Decryption method and decryption device

Abstract

To provide a decryption method capable of displaying the right images.SOLUTION: The decryption method includes the following steps: receiving video data, audio data, and descriptor including first information that indicates the transfer function of the video data, which are transmitted from a transmitting device (S111); generating multiple pictures and second information that indicates the transfer function of the video data by decoding the video data (S113); and converting multiple pictures into input signals to be input to the display unit while controlling the conversion method applied to multiple pictures based on at least one of first information and second information (S114-S116).SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a video reception method, a video transmission method, a video reception apparatus, and a video transmission apparatus.

Background Art

[0002] As a method corresponding to a luminance range in which the maximum luminance value is expanded in order to express bright light such as specular reflection light that cannot be expressed by the current TV signal with a brightness closer to reality while maintaining the dark gradation in conventional video, HDR (High Dynamic Range) has attracted attention. Specifically, the method of the luminance range corresponding to the conventional TV signal is called SDR (Standard Dynamic Range), and the maximum luminance value was 100 nit, whereas in HDR, it is assumed that the maximum luminance value is expanded up to 1000 nit or more.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the transmission or reception of a video signal corresponding to a plurality of luminance dynamic ranges as described above, it is desired that a more appropriate video can be displayed on the receiving apparatus.

[0005] Therefore, an object of the present invention is to provide a video reception method, a video transmission method, a video reception apparatus, or a video transmission apparatus that can display an appropriate video.

Means for Solving the Problems

[0006] A decoding method according to one aspect of the present invention receives video data, audio data, and a descriptor including first information indicating the transfer function of the video data transmitted from a transmitting device, decodes the video data to generate a plurality of pictures and second information indicating the transfer function of the video data, and converts the plurality of pictures into an input signal to be input to a display unit while controlling a conversion method applied to the plurality of pictures based on at least one of the first information and the second information. ,before The transfer function is information that identifies either the first transfer function corresponding to the first luminance dynamic range, or the second transfer function corresponding to the second dynamic range which is wider than the first luminance dynamic range. Furthermore, if the multiple pictures cannot be acquired correctly or decoded correctly, the video data is displayed with a brightness corresponding to the first transfer function. .

[0007] One aspect relating to the present invention ru The device comprises a receiving unit and a processor, the processor receiving, in operation, video data, audio data, and a descriptor including first information indicating the transfer function of the video data transmitted from the transmitting device via the receiving unit, decoding the video data to generate a plurality of pictures and second information indicating the transfer function of the video data, and converting the plurality of pictures into input signals to be input to the display unit while controlling a conversion method applied to the plurality of pictures based on at least one of the first and second information. ,before The transfer function is information that identifies either the first transfer function corresponding to the first luminance dynamic range, or the second transfer function corresponding to the second dynamic range which is wider than the first luminance dynamic range. Furthermore, if the multiple pictures cannot be acquired correctly or decoded correctly, the video data is displayed with a brightness corresponding to the first transfer function. .

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

[0009] The present invention can provide a video receiving method, a video transmission method, a video receiving device, or a video transmission device capable of displaying appropriate video. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a block diagram of a video receiving device according to Embodiment 1. [Figure 2] Figure 2 is a flowchart of the processing performed by the display control unit according to Embodiment 1. [Figure 3] Figure 3 is a flowchart of the video reception process according to Embodiment 1. [Figure 4] Figure 4 is a diagram showing the operation when the transfer characteristics change according to Embodiment 1. [Figure 5] Figure 5 shows the operation when the transfer characteristics change according to Embodiment 1. [Figure 6] Figure 6 is a block diagram of the video transmission device according to Embodiment 1. [Figure 7] Figure 7 is a flowchart of the video transmission process according to Embodiment 1. [Figure 8] Figure 8 shows the abnormal operation when the transfer characteristics change according to Embodiment 2. [Figure 9] Figure 9 is a block diagram of the video receiving device according to Embodiment 2. [Figure 10] Figure 10 is a flowchart of the processing performed by the display control unit according to Embodiment 1. [Modes for carrying out the invention]

[0011] (Knowledge that formed the basis of this invention) The OETF (Optical-Electro Transfer Function) or EOTF (Electro-Optical Transfer Function) of a video signal is notified, for example, in the ITU-T H.265|ISO / IEC 23008-2 HEVC video coding standard, through a syntax called "transfer characteristics" in the Video Usability Information (VUI) within the Sequence Parameter Set (SPS). Using these SPS transfer characteristics, it is possible to notify the switching of transfer characteristics (transfer functions) with frame precision. The video receiving device determines the control method of the video display unit based on these transfer characteristics.

[0012] In the MPEG-2 TS (Transport Stream) standard, used for multiplexing and transmitting video and audio signals such as television broadcasts, it is known that parameters included in the SPS and related information are described in the Program-specific information (PSI) descriptor, and information related to the operation of the video receiver is notified at a higher layer. Regarding transmission characteristics, by using the PSI descriptor, the video receiver can more easily determine the control method of the video display unit. Generally, since PSI is inserted into the multiplexed stream at a fixed period, it is not synchronized with the video signal frames. In addition, the MPEG-H MMT standard specifies a mechanism similar to PSI as MMT-SI.

[0013] The transmission characteristics are defined by standards such as ITU-R BT.2020 (hereinafter, BT.2020), ARIB STD-B67 (hereinafter, STD-B67), and SMPTE ST2084 (hereinafter, ST2084). STD-B67 and ST2084 can handle video signals that include 10 to 100 times higher brightness than conventional BT.2020, known as High Dynamic Range (HDR). In contrast to HDR, conventional BT.2020 and similar standards are called Standard Dynamic Range (SDR).

[0014] In TV broadcasting that supports HDR, HDR and SDR may coexist for each program or each commercial. Therefore, the video receiving device needs to operate by switching the control of the display unit according to whether it is HDR or SDR.

[0015] A video receiving method according to an aspect of the present invention is a video receiving method in a video receiving device including a display unit, the method including: a receiving step of receiving a received signal including video data and transfer characteristic information for specifying a transfer function corresponding to the luminance dynamic range of the video data with frame accuracy; and a displaying step of displaying the video data while controlling the luminance dynamic range of the display unit with frame accuracy according to the transfer characteristic information.

[0016] Thereby, since the luminance dynamic range of the display unit can be controlled with frame accuracy, a more appropriate video can be displayed.

[0017] For example, the video receiving method may further include a demultiplexing step of demultiplexing the received signal in which a video signal and an audio signal are multiplexed, and a decoding step of decoding the video signal obtained by demultiplexing to obtain the video data and the transfer characteristic information.

[0018] For example, the transfer characteristic information may be included in control information in a sequence unit included in the video signal.

[0019] For example, the transfer characteristic information is information for specifying, with frame accuracy, a first transfer function corresponding to a first luminance dynamic range or a second transfer function corresponding to a second dynamic range wider than the first luminance dynamic range, and in the displaying step, the luminance dynamic range of the display unit may be switched between the first luminance dynamic range and the second luminance dynamic range.

[0020] For example, the video reception method further includes a determination step in the reception step to determine whether the video data was successfully acquired, and in the display step, if it is determined in the determination step that the video data was not successfully acquired, the brightness dynamic range of the display unit may be set to the first brightness dynamic range.

[0021] This prevents excessively bright images from being displayed when an error occurs.

[0022] For example, in the determination step, the determination may be whether the intra-encoded frame was successfully decoded.

[0023] Furthermore, a video transmission method according to one aspect of the present invention includes a generation step of generating a transmission signal that includes video data and transfer characteristic information for identifying a transfer function corresponding to the luminance dynamic range of the video data with frame accuracy, and a transmission step of transmitting the transmission signal.

[0024] As a result, the video receiving device that receives the signal generated by this video transmission method can control the brightness dynamic range of the display unit with frame accuracy, thereby enabling it to display a more appropriate image.

[0025] For example, the generation step may include an encoding step of generating a video signal by encoding the video data and the transmission characteristics information, and a multiplexing step of generating the transmission signal by multiplexing the generated video signal and the audio signal.

[0026] For example, the transmission characteristics information may be included in the sequence-unit control information contained in the video signal.

[0027] For example, the transfer characteristic information may be information for identifying a first transfer function corresponding to a first luminance dynamic range, or a second transfer function corresponding to a second dynamic range wider than the first luminance dynamic range, with frame accuracy.

[0028] Furthermore, an image receiving device according to one aspect of the present invention includes image data and transfer characteristic information for identifying the transfer function corresponding to the luminance dynamic range of the image data with frame accuracy. The system includes a receiving unit that receives a received signal and a display unit that displays the video data while controlling the brightness dynamic range with frame accuracy according to the transmission characteristics information.

[0029] This allows the video receiving device to control the brightness dynamic range of the display unit with frame accuracy, enabling it to display more appropriate images.

[0030] Furthermore, an image transmission device according to one aspect of the present invention includes a generation unit that generates a transmission signal including image data and transfer characteristic information for identifying a transfer function corresponding to the luminance dynamic range of the image data with frame accuracy, and a transmission unit that transmits the transmission signal.

[0031] As a result, the video receiving device that receives the signal generated by the video transmitting device can control the brightness dynamic range of the display unit with frame accuracy, thereby enabling it to display a more appropriate image.

[0032] The embodiments will be described in detail below with reference to the drawings.

[0033] The embodiments described below are all specific examples of the present invention. The numerical values, shapes, materials, components, arrangement and connection configurations of the components, steps, and the order of steps shown in the following embodiments are examples only and are not intended to limit the present invention. Furthermore, among the components in the following embodiments, those components that are not described in the independent claim representing the highest-level concept will be described as optional components.

[0034] (Embodiment 1) The video receiving device according to this embodiment uses transmission characteristic information that shows the transmission characteristics with frame accuracy to control the brightness dynamic range of the display unit with frame accuracy. As a result, the video receiving device can display more appropriate images.

[0035] First, the configuration of the video receiving device according to this embodiment will be described. Figure 1 is a block diagram of the video receiving device 100 according to this embodiment. The video receiving device 100 is, for example, a television, and receives a received signal 111 transmitted by broadcast waves and displays a video based on the received signal 111. The video receiving device 100 comprises a receiving unit 101, a demultiplexing unit 102, a video decoding unit 103, a display control unit 104, and a display unit 105.

[0036] The receiving unit 101 receives the received signal 111. The received signal 111 is a system stream in which a video signal and an audio signal are multiplexed.

[0037] The demultiplexing unit 102 generates a video signal 112, which is a video stream, by demultiplexing (system decoding) the received signal 111. The demultiplexing unit 102 also outputs the transfer characteristics obtained from descriptors and other components contained in the received signal 111 as first transfer characteristic information 113. In other words, the first transfer characteristic information 113 is included in the multiplexing layer.

[0038] The video decoding unit 103 generates video data 114 by decoding the video signal 112. The video decoding unit 103 also outputs the transfer characteristics obtained from the SPS as second transfer characteristic information 115. In other words, the second transfer characteristic information 115 is included in the video coding layer.

[0039] This second transfer characteristic information 115 is information for identifying the frame-accurate transfer function (OETF or EOTF) corresponding to the luminance dynamic range of the video data 114. For example, this second transfer characteristic information 115 corresponds to the first luminance dynamic range (SDR) This information is for identifying, with frame accuracy, the first transfer function, or a second transfer function corresponding to a second dynamic range (HDR) wider than the first luminance dynamic range. In other words, the second transfer characteristic information 115 indicates whether the video data 114 is SDR or HDR. If there are multiple formats of HDR, the second transfer characteristic information 115 may also indicate which format of HDR it is. In other words, the second transfer characteristic information 115 indicates the luminance dynamic range of the video data 114, for example, one of a predetermined set of luminance dynamic ranges.

[0040] Furthermore, SPS refers to control information in sequence units (multiple frames) contained in the video signal 112.

[0041] The display control unit 104 generates control information 116 to control the display unit 105 according to the first transfer characteristic information 113 and the second transfer characteristic information 115.

[0042] The display unit 105 displays video data 114 while controlling the brightness dynamic range with frame accuracy according to the control information 116 (i.e., the first transfer characteristic information 113 and the second transfer characteristic information 115). This display unit 105 comprises a video characteristic conversion unit 106 and a display device 107.

[0043] The video characteristic conversion unit 106 generates an input signal 117 by converting the video data 114 according to the control information 116. Specifically, the video characteristic conversion unit 106 converts the video data 114 into an input signal 117 using a transfer function indicated by the first transfer characteristic information 113 or the second transfer characteristic information 115.

[0044] The display device 107 is, for example, a liquid crystal panel, and changes the brightness dynamic range of the displayed image according to the control information 116. For example, if the display device 107 is a liquid crystal panel, the display device 107 changes the maximum brightness of the backlight.

[0045] Next, the operation of the video receiving device 100 will be explained. Although Figure 1 shows a configuration that uses both the first transfer characteristic information 113 and the second transfer characteristic information 115, it is sufficient to use at least the second transfer characteristic information 115. The control using the second transfer characteristic information 115 will be explained in detail below.

[0046] Figure 2 is a flowchart of the display control process performed by the display control unit 104. The process shown in Figure 2 is performed on a frame-by-frame basis, or whenever the second transmission characteristic information 115 is changed.

[0047] First, the display control unit 104 determines whether to display SDR or HDR based on the second transfer characteristic information 115 (S101).

[0048] If HDR is indicated by the second transmission characteristic information 115 (Yes in S101), the display control unit 104 outputs control information 116 for HDR display (S102). As a result, the display unit 105 displays the image with a brightness dynamic range that corresponds to HDR.

[0049] On the other hand, if the second transfer characteristic information 115 indicates SDR (No in S101), the display control unit 104 outputs control information 116 for SDR display (S103). As a result, the display unit 105 displays the image with a brightness dynamic range corresponding to SDR.

[0050] In this way, by switching the control information 116 in accordance with the second transfer characteristic information 115 which is notified with frame accuracy, the switching of the transfer characteristics and the control of the display unit 105 can be synchronized with frame accuracy.

[0051] Furthermore, if multiple HDR formats exist (for example, STD-B67 and ST2084), the control information 116 for HDR display may include identification information for the HDR format. This allows the display unit 105 to display the image with the brightness dynamic range of the corresponding format.

[0052] Figure 3 is a flowchart of the video reception process by the video receiving device 100. First, the receiving unit 101 receives the received signal 111 (S111). Next, the demultiplexing unit 102 generates the video signal 112 by demultiplexing the received signal 111 (S112). Next, the video decoding unit 103 generates video data 114 by decoding the video signal 112 and also acquires the second transmission characteristic information 115 (S113).

[0053] Next, the display control unit 104 controls the luminance dynamic range of the display unit 105 according to the second transfer characteristic information 115. Specifically, the display control unit 104 determines with frame accuracy whether each frame is HDR or SDR based on the second transfer characteristic information 115 (S114). If it is HDR (Yes in S114), the display unit 105 displays the image with the HDR luminance dynamic range (S115). If it is SDR (No in S114), the display unit 105 displays the image with the SDR luminance dynamic range (S116).

[0054] Figure 4 shows the process when switching from an SDR program to an HDR program. Figure 5 shows the process when switching from an HDR program to an SDR program. As shown in Figures 4 and 5, the above process allows for appropriate switching between SDR and HDR with frame accuracy.

[0055] The following describes the video transmission device 200 that generates the transmission signal 212 corresponding to the received signal 111 described above. Figure 6 is a block diagram of the video transmission device 200 according to this embodiment. The video transmission device 200 shown in Figure 6 comprises a generation unit 201 and a transmission unit 202.

[0056] The generation unit 201 generates a transmission signal 212 that includes video data and second transfer characteristic information for identifying the transfer function corresponding to the luminance dynamic range of the video data with frame accuracy. The generation unit 201 includes a video encoding unit 203 and a multiplexing unit 204.

[0057] Figure 7 is a flowchart of the video transmission process by the video transmission device 200. First, the video encoding unit 203 generates a video signal 211 by encoding the video data and the second transfer characteristic information (S201). This second transfer characteristic information corresponds to the second transfer characteristic information 115 described above and is information for identifying with frame accuracy the first transfer function corresponding to the first luminance dynamic range (e.g., SDR) or the second transfer function corresponding to the second dynamic range wider than the first luminance dynamic range (e.g., HDR). The second transfer characteristic information is also stored in the SPS included in the video signal 211.

[0058] Next, the multiplexing unit 204 generates a transmission signal 212 by multiplexing the encoded video signal 211 and the audio signal (S202). Next, the transmission unit 202 transmits the generated transmission signal 212 (S203).

[0059] As a result, the video transmission device 200 generates a transmission signal 212 that includes second transfer characteristic information for identifying the transfer function with frame accuracy. This allows the video receiving device that receives the transmission signal 212 to control the brightness dynamic range of the display unit with frame accuracy, thereby enabling it to display a more appropriate image.

[0060] (Embodiment 2) TV broadcasts may experience errors depending on the radio wave conditions, whether terrestrial or satellite. Figure 8 shows what happens when a reception error occurs due to radio interference or other reasons. As shown in Figure 8, it is assumed that when switching from SDR to HDR, after the video receiving device acquires the second transmission characteristic information 115 in the SPS, the video stream is lost due to radio interference or other reasons, and the first frame of the HDR cannot be acquired. In this case, the video decoding unit 103 continues to display the previous frame to conceal the error. In other words, frames of the SDR program are repeatedly displayed.

[0061] In this case, when this frame is referenced by a subsequent frame, the subsequent video will display abnormal footage that is a mix of footage from past programs.

[0062] Furthermore, immediately after switching, the display's brightness dynamic range is set to HDR, causing frames from SDR programs to be displayed with the HDR brightness dynamic range. This results in the display of images that are brighter than intended.

[0063] This embodiment describes a video receiving device that addresses this problem. Figure 9 is a block diagram of the video receiving device 100A according to this embodiment. The video receiving device 100A shown in Figure 9 further includes an abnormality detection unit 108 and a message superposition unit 109 within the display unit 105A, compared to the video receiving device 100 shown in Figure 1. In addition, functions have been added to the display control unit 104A.

[0064] The anomaly detection unit 108 determines whether the video data 114 (video signal 112) was acquired correctly. Specifically, the anomaly detection unit 108 detects packet loss based on the packet sequence number and analyzes the packet payload to obtain the starting position of the frame data, thereby determining whether all of the frame data was acquired (normal) or only a portion of the frame data was acquired (abnormal). The anomaly detection unit 108 also outputs anomaly notification information 118 indicating the determination result to the display control unit 104A. In other words, the display control unit 104A is notified that an anomaly has occurred, or that information is available to identify the frame in which the anomaly occurred.

[0065] The display control unit 104A generates control information 116 and a message 119 in response to the first transmission characteristic information 113 and the second transmission characteristic information 115, as well as the abnormality notification information 118. Specifically, if there is an abnormality, the display control unit 104A generates a message 119 indicating that there is an abnormality, and also generates control information 116 for SDR display.

[0066] The message overlay unit 109 generates an input signal 120 by overlaying the message 119 onto the video data (input signal 117) according to the control information 116 and the message 119, and outputs the generated input signal 120 to the display device 107. As a result, a message such as "An error has occurred" is displayed on the display device 107, informing the viewer that the equipment is not malfunctioning.

[0067] Figure 10 is a flowchart of the display control process performed by the display control unit 104A. First, the display control unit 104A determines whether the second transfer characteristic information 115 has been updated (S121). If the second transfer characteristic information 115 has been updated (Yes in S121), the display control unit 104A starts determining whether to switch the display control.

[0068] First, the display control unit 104A determines whether the video data has been acquired correctly. Specifically, the display control unit 104A determines whether the intra-encoded frame has been successfully decoded based on the abnormality notification information 118 (S122). If the intra-encoded frame has not been successfully decoded (No in S122), the display control unit 104A outputs control information 116 for SDR display (S123). As a result, the display unit 105 displays the video with a brightness dynamic range corresponding to SDR. In other words, the display control unit 104A determines whether the video If it is determined that data could not be acquired correctly, the brightness dynamic range of the display unit 105 is set to SDR (Single Brightness Dynamic Range).

[0069] If an error occurs during switching, the displayed frame may contain pixels from the previous frame. In this embodiment, however, by setting the display control to SDR display in such cases, it is possible to suppress the display of SDR program frames with HDR high brightness settings.

[0070] Furthermore, if an intra-encoded frame that guarantees instant playback, such as HEVC IDR or CRA, is successfully decoded (Yes in S122), the display control is switched in the same manner as in Embodiment 1. In other words, the display control unit 104A determines whether to display SDR or HDR based on the updated second transfer characteristic information 115 (S124). If HDR is indicated by the second transfer characteristic information 115 (Yes in S124), the display control unit 104A outputs control information 116 for HDR display (S125). On the other hand, if SDR is indicated by the second transfer characteristic information 115 (No in S124), the display control unit 104A outputs control information 116 for SDR display (S126).

[0071] Thus, the video receiving device 100A according to this embodiment can suppress the display of excessively bright images when an error occurs by displaying the image within the luminance dynamic range of the SDR when an error occurs.

[0072] Although the video receiving device and video transmitting device according to embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

[0073] Furthermore, each processing unit included in the video receiving device and video transmitting device according to the above embodiment is typically implemented as an LSI (Large-Scale Integrated Circuit). These may be individually integrated into a single chip, or some or all of them may be integrated into a single chip.

[0074] Furthermore, integrated circuit implementation is not limited to LSIs; it may also be achieved using dedicated circuits or general-purpose processors. Field-Programmable Gate Arrays (FPGAs), which can be programmed after LSI manufacturing, or reconfigurable processors, which allow for the reconfiguration of the connections and settings of circuit cells within the LSI, may also be used.

[0075] Furthermore, in each of the above embodiments, each component may be implemented by being composed of dedicated hardware or by executing a software program suitable for each component. Each component may also be implemented 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.

[0076] Furthermore, the present invention may be implemented as a video receiving method or video transmission method performed by a video receiving device or a video transmitting device.

[0077] Furthermore, the division of functional blocks in the block diagram is just one example; multiple functional blocks can be implemented as a single functional block, a single functional block can be divided into multiple parts, or some functions can be moved to other functional blocks. In addition, the functions of multiple functional blocks with similar functions can be processed in parallel or time-sharing by a single piece of hardware or software.

[0078] Furthermore, the order in which each step in the flowchart is performed is illustrative for the purpose of specifically illustrating the present invention, and may be performed in a different order. Also, some of the above steps may be performed simultaneously (in parallel) with other steps.

[0079] Although one or more embodiments of a video receiving device and a video transmitting device have been described above based on embodiments, the present invention is not limited to these embodiments. Without departing from the spirit of the present invention, various modifications that a person skilled in the art can conceive of may be applied to these embodiments, and forms constructed by combining components from different embodiments may also be included within the scope of one or more embodiments. [Industrial applicability]

[0080] This invention can be applied to video receiving devices and video transmitting devices such as TVs. [Explanation of Symbols]

[0081] 100, 100A Video Receiver 101 Receiving Unit 102 Demultiplexer 103 Video Decoding Unit 104, 104A Display Control Unit 105, 105A display section 106 Video Characteristics Conversion Unit 107 Display Devices 108 Anomaly detection unit 109 Message Overlay Section 111 Received signal 112, 211 video signals 113 First Transfer Characteristics Information 114 Video Data 115 Second Transfer Characteristics Information 116 Control Information 117, 120 Input signals 118 Abnormality notification information 119 Message 200 Video transmission device 201 Generation part 202 Transmitter 203 Video Encoding Section 204 Multiplexer 212 Transmitted signal

Claims

1. The system receives video data, audio data, and a descriptor containing first information indicating the transfer function of the video data, transmitted from the transmitting device. By decoding the aforementioned video data, multiple pictures and second information indicating the transfer function of the video data are generated. The plurality of pictures are converted into input signals to be input to the display unit, while controlling the conversion method applied to the plurality of pictures based on at least one of the first information and the second information. The transfer function is information that identifies a first transfer function corresponding to a first luminance dynamic range, or a second transfer function corresponding to a second dynamic range wider than the first luminance dynamic range. If the aforementioned multiple pictures cannot be acquired correctly or decoded correctly, the video data is displayed with a brightness corresponding to the first transfer function. Decryption method.

2. The receiving unit, Equipped with a processor, The aforementioned processor, in its operation, The receiving unit receives video data, audio data, and a descriptor containing first information indicating the transfer function of the video data, transmitted from the transmitting device. By decoding the aforementioned video data, multiple pictures and second information indicating the transfer function of the video data are generated. The plurality of pictures are converted into input signals to be input to the display unit, while controlling the conversion method applied to the plurality of pictures based on at least one of the first information and the second information. The transfer function is information that identifies a first transfer function corresponding to a first luminance dynamic range, or a second transfer function corresponding to a second dynamic range wider than the first luminance dynamic range. If the aforementioned multiple pictures cannot be acquired correctly or decoded correctly, the video data is displayed with a brightness corresponding to the first transfer function. Decoding device.

Images