding a picture start position code carried on an applied bit stream; Detecting whether a currently applied bit stream corresponds to a predetermined region including the picture start position code; A second step of detecting a start position of the picture when the detection result corresponds to the predetermined area; Detecting a type of a picture when a start position of the picture is detected; A fourth step of decoding the start position code of the picture and storing the start position code and the picture type of the picture when the type of the picture is detected; When a control signal to be reproduced by the user is applied, a fifth process of reading a start position code of a corresponding picture among stored data and outputting the start position code as a selection control signal of a picture to be variable-length decoded is performed.

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

FIG. 2 is a diagram of a predetermined region in which coded bit stream data is selectively output as shown in FIG. 1 when the coded bit stream data is applied through the buffer 101 of FIG. When a code of a predetermined region is applied to the demultiplexer 201 for output to the decoder 202, the MPEG I decoder 205 for processing the picture data output from the demultiplexer 201, and the demultiplexer 201 as shown in FIG. A decoder 202 for decoding the currently applied picture type and picture start position code, a memory 203 for storing the picture type and picture start position code output from the decoder 202, and an externally applied user The picture type and start position code desired to be reproduced are read from the memory 203 according to the control signal of < RTI ID = 0.0 > and < / RTI > Only comprises a control unit 204 for controlling to output. As described above, the predetermined area in which data output from the demultiplexer 201 is loaded may use an extended area or an extended area in a group of picture (GOP) layer.

3 is a flowchart of a method of decoding a picture start position code, in particular, parsing a picture type and start position data made by the decoder 202 with respect to data output from the demultiplexer 201 and processing result data by parsing. Indicates the process

Next, the operation of FIG. 2 will be described with reference to FIG.

First, a position code relative to a start position code between an extended region or a consecutive picture transmitted through the extended region in the applied bit stream is encoded and applied as shown in Table 1 below. The encoding content for this is encoded and applied in the same manner as described in the above-described 'picture start position data coding method and apparatus'.

When the data of the applied bitstream structure is an extended region, the demultiplexer 201 transmits the output data to the decoder 202.

The decoder 202 decodes the data in the extended area. In particular, the decoder 202 parses the picture type code and the feature start position decoder into the applied data so as to parse and output the picture type code.

In more detail, when a predetermined code is applied, the codes are checked in units of 4 bits to determine whether the currently applied data is an extended area. This is determined by the start code of the predetermined extended area (step 301). If it is determined as the extended area, it is determined whether a head code of a picture is applied (step 302). Here, the head code is a code for notifying the start of the picture and is set to 2 bits (0, 0) in this embodiment. Therefore, when the head code is detected, it means that the picture starts from that point.

In step 302, when the head code of the picture is not applied, the next two-bit code is read and checked again (step 306).

If the head code of the picture is detected in step 302, the type of the applied picture is detected (step 303). In this case, since coding is allocated to each picture mode as described below, the type of the currently applied picture is detected based on this (step 303).

11: I (Inter-frame), 10: P (Predicted frame), 01: B (Bidirectionaly frame)

As described above, when the picture head code and the picture type are parsed, the picture start position code is decoded and output to the memory 203 (step 304). The memory 203 stores this in a predetermined area and outputs a corresponding picture start position code by a read control signal and a picture type signal applied from the controller 204.

The controller 204 reads the corresponding picture start position code from the memory 203 when a special playback mode is set according to a user's external control signal and a control signal for a picture to be played is applied. The picture start position code is output as a data transmission control signal of the demultiplexer 201. Here, the control signal applied by the user is a reproduction mode signal, for example, when a high speed reproduction of 3x speed is desired, a control signal for setting a 3x speed mode is applied.

As described above, the present invention provides an arrangement of a picture type, a picture start position code, and pictures without separately scanning a bit stream by separately processing a picture start position code coded and applied using an extended region and a user region in a video decoding system. Since the order and the like can be known, only the desired picture can be selected and played. In particular, there is an advantage that special playback is possible.

Claims (6)

A picture start position code decoding apparatus of a video decoding system for performing variable length decoding, inverse quantization, inverse discrete cosine transform, motion compensation, and restoring to an original signal when a bit stream including a start position code of a picture is applied; A demultiplexer 201 for demultiplexing and outputting the encoded bit stream when it is applied; A decoder 202 for receiving data of a predetermined region in the bit stream output from the demultiplexer 201 and parsing and outputting a picture type and a start position code of the picture; A memory 203 for storing a picture type and a start position code of a picture output from the decoder 202; The demultiplexer 201 is a control signal for selecting a picture to be variably decoded by reading a start position code of a picture corresponding to a picture type code to be reproduced by a user's control signal externally applied from the memory 203. And a control unit 204 for outputting to the picture start position code decoding apparatus. A picture start position code decoding method for decoding a picture start position code carried on an applied bit stream; Detecting whether a currently applied bit stream corresponds to a predetermined region including the picture start position code; A second step of detecting a start position of a picture when the detection result corresponds to the predetermined area; Detecting a type of a picture when a start position of the picture is detected; If the type of the picture is detected, decoding a start position code of the picture and storing the start position code and the picture type of the picture; And a fifth process of reading the start position code of the corresponding picture from among the stored data and outputting the start position code of the picture as a selection control signal of the picture to be variable-length decoded, if the control signal desired for reproduction is applied by the user. Picture start position code decoding method characterized in that. The picture start position code decoding method of claim 2, wherein the start position code is detected by detecting a head code of the picture in units of predetermined bits of the second process. The picture start position code decoding method according to claim 2, wherein the predetermined area of the first step is an area in which additional information can be inserted into a bit stream. The method of claim 4, wherein the predetermined area is detected according to whether a start code for notifying the start of the predetermined predetermined area is generated. The picture start position according to claim 2, wherein the decoding method further comprises, after performing the fourth process, repeating the second process to the fourth process until an end code is detected. Code decoding method.