Patent Description:
HDMI (High Definition Multimedia Interface) is used to send uncompressed audio and video signals, which benefits from transmitting audio and video simultaneously by using only one piece of new material, greatly simplifying the installation of audio and video systems. With the development of society, HDMI has become the most widely used multimedia digital interface with the highest market share.

The HDMI device includes an input source device and a display device-sink device. After the input source device and the display device are connected by the HDMI cable, before outputting images normally, there are following steps.

Step <NUM>, EDID (Extended Display Identification Data) reading and parsing; and the so-called EDID is all information written into the display by a display manufacturer according to the standard for display identification data (i.e. HDMI standard timing) established by the VESA (Video Electronics Standards Association), including the information about the supplier of the display, the maximum image size, colour, resolution, refresh rate, etc..

Step <NUM>, Audio and video transmission, namely, the input source device reads and parses the EDID of the display device via Step <NUM>, extracts audio and video information required to be output therefrom, and then outputs suitable audio and video to the display device.

With the development of HDMI, a series of HDMI-based intermediate devices, such as HDMI switches, HDMI distributors, HDMI matrices, HDMI extenders, etc. are derived according to various functional requirements in addition to the input source devices and the display devices. Various types of HDMI-based intermediate devices, such as those described above, require reading and analyzing the EDID of the display device and forwarding it to the input source device.

In the prior art, various types of HDMI intermediate devices mainly have the following processing methods for the EDID of the display device.

This approach has the following drawbacks.

The HDMI intermediate device directly replaces a default EDID and forwards the same to the input source device. If there is a big difference between the default EDID and the EDID of the display device, the display device will be unable to receive and parse the audio and video information input from the input source device.

<CIT>discloses a data processing method comprising obtaining extended display recognition data EDID of a receiving end display, and enabling the EDID to comprise a display resolution time sequence parameter; deleting or modifying the display control LCDC time sequence of the high pixel clock in the EDID, so that the deleted or modified EDID does not generate the high pixel clock; and writing the deleted or modified EDID into an collection end and transmitting the deleted or modified EDID to a video source, so that the video source outputs an image signal according to the deleted or modified EDID after identifying a hot plug event.

It can be seen therefrom that the existing HDMI intermediate device is difficult to be compatible with various types of HDMI devices, with poor compatibility.

With regard to the defects existing in the prior art, the technical problem to be solved by the present invention is how to be compatible with different models of HDMI devices.

To achieve the above object, the present invention provides a compatibility promotion method executable by a processor of a HDMI intermediate device for high definition multimedia interface, HDMI, the HDMI intermediate device having a first HDMI interface for connecting to an input source device and a plurality of second HDMI interfaces for connecting to a plurality of display devices, comprising the steps of:.

On the basis of the above-mentioned technical solution, the specific procedure of S3 comprises acquiring all non-standard Detailed Timing Descriptors, DTDs, recorded with non-standard parameters in the EDID to be analysed; determining a standard DTD corresponding to the non-standard DTD in the HDMI standard timing according to Hactive and Vactive described in the information about the non-standard DTD; and modifying the non-standard DTD according to the standard DTD.

On the basis of the above-mentioned technical solution, determining the situation <NUM> includes determining whether the timing of each EDID to be analysed is a standard timing; if so, it does not meet the situation <NUM>; if not, it meets the situation <NUM>; and determining the situation <NUM> includes acquiring the bandwidth supported by the resolution of the display device corresponding to the EDID to be analysed, and determining whether the bandwidth is greater than the maximum bandwidth of the HDMI intermediate device; if so, it meets the situation <NUM>; otherwise, it does not meet the situation <NUM>.

On the basis of the above-mentioned technical solution, the specific procedure of S1 comprises detecting by each of the plurality of display devices a 5V pin level change on a corresponding HDMI link when the display devices, the HDMI intermediate device and the input source device are connected; after raising a HPD pin level and feeding back the HPD signal to the HDMI intermediate device by each of the plurality of display devices, reading by the HDMI intermediate device the plurality of EDIDs of the plurality of display devices via a Display Data Channel (DDC) pin of the respective HDMI links; and the specific procedure of S5 comprises saving the modified EDID separately to a fixed position, lowering down the Hot Plug Detect (HPD) pin level of the HDMI link for the input source device, and actively raising the HPD pin level of the HDMI link for the input source device after a pre-set waiting duration.

The present invention provides a storage medium having stored thereon a computer program, wherein the computer program, when executed by a processor of a HDMI intermediate device connectable between a plurality of display devices and an input source device, implements the above method.

The present invention provides a HDMI intermediate device comprising a memory and a processor, with the memory having stored thereon a computer program for running on the processor, wherein the processor, when executing the said computer program, implements the method described above.

The present invention provides a system for enhancing HDMI compatibility comprising a plurality of display devices, a HDMI intermediate device and an input source device, wherein the plurality of display devices are configured for transmitting a plurality of EDIDs to the HDMI intermediate device; the input source device is configured for receiving the EDID transmitted by the HDMI intermediate device; wherein the HDMI intermediate device is the HDMI intermediate device described above.

The advantages of the present invention over the prior art include the followings.

Meanwhile, it can be seen from reference to S01-S04 that the present invention can enable personalized images set by some users to be displayed normally while being compatible with different display devices, thereby further improving the user experience.

<FIG> is a flowchart of a compatibility promotion method for HDMI in an embodiment of the present invention.

Hereinafter, the present invention will be described in further detail with reference to the accompanying drawings and embodiments.

Referring to <FIG>, a compatibility promotion method for HDMI in an embodiment of the present invention comprises the following steps:.

A situation <NUM> is defined as the bandwidth of the resolution supported by the display device is greater than a maximum bandwidth of an HDMI intermediate device; the determination criteria for the situation <NUM> includes acquiring a bandwidth supported by a resolution (acquired via information such as a horizontal pixel, a vertical pixel and a pixel clock described in the EDID) of a display device corresponding to each EDID to be analysed, and determining whether the bandwidth is greater than the maximum bandwidth of the HDMI intermediate device (the maximum bandwidth of the HDMI intermediate device is known); if so, it meets the situation <NUM>; otherwise, it does not meet the situation <NUM>.

A situation <NUM> is defined as a situation where both the situation <NUM> and the situation <NUM> are met.

As shown in the solid line part of <FIG>, the HDMI intermediate device determines the specific situations of each EDID to be analysed; if the EDID to be analysed meets the situation <NUM>, proceed to S3; if the EDID to be analysed meets the situation <NUM>, proceed to S4; and if the EDID to be analysed meets the situation <NUM>, S3 and S4 are respectively executed, namely, the execution order of S3 and S4 can be adjusted. Preferably, in order to facilitate execution, the present embodiment responds to the situation <NUM> by executing S3 first and then S4 (it is convenient to adjust the timing first and then change the EDID information). If the situations <NUM> and <NUM> are not met at the same time, it indicates that the display device and the intermediate device can be normally compatible and need not be processed in the manner of the present invention. At this time, it can proceed directly to S5 (not shown in the drawings).

S3: referring to the solid line part of <FIG>, after the HDMI intermediate device modifies the timing of the EDID to be analysed into the HDMI standard timing, the HDMI intermediate device forwards the same to the input source device for solving the compatibility problem described above.

The specific procedure of S3 include acquiring all the non-standard DTDs recorded with non-standard parameters in the EDID to be analysed; determining a standard DTD corresponding to the non-standard DTD in the HDMI standard timing according to information such as Hactive (active horizontal lines) and Vactive (active vertical lines) and so on described in the information about the non-standard DTD (the determination method can search for backward compatibility); and modifying the non-standard DTD according to the standard DTD, i.e. modifying the non-standard parameters in the non-standard DTD to be the standard parameters in the standard DTD.

S4: the reason why the bandwidth of the resolution supported by the display device according to the applicant's research is greater than the maximum bandwidth of the HDMI intermediate device will be explained first here. Specifically, the maximum bandwidth supported by various types of HDMIs is different. For example, various HDMI display devices supporting a resolution of 4K60Hz follow the HDMI <NUM> protocol, with its maximum theoretical bandwidth of 18Gbps; and various HDMI display devices supporting <NUM> <NUM> resolution follow the HDMI <NUM> protocol, with its maximum theoretical bandwidth of <NUM>. It can be seen that when a display device transmits a <NUM> * <NUM>@<NUM> (4K60Hz) 8bit RGB picture, the bandwidth occupied by the display device is twice as high as the bandwidth occupied by the <NUM> * <NUM>@<NUM> (4K30Hz) 8bit RGB picture (HDMI factors affecting the bandwidth include: horizontal pixel -<NUM>; vertical pixel -<NUM>; refresh rate -<NUM>; colour depth -<NUM> bit; and colour format-RGB).

For this reason, we need to adapt the high-bandwidth display device required by high resolution to the HDMI intermediate device with insufficient maximum bandwidth by modifying the EDID, as shown in the solid line part of <FIG>; the main procedure includes that the HDMI intermediate device acquires a specified colour depth sampling format supported by all the display devices (for example, <NUM> bits, <NUM> bits or <NUM> bits; in order to improve picture display quality, the specified colour depth sampling format is preferably the highest colour depth sampling format supported by all the display devices); after all the actual colour depth sampling formats of the EDID to be analysed are modified to the specified colour depth sampling format, the colour format with a resolution in all the EDID to be analysed which is greater than the maximum bandwidth of the HDMI intermediate device is modified to be YCbCr <NUM>:<NUM>:<NUM>.

In S4: the specific procedure of modifying the colour format of the resolution in all the EDID to be analysed which is greater than the maximum bandwidth of HDMI intermediate device into YCbCr <NUM>:<NUM>:<NUM> includes:.

S401: respectively determining by the HDMI intermediate device whether the display device corresponding to each EDID to be analysed supports the colour format YCbCr <NUM>:<NUM>:<NUM>; if so, proceed to S401a; if not, proceed to S401b.

It is added that if each bandwidth to be compared is greater than the comparison bandwidth, the display device does not support the colour format YCbCr <NUM>:<NUM>:<NUM>. Therefore, this will not occur in the procedure of S401a supporting the colour format YCbCr <NUM>:<NUM>:<NUM>.

The order of execution of (<NUM>) and (<NUM>) in S401a may be parallel or sequential; and after both (<NUM>) and (<NUM>) are completed, proceed to S5.

S401b: acquiring a specified resolution that can be supported by the maximum bandwidth of the HDMI intermediate device and all the display devices, and deleting all the resolution information other than the specified resolution in each EDID to be analysed (such as VIC information and DTD, namely, only the specified resolution is reserved), proceeding to S5; wherein the logic of S401b is that if it is not supported, only the resolution information which cannot be transmitted normally can be deleted, so that the subsequent input source device can output a picture with a low definition but normally displayed by all display devices; and the resolution is specified as the highest resolution supported by all display devices in order to improve the picture display quality.

With reference to S401a, it can be seen that the present invention can transmit a picture with a high definition even when the display device supports YCbCr <NUM>:<NUM>:<NUM>, and can normally transmit a picture with a relatively low definition even when the display device does not support YCbCr <NUM>:<NUM>:<NUM>. Therefore, the present invention can transmit a picture with an optimal resolution according to the specific situation of the display device, while ensuring that the intermediate device can be compatible with the display device, thereby improving the user experience.

In practical application, since a display device supporting a resolution of 4K50Hz or 4K59Hz has a same processing mode as a display device supporting 4K60Hz, S4 is exemplified below in the situation that the display device supports a resolution of 4K60Hz and the intermediate device supports only 4K30Hz.

In this situation, the specific procedure of S4 includes:.

Insofar as the above-mentioned procedures of S3 and S4 have been stated, it can be concluded that since both S3 and S4 may modify the EDID to be analysed to different degrees, in order to ensure the correctness of the modified EDID, the procedure needs to be verified after S3 and/or S4. Specifically, after completion of S3 and/or S4, according to the HDMI standard definition, the relevant position and length description information of the DTD is re-described according to the modification in the EDID to be analysed; and a check value of the corresponding Block after modification is calculated and written into the last bit of the corresponding Block.

The corresponding Block is understood as that if only S3 or S4 is performed, there is only one Block corresponding to S3 or S4; if S3 and S4 are performed, there are two Blocks respectively corresponding to S3 and S4; the verification procedure can be executed after S3 or S4 and before S5 (namely, performing a verification every modification); and it can also be performed after S3 and S4 and before S5 (namely, performing a verification after all the information has been modified).

S5: referring to the solid line part of <FIG>, the HDMI intermediate device transmits the modified EDID to the input source device; and at this moment, the input source device can output a picture which is compatible with both the HDMI intermediate device and the display device and has the lowest influence on the display effect according to the content described by the processed EDID. In actual use, S5 is performed after completion of S3 and/or S4.

The specific procedure of S5 includes saving the modified EDID separately to a fixed position by the HDMI intermediate device, and actively lowering down the HPD pin level of the HDMI link at the input end for a period of time (adjusting specifically according to different situations, usually <NUM>-<NUM>); wherein, at this moment, the input source device will determine that the HDMI intermediate device is disconnected from the port thereof; after <NUM>-<NUM>, the HDMI intermediate device actively raises the HPD pin level of the input end link; and at this time, the input source device will determine that the HDMI intermediate device is connected again.

Preferably, the above method may further include the following steps.

Before S1, creating an available timing database; and after associating the EDID timing required to be transmitted to the input source device in S5 with the corresponding length-width ratio and resolution (namely, corresponding to the length-width ratio and resolution of the display), saving the same to the available timing database. The creator of the timing database can be a main control single-chip microcomputer chip of the HDMI intermediate device, and can also be an independent storage chip mounted inside the HDMI intermediate device, which is specifically determined according to the situation of the HDMI device.

On this basis, before the HDMI intermediate device determines the specific situation of each EDID to be analysed in S2, it further includes the step of comparing each EDID to be analysed with the EDID timing in the available timing database by the HDMI intermediate device:.

It can be seen therefrom that the present invention stores the timing of the EDID of the modified normal display image which is associated with the corresponding length-width ratio and resolution, omitting the process of repeatedly modifying the same EDID timing, thereby improving the working efficiency and enhancing the user experience.

Preferably, the present application also obtains the following information at the time of technical development and test.

When the user needs to display the personalized graphic, the EDID timing of the display device is changed, so that the EDID timing that can normally display the graphic, but different from the standard timing of the EDID, occurs.

Therefore, in order to enable compatibility with different display devices while enabling a part of the personalized images set by the user to be displayed normally so as to improve the user experience, with reference to the dotted line part in <FIG>, the above-mentioned method may further include the following steps performed before S1:.

In S03, a implementation method for determining the display condition of the display device according to the feedback information from the user can be a hardware implementation. For example, a hardware key is provided outside the HDMI intermediate device; and the user clicks once within a specified time to display a normal state and twice to display an abnormal state. It also can be a software implementation. For example, a channel is established between an HDMI intermediate device and a user's PC end or a handheld terminal (a remote controller, a mobile phone, a tablet computer, etc.); and it appoints signals corresponding to normal and abnormal display.

S04: the HDMI intermediate device updates an available timing database according to the timing of the current EDID (namely, displaying a normal EDID in S03); namely, the HDMI intermediate device judges whether the timing of the current EDID already exists in the available timing database; if so, the procedure of the present invention ends; otherwise, the current timing is added to the available timing database.

The purpose of S04 lies in that if a new display device is subsequently accessed, and the user modifies the mode to the default mode, the subsequent modification process is not used when the EDID timing of the new display device is not the standard timing but exists in the available timing database, so as to improve the working efficiency and further optimize the user experience.

Embodiments of the present invention also provide a storage medium (e.g., a USB disk, an optical disk, etc.) having stored thereon a computer program which when executed by a processor implements the above-described compatibility promotion method for HDMI.

An embodiment of the present invention also provides an electronic device (namely, an HDMI intermediate device), including a memory and a processor, with the memory having stored thereon a computer program for running on the processor, wherein the compatibility promotion method for HDMI described above is implemented when the computer program is executed by the processor.

An embodiment of the present invention also provides a system (a computer in the present embodiment) for enhancing HDMI compatibility, including a display device (a display in the present embodiment), an HDMI intermediate device (an HDMI switch in the present embodiment) and an input source device (a server in the present embodiment), wherein the display device is connected to the input source device via the HDMI intermediate device. The display device is used for transmitting the EDID to the HDMI intermediate device; the input source device is used for receiving the EDID transmitted by the HDMI intermediate device; and the HDMI intermediate device is used for performing the above-mentioned compatibility promotion method for HDMI.

Claim 1:
A compatibility promotion method executable by a processor of a HDMI intermediate device for high definition multimedia interface, HDMI, the HDMI intermediate device having a first HDMI interface for connecting to an input source device and a plurality of second HDMI interfaces for connecting to a plurality of display devices, wherein the method comprises the steps of:
S <NUM>: reading the extended display identification data, EDID, from all of the display devices connected to the HDMI intermediate device, taking the EDID of each display device as an EDID to be analysed, and processing steps S2 to S4 in the order of either S2, S3, S4 or S2, S4, S3 for each EDID to be analysed, thereafter executing step S5;
S2: defining a situation <NUM> as the EDID to be analysed comprising a non-standard timing; defining a situation <NUM> as the bandwidth of the resolution supported by the display device corresponding to the EDID to be analysed being greater than a maximum bandwidth of the HDMI intermediate device; and determining the specific situation of the EDID to be analysed;
S3: if the EDID to be analysed meets the situation <NUM>, modifying the timing of the EDID to be analysed into an HDMI standard timing;
S4: if the EDID to be analysed meets the situation <NUM>, acquiring a specified colour depth sampling format supported by all the display devices; and after modifying an actual colour depth sampling format of the EDID to be analysed into the specified colour depth sampling format modifying the colour format with a resolution greater than the maximum bandwidth of the HDMI intermediate device into YCbCr <NUM>:<NUM>:<NUM>;
S5: transmitting an EDID having been processed according to steps S3 and S4 to the input source device.