JPH0686253A - Moving image data transmitter - Google Patents

Abstract

PURPOSE:To obtain a decoded picture without a sense of incompatibility by controlling the encoding parameter of each encoding circuit in common, thereby uniformizing the image quantity in respective areas even at the time of dividing a moving image into plural areas, and encoding it. CONSTITUTION:A video signal inputted to a dividing circuit 1 is divided into two areas, transmitted to encoding circuits 2 and 3, encoded by using the encoding parameters from an encoding control circuit 4, and transmitted to a multiplexing circuit 5. Then, two encoded data are multiplexed into one data by the circuit 5, smoothed through a buffer memory 6, and transmitted to a transmission path. The multiplexed data transmitted from the transmission path are stored in a buffer memory 7, separated into the two encoded data by a separator circuit 8, independently decoded by decoding circuits 9 and 10, and synthesized into one video signal by a synthesizing circuit 11, and outputted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving image data transmission device.

[0002]

2. Description of the Related Art Conventionally, when moving image data having a very large number of pixels such as a high-definition video signal is transmitted, a large amount of data processing is required in an encoding circuit and a decoding circuit. It is considered that the data processing amount of each circuit is reduced by dividing the moving image data in each area into a plurality of areas and operating a plurality of encoding circuits / decoding circuits in parallel for the moving image data in each area.

[0003]

FIG. 8 shows a conventional moving image data transmitting apparatus, in which a video signal area is divided into two by a dividing circuit 81, and each video signal is divided into two encoding circuits 82,
83, where it encodes each using the respective encoding parameters sent from the two encoding control circuits 84 and 85, and sends them to one multiplexing circuit 88 via two buffer memories 86 and 87, respectively. Therefore, it is multiplexed into one data and output to the transmission path. The multiplexed data sent from the transmission line is separated into two pieces of encoded data by a separation circuit 89, and is separated into two pieces via two buffer memories 90 and 91, respectively.
The two decoding video signals are decoded by one decoding circuit 92 and 93, and the two decoded video signals are combined by a combining circuit 94 to be returned to one video signal and output.

In the conventional moving image data transmission apparatus as described above, an image is divided into a plurality of areas, and a plurality of encoding circuits / decoding circuits are operated in parallel for moving image data in each area. Coding parameters such as the quantization step size are controlled for each coding circuit. For this reason,
The moving image data is encoded by different encoding parameters for each divided area, and the decoded image has different image quality for each area, which causes a feeling of strangeness. This is because the encoding parameter is controlled for each encoding circuit based on the code amount generated in the encoding circuit.

An object of the present invention is to solve the above problems and to provide a moving image data transmission apparatus which maintains the image quality of each area in a decoded image at the same level.

[0006]

In order to achieve the above-mentioned object, the present invention provides a plurality of encoding circuits for encoding each video signal divided into a plurality of areas, and a code of the plurality of encoding circuits. And an encoding control circuit for commonly controlling encoding parameters.

[0007]

According to the present invention, the image quality of the decoded image in each area becomes uniform by commonly controlling the encoding parameters of each encoding circuit.

[0008]

EXAMPLES Next, examples of the present invention will be described with reference to FIGS. 1 and 2 show a configuration example of a moving image data transmission apparatus according to the present invention, and FIG. 8 shows a conventional configuration example.

First, FIG. 1 will be described. Split circuit 1
Divides the input video signal into two regions and sends the respective video signals to the first coding circuit 2 and the second coding circuit 3. In the encoding circuit 2 and the encoding circuit 3, each video signal sent from the division circuit 1 is independently encoded using the encoding parameter sent from the encoding control circuit 4 and sent to the multiplexing circuit 5. At this time, the same encoding parameter is used for the encoding circuit 2 and the encoding circuit 3. The multiplexing circuit 5 multiplexes the two pieces of encoded data encoded by the encoding circuit 2 and the encoding circuit 3 into one data, and outputs it to the transmission path through one buffer memory 6 that smoothes the data. . The coding control circuit 4 feeds back the generated code amount to determine the coding parameter of the next frame.

The demultiplexing circuit 8 accumulates the multiplexed data sent from the transmission line in one buffer memory 7, and then stores the multiplexed data.
It is separated into one encoded data and sent to the first decoding circuit 9 and the second decoding circuit 10, respectively. The decoding circuit 9 and the decoding circuit 10 independently decode the encoded data sent from the separation circuit 8 and send the decoded video signal to the synthesis circuit 11. The synthesizing circuit 11 synthesizes the two video signals sent from the decoding circuits 9 and 10 into a single video signal and outputs it.

FIG. 2 is different from FIG. 1 only in the method of determining the coding parameters in the coding control circuit 4, and other configurations are the same as in FIG. That is, in the example of FIG. 1, the coding control circuit 4 determines the coding parameter of the next frame based on the data amount after multiplexing. In the example of FIG. 2, the coding control circuit 4 determines the coding parameter of the next frame based on the sum of the code amounts output from the coding circuits 2 and 3 before multiplexing.

FIG. 3 shows an example inside the encoding circuit. The input video signal is DCT-transformed by a DCT (discrete cosine transform) conversion circuit 12, quantized by a quantization circuit 13 using a quantization step size sent from a coding control circuit, and further, a variable length coding circuit. At 14, variable length coding is performed and output. FIG. 4 shows an example inside the decoding circuit. The input coded data is variable-length decoded by the variable-length decoding circuit 15, and then the same circuit 1
5 is inversely quantized by the inverse quantization circuit 16 using the quantization step size sent from 5, and the inverse DCT conversion circuit 17
Is inverse DCT-converted and decoded into a video signal.

FIG. 5 is for showing an example of the method of determining the coding parameter inside the coding control circuit, and shows the temporal change of the buffer occupation rate of the virtual buffer memory in the coding control circuit. . Here, the quantization step size Q used for encoding the previous frame is calculated according to the buffer occupancy.
_The generated code amount is controlled by changing _S. For example, if the previous frame is encoded with Q _S = 10 and the buffer occupancy rate is 82%, the change amount DS =
It becomes +2. Therefore, the quantization step size of the next frame will be Q _S = 10 + 2 = 12. As the step size increases, the quantization becomes coarser, the code amount decreases, and the buffer occupancy decreases.

FIGS. 6 and 7 show how the generated code amount changes with time when encoding is performed in the embodiment of the present invention and the conventional example.
It shows a state of image quality (S / N) of a decoded image.

FIG. 6 shows changes in the generated code amount, (a1) is the generated code amount in the first encoding circuit of the embodiment of the present invention, and (a1)
2) is the generated code amount in the second coding circuit of the embodiment of the present invention, and (a3) is the total generated code amount in both coding circuits of the embodiment of the present invention. Further, (b1) is a generated code amount of the first encoding circuit of the conventional example, (b2) is a generated code amount of the second encoding circuit of the conventional example, and (b3) is both encoding circuits of the conventional example. It is the total generated code amount. In this example, the pattern is smaller in the area coded by the second coding circuit than in the area coded by the first coding circuit. Although the total code amount is almost the same, since the same quantization step size is used in the first and second encoding circuits in the example of the present invention, it is smaller than the generated code amount in the first encoding circuit. Two
The amount of generated code in the encoding circuit of is larger. On the other hand, in the conventional example, since the first and second encoding circuits are independently controlled, the generated code amounts of the first and second encoding circuits are substantially equal.

In FIG. 7, (a1) is the image quality (S / N) of the moving image decoded by the first decoding circuit of the present invention, and (a2) is the moving image decoded by the second decoding circuit. Image quality of (b
1) shows the image quality of the moving image decoded by the first decoding circuit of the conventional example, and (b2) shows the image quality of the moving image decoded by the second decoding circuit of the conventional example. As can be seen from this figure, the image quality of the moving image decoded by the first decoding circuit and the second decoding circuit is obviously different in the conventional example, but in the present invention, it is different from the first decoding circuit. The image quality of the second decoding circuit is the same.

[0017]

As described above, according to the present invention, even when a moving image is divided into a plurality of regions and encoded, the image quality of each region becomes uniform, and a good decoded image with no discomfort can be obtained. can get.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a moving image data transmission apparatus according to the present invention.

FIG. 2 is a block diagram showing another example of a moving image data transmission apparatus according to the present invention.

FIG. 3 is a block diagram showing an internal configuration of an encoding circuit.

FIG. 4 is a diagram showing an internal configuration of a decoding circuit.

FIG. 5 is a diagram showing an example of a temporal change of a buffer occupancy rate of a virtual buffer memory of an encoding control circuit.

FIG. 6 is a diagram showing an example of generated code amounts in the present invention and a conventional example.

FIG. 7 is a diagram showing an example of image quality of a decoded image in the present invention and a conventional example.

FIG. 8 is a block diagram showing a conventional example.

[Explanation of symbols]

 1 division circuit 2,3 encoding circuit 4 encoding control circuit 5 multiplexing circuit 6,7 buffer memory 8 separation circuit 9,10 decoding circuit 11 combining circuit

Claims (4)

[Claims] 1. A plurality of encoding circuits for encoding each video signal divided into a plurality of areas, and an encoding control circuit for commonly controlling encoding parameters of the plurality of encoding circuits. A moving image data transmission device characterized by: 2. The encoding control circuit commonly controls the encoding parameters of the plurality of encoding circuits based on the data amount after multiplexing the encoded data from the plurality of encoding circuits. The moving image data transmission device according to claim 1. 3. The encoding control circuit commonly controls encoding parameters of the plurality of encoding circuits based on a total value of data amounts generated in the plurality of encoding circuits. Item 2. The moving image data transmission device according to item 1. 4. The plurality of encoding circuits, a data multiplexing circuit that multiplexes the data encoded by the plurality of encoding circuits, and the data multiplexed by the data multiplexing circuit is transmitted at a constant rate. A second buffer memory for smoothing the data and a coding control circuit on the transmitting side, for accumulating the coded data transmitted from the transmitting side; A data separation circuit for separating the multiplexed coded data extracted from the second buffer memory into coded data for each divided area, and decoding the coded data separated for each area from the separation circuit And a video signal synthesizing circuit for synthesizing video signals of a plurality of regions decoded by the plurality of decoding circuits and converting the video signals into one moving image signal on the receiving side. The moving image data transmission device according to claim 1, wherein