JP6861873B2 - Video playback method - Google Patents

Description

The technique disclosed in the present specification relates to a video reproduction method.

With the improvement of the quality of video contents, not only the resolution but also the color gamut and the brightness range are being expanded in the video equipment. Further, in addition to the conventional relative brightness-based brightness curve, an absolute brightness-based brightness curve has also been adopted.

For example, Ultra HD Blu-ray (registered trademark) is coded using an absolute luminance-based luminance curve defined in SMPTE ST2084, and represents a wide luminance range of 0.005 to 10000 nits as a luminance range. Has a range.

Here, it is assumed that the brightness curve indicates an EOTF (Electro-Optical Transfer Function) that connects the code value and the brightness.

Since it is difficult for a consumer display device to express the above-mentioned luminance range, the luminance range is adjusted to display within the displayable range of the display device.

For example, when displaying video content using up to 4000 nits on a display device capable of displaying up to 1000 nits, the brightness range of the image is truncated from 4000 nits to 1000 nits, or the brightness range is compressed by a brightness conversion function. ..

There are two methods for converting the luminance range: a method of switching the luminance curve and a method of converting the luminance code value into the luminance information and then processing the luminance conversion function. However, since they are the same in terms of the effect produced only by different procedures, these methods are treated as the same in the present specification unless otherwise specified.

The adjustment of the luminance range may be performed in the reproduction device or in the display device.

In order to efficiently adjust the brightness range, various metadata are added to the video content as hint information. As the metadata, for example, the maximum peak brightness in the content, the maximum value of the average brightness of one frame, information on whether to prioritize brightness or gradation, or brightness curve selection information according to the situation can be considered. ..

These metadata are classified into static metadata that does not change throughout the content and dynamic metadata that gives optimal hint information for each scene or frame.

For example, Ultra HD Blu-ray® employs the metadata defined in SMPTE ST2086 as static metadata, as well as dynamic metadata defined by technology vendors.

As a method of using the metadata, there are a case where it is used in a reproduction device, a case where it is sent to a display device and used in a display device, and a case where both are combined.

Content such as Blu-ray Disc (registered trademark) has a graphic function such as a menu or subtitles, and is combined with the content video and displayed as needed. The graphics are usually combined in the playback device, and are transmitted and displayed on the display device in a state of being combined with the content video. When the brightness is adjusted in the display device, the synthesized graphic portion is also affected by the brightness adjustment.

Various methods have been proposed for these luminance adjusting techniques, and for example, the techniques are also disclosed in Patent Document 1 and Patent Document 2.

International Publication No. 2016/103968 International Publication No. 2016/038950

In a method such as Blu-ray Disc (registered trademark), in which a graphic is combined with a content image and then transmitted to a display device, there is a problem that the brightness of the graphic fluctuates due to dynamic metadata control.

The technique disclosed in the present specification has been made to solve the above-mentioned problems, and an object thereof is to provide a technique for suppressing a change in the brightness of a graphic.

The first aspect of the technique disclosed in the present specification is a video reproduction method of reading and reproducing a video stream and graphic information including menus or subtitles from a video content medium, and as a brightness adjusting means, adjustment that does not change. It is provided with a static metadata method that uses a value and a dynamic metadata method that uses a changing adjustment value, and the brightness adjustment means is switched and used at the time of graphic composition, and is read from the video content medium. The graphic transition time information is used as the transition time when switching the brightness adjusting means.

According to the first aspect of the technique disclosed in the present specification, the change in the brightness of the graphic can be suppressed.

The objectives, features, aspects and advantages of the technology disclosed herein will be further clarified by the detailed description and accompanying drawings set forth below.

It is a schematic diagram which shows Embodiment 1. FIG. It is a figure which shows the example of the luminance adjustment curve (in the case of display maximum luminance 1000 nits). It is a figure which shows the example of the luminance adjustment curve (in the case of display maximum luminance 400 nits). It is a schematic diagram which shows the composition of the luminance adjustment curve. It is a schematic diagram which shows the second embodiment. It is a figure which shows the example of the luminance adjustment curve (in the case of graphic luminance threshold value of 300 nits, display maximum luminance 1000 nits). It is a figure which shows the example of the luminance adjustment curve (in the case of graphic luminance threshold value of 300 nits, display maximum luminance 400 nits). It is a figure which shows the example of the control by a graphic luminance threshold. It is a figure which shows the example of the control by a graphic luminance threshold (when it has two thresholds). It is a schematic diagram which shows Embodiment 3. It is a figure which shows the example of brightness adjustment by dynamic metadata. It is a figure which shows the example of the storage place of the luminance switching transition time. It is a figure which shows the example of the storage place of a graphic luminance threshold value, and a luminance switching transition time.

Hereinafter, embodiments will be described with reference to the attached drawings.

It should be noted that the drawings are shown schematically, and for convenience of explanation, the configuration is omitted or the configuration is simplified as appropriate. Further, the interrelationship between the sizes and positions of the configurations and the like shown in different drawings is not always accurately described and can be changed as appropriate.

Further, in the description shown below, similar components are illustrated with the same reference numerals, and their names and functions are also the same. Therefore, detailed description of them may be omitted to avoid duplication.

<Embodiment 1>
Hereinafter, the video content medium and the video playback device according to the present embodiment will be described.

The change in brightness of the content image depending on the presence or absence of graphics makes the viewer feel uncomfortable. For example, when the brightness of the background content image suddenly changes at the timing of turning on / off the menu or the presence / absence of subtitles.

In the following embodiment, a transition time is provided for switching between the normal dynamic metadata processing applied when there is no graphic and the metadata processing applied when there is a graphic, and the content image is suddenly set. A technique for avoiding changes in brightness and reducing discomfort will be described.

FIG. 1 is a schematic view of a reproduction device 1000 and a display device 2000. As illustrated in FIG. 1, content video data 1110 which is a video stream, graphic data 1120 which is graphic information such as menus or subtitles, dynamic metadata 1130 which is control information, and static metadata which is control information. The data 1140 and the brightness switching transition time 1150, which is the graphic transition time information, are stored in, for example, an optical disk as a video content medium, and are read by the playback device 1000.

The graphic synthesizing unit 1200 synthesizes the content video data 1110 and the graphic data 1120 to create video data including graphics. The graphic data may be given in the form of video data, may be dynamically generated by a program or command list stored in the content, or may be generated by a combination thereof.

The graphic data is, for example, subtitle data, for example, a pop-up menu, etc., and may be displayed or hidden depending on the progress of content playback or a user operation.

The content video data 1110 and the graphic data 1120 are stored in a form that has been subjected to processing such as compression or multiplexing, and are returned to the video by performing decoding processing or drawing processing before actually performing the composition. It is necessary, but the explanation is omitted here for the sake of simplicity.

The dynamic metadata 1130 is time-synchronized with the content video data 1110 and is stored in or as a separate stream in the multiplexed stream containing the content video data 1110.

The static metadata 1140 is, for example, a set of metadata defined by SMPTE ST2086, and stores values such as MaxCLL indicating the maximum brightness of the entire content and MaxFALL indicating the maximum value of the average value in one screen. There is. In FIG. 12, it is shown that the content maximum luminance (MaxCLL) 3110 and the content frame average luminance maximum value (MaxFALL) 3120 are stored together with the luminance transition time 3130 in the static metadata 3100. ..

The brightness switching transition time 1150 stores the transition time when switching the brightness range adjustment. The luminance switching transition time 1150 can be stored at the same position as other static metadata as shown by the luminance transition time 3130 in FIG. 12 when stored on an optical disk or the like, and is read out and used. To do. Further, the luminance switching transition time 1150 can be stored in advance as a set value in the reproduction device 1000 and the display device 2000.

The graphic presence / absence notification unit 1300 determines whether or not the graphic display is currently being performed, and sends the graphic display to the display device 2000.

These data are sent to the display device 2000 through an interface such as HDMI®. The dynamic metadata 1130, the static metadata 1140, and the luminance switching transition time 1150 are sent as data of a system different from the video data called InfoFrame. Alternatively, the dynamic metadata 1130, the static metadata 1140, and the luminance switching transition time 1150 may be superimposed on the video signal and sent to the display device 2000. The same applies to the transmission of the notification data created by the graphic presence / absence notification unit 1300.

The linear conversion unit 2100 converts the content video data from the code value to the linear value representing the content brightness value according to the conversion curve of the standard brightness curve 2500. The brightness adjusting unit 2200 converts the content brightness value into the brightness to be actually displayed according to the characteristics of the display device. The display unit 2300 displays the image of the content with the brightness value adjusted by the brightness adjustment unit 2200.

The display device characteristic value is, for example, a brightness range that can be displayed on the display unit 2300, an image quality adjustment value such as a cinema mode or a sports mode, or ambient light information around the display device. The brightness adjustment curve creation unit 2400 creates a brightness adjustment curve suitable for the situation by using the display device characteristic value 2600, the dynamic metadata 1130, the static metadata 1140, and the brightness switching transition time 1150, and the brightness adjustment unit 2200. To control.

The operation of the luminance adjusting unit 2200 and the luminance adjusting curve creating unit 2400 will be described with reference to FIG. FIG. 2 shows an example in which the maximum display brightness of the display unit 2300 is 1000 nits. For the sake of simplicity, the brightness adjustment curve is drawn as a straight line, but in reality, a curve that takes into consideration human visual characteristics is often used.

The horizontal axis of FIG. 2 is an absolute value representation of the content luminance value of the video data. In the case of the video data represented by ST2084, the brightness range can be represented up to 10000 nits.

The vertical axis of FIG. 2 is the display luminance value actually displayed on the screen. When the display unit 2300 is an ideal display device capable of displaying up to 10000 nits, the content luminance value and the display luminance value are the same. That is, the straight line N showing 1: 1 in FIG. 2 becomes the luminance adjustment curve, and it is not necessary to change it.

The actual display unit 2300 cannot display all 10000 nits. The TVs on the market at the present time are 400 nits or less for popular machines, and about 1000 nits even for high-end machines characterized by high brightness.

When trying to display the content brightness value as it is, as shown by the brightness adjustment curve B, it is faithful to the content brightness value up to the maximum display brightness, and when it exceeds the maximum display brightness, it is clipped and all are displayed as the maximum display brightness. Will be done. In this case, the image of the high-luminance portion exceeding the maximum display brightness is damaged.

Therefore, the brightness adjustment curve is changed by using the maximum value of the content brightness. That is, when the maximum value of the content brightness is 1000 nits or less, the brightness adjustment curve B is used, when it is 1500 nits, the brightness adjustment curve C is used, and when it is 2000 nits, the brightness adjustment curve D is used.

Static metadata control uses the maximum brightness value for the entire content as a reference when creating this brightness adjustment curve, and dynamic metadata control uses the maximum brightness value for each frame for each scene. ..

Here, it is explained that the maximum brightness value of the content is used to create the brightness adjustment curve, but in reality, which of the average brightness value, the high brightness and the low brightness of the content is emphasized, the image quality mode. Create a brightness adjustment curve in consideration of the settings or ambient light.

In the case of static metadata control, the brightness adjustment curve does not change from the beginning to the end during playback of the content video. If the maximum luminance value of the content is 2000 bits, the luminance adjustment curve D is applied to the entire content. Therefore, there is no change in brightness that is not present in the original video during playback.

On the other hand, even if a high-brightness scene exists only in a part of the content, the brightness of the entire content is lowered and the content is reproduced, so that the overall impression becomes dark. In addition, since the compression rate in the luminance region is high, there is a high possibility that the gradation of luminance is impaired.

In the case of dynamic metadata control, the brightness adjustment curve is changed for each scene, for example, during playback of the content video. If the scene being played is 1000 nits or less, the brightness adjustment curve B is applied, and if the scene is used up to 2000 nits, the brightness adjustment curve D is applied. Since the optimum brightness adjustment curve is used for each scene, the possibility of impairing the gradation of brightness can be reduced.

On the other hand, the standard brightness changes for each scene. For example, even in the same landscape, if the sun is reflected within the angle of view, the whole is dark, and if the sun is not reflected, the whole is displayed bright.

In a normal scene, such a change in brightness does not matter much. Since human vision also changes according to the situation, there is little discomfort even if the brightness of the image changes when the scene changes.

When graphics such as subtitles or pop-up menus are displayed, the change in brightness due to dynamic metadata control becomes a problem. Since the graphic is displayed independently of the scene, the user expects it to be displayed with the same brightness regardless of the scene, and the brightness of the graphic part changes due to the change of the brightness adjustment curve by dynamic metadata control. There is a great sense of discomfort in that.

FIG. 2 shows an example in which the graphic is drawn with a content luminance value of 200 nits. In the case of the brightness adjustment curve B, the display brightness value is 200 nits, which is the same as the content brightness value, but when the brightness adjustment curve D is switched to due to a change in the image, the display brightness value is 200 nits even though the graphic has not changed. Also changes to a small value.

This change becomes remarkable when the maximum display brightness of the display unit 2300 is low. FIG. 3 is an example when the maximum display brightness is 400 nits. The brightness adjustment curve is also changed according to the maximum display brightness, and is a brightness adjustment curve Ax, a brightness adjustment curve Bx, a brightness adjustment curve Cx, and a brightness adjustment curve Dx.

When the graphic is drawn at 200 nits, when the maximum brightness of the content changes from 400 nits to 2000 nits, the brightness adjustment curve changes from the brightness adjustment curve Ax to the brightness adjustment curve Dx, and the graphic part drawn at 200 nits is 200 nits. It changes to a smaller value than.

As a method of preventing such a change in the brightness of the graphic portion, a method of fixing the brightness conversion curve without performing dynamic metadata control when the graphic is displayed can be considered. For example, when graphic display is turned on, it switches from dynamic metadata control to static metadata control, and when graphic display is turned off, it switches from static metadata control to dynamic metadata control. Alternatively, when the graphic display is turned on, it is fixed to the brightness conversion curve created by the dynamic metadata control at that time, and then controlled so that the value of the dynamic metadata is not reflected, and the graphic display is turned off. If this happens, the dynamic metadata control that reflects the dynamic metadata value is performed again.

In this way, by changing the control of the luminance conversion curve according to the presence or absence of the graphic, it is possible to suppress the change in the luminance of the graphic portion during the graphic display. On the other hand, since the luminance conversion curve changes depending on the presence or absence of the graphic, the luminance change irrelevant to the scene being played occurs in the content video, which causes another discomfort.

In the present embodiment, a method of reducing the discomfort at the time of switching generated by the method of switching the control of the luminance curve according to the presence or absence of the graphic by providing a transition time will be described.

The reproduction device 1000 of FIG. 1 reads out the luminance transition time 3130 stored in the playlist data 3000 on the optical disc of FIG. 12 and uses it as the luminance switching transition time 1150.

The reproduction device 1000 sends a luminance switching transition time 1150 to the display device 2000 through an interface such as HDMI (registered trademark). When the display device 2000 receives the brightness switching transition time 1150, the display device 2000 sets it as one of the parameters used by the brightness adjustment curve creation unit 2400. The dynamic metadata 1130 and the static metadata 1140 are also sent to the luminance adjustment curve creation unit 2400.

When a graphic such as a subtitle or a menu is displayed due to the user's operation or the progress of playback, the graphic presence / absence notification unit 1300 notifies the display device 2000 of the graphic display from the playback device 1000.

The notification of the graphic display can be notified by setting a flag indicating the graphic display on the interface. The graphic display notification can also be notified by switching the flag indicating the HDR type defined in the HDMI (registered trademark) interface. Alternatively, the notification of the graphic display can be detected on the display device 2000 side by stopping the transmission of the dynamic metadata.

When the brightness adjustment curve creation unit 2400 detects that the graphic is displayed by the notification from the graphic presence / absence notification unit 1300, the brightness adjustment curve creation unit 2400 stops the dynamic metadata processing and replaces it with a fixed brightness adjustment curve to the brightness adjustment unit 2200. Send it out.

The fixed luminance adjustment curve refers to a luminance adjustment curve created using, for example, static metadata 1140. At this time, if the processing is simply switched, for example, the brightness adjustment curve B in FIG. 2 is switched to the brightness adjustment curve D, and the brightness of the content image being played is suddenly lowered regardless of the scene. Therefore, the brightness adjustment curve used continuously is changed over the time specified by the brightness switching transition time 1150.

FIG. 4 is a schematic diagram of metadata processing switching in the display device. The brightness adjustment curve 2410 for the content image is, for example, a brightness curve adjustment using the dynamic metadata 1130, and is a brightness adjustment curve suitable for the content image. The graphic brightness adjustment curve 2420 is, for example, a brightness adjustment curve using only static metadata 1140, and is a brightness adjustment curve suitable for graphics in which the brightness does not change.

The static metadata 1140 is stored in the luminance adjustment curve creation unit 2400 in advance. The luminance adjustment curve applied to the output video is obtained by synthesizing these luminance adjustment curves in the compositing unit 2430 with a compositing ratio α. As the brightness adjustment for graphics, dynamic metadata can be used so that the brightness adjustment values are the same below the threshold value instead of the static metadata.

At the time of switching, smooth switching can be performed, for example, by continuously changing the synthesis ratio α from 0 to 1 over the time specified by the luminance switching transition time 1150 in the synthesis unit 2430.

The same applies when the graphic is hidden. When the graphic presence / absence notification unit 1300 notifies that the graphic is not displayed, the luminance adjustment curve creation unit 2400 resumes the dynamic metadata control. At this time, by continuously changing the composition ratio α from 1 to 0 over a time specified by the luminance switching transition time, it is possible to smoothly shift to the dynamic metadata control.

In this way, it is possible to reduce the discomfort caused by switching the brightness adjustment curve during graphic display.

In the above embodiment, the operation of the luminance adjustment curve creating unit 2400 is simply switched depending on the presence or absence of the graphic, but in the case of a graphic such as a subtitle that is repeatedly displayed and hidden in a short time, it is temporal. It is also possible to regard the graphics close to the graphic as a group of graphics and adopt a method in which the operation switching of the luminance adjustment curve creating unit 2400 is not performed when the individual graphics are turned on and off.

<Embodiment 2>
The video content medium and the video playback device according to the present embodiment will be described. In the following description, components similar to the components described in the above-described embodiments will be illustrated with the same reference numerals, and detailed description thereof will be omitted as appropriate. Shown below is a modified example of the first embodiment.

By using a brightness adjustment curve that has a common value below the graphic brightness threshold and has different values above and below the graphic brightness threshold, the brightness changes below the graphic brightness threshold even when dynamic metadata control is performed. It is conceivable to perform brightness adjustment without threshold.

By setting the graphic luminance threshold value to a value larger than the maximum luminance value used in the graphic, it is possible to suppress the luminance fluctuation of the graphic even during dynamic metadata control.

On the other hand, in the brightness range below the threshold value, substantially static metadata control is performed, and the gradation is impaired. Therefore, it is conceivable to use the brightness adjustment curve with the threshold value and the brightness adjustment curve without the threshold value in combination and switch between them. Also in this case, as in the case of the first embodiment, the brightness change irrelevant to the scene occurs at the time of switching. In the present embodiment, a method for reducing the discomfort of the luminance change that occurs when the luminance conversion curve having a threshold value is switched will be described.

FIG. 5 is a schematic diagram illustrating the present embodiment, 1161 and 1162 are the first luminance threshold and the second luminance threshold, and 1151 and 1152 are the first luminance switching transition time and the second luminance switching transition time. is there.

Here, the graphic luminance threshold value and the luminance switching transition time will be described using two each, but each may be one or two or more. The brightness threshold value adjusting unit 1500 adjusts the graphic brightness threshold value according to the situation. The graphic luminance threshold value adjusted by the luminance threshold value adjusting unit 1500 is sent to the display device 2000.

FIG. 6 is an example of the brightness adjustment curve used in the present embodiment. The graphic luminance threshold in the figure is described as the first luminance threshold 1161, but the same applies to the case of the second luminance threshold 1162.

When the brightness adjustment curve creation unit 2401 receives the first brightness threshold value 1161, the brightness becomes the same value below the brightness set by the first brightness threshold value 1161 (z in the figure), and differs depending on the content brightness above that value. Create a luminance adjustment curve that takes a value (b, c or d in the figure).

FIG. 6 shows an example when the maximum display brightness of the display unit 2300 is 1000 nits. FIG. 7 shows an example when the maximum display brightness of the display unit 2300 is 400 nits (see zx, ax, bx, cx and dx in FIG. 7).

In this way, while dynamic metadata control is performed in the region having a brightness higher than the brightness set by the first luminance threshold 1161, the fluctuation of the luminance due to the luminance adjustment is suppressed in the region having a luminance lower than the first luminance threshold 1161. can do.

In order to reduce the discomfort due to the change in the image brightness when switching between the brightness adjustment curve having no threshold value and the brightness adjustment curve having a threshold value, the graphic brightness threshold value is continuously changed.

When the brightness threshold value adjusting unit 1500 receives a notification from the graphic presence / absence notification unit 1300 that the first brightness threshold value 1161 is applied, the brightness threshold value adjusting unit 1500 uses the first brightness threshold value 1161 and the first brightness switching transition time 1151 to display the display device 2000. Create a graphic brightness threshold to send to.

The graphic may be displayed or hidden depending on the progress of content playback or the user's operation.

FIG. 8 is an example of the graphic brightness threshold value transmitted from the brightness threshold value adjusting unit 1500. When the first luminance threshold 1161 is not applied, the graphic luminance threshold sent by the luminance threshold adjusting unit 1500 is 0. When the first luminance threshold 1161 is applied, such as when a graphic is displayed, the luminance threshold adjusting unit 1500 sets the value of the luminance threshold continuously transmitted at the time specified by the first luminance switching transition time 1151. The value is increased so that the value specified by the first luminance threshold 1161 becomes the transmitted graphic luminance threshold.

When the luminance threshold value adjusting unit 1500 is not applied, such as when the graphic is no longer displayed, the luminance threshold value adjusting unit 1500 sets the transmitted graphic luminance threshold value to 0 from the value specified by the first luminance threshold value 1161 for the first luminance switching transition. It is continuously reduced over the time specified by time 1151.

By continuously switching the brightness curve in this way, the change in brightness becomes smooth and the sense of incongruity can be reduced.

It may be convenient to use two graphic brightness thresholds with different values. For example, when using graphics with different brightness ranges for subtitles and pop-up menus.

FIG. 9 is an example when two graphic luminance thresholds are used. When the first luminance threshold value 1161 and the second luminance threshold value 1162 are applied independently, the same as the above description. When both the first luminance threshold 1161 and the second luminance threshold 1162 are applied, the luminance threshold adjusting unit 1500 sends out the higher value of the graphic luminance threshold.

The first luminance threshold 1161 will be described as being larger than the second luminance threshold 1162. When the graphic to which the first luminance threshold 1161 is applied is displayed, the luminance threshold is switched to the first luminance threshold 1161 at the time specified by the first luminance switching transition time 1151, and the second luminance threshold 1162 is applied from that state. Is displayed, the process switches to the second luminance threshold value 1162 at the time specified by the second luminance switching transition time 1152. This is also the case when the graphic disappears.

Since the brightness threshold value adjusting unit 1500 sets the maximum applicable graphic brightness threshold value as the graphic brightness threshold value, it is set while the graphic to which the second brightness threshold value 1162 having a large set value is applied is displayed. Even if the graphic to which the first brightness threshold 1161 having a small value is applied is displayed or hidden, the graphic brightness threshold sent by the brightness threshold adjusting unit 1500 does not change.

In FIG. 13, the static metadata 3100 includes the maximum luminance (MaxCLL) 3110, the maximum frame average luminance (MaxFALL) 3120 of the content, the first luminance transition time 3131, the second luminance transition time 3132, and the second. It is shown that the 1-luminance threshold 3141 and the 2nd luminance threshold 3142 are stored.

Here, although two types of time, the first luminance switching transition time 1151 and the second luminance switching transition time 1152, are provided, the luminance switching transition time is set to one, and the first luminance threshold value 1161 and the first luminance threshold value 1161 are provided. The two luminance thresholds 1162 may be switched at the same time.

In this way, even when the brightness adjustment curve having a threshold value is used, it is possible to reduce the discomfort of the change in brightness due to the change in the display state of the graphic by providing the transition time.

Here, the brightness threshold value adjusting unit 1500 has been described as being on the reproduction device 1000 side, but it is also possible to provide the brightness threshold value adjustment unit 1500 on the display device 2000 side, for example, the brightness adjustment curve creation unit 2401.

In this case, the first luminance threshold 1161, the second luminance threshold 1162, the first luminance switching transition time 1151 and the second luminance switching transition time 1152 are sent to the display device 2000 in advance.

<Embodiment 3>
The video content medium and the video playback device according to the present embodiment will be described. In the following description, components similar to the components described in the above-described embodiments will be illustrated with the same reference numerals, and detailed description thereof will be omitted as appropriate.

In the first embodiment, it has been described that the composition ratio can be adjusted according to the transition time on the display device side, but as a modification, an example in which the graphic transition time is processed on the playback device side will be described below.

FIG. 10 shows an example in which the graphic transition time is processed using the dynamic metadata on the playback device side. Here, an example of switching between dynamic metadata and static metadata will be described. The dynamic metadata adjustment unit 1400 adjusts the dynamic metadata and sends it to the brightness adjustment curve creation unit 2402 of the display device 2000.

Here, when the graphic is displayed, the value of the dynamic metadata is fixed to the value of the static metadata, and the control is substantially switched to the static metadata control. By doing so, it is possible to continuously switch the metadata control, unlike the case of simply switching between the dynamic metadata control and the static metadata control.

FIG. 11 is an example of dynamic metadata in this example. The dynamic CLL is a peak luminance value for each scene or frame included in the dynamic metadata 1130. MaxCLL is the peak luminance value throughout the content contained in the static metadata 1140. Actually, since the brightness adjustment curve is created including information other than the peak brightness value, it is necessary to perform control other than the peak brightness value, but here, only the peak brightness value will be described as a representative.

At the time of normal content video reproduction, the dynamic metadata adjustment unit 1400 transmits the peak luminance information of the dynamic metadata 1130 to the display device 2000 as it is. In FIG. 11, it corresponds to a solid line polygonal line portion represented as a dynamic CLL.

When the graphic display notification is received from the graphic presence / absence notification unit 1300, the MaxCLL value included in the static metadata 1140 is continuously changed at the time specified by the luminance switching transition time 1150 (indicated by tt in the figure). Part).

The original dynamic metadata is the broken line portion of the broken line in the figure, but the dynamic metadata sent to the display device 2000 is the value shown by the solid line while the graphic is displayed.

In the display device 2000, since the brightness adjustment curve is created by the value of the dynamic metadata received from the dynamic metadata adjustment unit 1400, the brightness fluctuation of the graphic part is suppressed by fixing the value of the dynamic metadata. Can be done.

In this way, by adjusting the value of the dynamic metadata on the playback device 1000 side, it is possible to substantially perform static metadata control using the dynamic metadata control mechanism, and it is possible to switch by providing a transition time. It is possible to reduce the discomfort that accompanies it.

When displaying the graphic, the peak brightness information of the original dynamic metadata is ignored, and the MaxCLL value of the static metadata is temporarily transmitted to the display device as the peak brightness information of the dynamic metadata. , Brightness fluctuation of the graphic part can be suppressed. At this time, by performing the change from the peak brightness information of the immediately preceding dynamic metadata to the MaxCLL value over the specified graphic transition time, it is possible to avoid a sudden change in the brightness of the content image.

In this way, by applying the graphic transition time corresponding to the content at the time of switching the brightness adjustment method, it is possible to provide a viewing environment with less discomfort even when the graphic is on and off.

In the embodiments described above, the dimensions, shapes, relative arrangement relationships, conditions of implementation, etc. of the respective components may also be described, but these are examples in all aspects and are described in the present specification. It is not limited to what is stated in the document.

Therefore, innumerable variations and equivalents not exemplified are envisioned within the scope of the techniques disclosed herein. For example, when transforming, adding or omitting at least one component, or when extracting at least one component in at least one embodiment and combining it with the components of another embodiment. Shall be included.

1000 playback device, 1110 content video data, 1120 graphic data, 1130 dynamic metadata, 1140, 3100 static metadata, 1150 brightness switching transition time, 1151 first brightness switching transition time, 1152 second brightness switching transition time, 1500 Luminance threshold adjustment unit, 1161,3141 1st brightness threshold, 1162,3142 2nd brightness threshold, 1200 graphic synthesis unit, 1300 graphic presence / absence notification unit, 1400 dynamic metadata adjustment unit, 2000 display device, 2100 linear conversion unit, 2200 Luminance adjustment unit, 2300 display unit, 2400, 2401,402 Brightness adjustment curve creation unit, 2410 Luminance adjustment curve for content video, 2420 Luminance adjustment curve for graphics, 2430 Synthesis unit, 2500 Standard brightness curve, 2600 Display device characteristic value, 3000 Playlist data, 3110 content maximum brightness (MaxCLL), 3120 content frame average brightness maximum value (MaxFALL), 3130 brightness transition time, 3131 first brightness transition time, 3132 second brightness transition time, Ax, B, Bx, C , Cx, D, Dx Luminance adjustment curve.

Claims (1)

It is a video playback method that reads and plays a video stream and graphic information including menus or subtitles from a video content medium.
As the brightness adjustment means, a static metadata method that uses an adjustment value that does not change and a dynamic metadata method that uses an adjustment value that changes are provided.
When synthesizing graphics, the brightness adjustment means is switched and used.
The graphic transition time information read from the video content medium is used as the transition time when switching the luminance adjusting means.
Video playback method.

Images