JPS6010887A - Coding system of video signal - Google Patents

Abstract

PURPOSE:To decrease the unnaturalness of a reproduced picture by including a region not finished for the coding of an existing frame to a coded region of the next frame when the coding is stopped in the coding region to code a picture element in the region after the coding is stopped in a next frame. CONSTITUTION:The coded region is to be designated by a picture element address (X, Y) at the upper left and a picture element address (X', Y') at the lower right. Further, the substantial coded region of the next frame is designated by a point (x, y) at upper left and a point (x', y') at lower right. When the coding is stopped, an address smaller between the preceding frame X and the next frame (x) is set to an FF17. Moreover, a point smaller between the (y) and Y' is set to an FF18, a larger point between x' and X' is set to an FF19 and a larger point between the y' and Y' is set to an FF20.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an interframe coding method for video signals, and in particular, the present invention relates to an interframe coding method for video signals, and in particular, to a method in which the coding region is variable, unnaturalness of reproduced images due to stopping of coding is solved. The present invention relates to an interframe coding method that solves the problem.

[Technology background]

Generally, when transmitting a video signal digitally, an interframe encoding method is used as one method in which differential data for each successive frame is encoded and transmitted. In such an interframe encoding method, instead of encoding all the data for one screen, the encoding method extracts only the portion where a change has occurred and determines the encoding area for each frame. This has the effect of reducing the bit rate for video signals with little movement.

[Conventional technology and problems]

Conventionally, in the encoding method in which the encoding area is determined for each frame as described above, a rectangular area that includes all the pixel addresses of pixels whose inter-frame difference value is greater than or equal to a certain threshold is determined as the encoding area. . By the way, when the current frame is encoded using this encoding method, if encoding stops due to an overflow of the parant memory, etc., the area after the encoding stops among the encoding areas of the current 7 frames will not be encoded. The next frame will be encoded without being encoded. Since the encoded area of the next frame does not necessarily match or include the encoded area of the current frame, data on the screen is updated for pixels included in the unencoded area in the encoded area of the current frame. There is a risk that the information may remain unresolved. As a result, unnaturalness may occur in a portion of the playback screen.

[Purpose of the invention]

In view of the above-mentioned problems, it is an object of the present invention, when there is a stop in coding in the coding area, to display in the coding area of the next frame that there is no part of the coding area of the current frame that has not yet been coded. By including the area, the pixels within the area after the encoding stops are encoded in the next frame, thereby reducing the unnaturalness of the reproduced image.

[Structure of the invention]

In order to achieve the above object, in the present invention, only pixels whose inter-frame difference value is equal to or higher than a predetermined darkness value are to be encoded, and the pixel address of the pixel to be encoded is In an interframe coding method that determines the coding area in one screen for each frame, if a coding stop occurs while coding the current frame, the code of the current frame is used as the coding area of the next frame. An expanded coding area is determined, including the area in the coding area where coding has not been completed and the coding area of the next frame, which is newly determined based on the difference value between the current frame and the next frame. A video signal encoding method is provided, which is characterized by the following.

[Embodiments of the invention]

A video signal encoding method as an embodiment of the present invention will be described below. Figures 1 (B) and 1 (C) show a method for determining the coding area for each frame in this coding method. FIG. 2 shows an example of a circuit for determining the coding area that is compressed in the first frame.] FIG. 1 (4) shows the coding area A of the N-th frame.

This encoding area A is determined to include all pixels whose interframe difference value is equal to or greater than a threshold value. In the encoding area A, the upper left corner point (X.

Encoding is started from Y), and pixels within the area are encoded along the scan line. When the right end of area A is reached, it returns to the left end and continues encoding along the scanning line one line below. In this way, the lower right point (X/ , Y/ )
When the number reaches up to N frames, encoding for N frames ends.

In this way, when the encoding of the entire encoding area of N frames is completed, that is, when there is no encoding stop,
The coding region B of the next N+1 frame is shown in FIG. 1(B). This encoding area B is determined to include all pixels for which the difference value between the N+1 frame and the N frame is equal to or greater than the dark value. Region B is designated by the upper left point of pixel address (x, y) and the lower right point of pixel address (x/, y/). For encoding region B, encoding starts from point (x, y) in the same way as above, and from point (x/y)
, y / ), the encoding ends.

By the way, if the capacity of the buffer memory overflows while encoding the encoding area A of N frames of chrysanthemum in Fig. 1, encoding of pixels in the subsequent area will be stopped. When a coding stop occurs as shown in FIG. 1 (C) K. This encoding area B8 is an unencoded area of the original N+1 frame encoding area B determined by the inter-frame difference value and the encoding area A of the previous frame. A'
is determined as an area containing.

An example of a circuit for determining the coding area of the next frame as described above is shown in FIG. The encoding area is specified by the pixel address (x, y) of the upper left end point and the pixel address (x', y) of the lower right end point.In addition, the original encoding of the next frame The area consists of a point (x, y) at the upper left end and a point (y' at the lower right end).

y′). In FIG. 2, 1 is a pel counter that counts the basic clock and pixel addresses on the scanning line, and 2 is a line counter that counts the number of the scanning line. The values of the pel and line counters indicate the stroke number currently being encoded. - Also, 3 is a buffer memory overflow detection circuit, 4 is a flip 70 that latches the scanning line number
．． 8 [Comparator, 9. IO, 11, 12 are AND circuits, 13, 14, 15.16 are selectors, 17° 18.
19.20 is a flip-flop. In the circuit shown in Fig. 2, if there is no coding stop, the original address (X h y + Pu 17, 18.

Latched at 19.20. Further, when encoding is stopped, the smaller address of X of the previous frame and X of the next frame is set in the flip-flop 17. The flip-flop 18 is set to the smaller of y and Y", the flip-flop 70 is set to the larger of /fix' and X', and the flip-flop 20 is set to y' The larger of Y' and Y' is set.

[Efficacy of invention]

According to the present invention, in the encoding of a video signal, even if encoding stops, the painting after the stopping in the next frame is also subject to encoding, so the possibility that pixels will be updated increases, It is possible to completely reduce unnaturalness in the movement of the reproduced image.

[Brief explanation of the drawing]

FIGS. 1(4), (B), and (C) are diagrams showing a method for determining the encoding area in the encoding method as an embodiment of the present invention, and FIG. 2 is a diagram showing the aforementioned encoding area. FIG. 3 is a diagram illustrating an example of a circuit for performing the determination. (Explanation of symbols)

Claims (1)

[Claims] A frame in which only pixels whose inter-frame difference value is equal to or higher than a predetermined threshold are to be encoded, and the encoding area in one screen is determined for each υ frame based on the pixel address of the pixel to be encoded. In the inter-coding method, when a code stop occurs while encoding the current frame, the area where encoding has not finished in the encoding area of the current frame and the area where encoding has not been completed in the encoding area of the current frame are used as the encoding area of the next frame. 1. An encoding method for a video signal, characterized in that an expanded encoding area is determined, including a code-enabled area of the next frame newly determined based on the difference value of the next frame.