Receiving method, receiving device, transmitting method, and transmitting device

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 transmitting method for transmitting an image, or a receiving 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 normal broadcasting (basic broadcasting), but also transmit text or graphics 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 the SDR image of Non-Patent Document 1 are transmitted by broadcasting or the like, a receiving device is unable to properly display these images.

[0005] Therefore, the present invention provides a transmission method and the like that can properly display an image. [Means for solving the problem]

[0006] A receiving method according to one embodiment of the present invention is a receiving method in which a receiving device receives content transmitted from a transmitting device, the method including receiving a first content transmitted from the transmitting device that is compatible with HDR (High Dynamic Range), receiving a second content transmitted from the transmitting device that is compatible with SDR (Standard Dynamic Range) and includes at least one of subtitles and images, and being displayed together with the first content on a display connected to the receiving device, receiving a scale factor written in Timed Text Markup Language (TTML) transmitted from the transmitting device, and using the scale factor to convert the second content into converted content that is compatible with HDR.

[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 is compatible with 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 is compatible with 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 the scale factor has been received, converts the second content into a first converted content that is compatible with HDR using the scale factor, and if it is determined that the scale factor has not been received, converts the second content into a second converted content that is compatible with 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. Effect of the Invention

[0009] The transmission method of the present invention can display the image appropriately. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an example of a configuration of a transmission / reception system according to an embodiment, and an example of a screen displayed on a receiving device. [Diagram 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 in 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. [Diagram 5] FIG. 5 is a block diagram showing another example of the configuration of the transmitting device according to the embodiment. In FIG. [Figure 6] FIG. 6 is a block diagram showing another example of the configuration of the transmitting device according to the embodiment. In FIG. [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 in the embodiment displays subtitles of a basic broadcast simultaneously with other video. [Figure 9] FIG. 9 is a block diagram showing an example of a configuration of a receiving device according to the embodiment. [Figure 10] FIG. 10 is a flowchart showing an example of a processing operation of the receiving device in the embodiment. [Figure 11] FIG. 11 is a diagram showing an example of a transition of an image displayed by the receiving device in the embodiment. [Figure 12] FIG. 12 is a block diagram showing another example of the configuration of the receiving device according to the embodiment. In FIG. [Figure 13] FIG. 13 is a flowchart showing another example of the processing operation of the receiving device in 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 embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0012] In Non-Patent Document 1, it is assumed that the graphics are created in SDR, and if the image onto which the graphics are overlaid is an HDR image, the dynamic range of the graphics is converted from SDR to HDR and the graphics are displayed in HDR.

[0013] Currently, there are more SDR images than HDR images on which graphics are overlaid, so it makes sense to provide graphics created in SDR and convert the dynamic range of the graphics from SDR to HDR only if the image on which the graphics are overlaid is HDR.

[0014] However, as HDR video becomes more widespread in the future, there is a possibility that the dynamic range of graphics will be converted to HDR and the graphics will be displayed in HDR more often than the graphics will be displayed in SDR. In general, displaying graphics created in HDR in HDR is preferable to converting graphics created in SDR to HDR graphics and displaying the graphics in HDR, because it 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 research and came up with various issues and solutions in a previously unimaginable environment in which graphics created in SDR and graphics created in HDR are provided together, as described in the embodiments below.

[0017] In order to solve such various problems, a transmission method according to one embodiment 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 including 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, the corresponding OETF or EOTF is transmitted by data broadcasting together with the graphic. Therefore, even in such an environment, a receiving device such as a television can display an image such as a graphic for data broadcasting in an appropriate dynamic range by using the OETF or EOTF.

[0019] In addition, in obtaining the image signal characteristic information, if the image is a character or graphic, the image signal characteristic information indicating an offset or scale factor for each code value contained in the image may be obtained 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 video for a core broadcast, which is a broadcast other than the data broadcast, is acquired, and when the image signal characteristics of the image for the data broadcast and the video for the core broadcast are different, the image signal characteristics of at least one of them are converted to make the image signal characteristics identical, and a core broadcast signal including the video for the core broadcast and image signal characteristic information indicating the made-identified image signal characteristic is transmitted by the core broadcast, and the image signal characteristic information included in the data broadcast signal may indicate the OETF or the EOTF as the made-identified image signal characteristic.

[0022] As a result, the image signal characteristics of the image for data broadcasting and the video for basic broadcasting, i.e., the OETF or EOTF, are unified, 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 image for data broadcasting and the video for basic broadcasting without switching the OETF or EOTF for each of these images and videos, i.e., without switching the display process. As a result, the implementation of the receiving device can be simplified. In addition, since 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 of the basic broadcasting and the reception process of the 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 sub 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] A receiving method according to an embodiment of the present invention includes receiving a first image and first image signal characteristic information indicating an image signal characteristic of the first image, receiving a second image and second image signal characteristic information indicating an image signal characteristic of the second image, and, if the first and second image signal characteristic information are different, converting the image signal characteristic 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, when 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] In addition, the receiving method may further include, 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, making the image signal characteristics of the first and second images 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 simultaneously displaying the first and second images having the same image signal characteristics after the conversion or the stop of the conversion of the image signal characteristics of the second image.

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

[0028] In addition, 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, when a first image of a data broadcast is displayed in SDR, even if the image signal characteristics of a second image of a basic broadcast displayed simultaneously with the first image are switched from SDR to HDR, the second image continues to be displayed in SDR. Therefore, it is possible to suppress the visual discomfort caused by the switching.

[0030] In addition, when receiving the first image and the first image signal characteristic information, the first image and the first image signal characteristic information transmitted by communication via a communication network 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 broadcasting.

[0031] As a result, for example, when a first image is being displayed in SDR, even if the image signal characteristics of a second image being displayed simultaneously with the first image in a broadcast 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.

[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 may be realized as any combination of the system, method, integrated circuit, computer program, or recording medium.

[0033] Hereinafter, the embodiment 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 arrangement and connection forms, steps, and order of steps 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 an independent claim showing a top concept 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 the present embodiment, and an example of a screen displayed on a receiving device.

[0036] The transmission / reception system includes a transmission device 100 at a broadcast station and a reception device 200 such as a television set installed 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, characters, or graphics. Furthermore, broadcasting includes 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 a plurality of 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 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] In the present embodiment, when transmitting a broadcast signal by superimposing a plurality of images having different dynamic ranges, which are one of the image signal characteristics, the transmitting device 100 unifies the image signal characteristics including the OETF (optical-electrical conversion characteristic) or EOTF (electrical-optical conversion characteristic) of the images. Then, the transmitting device 100 transmits the superimposed images and image signal characteristic information including the OETF / EOTF of the images. In the present embodiment, OETF and EOTF, or OETF or EOTF, are expressed as OETF / EOTF.

[0044] This eliminates the need for the receiving device 200 to switch display processing according to image signal characteristics for each screen area when simultaneously displaying an HDR main image and an SDR sub-image, 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. Also, the video signal characteristic information is information representing 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, for example 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 the display process 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 a configuration of transmitting device 100 in this embodiment.

[0049] The transmitting device 100 includes conversion units 101 and 105 , a synthesis unit 102 , a transmission 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, the control unit 104 outputs a control signal to the conversion unit 101 for converting the video signal characteristics of the main video to the video signal characteristics of the sub-video, based on the main video signal characteristic information and the sub-video signal characteristic information. Alternatively, conversely, the control unit 104 outputs a control signal to the conversion unit 105 for converting the video signal characteristics of the sub-video to the video signal characteristics of the main video, based on the main video signal characteristic information and the sub-video signal characteristic information. Alternatively, 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 to SDR, based on the main video signal characteristic information and the sub-video signal characteristic information.

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

[0052] The conversion unit 101 acquires a main video and converts the video signal characteristics of the main video based on a control signal output from the control unit 104. Similarly, the conversion unit 105 acquires a sub-video and converts the video signal characteristics of the sub-video based on a control signal output from the control unit 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, by broadcasting (specifically, basic broadcasting). Note that the sending unit 103 is a transmitting unit.

[0055] The transmission and reception system in 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 the present embodiment.

[0057] The transmission device 100A has the same functions as the above-described transmission device 100, and includes a synthesis 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. Then, 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, 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 secondary 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 sub-video and the main video signal characteristic information as a basic broadcast signal by broadcasting (specifically, basic broadcasting). This main video signal characteristic information is video signal characteristic information that indicates a unified video signal characteristic for each of the main video and the sub-video, that is, a video signal characteristic 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 core 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 sub-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 transmission device 100 or 100A, a transmission 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 reception device 200 to switch the video signal characteristic information for each broadcast type, and the implementation of the reception device 200 can be simplified.

[0067] FIG. 5 is a block diagram showing another example of the configuration of the transmitting device according to the present 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. Then, the control unit 112 outputs a control signal for converting the video signal characteristics of the sub-video to the video signal characteristics of the main video, based on the main video signal characteristic information and the sub-video signal characteristic information, to the conversion unit 113.

[0070] The conversion unit 113 receives 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 obtains 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 broadcast video signal characteristic information, which is video signal characteristic information of the data broadcast video, and main video signal characteristic information. Then, the control unit 112 outputs a control signal to the conversion unit 115 for converting the video signal characteristic of the data broadcast video into the video signal characteristic of the main video, based on the data broadcast video signal characteristic information and the main video signal characteristic information.

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

[0074] The control unit 117 acquires data broadcast graphic signal characteristic information, which is video signal characteristic information of the characters or graphics of the data broadcast, and main video signal characteristic information. Then, based on the data broadcast 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 characters or graphics of the data broadcast 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 obtains 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 by data broadcasting.

[0077] In this manner, the transmitting device 100B in this embodiment includes video signal characteristic information in each of the basic broadcasting signal and the data broadcasting signal. This eliminates the need for coordination regarding video signal characteristics between the reception process of the basic broadcasting signal and the reception process of the data broadcasting signal in the receiving device 200, and simplifies the implementation of the receiving device 200.

[0078] Also, if the receiving device 200 can always receive and process the core 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 obtained, a video for core broadcasting, which is a broadcast other than the data broadcasting, and when the image signal characteristics of the image for data broadcasting and the video for core broadcasting are different, the image signal characteristics of at least one of them are converted to make the image signal characteristics the same, a data broadcasting signal including the image for data broadcasting is transmitted by data broadcasting, and a core broadcasting signal including the video for core broadcasting and the image signal characteristic information indicating the image signal characteristic that has been made the same is transmitted by the core broadcasting.

[0079] The transmission and reception system in 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 the present embodiment.

[0081] The transmission 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 broadcast graphic signal characteristic information, which is video signal characteristic information of the text or graphics of the data broadcast, and main video signal characteristic information. Then, based on the data broadcast graphic signal characteristic information and the main video signal characteristic information, the control unit 117a outputs conversion information for converting the video signal characteristic of the text or graphics of the data broadcast into the video signal characteristic of the main video to the sending unit 116a. Specifically, the conversion information is an offset or a scale factor.

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

[0084] This transmitting device 100C transmits conversion information (such as offset and scale factor) 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 (such as dynamic range) of the text or graphics of the data broadcast to the video signal characteristics of the main video of the basic broadcast.

[0085] In this way, in the transmission method of the present embodiment, an image for data broadcasting and image signal characteristic information indicating OETF or EOTF as the image signal characteristic of the image are acquired. Then, a data broadcasting signal including the image for data broadcasting and the image signal characteristic information is transmitted by data broadcasting. Here, in acquiring the image signal characteristic information, if the image is a character or a 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] In addition, in the transmission method of this embodiment, a video for a basic broadcast, which is a broadcast other than the data broadcast, is further acquired. Then, when 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. Next, a basic broadcast signal including the video for the basic broadcast and image signal characteristic information indicating the image signal characteristic that has been made the same is transmitted by the basic broadcast. Here, the image signal characteristic information included in the data broadcast signal indicates OETF or EOTF as the image signal characteristic that has been made the same.

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

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

[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 value in the SDR EOTF contained in the image to the code value in the HDR EOTF. Figure 7 shows an example of code value conversion when converting the dynamic range from SDR, whose peak luminance is 100 nit, to HDR, whose peak luminance is 1000 nit.

[0090] In the example shown in FIG. 7, each of the conversion units converts the 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 the 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 the code values ​​in the SDR EOTF so that the luminance corresponding to the code values ​​in the SDR EOTF before conversion is the same as the luminance corresponding to the code values ​​in the HDR EOTF after conversion. In other words, each of the conversion units converts the code values ​​in the SDR EOTF by projecting the points in the SDR EOTF horizontally onto the curve of the HDR EOTF.

[0091] Such code value conversion converts the video signal characteristics of the image. Also, such conversion unifies the video signal characteristics of a plurality of images. As a result, in the receiving device 200, the EOTF / OETF (video signal characteristic information) applied to these images 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 main image and an SDR sub-image. Specifically, it is no longer necessary 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 a multiplexed layer in data broadcasting.

[0093] As the multiplexing layer, MPEG-2 TS (Transport Stream) or MPEG-H MMT (MPEG Media Transport) is used. The auxiliary information is stored, for example, by a descriptor in a TS section or an MMT message. Furthermore, when the dynamic range is switched on a program-by-program basis, the transmitting device may indicate whether the program is SDR or HDR in the program information such as 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 by using the default value. For example, when conversion information indicating the peak luminance at the time of conversion to HDR is included in data transmitted by broadcasting or communication, the receiving device 200 performs conversion to HDR according to the peak luminance. On the other hand, when the conversion information is not included, the receiving device 200 may perform conversion to HDR according to a default value set in itself, or a value obtained by using the default value. The receiving device 200 can also convert the dynamic range from HDR to SDR in the same way.

[0095] As the EOTF for HDR, a hybrid EOTF capable of applying the same code value to both HDR and SDR may be used. For example, when the receiving device 200 superimposes an SDR image 2 on an image 1 that is a hybrid HDR and outputs these images as SDR, the receiving device 200 can superimpose the pixel values ​​of the images 1 and 2 by regarding them as SDR. Therefore, the transmitting device may add information for identifying whether or not the image is a hybrid type as an HDR attribute of the main video, the sub-video, or the image of the data broadcasting.

[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 a main video of a basic broadcast, subtitle 1 which is a subtitle of the main video of the basic broadcast, video 3 of a data broadcast, and text or graphics of the data broadcast. Note that in this embodiment, the video for the basic broadcast is a main video, a sub video, or a subtitle corresponding to the main video.

[0098] A transmitting device (any of the transmitting devices 100, 100A to 100C described above) transmits subtitles in a basic broadcast separately from images such as a main image and a sub-image. The transmitting device unifies the video signal characteristics of the subtitles to the video signal characteristics of the image 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 value of the subtitles is expressed by RGB values. Therefore, information identifying whether the RGB values ​​specified in the XML correspond to the OETF / EOTF of SDR or HDR may be added to the XML document, or the information may be transmitted as video signal characteristic information of 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. In addition, the video signal characteristic information of data broadcasting may indicate whether each of the videos, still images, or text referenced by HTML is SDR or HDR, using HTML tags, etc.

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

[0102] FIG. 9 is a block diagram showing an example of a 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 convert the data format of the video into a format that can be processed by the display unit 205 by applying video signal characteristic information included in the basic broadcast signal to the video. For example, the broadcast receiving unit 201 converts a 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 a video included in the communication signal as a communication video to the conversion unit 204, and outputs 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 for converting 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 conversion unit 204 acquires communication video from the communication receiving unit 202, and converts the video signal characteristics of the communication video based on a control signal output from the control unit 203. Furthermore, the conversion unit 204 may acquire basic broadcast video signal characteristic information from the broadcast receiving unit 201 via the control unit 203, and apply the basic broadcast video signal characteristic information to the communication video having the converted video signal characteristics. By this application, the conversion unit 204 converts the data format of the communication video into a format that can be processed by the display unit 205. For example, the conversion unit 204 converts a code value included in the communication video into luminance by applying EOTF. The conversion unit 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, and simultaneously displays the video of the basic broadcast 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 (for example, OETF / EOTF or dynamic range, etc.). In such a case, 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 broadcasting, and displays the converted communication video. This makes it possible to improve the ease of viewing the communication video.

[0110] It should be noted that it is sufficient that the video signal characteristics are uniform for all images, and the video signal characteristics of each image may be unified 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 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 enhanced contrast.

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

[0113] The control unit 203 of the receiving device 200 judges 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 judges that they are the same (Yes in step S101), it outputs a control signal that does not 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 judges 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] Thus, in the receiving method in the present embodiment, a first image and first image signal characteristic information indicating the image signal characteristic of the first image are received. Next, a second image and second image signal characteristic information indicating the image signal characteristic of the second image are received. Then, when the first and second image signal characteristic information are different, the image signal characteristics of the first and second images are made the same by converting the image signal characteristic of at least one of the first and second images. Furthermore, the first and second images having the same image signal characteristic are simultaneously displayed. 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 characteristic. Here, in the reception of the first image and the first image signal characteristic information, the first image and the first image signal characteristic information transmitted by communication via a communication network are received. In the reception of the second image and the second image signal characteristic information, the second image and the second image signal characteristic information transmitted by broadcasting are received. 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 broadcasting other than data broadcasting.

[0115] FIG. 11 is a diagram showing an example of a 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 broadcasting image. In this case, if the dynamic range of the luminance of the main video switches while the data broadcasting image is being displayed, the brightness of the same video changes before and after the switch, creating a visual discomfort.

[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, a video 3, text, graphics, etc.) and a program 1 which is a main image of a basic broadcast, the main image is switched from the program 1 to the program 2 as shown in (b) of Fig. 11. Here, the dynamic range of the program 1 is SDR, the dynamic range of the program 2 is HDR, and the dynamic range of the image of the data broadcast is SDR from the time of playing back the program 1.

[0119] In the present embodiment, even after the main video is switched from program 1 in SDR to program 2 in HDR, when the data broadcast image is displayed in SDR, the receiving device 200A displays the main video, program 2, in SDR as shown in (b) of FIG. 11. That is, the receiving device 200A converts the video signal characteristics of program 2 into the video signal characteristics of SDR, and applies the EOTF / OETF of SDR 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 broadcast image. That is, the receiving device 200A does not convert the video signal characteristics of program 2, and applies the EOTF / OETF of HDR 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 video in HDR or SDR so as not to switch the dynamic range of the video already being displayed. In other words, the receiving device 200A controls whether to convert or not convert the video signal characteristics of the video already being displayed.

[0121] 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 main image displayed does not change. However, the receiving device 200A may perform the above-mentioned 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-mentioned control on the communication image and the image of the basic broadcast.

[0122] FIG. 12 is a block diagram showing an example of a 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 contained in the basic broadcast signal to the conversion unit 206. Furthermore, the broadcast receiving unit 201 outputs the video signal characteristic information contained 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 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 203a.

[0126] The control unit 203a acquires the basic broadcast video signal characteristic information and the communication video signal characteristic information. Then, the control unit 203a outputs a control signal to the conversion units 204 and 206 based on the basic broadcast video signal characteristic information and the communication video signal characteristic information. 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, when the video signal characteristics of one of the videos is switched during the display of the basic broadcast video and the communication video, that is, when the video signal characteristics of both videos are different, the control unit 203a outputs a control signal for converting the video signal characteristics of the one of the videos. By this conversion, the video signal characteristics of one of the videos become the same before and after the switch, and the video signal characteristics of both videos are maintained in the same state.

[0127] In addition, when the video signal characteristics of one of the above-mentioned videos are being converted, if the video signal characteristics are switched, the control unit 203a may maintain the video signal characteristics of both videos in the same state by causing the conversion unit 204 or 206 to stop the conversion. Specifically, the conversion unit 204 converts the video signal characteristics of the communication video from SDR to HDR, so that both the basic broadcast video and the communication video are displayed in HDR. In such a 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 video signal characteristics are switched.

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

[0129] The conversion unit 206 acquires the video of the basic broadcast from the broadcast receiving unit 201, and converts the video signal characteristics of the video of the basic broadcast based on a control signal output from the control unit 203a. Furthermore, the conversion unit 206 may acquire video signal characteristic information according to the converted video signal characteristics from the control unit 203a, and apply the video signal characteristic information to the video of the basic broadcast having the converted video signal characteristics. By this application, the conversion unit 206 converts the data format of the video of the basic broadcast 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 video of the basic broadcast into luminance by applying EOTF. The conversion unit 206 outputs the video of the basic broadcast with such a converted data format to the display unit 205.

[0130] The display unit 205 is a display device, and 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 judges whether the video signal characteristics of any of the multiple displayed videos have been switched (step S100). If it is judged 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 instruct the conversion unit 204 or 206 to convert or not convert the video signal characteristics so that the video signal characteristics before and after the switching are the same.

[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 of the video signal characteristics of at least one of the basic broadcast video and the communication video to the conversion unit 204 and the conversion unit 206 (step S103).

[0134] As described above, in the receiving method of the present embodiment, 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 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 same image signal characteristics are displayed simultaneously.

[0135] As a result, even if only the image signal characteristics of the second image are switched, the image signal characteristics of the first and second images displayed before and after the switch can be maintained the same, 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 an embodiment 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 an image signal characteristic of the image are obtained. In step S12, a data broadcasting signal including the image for data broadcasting and the image signal characteristic information is transmitted by 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 an embodiment of the present invention includes an acquisition unit 11 and a transmission unit 12. The acquisition unit 11 acquires an image for data broadcasting and image signal characteristic information indicating OETF or EOTF as an image signal characteristic of the image. The transmission unit 12 transmits a data broadcasting signal including the image for data broadcasting and the image signal characteristic information by 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 including 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, the corresponding OETF or EOTF is transmitted by data broadcasting together with the graphic. Therefore, even in such an environment, a receiving device such as a television can display an image such as a graphic 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 embodiment of the present invention.

[0145] A receiving device 20 according to an embodiment of the present invention includes a first receiving unit 21, a second receiving unit 22, a conversion 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 conversion 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, when 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-mentioned embodiment, 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 a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory. Here, the software for realizing the transmitting device or receiving device of the above-mentioned embodiment is a program that causes a computer to execute each step included in the flowchart shown in FIG. 10, FIG. 13, FIG. 14A, or FIG. 15A.

[0149] Although the transmitting device and the 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 it does not deviate from the spirit of the present invention, various modifications conceived by a person skilled in the art to the present embodiment and forms constructed by combining components in 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 appropriately display images, 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 a receiving device such as a television that receives and displays these images. [Explanation of symbols]

[0151] 10,100,100A~100C Transmitting device 11 Acquisition Department 12 Transmitter 20,200,200A receiving device 21 First receiving unit 22 Second receiving section 23,101,105,113,115,118,204,206 Conversion section 24,205 Display section 102,102a Synthesis section 103, 111, 116, 116a Sending section (transmitting section) 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 a first content that is transmitted from the transmitting device and conforms to HDR (High Dynamic Range); receiving a second content transmitted from the transmitting device, the second content conforming to a standard dynamic range (SDR) and including at least one of subtitles and images, 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 receiving device for receiving content transmitted from a transmitting device, A first receiving unit that receives a first content that is transmitted from the transmitting device and conforms to HDR (High Dynamic Range); a second receiving unit configured to receive a second content transmitted from the transmitting device, the second content conforming to a standard dynamic range (SDR) and including at least one of subtitles and images, and the second content being displayed on a display connected to the receiving device together with the first content; A third receiving unit that receives a scale factor described in Timed Text Markup Language (TTML) transmitted from the transmitting device; a conversion unit that converts the second content into a converted content conforming to HDR using the scale factor; A receiving device comprising:

3. A method for transmitting content from a transmitting device to a receiving device, comprising: Transmitting a 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, a second content that conforms to a standard dynamic range (SDR) and includes at least one of subtitles and images, and is displayed on a display connected to the receiving device together with the first content; transmitting the scale factor described in Timed Text Markup Language (TTML) from the transmitting device to the receiving device so that the second content is converted into HDR-compliant converted content using the scale factor in the receiving device; Transmission method.

4. A transmitting device that transmits content to a receiving device, A first transmission unit that transmits a first content conforming to HDR (High Dynamic Range) to the receiving device; a second transmission unit configured to transmit to the receiving device a second content that conforms to a standard dynamic range (SDR), includes at least one of subtitles and an image, and is displayed on a display connected to the receiving device together with the first content; a third transmission unit that transmits the scale factor described in Timed Text Markup Language (TTML) to the receiving device so that the second content is converted into HDR-compatible converted content using the scale factor; A transmitting device comprising:

Images