JP2020178274A - Video reproduction apparatus - Google Patents

Abstract

To provide a reproduction apparatus, even when a high luminance pixel exists in a portion of a region of a video image, capable of brightly displaying the video image in the rest of the region.SOLUTION: A reproduction apparatus 101, which reproduces video data in conformity with HDR 10+ and displays the reproduced video data on a display apparatus 102, includes: a detection means 109 configured to detect the maximum luminance of the video data by analyzing the video data; an obtaining means 113 configured to obtain the maximum luminance of the display apparatus 102; a comparison means 110 configured to compare the maximum luminance of the video data and the maximum luminance of the display apparatus 102; and a replacement means 111 configured to replace a value of MaxCLL added to the video data by the maximum luminance of the display apparatus 102 when the maximum luminance of the video data is greater than the maximum luminance of the display apparatus 102.SELECTED DRAWING: Figure 1

Description

The present invention relates to a video playback device, and more particularly to a playback device that reproduces HDR10 + compliant video data.

A high dynamic range video signal (hereinafter referred to as HDR video signal) capable of expressing brightness in a significantly wider range than a standard dynamic range video signal (SDR video signal) conventionally used has been proposed. According to the standard, HDR video can have a maximum brightness of 10,000 nits, but with current display devices such as consumer TV (television) devices and monitors, the maximum brightness that can be displayed is, for example, several hundred nits to several thousand nits. Up to. Therefore, it is difficult to completely reproduce the dynamic range of the input HDR video signal.

In many cases, metadata such as maximum brightness MaxCLL or maximum average brightness MaxFALL of the video is added to the video data obtained by encoding the HDR video signal. MaxCLL is an abbreviation for Maximum Content Light Level, and MaxFALL is an abbreviation for Maximum Frame Average Light Level. In this case, these metadata are used to execute the luminance conversion suitable for the reproduction of the video on the display device side (for example, the display device side selects the tone mapping suitable for the reproduction of the video).

Further, in recent years, a standard called HDR10 + has been proposed in which MaxCLL is added as dynamic metadata for each frame of video or each scene.

Patent Document 1 describes that when the metadata added to the video data is abnormal, the video data is subjected to luminance conversion using alternative data instead of the metadata.

Patent Document 2 describes that when the maximum brightness of an image exceeds the maximum brightness of a display device, the maximum brightness of the image is converted into a value that does not exceed the maximum brightness of the display device.

JP-A-2018-38019 WO2015 / 198552A1

However, the maximum brightness of the video data is not always the optimum MaxCLL. For example, MaxCLL is set so that this high-luminance value becomes the maximum value even when high-luminance pixels are present in a part of the image. When tone mapping is set on the display device so that the MaxCLL becomes the maximum value, the images in other areas are displayed relatively dark.

Therefore, an object of the present invention is to provide a playback device capable of brightly displaying an image in another area even when high-luminance pixels are present in a part area of the image.

In order to achieve the object, the reproduction device as one aspect of the present invention is a reproduction device that reproduces HDR10 + compliant video data and displays it on a display device, and analyzes the video data to display the video. A detection means for detecting the maximum brightness of data, an acquisition means for acquiring the maximum brightness of the display device, a comparison means for comparing the maximum brightness of the video data with the maximum brightness of the display device, and a maximum of the video data. It is characterized by having a replacement means for replacing the value of MaxCLL added to the video data with the maximum brightness of the display device when the brightness is larger than the maximum brightness of the display device.

It is possible to provide a playback device capable of displaying an image in another area brightly even when high-luminance pixels are present in a part area of the image.

Other aspects of the invention will be demonstrated in embodiments described below.

It is a block diagram of Example 1. It is a flowchart of Example 1. It is a relationship diagram between the MaxCLL value and the display. It is a flowchart of Example 2. It is a conceptual diagram of brightness change in a scene.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Hereinafter, description will be made with reference to FIGS. 1 to 3. However, the following examples are merely examples, and the present invention is not limited to the following examples. FIG. 1 is a diagram showing an example of a video system according to the first embodiment of the present invention.

As shown in FIG. 1, the video system according to the first embodiment includes a playback device 101 and a display device 102. The playback device 101 is, for example, a DVD player, a Blu-ray player, or the like, and the display device 102 is, for example, a display. The playback device 101 and the display device 102 are connected via an HDMI (registered trademark) cable 103. The HDMI cable 103 in this embodiment conforms to the HDMI standard, and has a + 5V signal, an HPD signal, a video signal (TMDS signal), and a signal line capable of transmitting EDID, which will be described later.

The reproduction device 101 includes a recording unit 104, a reading unit 105, an HDMI transmission unit 106, a detection unit 109, a comparison unit 110, a metadata replacement unit 111, an operation unit 112, and a control unit 113. The display device 102 includes an HDMI receiving unit 107 and a display unit 108. The reading unit 105, HDMI transmission unit 106, detection unit 109, comparison unit 110, metadata replacement unit 111, and control unit 113 are functions realized by a CPU or a circuit (for example, ASIC). For example, a CPU is one or more programmable processors, and these functions are realized by loading and executing a program such as an OS or an application stored in a ROM or a storage device in a RAM.

The recording unit 104 can record video data conforming to HDR10 +, and is a recording medium such as a BD (Blu-ray (registered trademark)) medium or an SD card.

The reading unit 105 reads out the video data recorded in the recording unit 104.

The HDMI transmission unit 106 converts the video data from the reading unit 105 into an HDMI-compliant TMDS signal and outputs it.

The HDMI receiving unit 107 returns the TMDS (Transition Minimized Differential Signaling) signal from the HDMI transmitting unit 106 to the original video data and outputs it to the subsequent stage.

EDID is an abbreviation for Extended Display Identification Data, and is data that describes device information of the display device 102 including video display capability, physical address, and the like. When the playback device 101 and the display device 102 are connected via the HDMI cable 103 (hereinafter, HDMI connection), the display device 102 transmits the display device 102 to the playback device 101. Various information of EDID is transmitted and received via the DDC (Display Data Channel) signal line of the HDMI cable.

The reproduction device 101 analyzes the contents of the received EDID, determines the type of signal that can be received by the display device 102, and then transmits a video signal to the display device 102 according to the determination result. At the same time, it receives information such as whether or not HDR10 + is supported and, if HDR10 + is supported, the maximum brightness and brightness range of the display device. Information such as the maximum brightness and the brightness range may be the maximum brightness and the brightness range in the display mode set in the display device. The EDID information received from the display device 102 is supplied from the HDMI transmission unit 106 to the control unit 113. The control unit 113 controls the reproduction device 101 according to the EDID information received from the display device 102.

The display unit 108 is a display panel, for example, a liquid crystal panel, an organic EL panel, or a micro LED panel.

The detection unit 109 detects the maximum brightness of the video data and the metadata (MaxCLL, MaxFALL, etc.) added to the video data. The maximum brightness of the video data is detected by analyzing the video data. Specifically, the detection unit 109 searches for the luminance values of all the pixels of the video data read by the readout unit 105, and extracts and extracts the luminance values higher than the threshold value set for each frame. Holds the largest brightness value among the brightness values.

The comparison unit 110 compares the brightness value held by the detection unit 109 with the maximum brightness of the display device received from the display device 102. As a result of the comparison, when the brightness value held by the detection unit 109 is higher, the metadata replacement unit 111 replaces the metadata of the video signal with the maximum brightness of the display device received from the display device 102.

The operation unit 112 is an input device such as a keyboard or a pointing device, and allows the user to input various instructions such as video reproduction and display execution to the reproduction device 101. In this embodiment, the threshold value and the like for detection by the detection unit 109 are also set.

Next, the control flow of the video system according to the present embodiment will be described with reference to FIG. This control flow is realized by the CPU executing a program. The program executed by the CPU may include an application, an OS, a printer driver, and the like.

First, it starts at s201. s202 sets a threshold value α for determining high-luminance pixels in the video data by a user operation from the operation unit 112. The threshold value α is an integer greater than 1.

In s203, the brightness value Y = 0 of the current pixel processed in the current flow and the maximum brightness value Y ′ = 0 up to the current pixel processed in the current flow are initialized, and the transition to s204 occurs.

In s204, the brightness value Y of the pixel of the video data is acquired.

In s205, the result of integrating MaxFALL, which is the average brightness value in the scene, and the threshold value α set by the user in s202, and the brightness value Y are compared. When the brightness value Y is larger, pixels sufficiently larger than the average brightness in the scene are detected. When the luminance value Y is larger, the transition is made to s206, and when the luminance value Y is smaller, the transition is made to s209.

s206 compares the maximum luminance value Y'up to the current pixel being processed in the current flow with the luminance value Y of the current pixel being processed in the current flow. When the brightness value Y of the current pixel is larger, the transition to s207 is performed, the brightness value Y'is replaced with the brightness value Y of the current pixel, and the maximum brightness value is updated. If the brightness value of the current pixel is smaller, the process transitions to s208 and the brightness value Y'is retained.

In s209, it is determined whether or not the processing for all the pixels of one frame is completed, and if it is finished, the transition to s210 is performed, and if not, the process returns to s204 and the processing is repeated for the next pixel.

Here, the relationship between the MaxCLL value in HDR10 + and the display luminance of the display device will be described with reference to an example of FIG. In FIG. 3A, the vertical axis represents the display luminance value and the horizontal axis represents the input level. When the display device receives the video data to which the metadata of the MaxCLL value 301 is added, the tone mapping 302 is set so that 301 becomes the maximum value on the display device side. Further, when the video data to which the metadata of the MaxCLL value 303 is added is received, the tone mapping 304 is set so that 303 becomes the maximum value on the display device side. In this way, the maximum brightness of the content is set for the MaxCLL value, and the display device that receives the MaxCLL sets the tone mapping so that the MaxCLL value becomes the maximum brightness of the display device. In FIG. 3B, the vertical axis represents the maximum luminance value of the video data and the horizontal axis represents the time (frame), and is a diagram showing the change in the maximum luminance of one scene. In this way, when there is a momentary peak brightness 310 in the scene, MaxCLL becomes the brightness value 311 which is the maximum brightness in the scene. However, if the tone mapping is set so that this brightness becomes the maximum brightness, the other 312 are displayed relatively dark.

In s210, the change in the MaxCLL value is confirmed, that is, the change in the scene or the end of the video data is determined, and if there is a change, the transition to s211 is performed. Move.

The maximum luminance value received from the display device 102 is compared with Y'in s211. If Y'is larger, the maximum luminance value of the display device 102 is replaced (overwritten) with MaxCLL in s212, and the process ends in s213. .. If the maximum luminance value of the display device 102 is smaller, the MaxCLL value is maintained and the process ends at s213.

According to this embodiment, even when high-brightness pixels are present in a part of the image, the image in the other area can be displayed brightly.

The second embodiment will be described with reference to FIGS. 1, 4, and 5.

The configuration of the video system according to the second embodiment is substantially the same as that of the first embodiment (FIG. 1). In the first embodiment, the detection unit 109 is configured to be able to analyze the video data, but in the present embodiment, the detection unit 109 may be configured to only detect the metadata of the video data. .. The control flow of the video system according to the present embodiment will be described with reference to FIG. This control flow is also realized by the CPU executing the program. The program executed by the CPU may include an application, an OS, a printer driver, and the like.

When started in s401, the detection unit 109 detects and acquires the maximum luminance value and the MaxCLL value of the display device in s402.

As for the relationship between the MaxCLL value and the display on the display in HDR10 +, as described above, the tone mapping that maximizes the MaxCLL value is selected on the display device.

Here, FIG. 5 is a conceptual diagram of a change in brightness in the scene, and the vertical axis shows the display brightness and the horizontal axis shows the time (frame), but in the case of video data having a change in maximum brightness such as 501. , MaxCLL is 502. However, when the maximum brightness that can be displayed by the display device is 503, the video data having a brightness of 503 or less is also displayed slightly dark.

Therefore, in s404, the maximum luminance value of the display device received from the display device 102 and MaxCLL are compared. When the maximum luminance value of the display device 102 is larger, the maximum luminance value of the display device 102 is set to MaxCLL in s405, and when the maximum luminance value of the display device 102 is smaller, the MaxCLL value is maintained and s406. It ends with.

According to this embodiment, even when high-brightness pixels are present in a part of the image, the image in the other area can be displayed brightly.

[Other Examples]
The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof. For example, the video system of the above embodiment may be mounted on an electronic device such as a digital camera, a smartphone, or a smart glass.

101 Playback device 102 Display device 109 Detection unit (detection means)
110 Comparison unit (comparison means)
111 Metadata replacement part (replacement means)

Claims (9)

A playback device that reproduces HDR10 + compliant video data and displays it on a display device.
A detection means for detecting the maximum brightness of the video data by analyzing the video data, and
An acquisition means for acquiring the maximum brightness of the display device, and
A comparison means for comparing the maximum brightness of the video data with the maximum brightness of the display device, and
It is characterized by having a replacement means for replacing the MaxCLL value added to the video data with the maximum brightness of the display device when the maximum brightness of the video data is larger than the maximum brightness of the display device. Video playback device. A playback device that reproduces HDR10 + compliant video data and displays it on a display device.
An acquisition means for acquiring the maximum brightness of the display device, and
A comparison means for comparing the MaxCLL value added to the video data with the maximum brightness of the display device, and
A reproduction device comprising a replacement means for replacing the MaxCLL value with the maximum brightness of the display device when the MaxCLL value is larger than the maximum brightness of the display device. The playback device according to claim 1 or 2, wherein the MaxCLL is dynamic metadata assigned to each frame or scene of the video data. The playback device according to claim 3, wherein the display device is an HDR10 + compatible display device that changes the tone mapping setting based on the change in the MaxCLL value. An electronic device comprising the reproduction device according to any one of claims 1 to 4. The electronic device according to claim 5, further comprising the display device. This is a video playback method that reproduces HDR10 + compliant video data and displays it on a display device.
A step of detecting the maximum brightness of the video data by analyzing the video data,
The step of acquiring the maximum brightness of the display device and
A step of comparing the maximum brightness of the video data with the maximum brightness of the display device,
It is characterized by having a step of replacing the MaxCLL value added to the video data with the maximum brightness of the display device when the maximum brightness of the video data is larger than the maximum brightness of the display device. How to play the video. This is a video playback method that reproduces HDR10 + compliant video data and displays it on a display device.
The step of acquiring the maximum brightness of the display device and
A step of comparing the MaxCLL value added to the video data with the maximum brightness of the display device, and
A method for reproducing a video, which comprises a step of replacing the value of the MaxCLL with the maximum brightness of the display device when the value of the MaxCLL is larger than the maximum brightness of the display device. A program for causing a computer to execute each step of the video reproduction method according to claim 7 or 8.

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