JPS6261485A - Interflame prediction decoder - Google Patents

Abstract

PURPOSE:To display a picture without error by providing the second frame memory for storing the frame data ahead of the frame data stored in the first frame memory. CONSTITUTION:A frame memory 5 for storing the frame data ahead of the frame data stored in a frame memory 2 is provided. When an error is detected in an error detecting part 3', switches SW1, SW2 are controlled and as the data fed to a display device 4, the data stored in the frame memory 5 is transmitted. Thereby, the frame data stored in the frame memory 5 is the frame data preceding the generated error, so that is has no error and a picture having no error is displayed until the new data comes to the display device 4.

Description

[Detailed description of the invention] [Already required] When decoding an image signal subjected to interframe predictive coding, in order to integrate the interframe difference, the data of the frame one before the one stored in the first frame memory is By providing a second frame memory for storing frame data and outputting the frame data stored in the second frame memory when a transmission path error occurs, even if a transmission path error occurs, the error can be avoided. This allows images that do not exist to be displayed on a display device.

[Industrial application field]

The present invention relates to an improvement of an interframe predictive decoding device for decoding an interframe predictively encoded image signal, which is used in a video conference system or the like.

Even if a transmission path error occurs, it is desirable to be able to display an error-free image when displaying the output of the interframe predictive decoding device on a display device.

[Conventional technology]

FIG. 2 is a block diagram of a conventional interframe predictive decoding device.

In the figure, 1 is an adder, 2 is a frame memory, 3 is an error detector, 4 is a display device, and SWI is a switch.

When interframe difference data of an image signal subjected to interframe predictive coding on the transmitting side is input, it is decoded by the adder 1 and the frame memory 2, and the image is displayed on the display device 4.

The error detection unit 3 monitors the presence or absence of errors using parity pits on a frame-by-frame basis, and if there is an error or interframe predictive coding is performed, even if the data is normal, if the data is input after that, it will be detected due to this error. Since the effect will continue for a while, send error information to the transmitting side to output normal data, control switch sw1, set the input signal to O, output the frame data stored in frame memory 2, and display it. It is displayed on device 4.

On the transmitting side, the data sent after receiving the error information is sent with a mode signal indicating that it is new data.
On the receiving side, when receiving this mode signal f8, the switch SWI is returned to its original state.

[3 points to be solved by the invention] However, in the conventional interframe predictive decoding device,
When an error is detected, the erroneous data is already stored in the frame memory 2, so there is a problem in that an image corrupted by the error is displayed on the display device 4 until new data arrives.

[Means for solving problems]

The above problem is solved by providing a second frame memory that stores frame data one frame before the frame data stored in the first frame memory in order to integrate the inter-frame difference.
This problem is solved by the interframe predictive decoding device of the present invention, which outputs the frame data stored in the second frame memory when a transmission path error occurs.

[Effect]

According to the present invention, when an error is detected, the data sent to the display device is the data immediately before the error occurred, so that an error-free image is displayed on the display device.

〔Example〕

FIG. 1 is a block diagram of an interframe predictive decoding device according to an embodiment of the present invention.

In the figure, 3 is an error detection unit, 5 is a frame memory, and SW2
indicates a switch, and the same reference numerals indicate the same functions throughout the figures.

The difference between FIG. 1 and FIG. 2 is that the frame memory 2
A frame memory 5 is provided to record (i) the frame data one frame before the frame data to be stored in the error detection unit 3.
When an error is detected at °, switch SWI, SW2
The data stored in the frame memory 5 is transmitted to the display device 4.

In this way, the frame data stored in the frame memory 5 is the frame data immediately before the error occurred, so there is no error, and the display device 4 displays an error-free image until new data arrives. It will be displayed.

〔Effect of the invention〕

As described in detail above, according to the present invention, an error-free image can be displayed on the display device even after a transmission path error occurs until new data arrives.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an interframe predictive decoding device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional interframe predictive decoding device. In the figure, 1 is an addition section, 2.5 is a frame memory, 3.3 is an error detection section, 4 is a display device, and SWI and SW2 are switches.

Claims (1)

[Claims] When decoding an image signal subjected to interframe predictive coding, a first frame memory (
A second frame memory (5) is provided to store frame data one frame before the frame data stored in 2), and the frame data stored in the second frame memory (5) is output when a transmission path error occurs. An interframe predictive decoding device characterized by the following.