Display adaptation method and display adaptation device without frame buffer

Abstract

The present invention discloses a display adaptation method and a display adaptation device without frame buffering, and the hardware involved includes: a host device, a display adaptation device and a display; the scheme can complete the display adaptation operation when the display adaptation device does not perform frame buffering processing; the beneficial technical effect of the present invention is: a display adaptation method and a display adaptation device without frame buffering are proposed, and the display adaptation device obtained by the scheme has the advantages of low cost, low power consumption and small size.

Description

Technical Field

[0001] The present invention relates to a display adaptation technology, and in particular to a display adaptation method and a display adaptation device without frame buffering. Background Art

[0002] The existing display adapter is usually composed of a host interface, a display engine, a frame buffer module, a rasterization processing module and a display interface. The host interface is used to connect to the host, and the display interface is used to connect to the display. When implementing display adaptation in the prior art, the display driver in the host usually compresses the image signal first (for example, using the H.263 / H.264 encoding format to compress the data), and then transmits the compressed image signal to the display engine through the host interface. The display engine decompresses the image signal and stores it in the frame buffer module for frame buffer processing. The image signal after the frame buffer processing is converted into an image signal that can be used by the display after passing through the rasterization processing module, and finally transmitted to the display by the display interface. However:

[0003] In the display adapter, the cost of implementing the frame buffer module is positively correlated with the capacity of the frame buffer. At the same time, the size of the buffer capacity determines the image quality (resolution, color depth, frame rate, etc.). In order to obtain higher image quality, the frame buffer module is required to have a larger capacity. The increase in buffer capacity will not only lead to an increase in manufacturing costs, but also an increase in the space occupied by the corresponding hardware. Moreover, a larger capacity frame buffer module will also lead to increased power consumption, and the display engine will also consume more power. In addition, from the perspective of the complete display adaptation process, the prior art performs two frame buffer processing. The first frame buffer processing is performed by the display driver, and its purpose is to achieve image data alignment and image data compression (compressing continuous video image data into a data stream with a low data bit rate). The display adapter performs the second frame buffer processing, and its purpose is to restore the video data before compression in the existing display adapter (adapting to the compression processing of the display driver) and cooperate with the rasterization signal alignment. The two frame buffer processing not only increases the complexity of the processing process, but also occupies a large amount of resources. Summary of the invention

[0004] In view of the problems in the background technology, the present invention proposes a display adaptation method, the hardware involved includes: a host device, a display adaptation device and a display; the innovation lies in: the host device has a built-in display adaptation device driver; the display adaptation device driver uses part of the memory of the host device as a display memory; when the host device outputs an image signal to the display adaptation device, the display adaptation device driver first controls the display memory to perform frame buffer processing on the image signal, and then transmits the image signal after the frame buffer processing to the display adaptation device through the data interface of the host device;

[0005] The display adapter device comprises a host interface, a buffer, a rasterization processing module and a display interface; the host interface of the display adapter device is connected to the data interface of the host device, and the display interface of the display adapter device is connected to the signal interface of the display; the host interface of the display adapter device transmits the image signal output by the host device to the buffer for buffering; the buffer transmits the buffered image signal to the rasterization processing module, and the rasterization processing module converts the image signal into a signal format supported by the display, and then transmits the image signal to the signal interface of the display through the display interface of the display adapter device; the capacity of the buffer is less than the image signal data amount required for one frame of image;

[0006] The display can display corresponding images according to the image signal output by the display adaptation device.

[0007] The principle of the present invention is that when the existing display adaptation method appeared, the communication bandwidth between devices was low due to the technical conditions at that time. In order to adapt to the low-bandwidth transmission, the image signal with a high data rate can only be compressed into an image signal with a low data rate before being transmitted. After the image signal with a low data rate is transmitted to the display adapter, the display adapter performs decompression processing to restore the image signal with a low data rate to an image signal with a high data rate. This is the fundamental reason why the existing display adaptation method needs to perform a large amount of frame buffer processing in the display adapter; and with the advancement of communication technology, the data transmission rate between devices has reached the Gbps level. Even if the image signal with a high data rate is not compressed, the transmission link can usually guarantee the bandwidth requirement of signal transmission. Therefore, the present invention proposes to cancel the video data compression processing process based on the video frame. In this way, it is not necessary to set a frame buffer module and a corresponding decompression circuit in the display adaptation device, which significantly reduces the manufacturing cost and power consumption of the display adaptation device. Moreover, the processing complexity of the entire display adaptation process is also simplified; because the frame buffer module and the display engine are omitted, the size of the display adaptation device can be significantly reduced, thereby obtaining a display adaptation device without a local frame buffer with low manufacturing cost and low power consumption.

[0008] The core innovation of the present invention is that the frame buffer in the display adapter device is eliminated and replaced by an extremely small (less than one frame) buffer, and the display engine used for frame decompression is eliminated, so that the physical size of the display adapter device is significantly reduced, and the power consumption and manufacturing cost are significantly reduced; in addition, it should be noted that there is an essential difference between the buffer in the display adapter device and the original frame buffer module. The purpose of setting the buffer is to compensate for the transmission rate fluctuation between the data interface and the host interface, and to ensure the processing timing requirements of the rasterization processing module; in addition, similar to the prior art, the display adapter device driver can detect the status of the display, and control the display adapter device to output an image signal adapted to the display according to the performance and / or status of the host device and / or the status and / or performance of the display and / or the needs of the user.

[0009] The host interface of the display adapter device and the data interface of the host device are connected via USB.

[0010] Based on the prior art, it is known that the rasterization processing module in the display adapter needs to output the corresponding isochronous signal according to the display requirements, but the host device output image signal and the working timing of the rasterization processing module are asynchronous, so the buffer is required to perform timing conversion between the host device output signal and the working timing of the rasterization processing module. In order to ensure the stability of the display adaptation process, the following preferred solution is adopted: the display adapter driver can dynamically adjust the data throughput transmitted from the host device to the display adapter according to the capacity utilization of the display adapter buffer. When the buffer capacity utilization is too high, the display adapter driver controls the host device to temporarily slow down or even stop transmitting the image signal to the display adapter, waits for the buffer capacity utilization to drop to a certain level, and then controls the host device to continue transmitting the image signal to the display adapter; when the buffer capacity utilization drops too fast or drops to a certain level, the display adapter driver controls the host device to resume outputting the image signal to the display adapter or increase the transmission rate. In this way, the buffer capacity utilization is maintained at an appropriate level, and the raster processing module can always read the image signal data from the buffer while ensuring the timing requirements, thereby realizing the conversion of different timings of the host device signal transmission and the rasterization processing module, and ensuring the smooth progress of the display adaptation process.

[0011] Considering certain situations: the transmission bandwidth between the host device data interface and the display adapter device data interface is difficult to meet the display signal transmission requirements, the present invention also proposes the following preferred implementation: the display adaptation method can use image signal processing technology that is unrelated to the local frame buffer processing of the display adapter device to process the image signal to adjust the bandwidth and performance requirements between the display adapter device host interface and the host device data interface. In specific implementation, the following two implementation methods can be adopted: Method 1, the output end of the display adapter device host interface is connected to the buffer through the processing circuit, and Method 2, the output end of the buffer is connected to the rasterization processing module through the processing circuit;

[0012] When the host device outputs an image signal to the display adapter device, the display adapter device driver first processes the image signal and then transmits the processed image signal to the display adapter device;

[0013] When the processing circuit is set in the first mode, the host interface of the display adapter transmits the image signal output by the host device to the processing circuit, and then the processing circuit transmits the processed image signal to the buffer; when the processing circuit is set in the second mode, the data output by the buffer is transmitted to the processing circuit, and then the processing circuit transmits the processed image signal to the rasterization processing module. When the display adapter driver processes the image signal, the following preferred modes can be adopted:

[0014] In some scenarios, the demand for communication bandwidth and / or the performance requirement for the host device can be reduced by reducing the display image resolution. For example, when the image resolution is 1920x1080, the color depth is 24bit, and the frame rate is 60 frames / second, the bandwidth requirement of the display signal communication path is approximately 1920x1080x24x60≈3Gbps. However, sometimes the display may not support such a high resolution, or the host device performance may not be sufficient to support this resolution, or the communication bandwidth rate between the display adapter host interface and the host device data interface is not so fast. In this case, the display image resolution can be reduced to reduce the bandwidth and performance requirements without significantly reducing the user experience. For example, the resolution can be reduced to 1366x768, and the bandwidth requirement can be reduced to about 1.5Gbps.

[0015] In some scenarios, the performance requirements for the host device and / or the communication bandwidth requirements can be reduced by lowering the display video frame rate. For example, when the image resolution is 1366x768, the color depth is 24bit, and the frame rate is 60 frames / second, the bandwidth requirement of the display signal communication path is about 1.5Gbps, but if the frame rate is reduced to 50 frames / second, the bandwidth requirement is only 1.3Gbps, and if the frame rate is reduced to 30 frames / second, only 0.8Gbps is required.

[0016] In some scenarios, the requirements on host device performance and / or communication bandwidth can be reduced by reducing the color depth. For example, if 24-bit true color is reduced to 16-bit color, the bandwidth requirement will be reduced by half.

[0017] In some scenarios, the demand for communication performance can be reduced by compressing the number of colors. For example, color clustering can be used to compress the color bit length into a shorter number, and similar colors can be treated as the same color, which can also reduce the bandwidth requirements for image signal transmission.

[0018] In some scenarios, the bandwidth requirement can be reduced by partially masking the image. For example, you can choose not to output part of the image signal. Of course, this part of the image will not be displayed on the monitor, but this also reduces the bandwidth requirement.

[0019] In some scenarios, re-encoding can be used to further reduce the demand, such as using variable-length encoding. Frequently occurring colors use shorter encodings, while colors with a lower probability of occurrence use longer encodings, which can reduce the average encoding length.

[0020] In some scenarios, length coding can be used to compress image signals to further reduce requirements. For example, if subsequent colors are similar or identical, only their statistics (such as mean / median / mode and length) need to be transmitted. In this way, the original display signal can be restored using a very simple circuit in the display adapter.

[0021] In some scenarios, linear coding can be used to compress images to further reduce requirements. For example, if the relationship between subsequent consecutive colors satisfies or approximates a linear relationship, compression can be achieved by transmitting only linear equation parameters or other similar methods. The display adapter can easily use the received parameters to calculate the original pixel value sequence through inverse operations.

[0022] The above description of the display signal processing method is only to illustrate one or more display signal processing technologies or their combined applications that can be applied in the display adaptation method proposed in the present invention. Any display signal processing method that does not require the cooperation of the local frame buffer of the display adaptation device is within the scope of the present invention.

[0023] In summary, after adopting the solution of the present invention, the display adapter device only needs to buffer a small amount of data (usually 64kbit or lower can meet the usage requirements), and does not need at least one frame or more frame buffer capacity like a traditional display adapter (for example, 1920x1080x24bit=50Mbit single frame requires 50M capacity).

[0024] The aforementioned buffer can be implemented in many ways, such as:

[0025] In some embodiments, a FIFO memory may be used to implement a buffer, and the display adapter writes the received image signal into the FIFO memory, which is then read by the rasterization processing module at another timing.

[0026] In some embodiments, two or more small memories may be used to implement a buffer, such as setting a cache circuit A and a cache circuit B, and allowing the two cache circuits to perform read and write operations alternately.

[0027] In some embodiments, a cache circuit may be used to implement the buffer, the write pointer and read pointer clocks of the cache circuit are asynchronous, the write pointer is controlled by the data port in the display adapter device, and the read pointer is controlled by the rasterization processing module.

[0028] The above is an example to illustrate the implementation of a small buffer. Any implementation and operation of a buffer that can realize a read / write buffer capacity not greater than the amount of data of a frame of display signal is within the scope of the present invention.

[0029] After the rasterization processing module takes out the display signal from the buffer, it is usually converted into a VGA signal through a ternary DAC (digital-to-analog converter) and output to the display (VGA display interface), or converted into a 10-bit encoded digital signal and output to the display (DVI / HDMI display interface). The present invention has nothing to do with the display interface adaptation signal format converted by the rasterization processing. The purpose of the above description is to illustrate the process of the rasterization processing module as a conversion display receiving signal format. The rasterization processing method that outputs any display display signal format is expected by the present invention.

[0030] The present invention also proposes a display adapter device without frame buffering, and its innovation lies in: the display adapter device includes a host interface, a buffer, a rasterization processing module and a display interface; the input end of the buffer is connected to the data interface of the host device through the host interface, the output end of the buffer is connected to the input end of the rasterization processing module, and the output end of the rasterization processing module is connected to the signal interface of the display through the display interface; the host interface transmits the image signal output by the host device to the buffer for buffering processing; the buffer transmits the buffered image signal to the rasterization processing module, and the rasterization processing module converts the image signal into a signal format supported by the display, and then transmits the image signal to the signal interface of the display through the display interface; the capacity of the buffer is less than the amount of image signal data required for one frame of image; the host interface of the display adapter device and the data interface of the host device are connected via USB.

[0031] The beneficial technical effect of the present invention is: a display adaptation method and a display adaptation device without frame buffer are proposed, and the display adaptation device obtained by the solution has the advantages of low cost, low power consumption and small size. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 , schematic diagram of the principle of the present invention. DETAILED DESCRIPTION

[0033] A display adaptation method, the hardware involved includes: a host device, a display adaptation device and a display; the innovation thereof lies in: the host device has a built-in display adaptation device driver; the display adaptation device driver uses part of the memory of the host device as a display memory; when the host device outputs an image signal to the display adaptation device, the display adaptation device driver first controls the display memory to perform frame buffer processing on the image signal, and then transmits the image signal after the frame buffer processing to the display adaptation device through the data interface of the host device;

[0034] The display adapter device comprises a host interface, a buffer, a rasterization processing module and a display interface; the host interface of the display adapter device is connected to the data interface of the host device, and the display interface of the display adapter device is connected to the signal interface of the display; the host interface of the display adapter device transmits the image signal output by the host device to the buffer for buffering; the buffer transmits the buffered image signal to the rasterization processing module, and the rasterization processing module converts the image signal into a signal format supported by the display, and then transmits the image signal to the signal interface of the display through the display interface of the display adapter device; the capacity of the buffer is less than the image signal data amount required for one frame of image;

[0035] The display can display corresponding images according to the image signal output by the display adaptation device.

[0036] Preferably, the host interface of the display adapter device and the data interface of the host device are connected via USB.

[0037] Preferably, the display adapter driver can dynamically adjust the transmission rate between the data interface of the host device and the host interface of the display adapter according to the usage rate of the buffer of the display adapter.

[0038] Preferably, the display adaptation method can process the image signal using an image signal processing technique that does not require frame buffer processing of the display adaptation device to adjust the bandwidth requirement and performance requirement between the host interface of the display adaptation device and the data interface of the host device.

[0039] A display adapter device without frame buffering, the innovation of which lies in: the display adapter device comprises a host interface, a buffer, a rasterization processing module and a display interface; the input end of the buffer is connected to the data interface of the host device through the host interface, the output end of the buffer is connected to the input end of the rasterization processing module, and the output end of the rasterization processing module is connected to the signal interface of the display through the display interface; the host interface transmits the image signal output by the host device to the buffer for buffering processing; the buffer transmits the buffered image signal to the rasterization processing module, and the rasterization processing module converts the image signal into a signal format supported by the display, and then transmits the image signal to the signal interface of the display through the display interface; the capacity of the buffer is less than the amount of image signal data required for one frame of image; the host interface of the display adapter device and the data interface of the host device are connected via USB.

Claims

1. A display adaptation method, the hardware involved includes: Host device, display adapter and display; The host device has a built-in display adapter driver, and the display adapter driver can use part of the memory of the host device as a display memory; the display adapter comprises a host interface, a buffer, a rasterization processing module and a display interface, the host interface of the display adapter is connected to the data interface of the host device, and the display interface of the display adapter is connected to the signal interface of the display, wherein the capacity of the buffer is less than the amount of image signal data required for one frame of image; The method comprises: When the host device outputs an image signal to the display adapter device, the display adapter device driver first controls the display memory to perform frame buffer processing on the image signal, and then transmits the image signal after the frame buffer processing to the display adapter device through the data interface of the host device; The host interface of the display adapter device transmits the image signal output by the host device to the buffer for buffering processing; The buffer transmits the buffered image signal to the rasterization processing module, and after the rasterization processing module converts the image signal into a signal format supported by the display, the image signal is transmitted to the signal interface of the display through the display interface of the display adapter device; and the display displays the corresponding image according to the image signal output by the display adapter device; wherein the display adapter device driver dynamically adjusts the transmission rate between the data interface of the host device and the host interface of the display adapter device according to the usage rate of the buffer of the display adapter device.

2. The display adaptation method according to claim 1, characterized in that: The host interface of the display adapter device and the data interface of the host device are connected via USB.

3. The display adaptation method according to claim 1, characterized in that: The display adaptation method processes the image signal using an image signal processing technique that does not require frame buffer processing of the display adaptation device to adjust the bandwidth requirement and performance requirement between the host interface of the display adaptation device and the data interface of the host device.

4. A display adapter device without frame buffer, the display adapter device comprising a host interface, a buffer, a rasterization processing module and a display interface; in, The input end of the buffer is connected to the host interface, the output end of the buffer is connected to the input end of the rasterization processing module, and the output end of the rasterization processing module is connected to the display interface; The display adapter device can be connected to the data interface of the host device through the host interface, and transmit the image signal output by the host device to the buffer for buffering; the buffer transmits the buffered image signal to the rasterization processing module, and the rasterization processing module converts the image signal into a signal format supported by the display, and then transmits the processed image signal to the display through the display interface; wherein the capacity of the buffer is less than the image signal data amount required for one frame of image; Wherein, the host interface of the display adapter device and the data interface of the host device are connected via USB; and Among them, the host device has a built-in display adapter driver, and the display adapter driver can use part of the host device's memory as display memory. When the host device outputs an image signal to the display adapter, the display adapter driver first controls the display memory to perform frame buffer processing on the image signal, and the image signal after frame buffer processing is transmitted to the display adapter through the data interface of the host device.

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