JP2021168447A - Transmission device, reception device, and program - Google Patents

Abstract

To generate a second resolution video by dividing a first resolution video into videos, and enable transmission of both videos with low delay maintaining the high quality while eliminating the need for a dedicated device to generate the second resolution video from the first resolution video.SOLUTION: A transmission device 1 includes: a video division unit 11 that performs wavelet transform on an input video frame of a first resolution video so as to generate a first division frame consisting of low frequency components of the video frame and a second division frame consisting of high frequency components of the video frame; a video compression unit 12 that performs first compression processing on the first division frame to generate a first compression division frame, and also performs second compression processing on the second division frame to generate a second compression division frame; and a transmission unit 13 that transmits the first compression division frame and the second compression division frame via a transmission line 4. The first division frame is used as a video frame for a second resolution video a resolution of which is lower than the first resolution.SELECTED DRAWING: Figure 1

Description

The present invention relates to a transmitter, a receiver, and a program.

In order to perform video transmission that requires low delay at the level of several lines, there is a technology called light compression as one of the video compression technologies. This compression technique has a compression ratio of about a fraction, which is not high, but can perform compression processing with low delay. Examples of the light compression method include TICO (Tiny Codec) and JPEG (Joint Photographic Experts Group) XS (see, for example, Non-Patent Documents 1 and 2).

Standardization of a program production system used for program production by transmitting a video signal or an audio signal on a general-purpose Ethernet work using IP (Internet Protocol) technology is progressing (for example, Non-Patent Documents 3 to 7).

It is called remote production in which the video and audio signals of the relay site are transmitted to the broadcasting station using the general-purpose Ethernet work using the program production system, and the program production that was conventionally performed at the relay site is performed from the remote broadcasting station. There is a program production method.

By using remote production, the number of personnel at the relay site can be reduced, and since the production equipment can be held at the broadcasting station, the personnel and production equipment can be operated efficiently. However, in remote production, it is required to transmit a video signal from a relay site to a broadcasting station with low delay and high image quality.

Since the transmission capacity of a general-purpose Ethernet work is limited and the amount of video signal data is particularly large, it is required to compress and transmit the data. Therefore, a light compression technique is used to perform compression with low delay and high image quality.

The amount of video signal data handled in remote production of 8K (hereinafter, appropriately referred to as "first resolution") programs is very large. When a video is lightly compressed and transmitted in order to perform video transmission using a line having a limited transmission capacity, the transmission capacity may not be sufficient by lightly compressing the video depending on the conditions of the transmission line. Further, since a narrow band line of about 10 Gbps is cheaper than a wide band line of 100 Gbps and the line provision range is wide and easy to use, the video frame is divided and the divided video frame is lightly compressed into a plurality of. There is a method of transmitting using a line. “8K” means that the number of horizontal pixels of the video frame is 7680 pixels.

When 8K video is compressed to about a fraction by light compression technology and a 10 Gbps Ethernet work line is used, the transmission of one 8K video is the limit. However, the image quality deterioration characteristics of JPEG XS during compression have been improved from the existing light compression technology, and it is considered that compression of 1/10 or more is possible while maintaining high image quality.

If compression of 1/10 or more is possible, it is possible to transmit two 8K images on a 10 Gbps Ethernet work line, and improvement in line utilization efficiency can be expected.

When monitoring the video shot in the production of the 8K video, the 4K video (hereinafter, appropriately referred to as "second resolution"), which has a lower resolution than 8K, is down-converted from the 8K video using a dedicated device. 4K video is generated and monitored on a monitor that supports 4K video. “4K” means that the number of horizontal pixels of the video frame is 3840 pixels. Further, the 8K image may be down-converted by a dedicated device to generate a 2K image and monitored by a monitor corresponding to the 2K image. “2K” means that the number of horizontal pixels of the video frame is 1920 pixels.

Further, in 4K / 8K integrated production in which the same program is produced by 4K video and 8K video, the 4K video is generated by down-converting the 8K video with a dedicated device.

By using 2SI (2 Sample Interleave Division), which is an existing video division method, it is possible to down-convert 8K video while dividing it to generate 4K and 2K video, but the divided video frame is light. Image quality deteriorates significantly when compressed.

SMPTE RDD35, "TICO Lightweight Codec Used in IP Networked or in SDI Infrastructure" ISO / IEC 21122 “Information technology --Low-latency light weight coding system” SMPTE ST 2110-10, "Professional Media Over Managed IP Networks: System Timing AND Definitions" SMPTE ST 2110-20, "Professional Media Over Managed IP Networks: Uncompressed Active Video" SMPTE ST 2110-21, “Professional Media Over Managed IP Networks: Traffic Shaping AND Delivery Timing FOR Video” SMPTE ST 2110-22, “Professional Media Over Managed IP Networks: Constant Bit-Rate Compressed Video” SMPTE ST 2110-30, "Professional Media Over Managed IP Networks: PCM Digital Audio"

In remote production, it is necessary to transmit a video signal from a relay site to a broadcasting station with low delay and high image quality using a band with a limited transmission capacity.

As described above, there is a high demand for generating a second resolution image from a first resolution image, but a dedicated device is required to generate a second resolution image from a first resolution image. There is a problem that the cost required for the dedicated device is high.

Therefore, the present invention generates a second resolution video by dividing the first resolution video into a video while eliminating the need for a dedicated device for generating the second resolution video from the first resolution video. It is an object of the present invention to provide a transmitting device, a receiving device, and a program capable of transmitting video with low delay while maintaining high image quality.

The transmission device according to the first aspect performs wavelet transform on the input video frame of the first resolution video, thereby performing the wavelet transform on the first divided frame composed of the low frequency component of the video frame and the height of the video frame. A video division unit that generates a second division frame composed of frequency components, a first compression division process is performed on the first division frame to generate a first compression division frame, and a second compression division frame is generated. The first compression division frame is provided with a video compression unit that performs two compression processes to generate a second compression division frame, and a transmission unit that transmits the first compression division frame and the second compression division frame via a transmission path. The gist is that the divided frame is used as a video frame for a video having a second resolution lower than the first resolution.

The receiving device according to the second aspect is a first compression divided frame composed of a low frequency component of a video frame of a first resolution video and a second compression composed of a high frequency component of the video frame from a transmitting device via a transmission path. The receiving unit that receives the divided frame and the first compressed divided frame are subjected to the first decoding process to generate the first divided frame, and the second compressed divided frame is subjected to the second decoding process. It is a gist to include a video decoding unit that generates a second divided frame and a video synthesizing unit that synthesizes the video frame from the first divided frame and the second divided frame.

The receiving device according to the third aspect transmits a first compression division frame composed of a low frequency component of a video frame of a first resolution video and a second compression division frame composed of a high frequency component of the video frame via a transmission path. A receiving device used in a transmission system that transmits from a transmitting device, the receiving unit that receives only the first compression division frame among the first compression division frame and the second compression division frame, and the first compression division. A video decoding unit that performs a first decoding process on a frame to generate a first divided frame is provided, and the first divided frame is used as a video frame of a video having a second resolution lower than the first resolution. The gist is that.

The program according to the fourth aspect performs wavelet transform on the video frame of the video of the first resolution input to the transmission device, thereby performing the wavelet transform on the first divided frame composed of the low frequency component of the video frame and the video. A video division process for generating a second divided frame composed of high frequency components of the frame and a first compression process for the first divided frame are performed to generate a first compressed divided frame, and the second divided frame is used. On the other hand, the video compression process of performing the second compression process to generate the second compression division frame and the transmission process of transmitting the first compression division frame and the second compression division frame via the transmission path are executed. The gist is that the first divided frame is used as a video frame for a video having a second resolution lower than the first resolution.

The program according to the fifth aspect comprises a first compression division frame composed of a low frequency component of a video frame of a first resolution video and a high frequency component of the video frame in a receiving device via a transmission path from the transmitting device. A reception process for receiving the second compression division frame and a first decoding process for the first compression division frame are performed to generate a first division frame, and a second decoding process for the second compression division frame. The gist is to execute the video decoding process for generating the second divided frame and the video compositing process for synthesizing the video frame from the first divided frame and the second divided frame.

The program according to the sixth aspect transmits a first compression division frame composed of a low frequency component of a video frame of a first resolution video and a second compression division frame composed of a high frequency component of the video frame via a transmission path. For the reception device used in the transmission system to transmit from the device, the reception process of receiving only the first compression division frame among the first compression division frame and the second compression division frame, and the first compression division frame. The video decoding process of performing the first decoding process to generate the first divided frame is executed, and the first divided frame is used as a video frame of a video having a second resolution lower than the first resolution. It is a summary.

According to the present invention, a second resolution image is generated by dividing the first resolution image into an image while eliminating the need for a dedicated device for generating the second resolution image from the first resolution image. It is possible to provide a transmitting device, a receiving device, and a program capable of obtaining an image with low delay while maintaining high image quality.

It is a figure which shows the structure of 1 of the transmission device which concerns on embodiment. It is a figure which shows the mode that the 1st video frame is divided into 4 by the WTD which concerns on embodiment. It is a figure which shows the mode that the 1st video frame is divided into 16 by the WTD which concerns on embodiment. It is a figure which shows the WTD which concerns on embodiment. It is a figure which shows an example of the histogram of each component before and after WTD. It is a figure which shows the structure of the 1st receiving apparatus which concerns on embodiment. It is a figure which shows the structure of the 2nd receiving apparatus which concerns on embodiment. It is a figure which shows the image division by 2SI. It is a figure which shows the evaluation system of the image quality deterioration characteristic at the time of performing video division using 2SI and WTD. It is a figure which shows the image quality deterioration characteristic acquired by the evaluation system shown in FIG.

An embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are designated by the same or similar reference numerals.

(Transmitter)
First, the transmission device 1 according to the present embodiment will be described. FIG. 1 is a diagram showing a configuration of a transmission device 1 according to the present embodiment.

As shown in FIG. 1, the transmitting device 1 according to the present embodiment transmits video to the first receiving device 2 and the second receiving device 3 via the transmission line 4. The first receiving device 2 is a receiving device corresponding to the first resolution and a second resolution video reception lower than the first resolution, and the second receiving device 3 is a receiving device corresponding to the second resolution video reception. be.

An example in which the first resolution is 8K will be described in the present embodiment, but the first resolution is not limited to 8K and may be, for example, 4K. Further, although an example in which the second resolution is 4K will be described in the present embodiment, the second resolution is not limited to 4K and may be, for example, 2K.

For example, in program production of 8K video (hereinafter referred to as "8K video"), the 8K video is down-converted to 4K video (hereinafter referred to as "4K video") and displayed as 4K video on a 4K compatible monitor. May be monitored.

Also, in the 4K / 8K integrated production that produces the same program with 4K video and 8K video, while producing the 8K video program, the 8K video is down-converted to 4K video to produce the 4K video program. In some cases.

In addition to program production, there is a demand for transmitting only video that is down-converted from 8K video to 4K video or 2K video using a low-cost narrow band line of about 10 Gbps.

In these cases, the transmitting device 1 transmits 8K video and 4K video to the first receiving device 2 via the transmission line 4. This makes it possible to monitor 8K video as 4K video on a 4K compatible monitor in the production of an 8K video program, or to produce a 4K video program while producing an 8K video program.

Further, the transmitting device 1 transmits a 4K video image to the second receiving device 3 via the transmission line 4. This makes it possible to transmit only the down-converted video using a narrow band line.

In this embodiment, it is assumed that the transmission line 4 is a wired line or an Ethernet work line. A narrowband Ethernet work of about 10 Gbps is used for the transmission line 4.

The transmission device 1 includes a video division unit 11, a video compression unit 12, and a transmission unit 13.

The video division unit 11 performs wavelet transform on the first video frame to obtain a first division frame composed of low frequency components of the first video frame and a second division frame composed of high frequency components of the first video frame. It is generated and the first and second divided frames are output to the video compression unit 12.

The video compression unit 12 performs the first compression processing on the first division frame to generate the first compression division frame, and also performs the second compression processing on the second division frame to generate the second compression division frame. Generate and output the first and second compression division frames to the transmission unit 13.

The transmission unit 13 transmits the first and second compression division frames to the first receiving device 2 via the transmission line 4, and transmits the first compression division frame to the first reception device 2 via the transmission line 4. Send to 2.

Specifically, the video compression unit 12 has video compression units 121 to 124. The transmission unit 13 has an IP packetization unit 131 and a transmission buffer 132. The IP packetization unit 131 includes IP packetization units 1311 to 1314.

A video signal is input to the video dividing unit 11 from a camera or the like. The video dividing unit 11 divides the video for each video frame constituting the video signal. In the present embodiment, this video frame is a video frame of 8K video. Hereinafter, such a video frame will be referred to as a “first video frame”.

The video dividing unit 11 performs wavelet transform on the input first video frame to obtain one first divided frame composed of low frequency components of the first video frame and high frequency components of the first video frame. Generates a plurality of second division frames. In the present embodiment, the video division unit 11 generates three second division frames from one first video frame.

Such a new method of video division is called WTD (Wavelet Transform Division). The video division unit 11 outputs one first division frame to the video compression unit 121, and outputs three second division frames to the three video compression units 122, 123, and 124, respectively.

FIG. 2 is a diagram showing how the first video frame is divided into four by the WTD according to the present embodiment. In the present embodiment, the wavelet of the wavelet transform used in WTD is a Haar wavelet.

As shown in FIG. 2, the video dividing unit 11 generates a low frequency component LL (x, y) of the first video frame from the first video frame by wavelet transform, and the low frequency component LL (x, y). A split frame (hereinafter, appropriately referred to as “LL split frame”) 51 composed of the above is generated.

The video dividing unit 11 generates a high frequency component LH (x, y) of the first video frame from the first video frame by wavelet transform, and divides a frame composed of the high frequency component LH (x, y) (hereinafter, appropriately “). (Called LH split frame) 52 is generated.

The video dividing unit 11 generates the high frequency component HL (x, y) of the first video frame from the first video frame by wavelet transform, and the divided frame composed of the high frequency component HL (x, y) (hereinafter, appropriately " (Called HL split frame) 53 is generated.

The video dividing unit 11 generates the high frequency component HH (x, y) of the first video frame from the first video frame by wavelet transform, and the divided frame composed of the high frequency component HH (x, y) (hereinafter, appropriately " (Called "HH split frame") 54 is generated.

In this way, the video dividing unit 11 divides the first video frame into four by WTD: LL, LH, HL, and HH dividing frames 51, 52, 53, and 54. In the present embodiment, since the resolution of the first video frame is 8K, the resolutions of the LL, LH, HL, and HH divided frames 51, 52, 53, and 54 are 4K.

The LL divided frame 51 (first divided frame) can be used as a video frame for 4K (second resolution) video lower than 8K (first resolution). That is, the video dividing unit 11 can generate a video frame of a 4K (second resolution) video generated by down-converting an 8K (first resolution) video by WTD without using a dedicated device.

When the second resolution is 2K, it is necessary to divide the first video frame into 16 parts. FIG. 3 is a diagram showing how the first video frame is divided into 16 by the WTD according to the present embodiment.

As shown in FIG. 3, when the first video frame is divided into 16 by WTD, the LL, LH, HL, and HH divided frames 51, 52, 53, and HH divided frames generated by dividing the first video frame into four by WTD, and Each of the 54 is further divided into four by WTD. As a result, a divided frame obtained by dividing the first video frame into 16 using WTD is generated. In this case, for example, as the video frame of the 2K video, the LL'divided frame generated from the LL divided frame 51 can be used.

FIG. 4 is a diagram showing a state before and after WTD according to the present embodiment. FIG. 4A shows pixel components P (x, y) constituting the first video frame before WTD. FIG. 4B shows the low frequency component LL (x, y) and the high frequency component LH (x, y), HL (x, y), and HH (x, y) of the first video frame after WTD. ing.

As shown in FIG. 4A, since the first video frame is a video frame of 8K video in the present embodiment, the first video frame of FIG. 4A has 4320 pixels in the vertical direction and 7680 pixels in the horizontal direction. It is shown.

As shown in FIG. 4B, according to WTD, the video dividing unit 11 includes a first video frame composed of P (x, y), a divided frame 51 composed of a low frequency component LL (x, y), and a high frequency. The split frames 52, 53, and 54 composed of the components LH (x, y), HL (x, y), and HH (x, y) are generated. The low frequency component LL (x, y) consists of the average value between adjacent pixels of the first video frame, and the high frequency components LH (x, y), HL (x, y), and HH (x, y) are It consists of a difference value between adjacent pixels of the first video frame.

The low frequency component LL (x, y) is a component obtained by applying a low-pass filter in the horizontal and vertical directions of the first video frame, and is obtained by the equation (1).

・・・（１）

... (1)

The high frequency component LH (x, y) is a component obtained by applying a low-pass filter in the horizontal direction of the first video frame and applying a high-pass filter in the vertical direction, and is obtained by the equation (2).

・・・（２）

... (2)

The high frequency component HL (x, y) is a component obtained by applying a high-pass filter in the horizontal direction of the first video frame and applying a low-pass filter in the vertical direction, and is obtained by the equation (3).

・・・（３）

... (3)

The high frequency component HH (x, y) is a component obtained by applying a high-pass filter in the horizontal and vertical directions of the first video frame, and is obtained by the equation (4).

・・・（４）

... (4)

As shown in FIG. 1, the video division unit 11 generates an LL division frame 51 as a first division frame by WTD, and outputs the LL division frame 51 to the video compression unit 121.

The video division unit 11 generates the LH division frame 52 as the second division frame by WTD, and outputs the LH division frame 52 to the video compression unit 122.

The video division unit 11 generates an HL division frame 53 as a second division frame by WTD, and outputs the HL division frame 53 to the video compression unit 123.

The video division unit 11 generates an HH division frame 54 as a second division frame by WTD, and outputs the HH division frame 54 to the video compression unit 124.

The video compression unit 121 performs the first compression process on the LL division frame 51 (first division frame) output by the video division unit 11 to generate an LL compression division frame (first compression division frame), and LL compression division frame. Is output to the IP packetization unit 1311.

The video compression unit 122 performs a second compression process on the LH division frame 52 (second division frame) output by the video division unit 11 to generate an LH compression division frame (second compression division frame), and the LH compression division frame. Is output to the IP packetization unit 1312.

The video compression unit 123 performs a second compression process on the HL division frame 53 (second division frame) output by the video division unit 11 to generate an HL compression division frame (second compression division frame), and HL compression division frame. Is output to the IP packetization unit 1313.

The video compression unit 124 performs a second compression process on the HH division frame 54 (second division frame) output by the video division unit 11 to generate an HH compression division frame (second compression division frame), and the HH compression division frame. Is output to the IP packetization unit 1314.

The first compression process is used when compressing the first divided frame composed of low frequency components. In the first compression process, the video compression unit 121 compresses the first divided frame using the first compression ratio.

The second compression process is used when compressing a second divided frame composed of high frequency components. The video compression units 122, 123, and 124 compress the second divided frame using the second compression rate in the second compression process.

Light compression technology is used for the first and second compression processes. In this embodiment, JPEG XS is used as the light compression technique. By using JPEG XS for the first and second compression processes, it is possible to compress the first video frame at a compression rate of 1/10 or more. Therefore, for example, two 8K videos on a 10 Gbps Ethernet work line. Can be transmitted, and line utilization efficiency can be expected to improve. However, other methods such as TICO may be used for the first and second compression processes.

In this embodiment, the second compressibility is equal to or higher than the first compressibility. FIG. 5 is a diagram showing an example of a histogram of pixel values of video frames before and after WTD. In FIG. 5, the horizontal axis represents the pixel value, and the vertical axis represents the cumulative number of pixels corresponding to the pixel value.

As shown in FIG. 5, the histogram of the low frequency component LL (x, y) is similar to the histogram of the pixel component P (x, y) of the video frame before WTD. On the other hand, the histograms of the high frequency components LH (x, y), HL (x, y), and HH (x, y) have a normal distribution centered on the pixel value "0".

As described above, since the LH, HL, and HH divided frames 52, 53, and 54 have a smaller amount of information than the LL divided frame 51, the compression efficiency can be improved as compared with the LL divided frame 51, so that the image quality deteriorates during compression. small.

Therefore, the video compression unit 121 performs the first compression process using a first compression rate equal to or lower than the second compression rate, and the video compression units 122, 123, and 124 perform the first compression rate. The second compression process may be performed using a second compression rate equal to or higher than this. The video compression units 121 to 124 lower the compression rate of the LL divided frame 51 having a large amount of information and increase the compression rate of the LH, HL, and HH divided frames 52, 53, and 54 having a small amount of information. Image quality deterioration due to compression can be suppressed.

Further, since the LL divided frame 51 is used as a video frame of a 4K video lower than 8K in the present embodiment, by lowering the compression rate of the LL divided frame 51, a video frame of a 4K video with less deterioration in image quality can be obtained. Can be provided.

The IP packetization unit 1311 converts the LL compression division frame (first compression division frame) output by the video compression unit 121 into an IP packet, and outputs the IP packet to the transmission buffer 132.

The IP packetization unit 1312 converts the LH compression division frame (second compression division frame) output by the video compression unit 122 into an IP packet, and outputs the IP packet to the transmission buffer 132.

The IP packetization unit 1313 converts the HL compression division frame (second compression division frame) output by the video compression unit 123 into an IP packet, and outputs the IP packet to the transmission buffer 132.

The IP packetization unit 1314 converts the HH compression division frame (second compression division frame) output by the video compression unit 124 into an IP packet, and outputs the IP packet to the transmission buffer 132.

The transmission buffer 132 temporarily stores the IP packets output by the IP packetization units 1311 to 1314, and outputs the IP packets to the transmission line 4.

The transmission unit 13 may transmit the first compression division frame and the second compression division frame in parallel using a plurality of communication lines. For example, the transmission unit 13 transmits four compressed division frames in parallel via the four communication lines.

The transmission unit 13 transmits an LL compression division frame (first compression division frame) to which identification information indicating that the LL compression division frame (first compression division frame) is composed of the low frequency component LL (x, y) is added. You may. As a result, the first and second receiving devices 2 and 3 identify and receive the first compression division frame (LL compression division frame) among the first and second compression division frames based on the identification information, and receive the LL division. The frame 51 can be used as a video frame for 4K video.

At this time, the transmission unit 13 may add a flag as identification information for each IP packet of the LL compression division frame. Alternatively, the transmission unit 13 may use the IP address as the identification information by using different IP addresses for the IP packetization units 1311 to 1314 of the transmission unit 13.

The identification information may indicate that the LL compression division frame (first compression division frame) can be used as a video frame for 4K video.

(1st receiving device)
Next, the first receiving device 2 according to the present embodiment will be described. The first receiving device 2 according to the present embodiment is a receiving device corresponding to 8K (first resolution) video reception. FIG. 6 is a diagram showing the configuration of the first receiving device 2.

As shown in FIG. 6, the first receiving device 2 includes a receiving unit 21, a video decoding unit 22, and a video compositing unit 23.

The receiving unit 21 receives the first and second compression division frames from the transmission device 1 via the transmission line 4, and outputs the first and second compression division frames to the video decoding unit 22.

The video decoding unit 22 performs the first decoding process on the first compression-divided frame to generate the first divided frame, and also performs the second decoding process on the second compressed-divided frame to generate the second divided frame. It is generated and the first and second divided frames are output to the video composition unit 23.

The video compositing unit 23 synthesizes the first video frame from the first and second divided frames and outputs the first video frame.

Specifically, the receiving unit 21 has a receiving buffer 211 and an IP depackaging unit 212. The IP depackaging unit 212 includes IP depackaging units 2121 to 2124. The video decoding unit 22 has video decoding units 221 to 224.

The receiving unit 21 receives the IP packets of the first compression division frame and the second compression division frame from the transmission device 1 via the transmission line 4. At this time, the receiving unit 21 may identify and receive only the first compression division frame based on the above-mentioned identification information.

The reception buffer 211 temporarily stores IP packets received from the transmission device 1 via the transmission line 4, and outputs the IP packets to the IP depacketization units 2121 to 2124.

The IP depacketization unit 2121 converts the IP packet output by the reception buffer 211 into an IP depacket, and outputs the LL compression division frame to the video decoding unit 221 as the first compression division frame.

The IP depacketization unit 2122 converts the IP packet output by the reception buffer 211 into an IP depacket, and outputs the LH compression division frame to the video decoding unit 222 as the second compression division frame.

The IP depacketization unit 2123 converts the IP packet output by the reception buffer 211 into an IP depacket, and outputs the HL compression division frame to the video decoding unit 223 as the second compression division frame.

The IP depacketization unit 2124 converts the IP packet output by the reception buffer 211 into an IP depacket, and outputs the HH compression division frame to the video decoding unit 224 as the second compression division frame.

The video decoding unit 221 performs the first decoding process on the LL compression division frame (first compression division frame) output by the IP depackaging unit 2121 to generate the LL division frame 51 (first compression division frame), and LL. The division frame 51 is output to the video composition unit 23. The first decoding process is a reverse process of the first compression process described above.

The video decoding unit 222 performs the second decoding process on the LH compression division frame (second compression division frame) output by the IP depackaging unit 2122 to generate the LH division frame 52 (second division frame), and LH. The division frame 52 is output to the video composition unit 23. The second decoding process is a reverse process of the second compression process described above.

The video decoding unit 223 performs a second decoding process on the HL compression division frame (second compression division frame) output by the IP depackaging unit 2123 using a light compression technique, and performs a second decoding process on the HL compression division frame 53 (second division frame). ) Is generated, and the HL division frame 53 is output to the video composition unit 23.

The video decoding unit 224 performs a second decoding process on the HH compression division frame (second compression division frame) output by the IP depackaging unit 2124 using a light compression technique, and performs a second decoding process on the HH compression division frame 54 (second division frame). ) Is generated, and the HH division frame 54 is output to the video composition unit 23.

The video compositing unit 23 includes an LL divided frame 51 (first divided frame) output by the video decoding unit 221 and LH, HL, and HH divided frames 52, 53, which are output by the video decoding units 222, 223, and 224, respectively. And 54 (the second divided frame) are combined to synthesize the first video frame, and the combined first video frame is output. The first video frame is a video frame of 8K (first resolution) video.

The video decoding unit 221 may output the LL divided frame 51 (first divided frame) as a second video frame which is a video frame of a 4K (second resolution) video without going through the video synthesizing unit 23. .. As a result, the video decoding unit 221 generates and outputs a video frame of the 4K (second resolution) video generated by down-converting the 8K (first resolution) video without using a dedicated device. be able to.

Therefore, the first receiving device 2 according to the present embodiment not only synthesizes and outputs an 8K video image frame from the first divided frame and the second divided frame, but also down-converts the 8K image without using a dedicated device. It is possible to output a video frame of the 4K video generated by the above. However, the first receiving device 2 may be a receiving device that outputs only a video frame of 8K video.

The first and second video frames output from the first receiving device 2 are output to, for example, a monitor (not shown) connected to the first receiving device 2.

(Second receiver)
Next, the second receiving device 3 according to the present embodiment will be described. The second receiving device 3 according to the present embodiment is a receiving device that does not support 8K (first resolution) video reception but supports at least 4K (second resolution) video reception. FIG. 7 is a diagram showing the configuration of the second receiving device 3.

As shown in FIG. 7, the second receiving device 3 has a receiving unit 31 and a video decoding unit 32.

The receiving unit 31 receives only the first compression-divided frame out of the first and second compression-divided frames from the transmission device 1 via the transmission line 4, and outputs the first compression-divided frame to the video decoding unit 32. ..

The video decoding unit 32 performs the first decoding process on the first compression division frame to generate the first division frame, and outputs the first division frame as the second video frame.

Specifically, the receiving unit 31 has a receiving buffer 311 and an IP depackaging unit 312.

The receiving unit 31 receives only the IP packet of the first compression division frame (LL compression division frame) among the IP packets of the first and second compression division frames from the transmission device 1 via the transmission line 4. At this time, the receiving unit 31 may identify the first compression division frame based on the above-mentioned identification information, and may receive only the IP packet of the first compression division frame among the first and second compression division frames.

The reception buffer 311 temporarily stores IP packets received from the transmission device 1 via the transmission line 4, and outputs the IP packets to the IP depacketization unit 312.

The IP depacketization unit 312 converts the IP packet output by the reception buffer 311 into an IP depacket, and outputs the LL compression division frame to the video decoding unit 32 as the first compression division frame.

The video decoding unit 32 performs the first decoding process on the LL compression division frame (first compression division frame) output by the IP depackaging unit 312 by using a light compression technique, and performs the LL division frame 51 (first compression division). Frame) is generated.

The video decoding unit 32 outputs the LL divided frame 51 (first divided frame) as a second video frame which is a video frame of a 4K (second resolution) video. As a result, the video decoding unit 221 generates and outputs a video frame of the 4K (second resolution) video generated by down-converting the 8K (first resolution) video without using a dedicated device. be able to.

Therefore, the second receiving device 3 according to the present embodiment is 4K (second) without using a dedicated device even when a video frame of 8K (first resolution) video is input to the transmitting device 1. It is possible to output a video frame of a video of (resolution).

The second video frame output from the second receiving device 3 is output to, for example, a monitor (not shown) connected to the second receiving device 3. At this time, the monitor connected to the second receiving device 3 does not have to support 8K (first resolution), and may support at least 4K (second resolution).

(Comparison with 2SI)
2SI will be described as a comparative example of WTD according to the present embodiment.

FIG. 8 is a diagram showing video division by 2SI. As shown in FIG. 8, the 2SI samples the even-numbered and odd-numbered lines of the video frame in the horizontal direction at intervals of two pixels and divides them into four. Therefore, when the video division by 2SI is used, the video frame of the 4K video can be generated by thinning out the pixel components of the video frame of the 8K video at intervals of 2 pixels. However, since the video frame of the 4K video is composed of sampling of discrete pixels of the original video frame, the high frequency component increases. Therefore, the deterioration of image quality when compressed / decrypted increases.

According to the WTD according to the present embodiment, the LL divided frame 51 composed of the average value between the adjacent pixels of the 8K video video frame is used as the 4K video video frame. Further, when the video is divided by 2SI with respect to the target compression rate, the image quality deterioration becomes large unless the first compression rate and the second compression rate are set to the same value, but the WTD is the LL division frame 51. Since the first compression rate, which is the compression rate of, can be suppressed more than the target compression rate, deterioration of image quality can be suppressed as compared with 2SI.

Next, the effectiveness of WTD is confirmed. FIG. 9 is a diagram showing an evaluation system of image quality deterioration characteristics when video division is performed using 2SI and WTD. PSNR (Peak signal to noise ratio) is used for the evaluation.

As shown in FIG. 9, a plurality of types of 8K video frames (Chromakey, Kimono, Moss, and Ship) are compressed and decoded without division while using PEG XS as a light compression technique while changing the compression ratio. The 8K video frame obtained by compressing and decoding 4 4K video frames or 16 2K video frames obtained by repeating 4 divisions or 4 divisions using 2SI and WTD and 16 divisions, and then synthesizing the images. The image quality deterioration characteristics of the 8K video frame were acquired. An ultra-high-definition, wide-color gamut standard image provided by the Video Information Media Society was used as the evaluation video frame.

FIG. 10 is a diagram showing image quality deterioration characteristics acquired by the evaluation system shown in FIG. When the PSNR value is large, the image quality deterioration is small, and when the PSNR value is small, the image quality deterioration is large.

As the compression ratio, 1/10 and 1/12 were used. When divided using the WTD according to the present embodiment, the first compression rate was set to 1/10 or 1/12 or less while keeping the overall compression rate at 1/10 or 1/12 or less.

Specifically, when the overall compression rate is 1/10, (first compression rate, second compression rate) = (1/10, 1/10), (3/20, 1/12), ( The compression ratio was changed to 4 patterns of 1/5, 1/15) and (3/10, 1/30). When the total compression rate is 1/12, (1st compression rate, 2nd compression rate) = (1/12, 1/12), (2/15, 1/15), (11/60, 1) The compression ratio was changed to 4 patterns of / 20) and (7/30, 1/30).

10 (a) and 10 (b) show the image quality deterioration characteristics when the compression ratios are 1/10 and 1/12, respectively, when the compression ratio is not divided and when the compression ratio is divided into four using 2SI and WTD. 10 (c) and 10 (d) show the image quality deterioration characteristics when the compression ratios are 1/10 and 1/12, respectively, when the compression ratio is not divided and when the compression ratio is divided into 16 using 2SI and WTD. There is.

As shown in FIGS. 10 (a) and 10 (b), when the compression ratio is 1/10, the image quality is about 2. When the compression ratio was 1/12 at 6 to 5.5 [dB], the image quality deteriorated by about 2.9 to 5.1 [dB]. On the other hand, when the image quality is divided into four using WTD, the first compression rate is 3/20 and the second compression rate is 3/20 for all images when the compression rate is 1/10 as compared with the image quality deterioration that occurs in the case of non-division. The image quality deterioration of about 2 to 3 [dB] occurred in the combination of 1/12, which is the most reduced image quality deterioration. When the compression rate is 1/12, the first compression rate is 2/15 and the second compression rate is 1/15 for all images, which is a combination that minimizes image quality deterioration and is about 1.3 to 2.3 [dB]. ] Image quality has deteriorated. That is, it was confirmed that the image quality deterioration of about 0.6 to 2.5 [dB] can be reduced in the case of dividing into four using WTD as compared with the case of dividing into four using 2SI.

As shown in FIGS. 10 (c) and 10 (d), when the compression ratio is 1/10, the image quality is about 5. When the compression ratio was 1/12 at 5 to 10 [dB], the image quality deteriorated by about 6 to 8.7 [dB]. On the other hand, when 16 divisions are performed using WTD, when the compression ratio is 1/10, the first compression ratios of Chromakey, Kimono, and Ship are 1/10 and the second, as compared with the image quality deterioration that occurs in the case of non-division. The compression rate is 1/10, and Moss is a combination in which the first compression rate is 3/20 and the second compression rate is 1/12, which reduces the deterioration of image quality, and is about 1.8 to 3.4 [dB]. Image quality deterioration has occurred. When the compression rate is 1/12, the first compression rate is 2/15 and the second compression rate is 1/15 for all images, which is about 2 to 3.3 [dB] in the combination with the least image quality deterioration. Image quality deterioration has occurred. That is, it was confirmed that the image quality deterioration of about 2.9 to 3.4 [dB] can be reduced when 16 divisions are performed using WTD as compared with the case where 16 divisions are performed using 2SI.

Therefore, in the evaluation of the image quality, it was found that the WTD according to the present embodiment had less deterioration in image quality than the 2SI of the existing method, and the effectiveness of the WTD was confirmed.

(Other embodiments)
A program for causing the computer to execute each process performed by the transmitting device 1 and a program for causing the computer to execute each process performed by the first and second receiving devices 2 and 3 may be provided. The program may be recorded on a computer-readable medium. Computer-readable media allow you to install programs on your computer. Here, the computer-readable medium on which the program is recorded may be a non-transient recording medium. The non-transient recording medium is not particularly limited, but may be, for example, a recording medium such as a CD-ROM or a DVD ROM.

Further, the functional unit (circuit) for executing each process performed by the transmission device 1 may be integrated, and the transmission device 1 may be configured as a semiconductor integrated circuit (chipset, SoC). Similarly, functional units (circuits) that execute each process performed by the first and second receiving devices 2 and 3 are integrated, and the first and second receiving devices 2 and 3 are used as semiconductor integrated circuits (chipset, SoC). It may be configured.

Although one embodiment has been described in detail with reference to the drawings above, the specific configuration is not limited to the above, and various design changes and the like can be made within a range that does not deviate from the gist. ..

1: Transmission device 2: First receiving device 3: Second receiving device 4: Transmission path 11: Video dividing unit 12: Video compression unit 13: Transmission unit 21: Reception unit 22: Video decoding unit 23: Video synthesis unit 31: Reception unit 32: Video decoding unit 51: LL division frame 52: LH division frame 53: HL division frame 54: HH division frame 121: Video compression unit 122: Video compression unit 123: Video compression unit 124: Video compression unit 131: IP Packetizing unit 132: Transmission buffer 211: Reception buffer 212: IP depacketizing unit 221: Video decoding unit 222: Video decoding unit 223: Video decoding unit 224: Video decoding unit 311: Reception buffer 312: IP depacketizing unit 1311: IP Packetization unit 1312: IP packetization unit 1313: IP packetization unit 1314: IP packetization unit 2121: IP depacketization unit 2122: IP depacketization unit 2123: IP depacketization unit 2124: IP depacketization unit

Claims (10)

By performing wavelet transform on the input video frame of the first resolution video, a first divided frame composed of a low frequency component of the video frame and a second divided frame composed of a high frequency component of the video frame are generated. Video division and
Video compression that performs the first compression process on the first divided frame to generate the first compressed divided frame, and also performs the second compression process on the second divided frame to generate the second compressed divided frame. Department and
A transmission unit that transmits the first compression division frame and the second compression division frame via a transmission line is provided.
The first divided frame is a transmission device characterized in that it is used as a video frame of a video having a second resolution lower than the first resolution. The transmission unit transmits both the first compression division frame and the second compression division frame to the first receiving device, and transmits the first compression division frame to the second receiving device.
The first receiving device is a receiving device corresponding to the video reception of the first resolution and the second resolution.
The transmission device according to claim 1, wherein the second receiving device is a receiving device that supports only the second resolution video reception among the first resolution and the second resolution video reception. .. The transmission device according to claim 1 or 2, wherein the first compression rate used in the first compression process is equal to or lower than the second compression rate used in the second compression process. The first compression division frame is any one of claims 1 to 3, wherein the transmission unit transmits the first compression division frame to which identification information indicating that the first compression division frame is composed of the low frequency component is added. The transmitter described in. The transmission device according to any one of claims 1 to 4, wherein the video compression unit uses JPEG XS in the first compression process and the second compression process. A receiving unit that receives a first compression-divided frame composed of a low-frequency component of a video frame of a first-resolution video and a second compression-divided frame composed of a high-frequency component of the video frame from a transmitting device via a transmission line.
Video decoding in which the first compression division frame is subjected to the first decoding process to generate the first division frame, and the second compression division frame is subjected to the second decoding process to generate the second division frame. Department and
A receiving device including the first divided frame and a video synthesizing unit that synthesizes the video frame from the second divided frame. Reception used in a transmission system that transmits a first compression-divided frame composed of low-frequency components of a video frame of a first-resolution video and a second compression-divided frame composed of high-frequency components of the video frame from a transmission device via a transmission line. It ’s a device,
Of the first compression division frame and the second compression division frame, a receiving unit that receives only the first compression division frame, and
A video decoding unit that performs a first decoding process on the first compressed divided frame to generate a first divided frame is provided.
The receiving device is characterized in that the first divided frame is used as a video frame of a video having a second resolution lower than the first resolution. To the transmitter
By performing wavelet transform on the input video frame of the first resolution video, a first divided frame composed of a low frequency component of the video frame and a second divided frame composed of a high frequency component of the video frame are generated. Video division processing and
Video compression that performs the first compression process on the first divided frame to generate the first compressed divided frame, and also performs the second compression process on the second divided frame to generate the second compressed divided frame. Processing and
The transmission process of transmitting the first compression division frame and the second compression division frame via the transmission line is executed.
The first divided frame is a program characterized in that it is used as a video frame of a video having a second resolution lower than the first resolution. In the receiving device
Reception processing for receiving the first compression division frame composed of the low frequency component of the video frame of the first resolution video and the second compression division frame composed of the high frequency component of the video frame from the transmission device via the transmission line.
Video decoding in which the first compression division frame is subjected to the first decoding process to generate the first division frame, and the second compression division frame is subjected to the second decoding process to generate the second division frame. Processing and
A program characterized by executing a video compositing process for synthesizing the video frame from the first split frame and the second split frame. Reception used in a transmission system that transmits a first compression-divided frame composed of low-frequency components of a video frame of a first-resolution video and a second compression-divided frame composed of high-frequency components of the video frame from a transmission device via a transmission line. On the device
A reception process for receiving only the first compression division frame among the first compression division frame and the second compression division frame, and
The video decoding process of performing the first decoding process on the first compressed divided frame to generate the first divided frame is executed.
The first divided frame is a program characterized in that it is used as a video frame of a video having a second resolution lower than the first resolution.

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