JP2008131281A - Transmitting method, transmission system, transmitting device, and receiving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily transmit video data having a wide color gamut by using an existent transmission standard for video data such as the HDMI standard. <P>SOLUTION: The present invention is applied to a transmitting device which transmits video data by using a transmission system which transmits video data in units of predetermined bits from a source-side device to a sink-side device in synchronism with a pixel clock by using individual transmission lines by color data. The video data transmitted from the source-side device to the sink-side device are video data of color data within a predetermined color band and video data of color data not within the predetermined color band. The video data of color data within the predetermined color band and video data of color data not within the predetermined color band are composed of a predetermined number of bits for each pixel, and transmitted in timing synchronized to the pixel clock to transmit video data exceeding the predetermined color band from the source-side device to the sink-side device. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a technique for transmitting video data having a wide color band using a digital video / audio input / output interface standard, and for example, a digital video / audio input / output called HDMI (High-Definition Multimedia Interface) standard. The present invention relates to a transmission method and a transmission system suitable for application to an interface standard and a DVI (Digital Video Interface) standard, and a transmission apparatus and a reception apparatus applied to the transmission system.

  In recent years, in addition to the DVI (Digital Video Interface) standard, which is an interface standard for connecting a computer and a display, the HDMI standard is an interface standard for transmitting uncompressed digital video data and the like between a plurality of video devices. What is called has been developed. The HDMI standard is a standard in which video data is individually transmitted in units of one pixel as primary color data for each color (hereinafter, pixels may be referred to as pixels). Audio data (audio data) is also transmitted using a video data transmission line during the blanking period of the video data. The primary color data to be transmitted is the case of transmitting three-channel primary color data (R data, G data, B data) of additive colors of red, green, and blue, and the case of transmitting luminance and color difference signals such as Y, Cb, and Cr. There is.

  FIG. 9 shows an example of transmitting primary data of R data, G data, and B data, and transmitting Y data, Cb data, and Cr data. As shown in FIG. 9A, when video data is transmitted from a video playback device such as a video disk playback device to a television receiver using an HDMI standard cable, R data, G data, B Either the case of transmitting primary data of data or the case of transmitting luminance data and color difference data of Y data, Cb data, and Cr data can be used. On the other hand, as shown in FIG. 9B, when video data is transmitted from a video playback device to a computer monitor using an HDMI standard cable, R data, G data, and B data are used. The primary color data is transmitted.

Y data, Cb data, Cr data and R data, G data, B data can be converted by a predetermined determinant. For example, Y data, Cb data, and Cr data as xvYCC signals, which will be described later, and R data, G data, and B data as sRGB signals can be converted by the following matrix. It is also possible to convert Y data, Cb data, and Cr data into R data, G data, and B data with the same arithmetic expression.
Y = 0.2126R + 0.7152G + 0.0722B
Cb = -0.1146R-0.3854G + 0.5000B
Cr = 0.5000R-0.4542G-0.0458B

  In the HDMI standard, 1-pixel data of each color is basically configured in units of 8 bits. Synchronization signals such as a horizontal synchronization signal and a vertical synchronization signal are also transmitted at the timing at which each synchronization signal is arranged. Also, a pixel clock transmission line for video data and a control data transmission line are provided.

  FIG. 10 is a diagram illustrating an outline of an example in which primary color data (R data, G data, and B data) is transmitted using an HDMI standard interface. As for video data, B data, G data, and R data are individually transmitted through three channels of channel 0, channel 1, and channel 2. In the example of FIG. 10, a period for transmitting data of four pixels, pixel 0, pixel 1, pixel 2, and pixel 3, is shown, and data of one pixel of each channel is composed of 8 bits.

  That is, for B data (blue data), 8-bit B0 data is sent during the period of pixel 0 using channel 0. Hereinafter, 8-bit B1 data, B2 data, and B3 data are transmitted from the pixel clock ( (Not shown) and sent sequentially. For G data (green data), 8-bit G0 data is sent during the period of pixel 0 using channel 1, and hereinafter, 8-bit G1 data, G1 data, G2 data, and G3 data are pixel clocks. Sent sequentially in sync with. For R data (red data), 8-bit R0 data is sent during the period of pixel 0 using channel 2, and hereinafter, 8-bit R1 data, R2 data, and R3 data are synchronized with the pixel clock. Sent in order.

  Although not shown in FIG. 10, in the HDMI standard interface, control data and a pixel clock are transmitted using another channel. For control data, not only transmission of video data from the sending device (source device) to the receiving device (sink device), but also from the receiving device (sink device) to the sending device (source device) Can be transmitted. The source device encrypts data in 8-bit units, and the sink-side device decrypts data from the encryption in 8-bit units.

  As described above, the interface of the HDMI standard is standardized on the assumption that one pixel is transmitted at 8 bits per color. On the other hand, in recent years, it has been studied to increase the color resolution, and it has been proposed that the number of bits per color per pixel is 8 bits or more. For example, it has been proposed that the number of bits per color per pixel is 16 bits.

  FIG. 11 is an example of a transmission state assuming that 16-bit data for one color of one pixel is transmitted by the interface of the HDMI standard. As described above, the HDMI standard is a standard that assumes that data is transmitted in units of 8 bits, and is configured to transmit 8 bits with 1 pixel clock. In order to transmit 16-bit data, Two pixel clocks are required. In the example of FIG. 11, the data arrangement is such that data of one pixel is transmitted with a two-pixel clock. Phases 0, 1, 2, and 3 shown in FIG. 11 each indicate one period of one pixel clock. As shown in FIG. 11, by using two clock periods, it is possible to transmit video data of 16 bits per pixel, which is twice the number of bits. In the case of the data transmission shown in FIG. 11, two pixel clock periods are required for the transmission of one pixel, so that the pixel clock needs to be doubled in frequency accordingly.

Patent Document 1 describes details of the HDMI standard.
WO2002 / 078336

  By the way, display devices that receive and display video data have been developed with improved color expression capabilities. In other words, the color representation capability of video data handled by a conventional display device is basically based on the assumption that a cathode ray tube (CRT) is used as a display means, assuming a color range that can be represented by the cathode ray tube, The color range represented by the primary color data of R data, G data, and B data described above is set.

  On the other hand, as display means using a display device, those having a color expression range superior to that of a cathode ray tube have appeared. For example, in the case of a liquid crystal display, the color expression range is determined by the characteristics of the light source used as the backlight, and it is relatively easy to make the color expression range wider than that of the cathode ray tube.

  In recent years, a standard called an xvYCC signal has been established as a standard for video data (moving picture data) handled by a display device that widens the color expression range. Display processing of video data expressed in accordance with the xvYCC signal makes it possible to display video with a wide color expression range. Details of the xvYCC signal will be described later in the embodiments of the invention. In the following description, R, G, and B data in the conventional color expression range are referred to as sRGB signals.

  By the way, when video data having a wide color expression range such as the xvYCC signal is transmitted through the transmission path of the sRGB signal, there is usually a problem that information other than the color gamut of the sRGB signal cannot be sent. In particular, as shown in FIG. 9, when transmitting to a monitor for a personal computer using an HDMI standard transmission line, since it can be transmitted only in the format of RGB data, the color gamut exceeding the color gamut of the sRGB signal. There was a problem that data could not be transmitted.

In order to handle a wider and wider color gamut, for example, there is a method of defining another chromaticity point and making it incompatible with the sRGB signal. Alternatively, it is possible to use a value that defines the chromaticity point of each RGB data. Specifically, in order to define a color outside the chromaticity point at the same chromaticity point, it means that each primary color RGB data value takes a value exceeding 1 or a negative value. To do.
However, in a normal monitor or video equipment, handling signals with different chromaticity points at the same terminal has a problem that switching is complicated and difficult to realize. Also, sending RGB values exceeding 1 or minus values has a problem that it is difficult to respond because the system configuration on the signal receiving side must respond to the signal. .

  The present invention has been made in view of this point, and an object thereof is to enable transmission of video data having different chromaticity points by using an existing video data transmission standard such as the HDMI standard.

  The present invention provides video data using a transmission method in which video data in a predetermined bit unit is transmitted from a source side device to a sink side device using a separate transmission line for each color data in synchronization with a pixel clock. Applies to those that transmit The video data transmitted from the source side device to the sink side device is video data of color data within a specified color band and video data of color data outside the specified band. The video data of the color data within the specified color band and the video data of the color data outside the specified band are configured with a predetermined number of bits for each pixel and transmitted at a timing synchronized with the pixel clock. Thus, video data exceeding a specified color band is transmitted from the source side device to the sink side device.

  By doing so, video data exceeding the specified color band is transmitted separately to color data within the color band and color data exceeding the color band using one set of transmission lines, and a bit is transmitted. It can be applied to a transmission standard capable of transmitting a large amount of video data.

  According to the present invention, using one set of transmission lines, video data exceeding the specified color band is transmitted separately into color data within the color band and color data exceeding the color band. The present invention can be applied to a transmission standard capable of transmitting a large amount of video data. For example, video data exceeding a color band defined easily can be transmitted using the HDMI standard. In addition, if the display device on the receiving side does not support the processing of video data exceeding the specified color band, it is sufficient to perform reception processing ignoring the color data exceeding the color band, and it supports a wide color gamut. Compatibility between video transmission for display and video transmission for display corresponding to a normal color gamut can be maintained. Furthermore, the transmission mode is a transmission mode that maintains a transmission unit of the number of bits (for example, 8 bits) defined in the transmission standard, and encryption and decryption in a predetermined bit unit are performed in a state defined by the standard. Yes.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  In this example, the present invention is applied to a transmission system that transmits video data or the like from a source device to a sink device according to the HDMI standard. FIG. 1 is a diagram showing an example of the system configuration of this example. A video recording / reproducing apparatus 10 that is a source side device and a television receiver 30 that is a sink side device are connected by an HDMI cable 1 and video. Video data and audio data are transmitted from the recording / reproducing apparatus 10 to the television receiver 30. The video recording / reproducing apparatus 10 of this example is configured to record and reproduce video data having a wide color gamut, and the television receiver 30 is a receiver capable of displaying video having a wide color gamut. is there.

  In the following description, necessary configurations and the like of the HDMI standard will be described in order. Basically, the existing HDMI standard is applied as it is, and the configuration of the HDMI cable 1 is the same as the conventional one. In the case of this example, the HDMI cable 1 is used to transmit R data, G data, and B data, which are primary color signals. In addition, a signal with a conventional color gamut handled by the system of this example is referred to as an sRGB signal, and a signal with a wide color gamut is referred to as an xvYCC signal. As R data, G data, and B data in the sRGB signal, when the data value is 0 to 1 and indicates the value of each color, the R data, G data, and B data in the xvYCC signal are data of each color. May be a negative value less than 0 and a value greater than 1. A negative value less than 0 and a value exceeding 1 indicate a color gamut that cannot be represented by a conventional sRGB signal.

  First, the video recording / reproducing apparatus 10 will be described. The video recording / reproducing apparatus 10 includes a recording / reproducing unit 11 and can record and reproduce video data and audio data. As the recording / reproducing unit 11, for example, a hard disk drive (HDD) device can be used. When the video data reproduced by the recording / reproducing unit 11 is an analog signal, it is supplied to the analog / digital conversion circuit 12, converted into digital data, and transmitted. The audio data obtained by reproduction is supplied to the audio processing unit 14.

  The RGB data digitized for each color by the analog / digital conversion circuit 12 or the RGB data already digitized and supplied from the recording / reproducing unit 11 is supplied to the separation circuit 13. The separation circuit 13 separates, for each color, the primary color signal having a wide color gamut into video data RGBin within the color gamut of the sRGB signal and video data RGBout having a color gamut exceeding the color gamut of the sRGB signal. For example, the video data RGBin within the sRGB signal color gamut for pixels that exceed the sRGB signal color gamut is the upper or lower chromaticity value, and the video data in the color gamut that exceeds the sRGB signal color gamut. RGBout is a value indicating a difference value between the upper limit value or the lower limit value and the original value. In the case of this example, the video data RGBin within the color gamut of the sRGB signal and the video data RGBout of the color gamut exceeding the color gamut of the sRGB signal are each 8-bit data per pixel (that is, three colors combined). 24 bit data per pixel). After all, when both video data are combined, one pixel data is composed of 48 bits.

  The audio processing unit 14 performs processing for converting audio data obtained by reproduction or reception into audio data for transmission.

  The video data and audio data output from the separation circuit 13 and the audio processing unit 14 are supplied to the HDMI transmission processing unit 20. The HDMI transmission processing unit 20 is a circuit unit that performs transmission processing of the interface of the HDMI standard, and is integrated, for example. Video data and audio data supplied to the HDMI transmission processing unit 20 are multiplexed by the multiplexing circuit 21.

  Here, since the video data RGBin within the color gamut of the sRGB signal and the video data RGBout of the color gamut exceeding the color gamut of the sRGB signal are configured with 8 bits for each color of one pixel, A 16-bit period is used for transmission of one color. In-gamut video data RGBin is arranged in the first half of the 16-bit transmission period, and gamut video data RGBout is arranged in the latter half. Details of the specific data arrangement and transmission state will be described later.

  The audio data is multiplexed so as to be transmitted using the blanking period of the channel through which the video data is transmitted. The process of transmitting the audio data while being arranged in the blanking period is a general transmission process formatted according to the HDMI standard.

  Then, the transmission data multiplexed by the multiplexing circuit 21 is encrypted by the HDCP encryption unit 22. The HDCP encryption unit 22 encrypts at least a channel through which video data is transmitted according to the HDCP (High-bandwidth Digital Content Protection System) standard. The encryption here is performed in units of 8-bit data of one channel.

  The data encrypted by the HDCP encryption unit 22 is supplied to the transmission processing unit 23, the pixel data of each color is arranged in an individual channel, and the pixel clock channel and the control data channel also have their corresponding clocks and data. And sent to the HDMI cable 1 connected to the HDMI terminal 24.

The HDMI cable 1 is connected to the HDMI terminal 41 of the television receiver 30.
Next, the configuration of the television receiver 30 will be described. Data transmitted through the HDMI cable 1 connected to the HDMI terminal 41 of the television receiver 30 is detected (received) by the transmission processing unit 42 in the HDMI transmission processing unit 40 in synchronization with the pixel clock. The detected data of each channel is decrypted by the HDCP decrypting unit 42 from encryption at the time of transmission. The decoding here is also performed in units of 8 bits for each channel.

  The decoded data is supplied to the demultiplexing circuit 44 to separate the data multiplexed on each channel. In this separation process, the audio data arranged in the blanking period of the channel through which the video is transmitted is separated from the video data. When the video data is video data with a wide color gamut, video data RGBin within the color gamut of the sRGB signal and video data RGBout with a color gamut exceeding the color gamut of the sRGB signal are separated. .

  Each video data separated by the demultiplexing circuit 44 is supplied to the video adder 31. In the video addition unit 31, based on an instruction from the control unit 36 of the television receiver 30, video data RGBin within the color gamut of the sRGB signal and video data RGBout of a color gamut exceeding the color gamut of the sRGB signal are obtained. These are added to obtain one video data per pixel of each color. The added video data is supplied to the digital / analog conversion circuit 32 to be converted into individual analog video data RA, GA, BA for each color pixel.

  The converted analog video data RA, GA, BA are supplied to the display processing unit 33. The display processing unit 33 performs processing for driving the display panel 60.

  The audio data separated by the demultiplexing circuit 44 is supplied to the audio processing unit 34, performs audio processing such as analog conversion, and the processed output is supplied to the output processing unit 35 to be amplified for driving the speaker. This processing is performed and output from the speakers 51 and 52 connected to the output processing unit 35.

  The control data separated by the demultiplexing circuit 44 is supplied to the control unit 36. The control data can also be sent from the control unit 36 of the television receiver 30 to the control unit 15 on the video recording / reproducing apparatus 10 side using the control data channel.

  FIG. 2 is a diagram illustrating a data configuration example of each channel transmitted through the HDMI cable 1 between the transmission processing unit 23 of the video recording / reproducing apparatus 10 and the transmission processing unit 42 of the television receiver 30. . As shown in FIG. 2, three channels of channel 0, channel 1, and channel 2 are prepared as channels for transmitting video data, and a clock channel for transmitting a pixel clock is also prepared. In addition, a display data channel (DDC) line and a consumer electronics control (CEC) line are prepared as control data transmission channels. The DDC line is a transmission path for mainly transmitting data for controlling display, and the CEC line is a transmission path for transmitting data for device control between the connected devices.

  On the transmission side, transmission processing units (transmission units) 23a, 23b, and 23c are prepared in the transmission processing unit 23 for each channel for transmitting video data, and on the reception side, each channel for transmitting video data is provided. Transmission processing units (data receiving units) 42 a, 42 b, 42 c are prepared in the transmission processing unit 42.

  The configuration of each channel will be described. Channel 0 transmits pixel data of B data, vertical synchronization data, horizontal synchronization data, and auxiliary data. In channel 1, pixel data of G data, two types of control data (CTL0, CTL1), and auxiliary data are transmitted. In channel 2, pixel data of R data, two types of control data (CTL2, CTL3), and auxiliary data are transmitted.

  FIG. 3 is a diagram illustrating a line configuration and a pixel configuration of one frame of video data transmitted with the transmission configuration of this example. The video data (main video data) transmitted in the case of this example is non-compressed data (that is, video data in units of one pixel), and a vertical blanking period and a horizontal blanking period are added. Specifically, in the example of FIG. 3, the display video area (area shown as the active video area) is pixel data of 480 lines × 720 pixels, and the number of lines and the number of pixels including the blanking period is 525. There are as lines and 858 pixels. An area indicated by double hatching (the overlapping portion of the right oblique line and the left oblique line) during the blanking period is called a data island and is a period in which auxiliary data can be added.

  Next, a state in which video data is transmitted using channel 0, channel 1, and channel 2 in which pixel data is transmitted in the transmission configuration of this example will be described. The transmission configuration of this example is a transmission configuration compliant with the HDMI standard, and in the case of transmitting normal video data (that is, video data in which the color gamut is not expanded), as described in the background art section, FIG. Alternatively, video data is transmitted in the transmission configuration of FIG. That is, when one pixel of each color is composed of 8 bits, 8-bit data, which is 1-pixel data, is arranged and transmitted on channels 0, 1, and 2 in synchronization with the 1-pixel clock. (Transmission processing in FIG. 10). The 8-bit data here is the number of bits of data input for transmission, and is the number of bits of data extracted on the receiving side. When actually transmitting in accordance with the HDMI standard, 8-bit data is converted to 10-bit data by 8-10 conversion, transmitted to the other side by a cable, and 10-bit data is converted back to 8 bits on the receiving side. Transmission is performed by a serial transmission method called TMDS (Transition Minimized Differential Signaling) that performs eight conversions.

  When video data having a wide color gamut is transmitted from the video recording / reproducing apparatus 10 to the television receiver 30, the transmission configuration shown in FIG. In this example, the video data RGBin within the color gamut of the sRGB signal is composed of 8 bits per pixel, and the video data RGBout of the color gamut exceeding the color gamut of the sRGB signal is also composed of 8 bits per pixel. The video data has the same amount of data. As a transmission configuration, one-pixel video data RGBin and video data RGBout are transmitted in a two-clock cycle of a pixel clock transmitted through a clock channel. That is, in the first half of the two-pixel clock period (phases 0 and 2 in FIG. 4), the video data RGBin for each color of B, G, and R is used in channels 0, 1, and 2, respectively. Then transmit. In the latter half of the two-pixel clock period (periods 1 and 3 in FIG. 4), the video data RGBout of the colors B, G, and R that exceed the color gamut are respectively transmitted to channels 0, 1, 2, and 4, respectively. Use to transmit. The first half video data RGBin and the second half video data RGBout are data at the same pixel position. Also for the blanking period, data for the blanking period having the same data configuration is transmitted in the first half and the second half of the two-pixel clock period.

The transmission state in FIG. 4 will be described in more detail. The data indicated by adding [in] for each of R, G, and B is video data in the color gamut of the sRGB signal for the corresponding primary color. The data indicated by adding [out] is video data outside the color gamut of the sRGB signal for the corresponding primary color.
For example, for pixel 0 data, 8-bit in-gamut blue data B0in is transmitted in phase 0 and 8-bit out-of-gamut blue data B0out is transmitted in the next phase 1 for channel 0 B data. . For the G data of channel 1, 8-bit in-gamut green data G 0 in is transmitted in phase 0, and 8-bit out-of-gamut green data G 0 out is transmitted in the next phase 1. For the R data of channel 2, 8-bit in-gamut red data R0in is transmitted in phase 0, and 8-bit out-of-gamut red data R0out is transmitted in the next phase 1. Note that when transmitting video data with a wide color gamut in FIG. 4, the pixel clock has a frequency twice that of the case of transmitting 8-bit video data for each color for normal display shown in FIG. 10. There is a need to.

  FIG. 5 shows an example of multiplexed data, which is data called VSDB, which is data instructing the configuration of transmission data from the source side in the case of such a video data transmission configuration with a wide color gamut. This is an example of instructing the sink side. The VSDB data is data transmitted using the DDC line (FIG. 2). In the case of the VSDB in this example, the 6th byte data indicates how many bits each pixel is. In the case of this example, it is indicated that the data is 8 bits for each pixel of one color and a total of 24 bits. Then, whether or not video data with a wide color gamut is transmitted (that is, whether or not xvYCC signal is transmitted) is indicated using a predetermined bit position.

  The control unit 36 (FIG. 1) of the sink-side device (television receiver 30) judges the data of the VSDB and transmits the video data with a wide color gamut shown in FIG. Alternatively, it is determined whether or not the normal video data transmission shown in FIG. Whether the 1 pixel in the example of FIG. 10 is 8 bits or 1 bit in the example of FIG. 11 is 167 bits is also determined by how many bits of data the 1 pixel of the 6th byte in FIG.

  Based on this determination, the control unit 36 of the television receiver 30 separates in-band video data and out-of-band video data from the received video data, and performs display processing that expands the color gamut using each video data. Is executed.

  When the television receiver 30 has a conventional color gamut display capability that cannot display an enlarged color gamut, the demultiplexing circuit 44 shown in FIG. 1 performs in-band video data and out-of-band video data. If only the video data RGBin within the color gamut of the sRGB signal is supplied to the subsequent circuit, the same processing as in the prior art can be performed. In the case of this conventional configuration, the video adder 31 is unnecessary.

Here, a color range that can be expressed by a television receiver, a monitor for a computer device, or the like will be described with reference to FIGS.
FIG. 6 is a u ′, v ′ chromaticity diagram obtained by projecting a solid (color space) in a display device that can receive and display RGB data as primary color signals. The horizontal axis is u ′ and the vertical axis is v ′. In FIG. 6 shown as the u ′, v ′ chromaticity diagram, the range of colors existing in the natural world is shown by the outer fan shape. In FIG. 6, for example, a triangular range surrounded by three points Rs, Gs, and Bs is a color gamut that can be expressed by normal RGB data. The color inside the triangle can be uniquely determined by giving each primary color RGB value in the range of 0 to 1 in the case of analog values. A color gamut that can be displayed is determined depending on where the three primary colors RGB are used. One of the standards is the sRGB standard. In the case of an analog signal, a value expressed in the range from 0 to 1 is indicated by a value quantized with, for example, 8 bits in the case of digital.

  Conventionally, from the characteristics of the phosphor of the cathode ray tube (CRT) used as the display means, the sRGB standard apex (three chromaticity points) Rs, Gs, Bs as shown in FIG. The three primary color points that can be expressed are the same. However, various types of FPDs other than CRT and projector type monitors have recently increased, and the color gamut that can be reproduced by the monitor has spread outside the color gamut defined by the sRGB standard, making it possible to reproduce a wider color gamut. . An example of a color gamut indicated by a broken line in FIG. 6 surrounded by the vertices Rf, Gf, and Bf shows a color gamut that can be displayed when video data is configured as an xvYCC signal. Each point shown in FIG. 6 indicates the chromaticity that actually exists. As can be seen from FIG. 6, there are cases where the image has a color that exceeds the color gamut that can be expressed by the sRGB signal and that can be expressed by the color gamut of the xvYCC signal.

  FIG. 7 is a diagram illustrating the relationship between the color gamuts of the xvYCC signal and the sRGB signal. The vertical axis represents the luminance signal Y, and the horizontal axis represents the color difference signals Cb and Cr. As shown in FIG. 7, the xvYCC signal standard uses the same primary color point as that of the sRGB signal, is expressed by one luminance signal Y and two color difference signals Cb and Cr, and includes the color gamut of the sRGB signal. It has become. The conversion determinants to R data, G data, and B data when the xvYCC signal is expressed by Y data, Cb data, and Cr data are as described in the background art section. As shown in FIG. 7, the area as the sRGB signal is indicated by a rhombus area, and the extended area as the xvYCC signal is set around the rhombus sRGB signal.

  FIG. 8 shows the color gamut of the sRGB signal and the color gamut of the xvYCC signal on the color space shown three-dimensionally. The square cube indicating the color gamut of the sRGB signal is expressed smaller than the square cube indicating the color gamut of the xvYCC signal. Each point in FIG. 8 indicates the chromaticity that actually exists when the video data is configured as an xvYCC signal. Here, the points located outside the rectangular cube indicating the color gamut of the sRGB signal are data expressed as data outside the sRGB signal in this example.

  Therefore, when the data transmitted by the source device is an xvYCC signal, the separation circuit 13 shown in FIG. 1 can easily separate the xvYCC signal into pixel data within the color gamut and pixel data outside the color gamut. It can be easily handled as the data structure shown in FIG. On the sink device side, by simply adding pixel data in the color gamut and pixel data outside the color gamut, a signal in the color gamut of the original xvYCC signal can be obtained, and a signal with a wide color gamut can be easily received.

  In addition, in the case of transmission as shown in FIG. 4, the video data RGBin within the sRGB signal color gamut for the pixels that exceed the sRGB signal color gamut is the upper limit value or lower limit value of the chromaticity. When display processing is performed using only the video data RGBin within the color gamut of the sRGB signal, complete display is possible as display in the color gamut of the conventional sRGB signal. In the case of such a display device capable of displaying in the color gamut of the sRGB signal, it is only necessary to separate the video data RGBin in the color gamut of the sRGB signal from the received data, which can be dealt with easily.

  In this way, by performing the transmission processing of this example, the video data transmission of the wide color gamut and the video data transmission for normal display can be performed only by connecting the source device and the sink device with the HDMI cable 1. It is possible to transmit video data corresponding to both with a simple connection configuration in which only one set of cables is used for connection. Moreover, the normal display video data transmission shown in FIGS. 10 and 11 and the wide color gamut video data transmission shown in FIG. 4 have the same basic transmission configuration and conform to the HDMI standard. In the above, video data transmission in a wide color gamut becomes possible.

  In the description of FIG. 4 described above, an example in which data of 8 bits for each color of one pixel is transmitted. However, other data such as color data in the color gamut of 16 bits for each color of one pixel and data outside the color gamut are used. It is possible to cope with the case of transmitting video data composed of bits. In this case, the period of the pixel clock necessary for transmission of one pixel is increased correspondingly, and the clock frequency is increased correspondingly.

  In the above-described embodiment, the description has been made on the premise of the interface of the HDMI standard, but the present invention can be applied to other similar transmission standards. The source device and the sink device connected by the HDMI standard cable may be connected by a video device other than the recording / reproducing apparatus and the television receiver shown in FIG.

It is a block diagram which shows the system configuration example by one embodiment of this invention. It is explanatory drawing which shows the example of a transmission channel structure by one embodiment of this invention. It is explanatory drawing which shows the bit structural example by one embodiment of this invention. It is explanatory drawing which shows the example of data packing by one embodiment of this invention. It is explanatory drawing which shows the data structural example of VSDB by one embodiment of this invention. It is explanatory drawing which shows the example of a relationship between the displayable area | region of the display by one Embodiment of this invention, and the color gamut expressed by sRGB signal. It is explanatory drawing which shows the relationship of the color gamut of a sRGB signal and a xvYCC signal. It is explanatory drawing which showed the color gamut of sRGB signal and xvYCC signal in the color space. It is explanatory drawing which showed the example of transmission by HDMI specification. It is explanatory drawing which shows the data packing example (example of 1 pixel 8 bits) of HDMI specification. It is explanatory drawing which shows the data packing example (example of 1 pixel 16 bits) of HDMI specification.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... HDMI cable, 10 ... Video recording / reproducing apparatus (source side apparatus), 11 ... Recording / reproducing part, 12 ... Analog-digital conversion circuit, 13 ... Separation part, 14 ... Audio processing part, 15 ... Control part, 16 ... Tuner 20 ... HDMI transmission processing unit, 21 ... multiplexing circuit, 22 ... HDMIP encryption unit, 23 ... transmission processing unit, 24 ... HDMI terminal, 30 ... TV receiver (sink side device), 31 ... video selection unit, 32 ... Digital / analog conversion circuit, 33 ... Display processing unit, 34 ... Audio processing unit, 35 ... Output processing unit, 36 ... Control unit, 37 ... Video processing unit, 38 ... Display processing unit, 40 ... HDMI transmission processing unit, 41 ... HDMI terminal, 42 ... transmission processing unit, 43 ... HDCP decoding unit, 44 ... demultiplexing circuit, 60 ... display panel

Claims (8)

Video data is transmitted using a transmission method in which video data of a predetermined bit unit is transmitted from the source side device to the sink side device using an individual transmission line for each color data in synchronization with the pixel clock. A transmission method,
As video data for each color data transmitted from the source side device to the sink side device, video data of color data within a specified color band and video data of color data outside the specified band,
The video data of the color data within the specified color band and the video data of the color data outside the specified band are each configured with the predetermined number of bits for each pixel and synchronized with the pixel clock. Transmit at the timing,
A transmission method, comprising: transmitting video data exceeding a specified color band from the source device to the sink device. A transmission system for transmitting video data in a predetermined bit unit from a source device to a sink device using a separate transmission line for each color data in synchronization with a pixel clock,
As the source side device,
A separation unit that separates color data constituting the video data into color data within a prescribed color band and color data outside the prescribed band;
The color data within the specified color band separated by the separation unit and the color data outside the specified band are configured as data of a predetermined number of bits for each pixel, and the respective color data are synthesized. A synthesis unit;
A sending unit for sending the video data synthesized by the synthesizing unit to the transmission line in synchronization with the pixel clock;
As the sink side device,
A receiving unit for detecting data received from the transmission line in synchronization with the pixel clock;
A separation unit that separates the video data received by the reception unit into color data within the defined color band and color data outside the defined band in synchronization with the pixel clock;
A transmission system comprising: a display processing unit that performs display processing using at least color data in a color band among the prescribed color data separated by the separation unit. The transmission system according to claim 2, wherein
The display processing unit of the sink side device combines the color data within the specified color band separated by the separation unit and the color data outside the specified band, and is defined for each pixel. A transmission system that performs display processing based on color data in a band that exceeds the color band. The transmission system according to claim 2, wherein
When the display processing unit of the sink side device is a display processing unit that does not process color data outside the specified band, the color outside the specified band that is separated by the separation unit A transmission system characterized in that data is displayed and ignored. A transmission device that transmits video data in units of a predetermined bit using a separate transmission line for each color data in synchronization with a pixel clock,
A separation unit that separates color data constituting the video data into color data within a prescribed color band and color data outside the prescribed band;
The color data within the specified color band separated by the separation unit and the color data outside the specified band are configured as data of a predetermined number of bits for each pixel, and the respective color data are synthesized. A synthesis unit;
A transmission apparatus, comprising: a transmission unit configured to transmit the video data synthesized by the synthesis unit to the transmission line in synchronization with the pixel clock. A receiving device that receives video data in units of a predetermined bit in synchronization with a pixel clock and uses a separate transmission line for each color data, and displays the received video data,
A receiving unit for detecting data received from the transmission line in synchronization with the pixel clock;
A separation unit that separates the video data received by the reception unit into color data within the defined color band and color data outside the defined band in synchronization with the pixel clock;
A receiving apparatus comprising: a display processing unit that performs display processing using at least color data within a color band among the prescribed color data separated by the separation unit. The receiving apparatus according to claim 6, wherein
The display processing unit synthesizes the color data within the defined color band separated by the separation unit and the color data outside the defined band and exceeds the color band defined for each pixel. A receiving device that performs display processing based on band color data as band color data. The receiving apparatus according to claim 6, wherein
When the display processing unit is a display processing unit that does not process the color data outside the specified band, the color data outside the specified band that is separated by the separation unit, A receiving device that performs display processing while ignoring.