JP2003309835A - Video distribution and reception system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that a video image with high quality cannot be displayed by selecting a part of an image region while receiving a video image with low quality in the case of video data at a low transfer rate. <P>SOLUTION: A receiver side selects an image region to be desired to display a video image with high quality, informs a distributor about this information, and the distributor uses an image region discrimination means for discriminating whether or not an image region is the desired image region to control a compression rate, connects compression coded data with different compression rates being distributed video data and distributes the result. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video distribution and reception system that compresses and codes video data and distributes it by streaming.

[0002]

2. Description of the Related Art As a first prior art as an image compression apparatus, as described in Japanese Patent Laid-Open No. 5-176184, one or more areas are designated in a target image and the compression rate for each area is set. Equipped with a compression ratio and area specification means to specify,
The image data is compressed based on the information on the screen area and the information on the compression rate / area designated by the compression rate / area designating means. However, the above-mentioned conventional technique does not consider compression of video data with a changing pattern, and responds to a request by a video receiver who operates a video data receiving device which area is desired to be viewed as a high-quality video. It wasn't something.

A second conventional technique is disclosed in Japanese Patent Laid-Open No. 5-34435.
As described in Japanese Patent Publication No. 7, an input section of the frame memory before entering the compressor on the transmission side and an output section of the frame memory after exiting from the decompressor on the receiving side according to area information given from the outside. The compression ratio and the expansion ratio are changed while switching the frame memories according to the area data designated by the area information or the data outside the area. However, the above-mentioned prior art requires a pair of frame memories on the compressor side and the decompressor side, respectively, and does not meet the demand of which screen area a video receiver wants to see as a high-quality video. .

A third conventional technique is disclosed in Japanese Patent Laid-Open No. 10-1740.
As described in Japanese Patent Publication No. 86-86, in order to reduce the load on the network, a low data amount of video data is transmitted for normal display, and if necessary, the normal data amount stored in the storage device in advance is stored. It was to send video data. However, in the above-mentioned conventional technology, streaming reception is performed regardless of the download method via a network with a low transfer rate, and a narrow screen area is obtained by freely selecting a screen area while displaying a full-screen image on the receiving side. Was not able to be displayed as a high quality image.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to provide a narrow screen by displaying a full screen image on the receiving side and selecting a free screen area even if the delivery is performed via a network with a low transfer rate. In the screen area, high-quality video can be received by streaming.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a receiving side selects a narrow screen area and informs the distributing side of the information of this screen area. At the distributing side, an ordinary compression code is used within the selected narrow screen area. Data is created, compressed coded data with a high compression rate is created in other screen areas, distributed at a low bit rate as a whole, and this data is received and decompressed to achieve high quality in a narrow screen area. While displaying the image of, the low-quality image is displayed in the other screen area.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. 1 is a block diagram showing a video distribution and reception system according to Embodiment 1 of the present invention. In FIG. 1, 1 is a video signal input device, 2 is a distribution device, 3 is a network, 4 is a receiving device, and 5 is a receiving device. The display device 6 is an input means. The distribution device includes a compression device 21 that compresses and encodes a video signal input from the video signal input device 1, and its output is distributed through the network 3 in response to a request from the reception device 4. . The decompressing device 41 of the receiving device 4 decompresses the compression-coded video signal distributed through the network 3, and further, the video signal processing device 4
After passing through 3, the image is input to the display device 5 and an image is displayed on the display screen 51.

In FIG. 1, when the input means 6 is operated, information relating to a specific screen area 52a which is narrower than the entire display screen 51 passes through the screen position transmission means 42 and is processed by the video signal processing device to be displayed on the display screen 51. Very narrow screen area 52a
Information is displayed. Then, when a selection operation is performed by the input means 6 while looking at the display screen 51, the specific screen area 52a is set as a screen area in which a high quality image is desired to be displayed.
The information regarding the
Is notified to the screen area determination means of the distribution device. The compression rate in the compression device 21 is controlled based on this information, and the video signal in the screen area 52a is encoded at the normal compression rate. Further, in the screen area 52b excluding the screen area 52a, the video signal is encoded at a high compression rate. As a result, the video displayed in the screen area 52b becomes a low-quality video because the amount of information decreases when encoded at a high compression rate, but the transfer rate distributed through the network can be reduced, and High-quality video can be displayed in the screen area 52a selected on the receiving side.

In the case of conforming to MPEG2 of the video coding standard, as shown in FIG. 2, the video has a macroblock (MB) as a minimum screen unit which can individually specify a quantization step size (also referred to as QSC) used for compression coding. Also called)
It is subdivided into 53, and the change of the compression rate of the compression coding is realized by changing the quantization step size for each macroblock 53. 54 is a pixel. Usually, one macroblock is composed of 16 × 16 pixels. If a quantization step size that reduces the amount of information when quantizing the coefficient of the discrete cosine transform (also referred to as DCT coefficient) is applied, encoding can be performed at a high compression rate. Therefore, when the compression-coded video data is expanded and displayed on the receiving side, the quality of the video becomes low because the amount of information is small.

FIG. 2 is an explanatory diagram of a method of selecting the circular screen area 52a. The screen area 52a has a circular shape, and the diameter d of the screen area 52a is set to the horizontal screen size L1.
Enter it in advance as a ratio to, or specify it as a default value. Then, in the middle of receiving a low-quality video of a low bit rate, the pointer 55 displayed on the screen by the input means 6 is moved to the screen area 52a desired to be displayed in high quality, and then the input means 6 is selected at an arbitrary timing. I press the button. As a result, the distribution device is notified of this information with the screen position of the pointer 55 as the center position of the screen area 52a, and only the video within the screen area 52a is compression-encoded at a normal compression ratio and distributed to display a high-quality video. To be done. Subsequently, if the pointer 55 is moved to another position and the same operation is performed, the screen area where the high-quality image is displayed can be moved.

A mouse is a specific example of the input means 6. Further, when the pointer 55 (also referred to as a mouse pointer when the input means 6 is a mouse) is displayed in this operation, it is not necessary to display a circle indicating the boundary of the screen area 52a, but another method is used. As a screen area 52a by displaying a circle without displaying the pointer 55.
May be selected.

FIG. 3 is an explanatory diagram of a method of selecting the square screen area 52a. The screen area 52a is a square, and the length L2 of one side of the screen area 52a is input in advance as a ratio to the horizontal screen size L1 or is designated as a default value. Then, in the middle of receiving a low-quality video of a low bit rate, the pointer 55 displayed on the screen by the input means 6 is moved to the screen area 52a desired to be displayed in high quality, and then the input means 6 is selected at an arbitrary timing. I press the button. As a result, pointer 5
This information is notified to the distribution device with the screen position of 5 as the center position of the screen area 52a, and only the video of the screen area 52a is compression-encoded at a normal compression ratio and distributed, and a high-quality video is displayed. Subsequently, if the pointer 55 is moved to another position and the same operation is performed, the screen area where the high-quality image is displayed can be moved.

FIG. 4 is an explanatory view of another selection method of the circular screen area 52a. The diagonal position of the square 56 is selected by the input means 6. First, the pointer 55a displayed on the screen is moved to a desired position and selected. Next, the pointer 55b is moved and selected so as to be located at a desired position. As this operation method, a method generally known as an operation of dragging the pointer from 55a to 55b may be applied. The screen area 52a is designated as a circle inscribed in the square 56. In this case, it is not necessary to specify the diameter of the circle in advance.

FIG. 5 is a block diagram showing a video distribution and reception system according to a second embodiment of the present invention. In FIG. 5, those having the same operations as those in FIG. 1 are designated by the same reference numerals. In the distribution device 2, the output from the compression device 21 is not immediately sent to the network 3, but is temporarily stored in the storage device. At this time, the high compression data compressed at a high compression rate and the compressed data at a normal compression rate are stored in the storage device. Then, the narrow screen area 52a in which the high-quality video notified from the screen position transmission means 42 of the receiving device 4 should be displayed.
Information is received by the screen area determination means 22, and when the video data is sent to the network, the screen area determination means 22
Storage device 23 via a switching device 24 controlled by
From low compression data and high compression data to the screen areas 52a, 5
The data is switched every 2b for transmission.

In this embodiment, since the high compression data and the low compression data are stored in the storage device in advance,
Since only the data switching process needs to be performed at the time of distribution, there is an effect that the desired screen area 52a can be displayed on the receiving side with high quality and an effect that the load on the distribution device is reduced.

[0016]

As described above in detail, according to the present invention, a video is compressed into a small amount of data that can be distributed at a low bit rate as a screen unit and distributed, and the video is displayed within a narrow area selected by the receiving device. Can be displayed as a high-definition image to see the details, and in other areas, a low-definition image can be used to see a rough content. Therefore, there is an effect that it is possible to observe the details of the image even though the image is distributed via the network having a low transfer rate.

[Brief description of drawings]

FIG. 1 is a system configuration diagram showing a video distribution and reception system according to a first embodiment of the present invention.

FIG. 2 is a first explanatory diagram of a display screen of the display device according to the first embodiment of the present invention.

FIG. 3 is a second explanatory diagram of a display screen of the display device according to the first embodiment of the present invention.

FIG. 4 is a third explanatory diagram of a display screen of the display device according to the first embodiment of the present invention.

FIG. 5 is a system configuration diagram showing a video distribution and reception system according to a second embodiment of the present invention.

[Explanation of symbols]

1 Video signal input device 2 distribution devices 3 network 4 Receiver 5 Display device 6 input means 21 Compressor 22 Screen area determination device 23 Storage device 24 Switching device 41 Expander 42 screen position transmission means 43 Video signal processing device 51 screens 52a Screen area for displaying high-definition video 52b Screen area for displaying low- and high-definition video 53 macroblocks 54 pixels 55, 55a, 55b pointers 56 squares.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H04N 5/92 H04N 5/92 H 7/24 7/13 Z (72) Inventor Satoshi Mio Yokohama City, Kanagawa Prefecture 292 Yoshida-cho, Totsuka-ku, Ltd. F-Term in the Digital Media Development Division, Hitachi, Ltd. (Reference) 5C052 AA01 CC11 DD04 5C053 FA28 GB21 GB28 LA06 LA11 LA14 5C059 MA00 MA23 MC11 SS06 TA46 TB07 TC34 TC45 TC47 TD18 UA02 UA05 5C064 BC18 BC20 BD02 5J064 AA01 BA16 BC02 BC16 BD02

Claims (6)

[Claims] 1. A video distribution and receiving system comprising a distribution device for compressing and coding and distributing video data and a receiving device for receiving the distributed video data via a network, wherein the distribution device is video data. During delivery, the receiving device is provided with a screen position input means for designating a specific screen area narrower than the entire display screen at an arbitrary timing, and information about the specific screen area is transmitted from the receiving device to the network. Via the information about the specific screen area, the video distribution apparatus encodes the video data at a predetermined compression rate within the specific screen area, and outside the specific screen area. By encoding and distributing the video data at a compression rate higher than the predetermined compression rate, the receiving device can make the video within the specific screen area have higher quality than the video outside the screen area. A video distribution and reception system characterized by being displayed in. 2. The video distribution and reception system according to claim 1, wherein the compression device of the distribution device sets a screen area of a video as a minimum screen unit capable of individually specifying a quantization step size used for compression encoding. It is subdivided into macroblocks, the macroblocks in the specific screen area are coded at a predetermined compression rate using a predetermined quantization step size, and the macroblocks outside the specific screen area are more than the predetermined compression rate. A video distribution and reception system characterized by encoding at a high compression rate using a quantization step size corresponding to a high compression rate. 3. The video distribution and reception system according to claim 2, wherein the distribution device encodes video data in advance at a predetermined compression rate using a normal quantization step size, and low compression data for high-quality video. And a storage device that stores high-compression data for low-definition video, which is obtained by encoding the video data at a high compression ratio using a quantization step size corresponding to a high compression ratio, and the specification notified from the receiving device. A switching device for determining whether or not it is within the specific screen area based on the information of the screen area and switching between the high compression data for the low definition video and the low compression data for the high definition video to read out. Video distribution and receiving system. 4. The video distribution and reception system according to claim 1, wherein the information on the specific screen area is information on the shape and size of the specific screen area, and the specific screen. It is the information of the center position of the area,
A video distribution and reception system, characterized in that at least information on the center position of the specific screen area can be input by an input device for the screen position at an arbitrary timing. 5. The video distribution system according to claim 4, wherein when a circle is designated as the shape of the screen area, the size information is designated by the ratio of the diameter of the circle to the horizontal screen size. When a square is designated as the shape, the video distribution and reception system is characterized in that the size information is designated by the ratio of the length of one side of the square to the horizontal screen size. 6. The video distribution and reception system according to claim 1, wherein the information on the specific screen area is information on the shape of the specific screen area and the position of the specific screen area. And image size information which can define the size, and at least the information on the screen positions of the two points can be inputted by the screen position input means at an arbitrary timing. Receiving system.