How to receive and send

Abstract

To provide an image receiving method capable of appropriately displaying an image.SOLUTION: A receiving method includes receiving a first content that is compatible with HDR (step S21), receiving a second content that is compatible with SDR and includes at least one of subtitles and images and is displayed together with the first content (step S22), receiving a scale factor described in TTML, and converting the second content into a converted content that is compatible with HDR using the scale factor (step S23).SELECTED DRAWING: Figure 15A

Description

[Technical Field]

[0001] The present invention relates to a transmission method for transmitting an image, or a reception method for receiving the image. [Background technology]

[0002] In recent years, studies have been conducted to expand the dynamic range of video luminance from SDR (Standard Dynamic Range) to HDR (High Dynamic Range) (see, for example, Non-Patent Document 1). Furthermore, broadcasting stations not only transmit video through regular broadcasting (basic broadcasting), but also transmit text, graphics, and the like through data broadcasting. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] White Paper Blu-ray(registered trademark) Disc Read-Only Format(Ultra HD Blu-ray)Audio Visual Application Format Specifications for BD-ROM Version 3.0 July 2015,Blu-ray Disc Association Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the HDR image and SDR image of Non-Patent Document 1 are transmitted by broadcasting or the like, there is a problem that the receiving device cannot properly display these images.

[0005] Therefore, the present invention provides a transmission method and the like that allows images to be displayed appropriately. [Means for solving the problem]

[0006] A receiving method according to one aspect of the present invention is a receiving method in which a receiving device receives content transmitted from a transmitting device, the receiving device receiving first content transmitted from the transmitting device that conforms to HDR (High Dynamic Range), and second content transmitted from the transmitting device that conforms to SDR (Standard Dynamic Range), and Is textual or graphic picture Statue The receiving device receives second content, which includes the first content and is displayed together with the first content on a display connected to the receiving device, receives a scale factor described in TTML (Timed Text Markup Language) transmitted from the transmitting device, and converts the second content into converted content that is compatible with HDR using the scale factor.

[0007] Furthermore, a receiving method according to one embodiment of the present invention is a receiving method performed by a receiving device, which receives first content that conforms to HDR (High Dynamic Range) and characteristic information of the first content indicating one of OETF (opto-electrical transfer function) and EOTF (electro-optical transfer function), receives second content that conforms to SDR (Standard Dynamic Range) and includes at least one of subtitles and images, and is displayed together with the first content, determines whether a scale factor described in TTML (Timed Text Markup Language) has been received, and if it is determined that a scale factor has been received, converts the second content into first converted content that conforms to HDR using the scale factor, and if it is determined that a scale factor has not been received, converts the second content into second converted content that conforms to HDR using a default value stored in the receiving device.

[0008] These comprehensive or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM, or may be realized as any combination of a system, a method, an integrated circuit, a computer program, and a recording medium. [Effects of the Invention]

[0009] The transmission method of the present invention allows the image to be displayed appropriately. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a transmission / reception system according to an embodiment, and an example of a screen displayed on a receiving device. [Figure 2] FIG. 2 is a diagram showing an example in which the receiving device according to the embodiment simultaneously displays an HDR main video and an SDR sub-video. [Figure 3A] FIG. 3A is a block diagram showing an example of a configuration of a transmission device according to an embodiment. [Figure 3B] FIG. 3B is a block diagram showing another example of the configuration of the transmitting device according to the embodiment. [Figure 4] FIG. 4 is a diagram showing an example in which the receiving device according to the embodiment simultaneously displays a video of a basic broadcast and a video of a data broadcast. [Figure 5] FIG. 5 is a block diagram showing another example of the configuration of the transmitting device according to the embodiment. [Figure 6] FIG. 6 is a block diagram showing another example of the configuration of the transmitting device according to the embodiment. [Figure 7] FIG. 7 is a diagram showing the HDR EOTF and the SDR EOTF in the embodiment. [Figure 8] FIG. 8 is a diagram showing an example in which the receiving device according to the embodiment displays subtitles of a basic broadcast simultaneously with other video. [Figure 9] FIG. 9 is a block diagram showing an example of the configuration of a receiving device according to the embodiment. [Figure 10] FIG. 10 is a flowchart showing an example of the processing operation of the receiving device according to the embodiment. [Figure 11] FIG. 11 is a diagram showing an example of transition of an image displayed by the receiving device according to the embodiment. [Figure 12] FIG. 12 is a block diagram showing another example of the configuration of the receiving device according to the embodiment. [Figure 13] FIG. 13 is a flowchart showing another example of the processing operation of the receiving device according to the embodiment. [Figure 14A] FIG. 14A is a flowchart illustrating a transmission method according to one embodiment of the present invention. [Figure 14B] FIG. 14B is a block diagram showing a configuration of a transmission device according to an embodiment of the present invention. [Figure 15A] FIG. 15A is a flowchart illustrating a receiving method according to one embodiment of the present invention. [Figure 15B] FIG. 15B is a block diagram showing a configuration of a receiving device according to an aspect of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Findings that form the basis of the present invention) The present inventors have found that the following problems arise with respect to Non-Patent Document 1 described in the "Background Art" section.

[0012] Non-Patent Document 1 assumes that graphics are created in SDR, and if the video onto which the graphics are superimposed is HDR video, the dynamic range of the graphics is converted from SDR to HDR and the graphics are displayed in HDR.

[0013] Currently, more video images than HDR images are overlaid with graphics. Therefore, it makes sense to provide graphics created in SDR and convert the dynamic range of the graphics from SDR to HDR only when the video image onto which the graphics are overlaid is HDR.

[0014] However, as HDR video becomes more widespread in the future, it is possible that we will see more cases where the dynamic range of graphics is converted to HDR and then displayed in HDR, rather than graphics being displayed in SDR. In general, displaying graphics created in HDR in HDR is preferable to converting graphics created in SDR to HDR graphics and then displaying them in HDR, as this allows the graphics to be displayed as intended by the creator.

[0015] Therefore, in the future, as HDR video becomes more widespread, it is possible that graphics will also be created in HDR and provided in advance.

[0016] The inventors of the present application, having become aware of the above-mentioned possibility, conducted detailed studies and came up with various issues and solutions in a previously unimaginable environment in which graphics created in SDR and graphics created in HDR coexist, as will be described in the embodiments below.

[0017] In order to solve these various problems, a transmission method according to one aspect of the present invention acquires an image for data broadcasting and image signal characteristic information indicating OETF (Opto-Electrical Transfer Function) or EOTF (Electro-Optical Transfer Function) as the image signal characteristic of the image, and transmits a data broadcasting signal including the image for data broadcasting and the image signal characteristic information via data broadcasting.

[0018] As a result, whether the dynamic range of an image (e.g., a graphic) for data broadcasting is SDR or HDR, a data broadcasting signal containing image signal characteristic information indicating the corresponding OETF or EOTF is transmitted by data broadcasting. In other words, even in an environment where graphics created in SDR and graphics created in HDR are provided by data broadcasting together, the corresponding OETF or EOTF is transmitted by data broadcasting together with the graphics. Therefore, even in such an environment, a receiving device such as a television can display images such as graphics for data broadcasting in an appropriate dynamic range by using the OETF or EOTF.

[0019] Furthermore, when acquiring the image signal characteristic information, if the image is a character or graphic, the image signal characteristic information may be acquired that indicates an offset or a scale factor for each code value included in the image, instead of the OETF or the EOTF.

[0020] This allows the receiving device to easily convert image signal characteristics such as the dynamic range of an image for data broadcasting by using the offset or scale factor.

[0021] In addition, when a video for a basic broadcast, which is a broadcast other than the data broadcast, is acquired, and the image signal characteristics of the image for the data broadcast and the video for the basic broadcast are different, the image signal characteristics of at least one of them are converted to make the image signal characteristics the same, and a basic broadcast signal including the video for the basic broadcast and image signal characteristic information indicating the made-to-match image signal characteristic is transmitted by the basic broadcast, and the image signal characteristic information included in the data broadcast signal may indicate the OETF or the EOTF as the made-to-match image signal characteristic.

[0022] This unifies the image signal characteristics, i.e., OETF or EOTF, of the images for data broadcasting and the video for basic broadcasting, and image signal characteristic information indicating the unified image signal characteristics is transmitted by both the basic broadcasting and the data broadcasting. Therefore, the receiving device can simultaneously display the images for data broadcasting and the video for basic broadcasting without switching the OETF or EOTF for each, i.e., without switching the display process. As a result, the implementation of the receiving device can be simplified. Furthermore, because the image signal characteristic information indicating the unified image signal characteristics is transmitted by both the basic broadcasting and the data broadcasting, coordination regarding the image signal characteristics is not required between the reception process for basic broadcasting and the reception process for data broadcasting in the receiving device. As a result, the implementation of the receiving device can be simplified.

[0023] For example, the video for basic broadcasting may be a main video, a secondary video, or a subtitle corresponding to the main video. Also, for example, the image signal characteristic information may indicate the OETF or the EOTF and at least one of a dynamic range, a color gamut, and a white point as the image signal characteristics.

[0024] According to another aspect of the present invention, a receiving method includes receiving a first image and first image signal characteristic information indicating image signal characteristics of the first image, receiving a second image and second image signal characteristic information indicating image signal characteristics of the second image, and, if the first and second image signal characteristic information are different, converting the image signal characteristics of at least one of the first and second images to make the image signal characteristics of the first and second images the same, and simultaneously displaying the first and second images having the same image signal characteristics. For example, the first and second image signal characteristic information indicates at least one of an OETF (Opto-Electrical Transfer Function), an EOTF (Electro-Optical Transfer Function), a dynamic range, a color gamut, and a white point as the image signal characteristics.

[0025] As a result, if the image signal characteristics of the first image are, for example, SDR OETF or EOTF and the image signal characteristics of the second image are, for example, HDR OETF or EOTF, the first and second images, both of which have the same OETF or EOTF, are displayed simultaneously, thereby improving the visibility of the first and second images.

[0026] Furthermore, in the receiving method, when the first and second images are displayed simultaneously, if only the image signal characteristics indicated by the second image signal characteristic information among the received first and second image signal characteristic information are switched, the image signal characteristics of the first and second images may be made identical by converting the image signal characteristics after the second image is switched or by stopping the conversion being performed on the image signal characteristics before the second image is switched, and after the conversion or the conversion of the image signal characteristics of the second image is stopped, the first and second images having the identical image signal characteristics may be displayed simultaneously.

[0027] This allows the image signal characteristics of the first and second images being displayed to be maintained the same before and after the switch, even if only the image signal characteristics of the second image are switched, thereby reducing the visual discomfort caused by the switch.

[0028] Furthermore, when receiving the first image and the first image signal characteristic information, the first image and the first image signal characteristic information transmitted by data broadcasting may be received, and when receiving the second image and the second image signal characteristic information, the second image and the second image signal characteristic information may be received by core broadcasting, which is a broadcast other than data broadcasting.

[0029] As a result, for example, if a first image from a data broadcast is displayed in SDR and the image signal characteristics of a second image from a core broadcast that is being displayed simultaneously with the first image are switched from SDR to HDR, the second image will continue to be displayed in SDR, thereby reducing the visual discomfort caused by the switch.

[0030] Furthermore, when receiving the first image and the first image signal characteristic information, the first image and the first image signal characteristic information may be received by communication via a communication network, and when receiving the second image and the second image signal characteristic information, the second image and the second image signal characteristic information may be received by broadcasting.

[0031] As a result, for example, if a first image is being displayed in SDR and the image signal characteristics of a second image being broadcast simultaneously with the first image are switched from SDR to HDR, the second image will continue to be displayed in SDR, thereby minimizing the visual discomfort caused by the switch.

[0032] These comprehensive or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM, or as any combination of a system, a method, an integrated circuit, a computer program, or a recording medium.

[0033] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0034] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, among the components in the following embodiments, components that are not described in the independent claims that represent the highest concepts are described as optional components.

[0035] (Embodiment) FIG. 1 is a diagram showing an example of the configuration of a transmission / reception system according to this embodiment and an example of a screen displayed on a receiving device.

[0036] The transmission / reception system includes a transmission device 100 at a broadcasting station and a reception device 200 such as a television set located in a home, for example.

[0037] The transmitting device 100 transmits broadcast content to the receiving device 200 by broadcasting through a broadcast network including a satellite. Furthermore, the transmitting device 100 transmits communication content to the receiving device 200 by communication through a communication network such as the Internet. The broadcast content and communication content include images or audio. The images are, for example, video, subtitles, text, or graphics. Furthermore, broadcasting is classified into core broadcasting and data broadcasting, which are different from each other.

[0038] The receiving device 200 receives and plays back broadcast content and communication content, and by this playback, the receiving device 200 simultaneously displays multiple images included in the content on the screen of a display device such as a display.

[0039] For example, the receiving device 200 simultaneously displays video 1 and video 2, which are the main video and sub-video of the basic broadcast, video 3 of the data broadcast, text or graphics of the data broadcast, video 4 of the communication, and text or graphics of the communication. Note that the main video and sub-video are each video images that are simultaneously displayed in picture-in-picture.

[0040] The images included in the transmitted content include images with the conventional standard dynamic range (SDR) brightness and images with high dynamic range (HDR) brightness, which expands the dynamic range by several to 100 times.

[0041] This embodiment relates to a method and device for simultaneously displaying HDR video and SDR video on the screen of a receiving device 200.

[0042] FIG. 2 is a diagram showing an example in which the receiving device 200 simultaneously displays an HDR main video and an SDR sub-video.

[0043] When transmitting a broadcast signal by superimposing multiple images having different dynamic ranges, which is one of the image signal characteristics, the transmitting device 100 in this embodiment unifies the image signal characteristics, including the optical-electrical transfer function (OETF) or electrical-to-optical transfer function (EOTF), of the images. The transmitting device 100 then transmits the superimposed multiple images and image signal characteristic information, including the OETF / EOTF of the images. In this embodiment, OETF and EOTF, or OETF or EOTF, are referred to as OETF / EOTF.

[0044] This eliminates the need for the receiving device 200 to switch display processing according to the image signal characteristics for each screen area when simultaneously displaying an HDR primary video and an SDR secondary video, as shown in Fig. 2. Specifically, it eliminates the need to switch the OETF / EOTF applied to each image. As a result, the implementation of the receiving device 200 can be simplified.

[0045] In this embodiment, the image signal characteristics and image signal characteristic information corresponding to an image are referred to as video signal characteristics and video signal characteristic information, respectively, regardless of whether the image is a video or not. The video signal characteristic information is information that represents the characteristics of the image signal (i.e., the video signal characteristics), and the characteristics are at least one of OETF / EOTF, dynamic range, color gamut, white point, etc.

[0046] In this embodiment, either (1) or (2) may be performed as long as the video signal characteristics of the main video and the secondary video are unified by (1) matching them to the main video or (2) unifying them to HDR.

[0047] By fixing the video signal characteristics to either HDR or SDR within a certain period of time, such as for one program, the frequency of switching display processing in the receiving device 200 can be reduced, and image distortion caused by switching can be suppressed.

[0048] FIG. 3A is a block diagram showing an example of the configuration of transmitting apparatus 100 according to this embodiment.

[0049] The transmitting device 100 includes converting units 101 and 105 , a synthesizing unit 102 , a sending unit 103 , and a control unit 104 .

[0050] The control unit 104 acquires main video signal characteristic information, which is video signal characteristic information of the main video, and sub-video signal characteristic information, which is video signal characteristic information of the sub-video. Then, based on the main video signal characteristic information and the sub-video signal characteristic information, the control unit 104 outputs a control signal to the conversion unit 101 for converting the video signal characteristics of the main video into the video signal characteristics of the sub-video. Alternatively, conversely, based on the main video signal characteristic information and the sub-video signal characteristic information, the control unit 104 outputs a control signal to the conversion unit 105 for converting the video signal characteristics of the sub-video into the video signal characteristics of the main video. Alternatively, based on the main video signal characteristic information and the sub-video signal characteristic information, the control unit 104 outputs a control signal to the conversion unit 101 or 105 for converting both the video signal characteristics of the main video and the sub-video to HDR or for converting both the video signal characteristics of the main video and the sub-video to SDR.

[0051] Furthermore, the control unit 104 outputs to the sending unit 103 video signal characteristic information indicating video signal characteristics that are unified for the main video and the sub-video, that is, video signal characteristic information indicating video signal characteristics that are common to each of the main video and the sub-video.

[0052] The converter 101 acquires a main video signal and converts the video signal characteristics of the main video signal based on a control signal output from the controller 104. Similarly, the converter 105 acquires a sub-video signal and converts the video signal characteristics of the sub-video signal based on a control signal output from the controller 104.

[0053] The synthesizing unit 102 synthesizes (or superimposes) the main video and the sub-video output from the conversion units 101 and 104 and outputs the result to the sending unit 103 .

[0054] The sending unit 103 transmits, as a basic broadcast signal, a signal including the combined main video and sub-video and the unified video signal characteristic information output from the control unit 104 via broadcasting (specifically, basic broadcasting). The sending unit 103 is a transmitting unit.

[0055] The transmission / reception system according to this embodiment may include a transmission device having another configuration instead of transmission device 100, as shown in FIG. 3B.

[0056] FIG. 3B is a block diagram showing another example of the configuration of the transmitting device according to this embodiment.

[0057] The transmitting device 100A has the same functions as the transmitting device 100 described above, and includes a combining unit 102a, a sending unit 103, a control unit 104a, and a conversion unit 105.

[0058] The control unit 104a acquires the main video signal characteristic information and the sub-video signal characteristic information, and outputs a control signal to the conversion unit 105 to convert the video signal characteristics of the sub-video into the video signal characteristics of the main video, based on the main video signal characteristic information and the sub-video signal characteristic information.

[0059] The conversion unit 105 acquires the sub-picture and converts the video signal characteristics of the sub-picture based on the control signal output from the control unit 104a.

[0060] The synthesizing unit 102a acquires the main video, synthesizes (or superimposes) the main video with the sub-video output from the conversion unit 105, and outputs the result to the sending unit 103.

[0061] The sending unit 103 transmits the signal including the combined main video and secondary video and the main video signal characteristic information as a basic broadcast signal via broadcasting (specifically, basic broadcasting). This main video signal characteristic information is video signal characteristic information that indicates video signal characteristics that are unified for each of the main video and secondary video, i.e., video signal characteristic information that is common to each of them.

[0062] In such transmission devices 100 and 100A, the conversion unit 101 or 105 converts the main video or secondary video signal from an SDR signal to an HDR signal or from an HDR signal to an SDR signal in response to a control signal.

[0063] FIG. 4 is a diagram showing an example in which the receiving device 200 simultaneously displays a video of a basic broadcast and a video of a data broadcast.

[0064] The receiving device 200 simultaneously displays, for example, video 1 and video 2, which are the main video and sub-video of the basic broadcast, video 3 of the data broadcast, and text or graphics of the data broadcast.

[0065] Here, there are cases where video signal characteristics such as dynamic range differ between the main video of the basic broadcast and the secondary video of the basic broadcast, or the image (video, text, or graphics) of the data broadcast.

[0066] In such a case, the transmission / reception system in this embodiment may include, instead of the transmitting device 100 or 100A, a transmitting device that unifies the video signal characteristics of each image other than the main video of the basic broadcast to the video signal characteristics of the main video of the basic broadcast, as shown in Fig. 5. This eliminates the need for the receiving device 200 to switch video signal characteristic information for each type of broadcast, making it possible to simplify the implementation of the receiving device 200.

[0067] FIG. 5 is a block diagram showing another example of the configuration of the transmitting device according to this embodiment.

[0068] The transmitting device 100B includes sending units (transmitting units) 111 and 116, control units 112, 114 and 117, and conversion units 113, 115 and 118.

[0069] The control unit 112 acquires the main video signal characteristic information and the sub-video signal characteristic information, and outputs a control signal to the conversion unit 113 to convert the video signal characteristics of the sub-video into the video signal characteristics of the main video, based on the main video signal characteristic information and the sub-video signal characteristic information.

[0070] The conversion unit 113 acquires the sub-picture and converts the video signal characteristics of the sub-picture based on the control signal output from the control unit 112 .

[0071] The sending unit 111 acquires the main video, the main video signal characteristic information, and the secondary video output from the conversion unit 113, and transmits a signal including these as a basic broadcast signal by basic broadcasting.

[0072] The control unit 114 acquires data broadcasting video signal characteristic information, which is video signal characteristic information of the data broadcasting video, and main video signal characteristic information. Then, based on the data broadcasting video signal characteristic information and the main video signal characteristic information, the control unit 112 outputs a control signal to the conversion unit 115 for converting the video signal characteristics of the data broadcasting video into the video signal characteristics of the main video.

[0073] The conversion unit 115 acquires the data broadcast video, which is the video of the data broadcast, and converts the video signal characteristics of the data broadcast video based on the control signal output from the control unit 114.

[0074] The control unit 117 acquires data broadcasting graphic signal characteristic information, which is video signal characteristic information of data broadcasting characters or graphics, and main video signal characteristic information. Then, based on the data broadcasting graphic signal characteristic information and the main video signal characteristic information, the control unit 117 outputs a control signal to the conversion unit 118 for converting the video signal characteristics of the data broadcasting characters or graphics into the video signal characteristics of the main video.

[0075] The conversion unit 118 acquires a data broadcast graphic, which is a character or graphic of a data broadcast, and converts the video signal characteristics of the data broadcast graphic based on a control signal output from the control unit 117 .

[0076] The sending unit 116 acquires the main video signal characteristic information, the data broadcast video output from the conversion unit 115, and the data broadcast graphic output from the conversion unit 118, and transmits a signal including these as a data broadcast signal via data broadcasting.

[0077] In this way, the transmitting device 100B in this embodiment includes video signal characteristic information in both the basic broadcast signal and the data broadcast signal. This eliminates the need for coordination regarding video signal characteristics between the reception process of the basic broadcast signal and the reception process of the data broadcast signal in the receiving device 200, making it possible to simplify the implementation of the receiving device 200.

[0078] Furthermore, if the receiving device 200 can always receive and process the basic broadcast signal and the data broadcast signal as a pair, the transmitting device 100B may omit the video signal characteristic information in the data broadcast signal. In this case, the transmitting method in this embodiment is a transmitting method in which an image for data broadcasting is acquired, and a video for basic broadcasting, which is a broadcast other than the data broadcasting, and if the image signal characteristics of the image for data broadcasting and the video for basic broadcasting are different, the image signal characteristic of at least one of them is converted to make the image signal characteristics the same, the data broadcasting signal including the image for data broadcasting is transmitted by data broadcasting, and a basic broadcasting signal including the video for basic broadcasting and image signal characteristic information indicating the made-to-be-equal image signal characteristic is transmitted by the basic broadcasting.

[0079] The transmission / reception system according to this embodiment may include a transmission device having another configuration instead of the transmission device 100B, as shown in FIG.

[0080] FIG. 6 is a block diagram showing another example of the configuration of the transmitting device according to this embodiment.

[0081] The transmitting device 100C includes sending units (transmitting units) 111 and 116a, control units 112, 114 and 117a, and conversion units 113 and 115.

[0082] The control unit 117a acquires data broadcasting graphic signal characteristic information, which is video signal characteristic information for data broadcasting text or graphics, and main video signal characteristic information. Then, based on the data broadcasting graphic signal characteristic information and the main video signal characteristic information, the control unit 117a outputs conversion information for converting the video signal characteristics of the data broadcasting text or graphics into the video signal characteristics of the main video to the sending unit 116a. Specifically, the conversion information is an offset, a scale factor, or the like.

[0083] The sending unit 116a acquires the conversion information output from the control unit 117a, the main video signal characteristic information, the data broadcast video output from the conversion unit 115, and the data broadcast graphic, and transmits a signal including these as a data broadcast signal via data broadcasting.

[0084] This transmitting device 100C transmits conversion information (offset, scale factor, etc.) without converting the video signal characteristics of the text or graphics of the data broadcast. This allows the receiving device 200 to easily perform conversion to match the video signal characteristics (e.g., dynamic range) of the text or graphics of the data broadcast with the video signal characteristics of the main video of the basic broadcast.

[0085] As described above, in the transmission method of this embodiment, a data broadcast image and image signal characteristic information indicating OETF or EOTF as the image signal characteristic of the image are acquired. Then, a data broadcast signal including the data broadcast image and the image signal characteristic information is transmitted via data broadcast. Here, when acquiring the image signal characteristic information, if the image is a character or graphic, image signal characteristic information indicating an offset or scale factor for each code value included in the image may be acquired instead of OETF or EOTF.

[0086] Furthermore, the transmission method of this embodiment further acquires video for basic broadcasting, which is a broadcast other than the data broadcasting. If the image signal characteristics of the data broadcasting image and the basic broadcasting video are different, the image signal characteristics of at least one of them are converted to make the image signal characteristics the same. Next, a basic broadcasting signal containing the basic broadcasting video and image signal characteristic information indicating the made-to-match image signal characteristic is transmitted via the basic broadcasting. Here, the image signal characteristic information included in the data broadcasting signal indicates OETF or EOTF as the made-to-match image signal characteristic.

[0087] Here, the conversion of the video signal characteristics will be specifically described.

[0088] FIG. 7 is a diagram showing the EOTF of HDR and the EOTF of SDR.

[0089] When converting the dynamic range, which is one of the video signal characteristics of an image, from SDR to HDR, each of the above-mentioned conversion units converts the code values ​​in the SDR EOTF contained in the image into code values ​​in the HDR EOTF. Figure 7 shows an example of code value conversion when converting the dynamic range from SDR, which has a peak luminance of 100 nit, to HDR, which has a peak luminance of 1000 nit.

[0090] In the example shown in Fig. 7, each of the conversion units converts code values ​​in the SDR EOTF to code values ​​in the HDR EOTF so that the luminance range (dynamic range) of the SDR image is converted to the luminance range of the HDR image. However, each of the conversion units may convert code values ​​in the SDR EOTF to code values ​​in the HDR EOTF so that the luminance range of the SDR image is not converted. In this case, each of the conversion units converts code values ​​in the SDR EOTF so that the luminance corresponding to the code value in the SDR EOTF before conversion is the same as the luminance corresponding to the code value in the HDR EOTF after conversion. In other words, each of the conversion units converts code values ​​in the SDR EOTF by projecting points in the SDR EOTF horizontally onto the HDR EOTF curve.

[0091] This code value conversion converts the video signal characteristics of the image. This conversion also unifies the video signal characteristics of multiple images. As a result, the EOTF / OETF (video signal characteristic information) applied to these images in the receiving device 200 is also unified. As a result, as shown in FIG. 2, the receiving device 200 does not need to switch display processing according to the image signal characteristics for each screen area when simultaneously displaying an HDR primary video and an SDR secondary video. Specifically, there is no need to switch the OETF / EOTF applied to each image. As a result, the implementation of the receiving device 200 can be simplified.

[0092] Here, the peak luminance of HDR may be an absolute value or a relative value such as a scaling coefficient for the dynamic range of SDR. In addition, the peak luminance may be included in auxiliary information of the multiplexed layer in data broadcasting.

[0093] The multiplexing layer may be MPEG-2 Transport Stream (TS) or MPEG-H MMT (MPEG Media Transport). The auxiliary information is stored, for example, in a TS section or a descriptor in an MMT message. Furthermore, when dynamic range switching is performed on a program-by-program basis, the transmitting device may indicate whether the program is SDR or HDR in program information such as an EIT (Event Information Table).

[0094] The peak luminance of HDR when converting the dynamic range to HDR may be a default value preset in the receiving device 200 or a value obtained using the default value. For example, if data transmitted via broadcasting or communication contains conversion information indicating the peak luminance at the time of conversion to HDR, the receiving device 200 performs the conversion to HDR according to the peak luminance. On the other hand, if the conversion information is not contained, the receiving device 200 may perform the conversion to HDR according to a default value set therein or a value obtained using the default value. The receiving device 200 can also convert the dynamic range from HDR to SDR in a similar manner.

[0095] The HDR EOTF can also be a hybrid EOTF that can apply the same code values ​​to both HDR and SDR. For example, when receiving device 200 superimposes SDR image 2 on hybrid HDR image 1 and outputs the images as SDR, it can superimpose the pixel values ​​of image 1 and image 2 as SDR. Therefore, the transmitting device may assign information identifying whether the image is hybrid as an HDR attribute of the main video, secondary video, or data broadcast image.

[0096] FIG. 8 is a diagram showing an example in which the receiving device 200 displays subtitles of a basic broadcast simultaneously with other video.

[0097] The receiving device 200 simultaneously displays, for example, video 1 which is the main video of the basic broadcast, subtitle 1 which is the subtitle of the main video of the basic broadcast, video 3 of the data broadcast, and text or graphics of the data broadcast. Note that in this embodiment, the video for the basic broadcast is the main video, the sub-video, or the subtitle corresponding to the main video.

[0098] A transmitting device (any of the above-mentioned transmitting devices 100, 100A to 100C) transmits subtitles in a basic broadcast separately from the video such as the main video and the secondary video. The transmitting device unifies the video signal characteristics of the subtitles with the video signal characteristics of the video on which the subtitles are superimposed, and transmits the subtitles.

[0099] Subtitles are written in an XML (Extensible Markup Language)-based language such as W3C (World Wide Web Consortium) Timed Text Markup Language (TTML), and the color or brightness values ​​of the subtitles are expressed as RGB values. Therefore, information identifying whether the RGB values ​​specified in the XML correspond to the SDR or HDR OETF / EOTF may be added to the XML document, or this information may be transmitted as video signal characteristic information for the entire subtitles.

[0100] Data broadcasting is also composed of applications such as HTML (HyperText Markup Language). The video signal characteristic information of data broadcasting may indicate either SDR or HDR as the video signal characteristic of the entire application. Furthermore, the video signal characteristic information of data broadcasting may indicate, using HTML tags, whether each of the video, still images, or text referenced by the HTML is SDR or HDR.

[0101] Video signal characteristics of multiple images, including subtitles, displayed simultaneously include not only dynamic range but also color gamut. In particular, for high-resolution images such as 4K, it is expected that BT.2020 (Recommendation ITU-R BT.2020), which can express a wider color gamut than BT.709, will be used in addition to the conventional BT.709 (Recommendation ITU-R BT.709). When simultaneously displaying images with different color gamuts, the receiving device 200 must unify the color gamuts into one of the two. In this case, too, the transmitting device (or receiving device 200) can determine the unified color gamut using the same criteria as for dynamic range (or OETF / EOTF).

[0102] FIG. 9 is a block diagram showing an example of the configuration of receiving device 200 according to this embodiment.

[0103] The receiving device 200 includes a broadcast receiving unit 201 , a communication receiving unit 202 , a control unit 203 , a conversion unit 204 , and a display unit 205 .

[0104] The broadcast receiving unit 201 receives a basic broadcast signal and outputs the video included in the basic broadcast signal to the display unit 205. At this time, the broadcast receiving unit 201 may apply video signal characteristic information included in the basic broadcast signal to the video to convert the data format of the video into a format that can be processed by the display unit 205. For example, the broadcast receiving unit 201 converts the code value included in the video into luminance by applying EOTF. The broadcast receiving unit 201 outputs the video whose data format has been converted to the display unit 205. Furthermore, the broadcast receiving unit 201 outputs the video signal characteristic information included in the basic broadcast signal to the control unit 203 as basic broadcast video signal characteristic information.

[0105] The communication receiving unit 202 receives a communication signal, outputs the video included in the communication signal as communication video to the conversion unit 204, and outputs the video signal characteristic information included in the communication signal as communication video signal characteristic information to the control unit 203. Note that the communication signal is a signal transmitted by communication via a communication network such as the Internet.

[0106] The control unit 203 acquires the basic broadcast video signal characteristic information and the communication video signal characteristic information. Then, the control unit 104 outputs a control signal to the conversion unit 204 to convert the video signal characteristic of the communication video into the video signal characteristic of the basic broadcast video, based on the basic broadcast video signal characteristic information and the communication video signal characteristic information.

[0107] The converter 204 acquires communication video from the communication receiver 202 and converts the video signal characteristics of the communication video based on a control signal output from the controller 203. Furthermore, the converter 204 may acquire basic broadcast video signal characteristic information from the broadcast receiver 201 via the controller 203 and apply the basic broadcast video signal characteristic information to the communication video having the converted video signal characteristics. By this application, the converter 204 converts the data format of the communication video into a format that can be processed by the display unit 205. For example, the converter 204 converts the code value included in the communication video into luminance by applying EOTF. The converter 204 outputs the communication video whose data format has been converted to the display unit 205.

[0108] The display unit 205 is a display device that simultaneously displays the basic broadcast video output from the broadcast receiving unit 201 and the communication video output from the conversion unit 204 .

[0109] Even if the video signal characteristics of the basic broadcasting and the data broadcasting are unified by the above-mentioned transmitting device 100 or the like, there are cases where those video signal characteristics do not match the video signal characteristics of the communication (e.g., OETF / EOTF or dynamic range, etc.). In such cases, the receiving device 200 in this embodiment converts the video signal characteristics of the communication video so that the video signal characteristics of the communication match the video signal characteristics of the broadcast, and displays the converted communication video. This improves the ease of viewing the communication video.

[0110] It is sufficient that the video signal characteristics are uniform for all images, and the video signal characteristics of each image may be uniform based on the image of data broadcasting or the image of communication.

[0111] The receiving device 200 may change the video signal characteristics (brightness, color, contrast, etc.) of an OSD (On Screen Display) such as channel selection information or volume displayed on the display unit 205 according to the video signal characteristics of the basic broadcast. For example, when the dynamic range of the video of the basic broadcast is HDR, the receiving device 200 can improve visibility by displaying the OSD such as channel selection information or volume with increased contrast.

[0112] FIG. 10 is a flowchart showing the processing operation of the receiving device 200 in this embodiment.

[0113] The control unit 203 of the receiving device 200 determines whether the basic broadcast video signal characteristic information and the communication video signal characteristic information are the same (step S101). If the control unit 203 determines that they are the same (Yes in step S101), it outputs a control signal that instructs not to convert the video signal characteristics of the communication video to the conversion unit 204 (step S102). On the other hand, if the control unit 203 determines that they are not the same (No in step S101), it outputs a control signal that instructs conversion of the video signal characteristics of the communication video to the conversion unit 204 (step S103).

[0114] As described above, the receiving method of this embodiment includes receiving a first image and first image signal characteristic information indicating the image signal characteristics of the first image. Next, receiving a second image and second image signal characteristic information indicating the image signal characteristics of the second image. If the first and second image signal characteristic information are different, converting the image signal characteristics of at least one of the first and second images to make the image signal characteristics of the first and second images the same. Furthermore, simultaneously displaying the first and second images having the same image signal characteristics. Here, the first and second image signal characteristic information indicates at least one of OETF, EOTF, dynamic range, color gamut, and white point as the image signal characteristics. Here, receiving the first image and the first image signal characteristic information includes receiving the first image and the first image signal characteristic information transmitted via communication over a communication network. Receiving the second image and the second image signal characteristic information includes receiving the second image and the second image signal characteristic information transmitted via broadcasting. Alternatively, the first image and the first image signal characteristic information may be received by receiving the first image and the first image signal characteristic information transmitted by data broadcasting. Similarly, the second image and the second image signal characteristic information may be received by receiving the second image and the second image signal characteristic information transmitted by basic broadcasting, which is a broadcast other than data broadcasting.

[0115] FIG. 11 is a diagram showing an example of transition of an image displayed by the receiving device in this embodiment.

[0116] For example, while a receiving device is simultaneously displaying multiple videos, the dynamic range of some of the videos may switch from SDR to HDR, or from HDR to SDR, etc. A typical example is when the dynamic range of the main video program switches while the receiving device is displaying a data broadcast image. In this case, if the dynamic range of the main video brightness switches while the data broadcast image is being displayed, the brightness of the same video changes before and after the switch, creating a visually uncomfortable feeling.

[0117] Therefore, the transmission / reception system in this embodiment may include a receiving device 200A instead of the receiving device 200. This receiving device 200A fixes the dynamic range when displaying an image of a data broadcast.

[0118] For example, as shown in (a) of Fig. 11, when the receiving device 200A is displaying an image of a data broadcast (specifically, video 3, text, graphics, etc.) and program 1, which is the main image of a basic broadcast, the main image switches from program 1 to program 2, as shown in (b) of Fig. 11. Here, the dynamic range of program 1 is SDR, the dynamic range of program 2 is HDR, and the dynamic range of the image of the data broadcast is SDR from the time program 1 is played back.

[0119] In this embodiment, even after the main video has switched from Program 1 in SDR to Program 2 in HDR, when the data broadcasting image is being displayed in SDR, the receiving device 200A displays Program 2, which is the main video, in SDR, as shown in (b) of Fig. 11. That is, the receiving device 200A converts the video signal characteristics of Program 2 into SDR video signal characteristics and applies the SDR EOTF / OETF to Program 2. Then, as shown in (c) of Fig. 11, the receiving device 200A displays Program 2 in HDR after finishing displaying the data broadcasting image. That is, the receiving device 200A does not convert the video signal characteristics of Program 2 and applies the HDR EOTF / OETF to Program 2.

[0120] In this way, when the dynamic range of some of the videos is switched during reception while a plurality of videos are being displayed, the receiving device 200A in this embodiment determines whether to display the videos in HDR or SDR so as to prevent switching of the dynamic range of the videos already being displayed. In other words, the receiving device 200A controls whether to convert or not convert the video signal characteristics of the videos already being displayed.

[0121] Note that, when displaying an image of a data broadcast, the receiving device 200A controls the conversion of the video signal characteristics of the main image of the basic broadcast so that the dynamic range of the displayed main image does not change. However, the receiving device 200A may perform the above-described control on any multiple images without performing such control only on the image of the data broadcast and the main image of the basic broadcast. For example, the receiving device 200A may perform the above-described control on the communication image and the image of the basic broadcast.

[0122] FIG. 12 is a block diagram showing an example of the configuration of a receiving device 200A according to this embodiment.

[0123] The receiving device 200A includes a broadcast receiving unit 201, a communication receiving unit 202, a control unit 203a, conversion units 204 and 206, and a display unit 205.

[0124] The broadcast receiving unit 201 receives a basic broadcast signal and outputs the video included in the basic broadcast signal to the conversion unit 206. Furthermore, the broadcast receiving unit 201 outputs the video signal characteristic information included in the basic broadcast signal to the control unit 203a as basic broadcast video signal characteristic information.

[0125] The communication receiving unit 202 receives a communication signal, outputs the video included in the communication signal as communication video to the converting unit 204, and outputs the video signal characteristic information included in the communication signal as communication video signal characteristic information to the control unit 203a.

[0126] The control unit 203a acquires the basic broadcast video signal characteristic information and the communication video signal characteristic information. Then, based on the basic broadcast video signal characteristic information and the communication video signal characteristic information, the control unit 203a outputs a control signal to the conversion units 204 and 206. This control signal is a signal for converting the video signal characteristics of both the basic broadcast video and the communication video to HDR, or for converting both to SDR. In other words, if the video signal characteristics of either the basic broadcast video or the communication video are switched while the video is being displayed, that is, if the video signal characteristics of both videos are different, the control unit 203a outputs a control signal for converting the video signal characteristics of one of the videos. This conversion makes the video signal characteristics of one of the videos the same before and after the switch, and maintains the video signal characteristics of both videos in the same state.

[0127] Note that if the video signal characteristics of one of the above-mentioned videos are being converted and then switched, the control unit 203a may cause the conversion unit 204 or 206 to stop the conversion, thereby maintaining the video signal characteristics of both videos in the same state. Specifically, the conversion unit 204 is converting the video signal characteristics of the communication video from SDR to HDR, and both the basic broadcast video and the communication video are displayed in HDR. In this situation, if the video signal characteristics received by the communication receiving unit 202 are switched from SDR to HDR, the control unit 203a stops the conversion by the conversion unit 204. This allows both the basic broadcast video and the communication video to be continuously displayed in HDR before and after the switch in the video signal characteristics.

[0128] The converter 204 acquires communication video from the communication receiver 202 and converts the video signal characteristics of the communication video based on a control signal output from the controller 203a. Furthermore, the converter 204 may acquire video signal characteristic information corresponding to the converted video signal characteristics from the controller 203a and apply the video signal characteristic information to the communication video having the converted video signal characteristics. By this application, the converter 204 converts the data format of the communication video into a format that can be processed by the display unit 205. For example, the converter 204 converts a code value included in the communication video into luminance by applying EOTF. The converter 204 outputs the communication video, whose data format has been converted, to the display unit 205.

[0129] The conversion unit 206 acquires the basic broadcast video from the broadcast receiving unit 201 and converts the video signal characteristics of the basic broadcast video based on a control signal output from the control unit 203a. Furthermore, the conversion unit 206 may acquire video signal characteristic information corresponding to the converted video signal characteristics from the control unit 203a and apply the video signal characteristic information to the basic broadcast video having the converted video signal characteristics. By this application, the conversion unit 206 converts the data format of the basic broadcast video into a format that can be processed by the display unit 205. For example, the conversion unit 206 converts the code value included in the basic broadcast video into luminance by applying EOTF. The conversion unit 206 outputs the basic broadcast video whose data format has been converted to the display unit 205.

[0130] The display unit 205 is a display device that simultaneously displays the basic broadcast video output from the conversion unit 206 and the communication video output from the conversion unit 204 .

[0131] FIG. 13 is a flowchart showing the processing operation of the receiving device 200A in this embodiment.

[0132] First, the control unit 203a of the receiving device 200A determines whether the video signal characteristics of any of the multiple displayed videos have been switched (step S100). If it is determined that the video signal characteristics have been switched (Yes in step S100), the control unit 203a outputs a control signal to the conversion unit 204 or 206 to convert the video signal characteristics so that the video signal characteristics before and after the switch are the same, or to instruct not to convert the video signal characteristics.

[0133] On the other hand, if it is determined that they have not been switched (No in step S100), the control unit 203a determines whether the basic broadcast video signal characteristic information and the communication video signal characteristic information are the same (step S101). If the control unit 203a determines that they are the same (Yes in step S101), it outputs a control signal that does not convert the video signal characteristics to the conversion units 204 and 206 (step S102). On the other hand, if the control unit 203a determines that they are not the same (No in step S101), it outputs a control signal that instructs the conversion unit 204 and the conversion unit 206 to convert the video signal characteristics of at least one of the basic broadcast video and the communication video (step S103).

[0134] As described above, in the receiving method of the present embodiment, when the first and second images are simultaneously displayed, if only the image signal characteristics indicated by the second image signal characteristic information among the received first and second image signal characteristic information are switched, the image signal characteristics of the first and second images are made identical by converting the image signal characteristics after the second image is switched or by stopping the conversion being performed on the image signal characteristics before the second image is switched. Then, after the conversion or the conversion of the image signal characteristics of the second image is stopped, the first and second images having the identical image signal characteristics are simultaneously displayed.

[0135] This allows the image signal characteristics of the first and second images being displayed to be maintained the same before and after the switch, even if only the image signal characteristics of the second image are switched, thereby reducing the visual discomfort caused by the switch.

[0136] (summary) FIG. 14A is a flowchart illustrating a transmission method according to one embodiment of the present invention.

[0137] A transmission method according to one aspect of the present invention includes steps S11 and S12. In step S11, an image for data broadcasting and image signal characteristic information indicating OETF or EOTF as the image signal characteristic of the image are acquired. In step S12, a data broadcasting signal including the image for data broadcasting and the image signal characteristic information is transmitted via data broadcasting.

[0138] FIG. 14B is a block diagram showing a configuration of a transmission device according to an embodiment of the present invention.

[0139] A transmitting device 10 according to one aspect of the present invention includes an acquiring unit 11 and a transmitting unit 12. The acquiring unit 11 acquires an image for data broadcasting and image signal characteristic information indicating OETF or EOTF as the image signal characteristic of the image. The transmitting unit 12 transmits a data broadcasting signal including the image for data broadcasting and the image signal characteristic information via data broadcasting.

[0140] As a result, whether the dynamic range of an image (e.g., a graphic) for data broadcasting is SDR or HDR, a data broadcasting signal containing image signal characteristic information indicating the corresponding OETF or EOTF is transmitted by data broadcasting. In other words, even in an environment where graphics created in SDR and graphics created in HDR are provided by data broadcasting together, the corresponding OETF or EOTF is transmitted by data broadcasting together with the graphics. Therefore, even in such an environment, a receiving device such as a television can display images such as graphics for data broadcasting in an appropriate dynamic range by using the OETF or EOTF.

[0141] FIG. 15A is a flowchart illustrating a receiving method according to one embodiment of the present invention.

[0142] A receiving method according to an aspect of the present invention includes steps S21 to S24.

[0143] In step S21, a first image and first image signal characteristic information indicating the image signal characteristics of the first image are received. In step S22, a second image and second image signal characteristic information indicating the image signal characteristics of the second image are received. In step S23, if the first and second image signal characteristic information are different, the image signal characteristics of at least one of the first and second images are converted to make the image signal characteristics of the first and second images the same. In step S24, the first and second images having the same image signal characteristics are simultaneously displayed.

[0144] FIG. 15B is a block diagram showing a configuration of a receiving device according to an aspect of the present invention.

[0145] A receiving device 20 according to an aspect of the present invention includes a first receiving unit 21, a second receiving unit 22, a converting unit 23, and a display unit 24.

[0146] The first receiving unit 21 receives a first image and first image signal characteristic information indicating the image signal characteristics of the first image. The second receiving unit 22 receives a second image and second image signal characteristic information indicating the image signal characteristics of the second image. If the first and second image signal characteristic information are different, the converting unit 23 converts the image signal characteristics of at least one of the first and second images to make the image signal characteristics of the first and second images the same. The display unit 24 simultaneously displays the first and second images having the same image signal characteristics.

[0147] As a result, if the image signal characteristics of the first image are, for example, SDR OETF or EOTF and the image signal characteristics of the second image are, for example, HDR OETF or EOTF, the first and second images, both of which have the same OETF or EOTF, are displayed simultaneously, thereby improving the visibility of the first and second images.

[0148] In the above embodiments, each component may be configured with dedicated hardware or may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory. Here, the software that realizes the transmitting device or receiving device of the above embodiments is a program that causes a computer to execute each step included in the flowchart shown in Figure 10, Figure 13, Figure 14A, or Figure 15A.

[0149] While the transmitting device and receiving device according to one or more aspects have been described based on the embodiments, the present invention is not limited to these embodiments. As long as they do not deviate from the spirit of the present invention, various modifications conceivable by those skilled in the art to the present embodiments and configurations constructed by combining components of different embodiments may also be included within the scope of one or more aspects. [Industrial Applicability]

[0150] The present invention has the effect of being able to display images appropriately, and can be used, for example, in a transmitting device that transmits images such as television pictures, subtitles, text, or graphics via broadcast or communication, and in a receiving device such as a television that receives and displays these images. [Explanation of symbols]

[0151] 10, 100, 100A~100C transmitter 11 Acquisition Department 12 Transmitter 20,200,200A receiving device 21 First receiving unit 22 Second receiving unit 23,101,105,113,115,118,204,206 Conversion section 24,205 Display section 102,102a Synthesis section 103, 111, 116, 116a Sending unit (transmitting unit) 104, 104a, 112, 114, 117, 117a, 203, 203a Control unit 201 Broadcast receiving unit 202 Communication receiving unit

Claims

1. A receiving method in which a receiving device receives content transmitted from a transmitting device, comprising: receiving first content that is transmitted from the transmitting device and conforms to HDR (High Dynamic Range); receiving second content transmitted from the transmitting device, the second content conforming to Standard Dynamic Range (SDR) and including an image that is a character or graphic, and the second content being displayed on a display connected to the receiving device together with the first content; receiving a scale factor written in Timed Text Markup Language (TTML) transmitted from the transmitting device; converting the second content into HDR compatible converted content using the scale factor; Receiving method.

2. A transmission method for transmitting content from a transmitting device to a receiving device, comprising: transmitting first content conforming to HDR (High Dynamic Range) from the transmitting device to the receiving device; transmitting, from the transmitting device to the receiving device, second content that conforms to Standard Dynamic Range (SDR) and includes an image that is text or a graphic, and that is displayed on a display connected to the receiving device together with the first content; transmitting the scale factor described in TTML (Timed Text Markup Language) from the transmitting device to the receiving device so that the second content is converted into HDR-compatible converted content using the scale factor in the receiving device; Sending method.

Images