KR101030683B1 - Video Data Interface Device and Method - Google Patents

Abstract

Disclosed are a video data interface device and method. The disclosed apparatus includes a transmission interface device mounted to a video data transmitting end and including a data cropper for cropping a portion of the video data corresponding to channel state information; And receiving the video data received from the transmission interface device and providing the received video data to the video data receiving end, and receiving the channel state information including a transmission rate and a bit error ratio (BER) for the received video data. And a reception interface device including a channel state reporter providing the transmission interface device. According to the disclosed apparatus, video data can be transmitted while maintaining the quality of a video service even if other media than HDMI cable is used, and video data can be transmitted while maintaining stable QoS through data cropping.

HDMI, Cropping

Description

Video Data Interface Device and Method

The present invention relates to a video data interface device and method, and more particularly, to a video data interface device and method for transmitting and receiving video data while maintaining a quality of service (QoS).

With the development of various multimedia broadcasting receivers, playback devices, and display devices, interface-related technologies for simplifying signal line connections between complex multimedia related devices and providing high quality information are also being developed.

DVI (Digital Video Interface) is widely used to connect devices such as computers or DVD players with display devices, and High Definition Multimedia Interface (HDMI), which is developed for more multimedia signal transmission based on such DVI, is commercially available. It is used.

HDMI is a multimedia interface that can transmit uncompressed digital audio / video data, providing an interface between consumer electronic devices such as computers, digital televisions, DVDs, and Blu-ray disc players.

1 is a diagram illustrating a configuration of a general HDMI system.

Referring to FIG. 1, four high-speed channels 100, 102, 104, and 106 and two low-speed channels 108 and 110 are used in a typical HDMI system. The high speed channel comprises three transition minimized differential signal (TMDS) channels 100, 102, 104 and one TMDS clock channel 106, and the low speed channel is a display data channel (DDC, 108) and a CEC. (Consumer Electronics Control, 110) channel.

TMDS reduces wired electromagnetic interference by transmitting high-speed serial data. The TMDS fire rate clock rates range from 25MHz to 340MHz based on the HDMI 1.3a standard, with data rates ranging from 250Mbps to 3.4Gbps, with 10 bits per pixel clock transmitted on one TMDS data channel. Since there are three TMDS channels in total, the maximum data rate is 10.2Gbps, which enables the transmission of high-definition HDTV signals of 1920x1080p or higher.

For the transmission of audio data and other data, the HDMI standard uses a BCH error correction code. However, with regard to video data transmission, the HDMI standard does not define a separate error correction technique. However, it requires a design and implementation that can guarantee at least 10 ^-9 TMDS Character Error Rate for a medium (eg, HMDI cable) that transmits video data of the HDMI standard. When transmitting video data, TMDS symbol is the same as one pixel data and 30 bits per symbol must ensure minimum 3x10 ^-11 bit error rate (BER).

Due to digital convergence in which various protocols and media are used interchangeably, HDMI data has conventionally been transmitted through an HDMI cable, but in the future, it is required to be transmitted through various media such as wireless and Ethernet LAN. Wireless transmission of HDMI data has been actively studied and attracted attention in terms of user convenience of eliminating an inconvenient wired cable.

If a medium other than an HDMI cable is used to transmit HDMI data, various problems will occur. Depending on the characteristics of the medium, data bandwidth and throughput may change, thereby limiting data transmission of the HDMI. In addition, because the HDMI cable is not used as a medium, the BER given in the standard cannot be guaranteed. If the BER is not guaranteed, the quality of video service experienced by the user is low.

In general, video is compressed and transmitted due to the huge amount of data, and the video quality is controlled through a transcoding technique that applies various conversion codecs according to the capacity of the medium and the channel state. You can. However, in time critical applications, video may be sent in uncompressed form to reduce the time required for compression encoding. If it is necessary to transmit uncompressed video such as HDMI, there is no applicable codec because it is pure raw data transmission.

When transmitting video data using a medium other than an HDMI cable (especially when transmitting HDMI data wirelessly), it is difficult to meet the maximum data rate of 10.2Gbps defined by the HDMI standard. As such, when HDMI video data is transmitted through a medium that does not meet the HDMI data rate, data loss occurs due to insufficient transmission capacity, and the user is forced to experience a low quality service.

In addition, since HDMI data transmission requires transmission of video data in an uncompressed form, there is a problem in that the amount of data cannot be reduced by compression.

In order to solve the problems of the prior art as described above, the present invention proposes a video data interface device and method capable of transmitting video data while maintaining the quality of video service even if other media are used.

Another object of the present invention is to propose a video data interface apparatus and method capable of transmitting video data while maintaining stable QoS through data cropping.

Another object of the present invention is to propose a video data interface device and method capable of maintaining stable QoS by flexibly adjusting the amount of video data transmission according to the channel state of a transmission medium.

Other objects of the present invention will be readily apparent to those skilled in the art through the following examples.

In order to achieve the above object, according to an aspect of the present invention, a transmission interface device mounted to the video data transmitting end, and comprising a data cropper for cropping a portion of the video data corresponding to the channel state information; And receiving the video data received from the transmission interface device and providing the received video data to the video data receiving end, and receiving the channel state information including a transmission rate and a bit error ratio (BER) for the received video data. A video data interface device is provided that includes a reception interface device including a channel state reporter for providing to the transmission interface device.

The data cropper adjusts the video data size to be cropped corresponding to the data rate and BER.

The transmission interface device includes a multiplexer for multiplexing video data provided through the multiple paths from the video data transmitter, and the reception interface device includes a demultiplexer for demultiplexing the video data multiplexed by the multiplexer.

The transmission interface device is coupled with a multiplexer and includes an error correction encoder for encoding the output data of the multiplexer for error correction, wherein the receiving interface device corrects an error of video data transmitted from the transmission interface device. It includes.

The receiving interface device includes a data inserter for inserting a pixel of a predetermined color for the portion cropped by the data cropper.

The transmission interface device includes a channel state monitor that receives channel state information received from the channel state reporter and provides the data to the data cropper.

The data cropper crops the video data of the edge portion corresponding to the data rate and the BER, and determines the cropping shape according to the distribution of error bits.

The cropping type includes window box cropping, pillar box cropping, and letter box cropping, and one of the window box cropping, pillar box cropping, and letter box cropping is selected according to the distribution of error bits.

The data cropper adaptively changes the data size and the cropping form that is cropped in response to the change of the data rate and the BER, and the cropping data size and the cropping form so that the cropping size and the cropping form are not changed suddenly. Resets the quality counter when is changed, increases the quality counter when the currently set cropped data size and cropping type are not appropriate, and crops the cropped data size and cropping type when the quality counter is above the preset value. To change.

The transmission interface device and the reception interface device may transmit and receive video data via a wireless channel, and the video data may be HDMI video data.

According to another aspect of the invention, the step of cropping the video data provided by the video data transmitting end corresponding to the channel state information (a); (B) transmitting the cropped video data to a receiving interface device; And (c) providing, at the receiving interface device, the channel state information including a transmission rate and bit error ratio (BER) information to the transmitting interface device with respect to the received cropped video data. A method is provided.

According to still another aspect of the present invention, a data cropper mounted on a video data transmitting end and cropping a part of video data in accordance with channel state information; A multiplexer for multiplexing the data cropped by the data cropper; An error correction encoder that performs error correction on the output signal of the multiplexer and transmits the encoded signal to a receiving interface device; And a channel state monitor for receiving the channel state information including a transmission rate and bit error ratio (BER) information from the receiving interface device, wherein the data cropper corresponds to an edge portion of video data corresponding to the channel state information. A video data transmission interface device is provided that crops data.

According to the present invention, even if other media are used in addition to the HDMI cable, the video data can be transmitted while maintaining the quality of the video service, and the data can be transmitted while maintaining stable QoS through data cropping.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the video data interface device and method according to the present invention.

In the present embodiment, a video data interface device and method will be described by taking HDMI video data as an example. However, those skilled in the art will understand that the idea of the present invention can be applied not only to HDMI video data transmission but also to other types of video data transmission.

2 is a block diagram illustrating a configuration of a video data interface device according to an embodiment of the present invention.

The video data interface device according to an embodiment of the present invention includes a transmission interface device 200 coupled to the HDMI transmitter and a reception interface device 250 coupled to the HDMI receiver.

The transmission interface device 200 may include a data cropper 210, a data multiplexer 212, an error correction encoder 214, and a channel state monitor 216. In addition, the receiving interface device 250 may include an error correction decoder 260, a data demultiplexer 262, a data inserter 264, and a channel state reporter 266.

The data cropper 200 is connected to an HDMI transmitter and receives an encoded TDMS signal from a TDMS encoder. The data cropper 200 functions to adjust the data capacity to be transmitted to the receiving end according to the channel state information provided from the channel state monitor 216. The data cropper 200 does not perform data cropping when the channel condition is good, and when the channel condition is not good, the data cropper 200 crops some data to adjust the data capacity transmitted to the receiver. That is, the data cropper adjusts the amount of data provided to the receiving end by cropping without transmitting some data.

The manner in which the data cropper 210 crops the video data will be described with reference to a separate drawing.

The data multiplexer 212 multiplexes three cropped signals output from the data cropper 200. The data multiplexer performs multiplexing so that three independent cropped signals are output to one stream through one output. Since the data multiplexer is widely used in the data processing device, a detailed description of the operation of the data multiplexer will be omitted.

The cropped signal output by the data multiplexer 212 is input to an error correction encoder 214. The error correction encoder 214 performs encoding for error correction at the receiving end. The error correction encoder may perform error correction encoding by adding a separate data bit for error correction.

As the error correction method, various known error correction methods may be used. According to a preferred embodiment of the present invention, a Forward Error Correction (FEC) encoding scheme may be used, and an FEC encoder may be used as the error correction encoder 214.

The error correction encoder 214 transmits the encoded signal through the medium to the receiving interface device for error correction. The medium may be a wireless channel or a wired cable may be used. The present invention can be usefully applied when video data is transmitted through a wireless channel such as WLAN or Bluetooth.

The error correction decoder 260 receives the output signal of the error correction encoder 214 transmitted via the medium. The error correction decoder 260 decodes the encoded signal for error detection in the error correction encoder. When the FEC encoder is used, the FEC decoder is also used as an error correction decoder, and the FEC decoder detects data errors and performs correction by using error correction data added by the FEC encoder.

In addition, the error correction decoder 260 is coupled to means for detecting the transmission rate of the bit stream transmitted through the medium. The transmission rate may be sensed in various ways, and since this is a known technology, a detailed description thereof will be omitted.

 The error correction decoder 260 provides the bit state ratio (BER) information and the rate information detected in the error correction decoding process to the channel state reporter 266. The channel state reporter 266 transmits channel state information including the BER and the rate information provided from the error correction decoder 260 to the channel state monitor 216 of the transmission interface. The channel state reporter 266 periodically transmits information about the channel state. The data cropper 210 of the transmission interface device performs data cropping according to the channel state information received by the channel state monitor 216.

The data demultiplexer 262 demultiplexes the signal output from the error correction decoder 260. Since the data multiplexer 212 of the transmission interface device 200 multiplexes three types of TMDS data into one bit stream, the data demultiplexer 262 demultiplexes the data into three outputs.

In the embodiment shown in FIG. 2, data multiplexer 212 and data demultiplexer 262 are components provided because they transmit data using a single data channel. If a plurality of data channels are supported, such as an HDMI cable, the data multiplexer 212 and the data demultiplexer 262 may not be provided.

The demultiplexed signal from the data demultiplexer 262 is output to the data inserter 264. The data inserter 264 functions to insert black pixel data for the portion cropped by the data cropper 210. The black pixel is inserted by the data inserter 264 so that the cropped region is displayed as the black region. Of course, it will be apparent to those skilled in the art that pixels of colors other than black pixels may be inserted according to the background color of the display device. The output signal of the data inserter 264 is output to the HDMI receiver.

3 is a diagram illustrating an example in which data cropping is performed according to an embodiment of the present invention.

Referring to FIG. 3, when it is determined that it is not appropriate to transmit the entire data in consideration of the channel state, the transmission capacity is controlled by cropping a part of the data. In this case, the size of the data to be cropped is calculated according to the aspect ratio, and it is preferable that the data of the edge portion of the screen is cropped so as not to affect the viewing of the video data.

The area where data is cropped in the video image is replaced by black pixels by the data inserter.

According to the present invention, the quality of a video image can be maintained even when a wireless channel, which is a medium other than an HDMI cable, is used by cropping video data to be transmitted according to channel conditions.

Hereinafter, a method of controlling cropping of video image data according to channel conditions will be described in more detail.

4 is a flowchart illustrating a process in which data cropping is performed according to an embodiment of the present invention.

Referring to FIG. 4, the video data interface device according to an embodiment of the present invention is in a transmission waiting state for monitoring whether video data is transmitted from an HDMI transmitter (step 400).

When transmission data is generated from the HDMI transmitter (step 402), a data rate that can be transmitted through the channel is determined (step 402).

When video data is initially transmitted (that is, when there is no feedback information on the transmission rate from the receiving interface device), the data transmission rate is determined based on the general transmission rate of the medium used.

When the information on the data rate between the transmitting interface device and the receiving interface device is fed back from the receiving interface device, the feedback rate information is determined as the current data rate.

Once the data rate is determined, it is determined whether data cropping is required (step 406). If the data rate is sufficient to transmit the entire video data, it is determined that no data cropping is necessary. If the data rate is not sufficient to transmit the entire video data, it is determined that data cropping is necessary.

If it is determined that data cropping is necessary, the data size to be cropped is determined according to the transmission rate, and data cropping according to the aspect ratio is performed as shown in FIG. 3 (step 408). As shown in FIG. The video data present in the screen frame is cropped based on the coordinate of. The lower the data rate, the larger the cropping size.

When the cropping according to the transmission rate is performed, it is determined whether the data cropping according to the BER is additionally required, and if the data cropping is necessary, the data cropping according to the BER is performed (step 410). The BER is periodically fed back from the channel state reporter 266 of the receiving interface device.

Cropping according to BER is performed corresponding to the distribution of BER numbers and error bits. Whether cropping according to BER is required is determined by whether the BER fed back from the channel state reporter is lower than the preset reference BER. In addition, in cropping according to BER, it is preferable to change the cropping shape according to the distribution of error bits.

FIG. 5 is a diagram illustrating types of cropping types according to an error bit distribution in the present invention.

The portion indicated by black dots in the video image of FIG. 5 is an error bit. Referring to FIG. 5, when the error bits are evenly distributed throughout the video image, it is preferable to perform windowbox cropping in which the edge of the video image is cropped as a whole.

On the other hand, if the error bits are distributed intensively on both sides of the video image, it is preferable to perform pillarbox cropping that only crops data of the side edges of the video image.

In addition, when error bits are concentrated in the upper and lower portions of the video image, it is preferable to perform letterbox cropping, which crops only the upper and lower edges of the video image.

In the above-described embodiment of FIG. 4, a case in which data cropping for a BER is performed after performing data cropping for a data rate is illustrated. However, it will be apparent to those skilled in the art that an embodiment of the present invention is not limited thereto, and that data cropping may be performed at one time in consideration of the transmission rate and the BER.

As described above, when providing video data through data cropping, a user may receive a seamless video service without an error due to data loss, although a part of the original video screen may not be viewed.

In addition, the conventional HDMI video transmission system does not provide a separate error correction means, but in the present invention, by applying an error correction means such as FEC, it is possible to detect and correct errors in the HDMI receiver.

Additional data is used for error correction and this additional data should be considered when determining whether cropping is required.

7 is a flowchart illustrating a process of adjusting data cropping according to a feedback rate and a BER according to an embodiment of the present invention.

Referring to FIG. 7, the rate and the BER are periodically checked (step 700). The rate and BER can be checked using information fed back from the channel state reporter.

If the rate and BER are checked, it is determined whether the current cropping parameter is properly set (step 702). The cropping parameter here includes a cropping size and a cropping type.

For example, when the current rate is higher than the currently set cropping parameter, it is determined that the cropping parameter is not properly set, even when the current rate is lower than the cropping parameter.

If the cropping parameter is appropriately set according to the feedback rate and the BER, the flow returns to the step of checking the feedback rate and the BER.

If it is determined that the cropping parameter is not set appropriately in accordance with the feedback rate and the BER, it is determined whether the quality counter is equal to or greater than a preset value (step 704).

The quality counter is a parameter that is set to prevent the cropping parameter from changing drastically in accordance with the rate and the BER change. The specific cropping parameter is increased in accordance with the time to be maintained. If the quality counter is less than or equal to the preset value, the quality counter is increased by one (step 706), and the flow returns to the step of checking the transmission rate and the BER.

If the quality counter is greater than or equal to a preset value, the cropping parameter is changed according to the current rate and BER (step 708). When the cropping parameter is changed, an error distribution of error bits is analyzed to set the cropping type in the manner described above.

If the cropping parameter is changed, the quality counter is reset and set back to zero (step 710).

 In addition, if the cropping parameter is changed, video data cropping is performed corresponding to the changed cropping parameter (step 712).

6 is a diagram illustrating an example in which a cropping parameter is changed according to a transmission rate and a BER according to an embodiment of the present invention.

Referring to FIG. 6, when the channel state worsens during video data transmission in state (a), a portion of the video data is cropped and transmitted as shown in state (b). If the channel condition continues to worsen, the cropping size further increases as in state (c).

When the worse channel condition improves again, the cropping size decreases as in state (e). If the channel condition continues to improve and no cropping is required, then cropping is not performed as in state (f).

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the present invention described in the claims below. It will be appreciated that it can be changed.

1 is a diagram illustrating a configuration of a general HDMI system.

2 is a block diagram showing a configuration of a video data interface device according to an embodiment of the present invention.

3 illustrates an example in which data cropping is performed according to an embodiment of the present invention.

4 is a flowchart illustrating a process in which data cropping is performed according to an embodiment of the present invention.

5 is a diagram illustrating types of cropping types according to error bit distributions in the present invention.

6 is a diagram illustrating an example in which a cropping parameter is changed according to a transmission rate and a BER according to an embodiment of the present invention.

7 is a flowchart illustrating a process of adjusting data cropping according to a feedback rate and a BER according to an embodiment of the present invention.

Claims (19)

A transmission interface device mounted to the video data transmission end, the transmission interface device including a data cropper for cropping a part of the video data corresponding to the channel state information; And A receiving interface device mounted to a video data receiving end and receiving the video data received from the transmitting interface device and providing the received video data to the video data receiving end; And the receiving interface device comprises a channel state reporter for providing the channel interface information to the transmitting interface device including a transmission rate and a bit error ratio (BER) for the received video data. The method of claim 1, And the data cropper adjusts the size of video data cropped according to the data rate and BER. The method of claim 2, The transmission interface apparatus includes a multiplexer for multiplexing video data provided through the multiple paths from the video data transmitter, and the receiving interface apparatus includes a demultiplexer for demultiplexing video data multiplexed by the multiplexer. Video data interface device. The method of claim 3, The transmission interface device is coupled with the multiplexer and includes an error correction encoder that encodes the output data of the multiplexer for error correction, wherein the receiving interface device corrects an error of video data transmitted from the transmission interface device. And a decoder. The method of claim 4, wherein And the receiving interface device comprises a data inserter for inserting a pixel of a predetermined color for the portion cropped by the data cropper. The method of claim 5, And the transmission interface device comprises a channel state monitor for receiving channel state information received from the channel state reporter and providing the channel state information to the data cropper. The method of claim 1, And the data cropper crops the video data of the edge portion corresponding to the data rate and the BER, and determines the cropping shape according to the distribution of error bits. The method of claim 7, wherein The cropping type includes window box cropping, pillar box cropping, and letter box cropping, wherein one of the window box cropping, pillar box cropping, and letter box cropping is selected according to the distribution of error bits. A video data interface device. The method of claim 7, wherein The data cropper adaptively changes the data size and the cropping form that is cropped in response to the change of the data rate and the BER, and the cropping data size and the cropping form so that the cropping size and the cropping form are not changed suddenly. Resets the quality counter when is changed, judges whether the currently set cropped data size and cropping type are appropriate according to the distribution of the transmission rate, BER and error bits, and if not appropriate, increases the quality counter. And changing the data size and the cropping form to be cropped when the counter is greater than or equal to a preset value. The method according to any one of claims 1 to 9, And the transmission interface device and the reception interface device transmit and receive video data via a wireless channel. 10. The video data interface device according to any one of the preceding claims, wherein said video data comprises HDMI video data. Cropping the video data provided from the video data transmitter in correspondence with the channel state information (a); (B) transmitting the cropped video data to a receiving interface device; And (C) providing, at the reception interface device, the channel state information including a transmission rate and bit error ratio (BER) information to the transmission interface device coupled to the video data transmitting end with respect to the received cropped video data. And a video data interface method. The method of claim 12, Multiplexing the cropped data in the step (a) when the video data from the video data transmitter is provided through multiple paths; And And demultiplexing the demultiplexed video data at the receiving interface device. The method of claim 13, An error correction encoding step of performing encoding for error correction on the cropped data; And And an error correction decoding step of correcting an error on the encoded data at the receiving interface device. The method of claim 14, And a data insertion step of inserting a pixel of a predetermined color for the cropped portion in the reception interface device. The method of claim 15, And the step (a) crops the video data of the edge portion according to the channel state information including the data rate and the BER, and determines the cropping shape according to the distribution of error bits. The method of claim 16, The cropping type includes window box cropping, pillar box cropping, and letter box cropping, wherein one of the window box cropping, pillar box cropping, and letter box cropping is selected according to the distribution of error bits. Video data interface method. The method of claim 17, The data size and cropping shape that are cropped in step (a) are adaptively changed according to the change of the transmission rate and the BER. Resets the quality counter when changed, determines whether the currently set cropped data size and cropping type are appropriate according to the distribution of the rate, BER and error bits, and if not appropriate, increments the quality counter. The video data interface method according to claim 1, wherein the cropped data size and cropping shape are changed when is greater than or equal to a preset value. A data cropper mounted at the video data transmitting end and cropping a part of the video data corresponding to the channel state information; A multiplexer for multiplexing the data cropped by the data cropper; An error correction encoder that performs error correction on the output signal of the multiplexer and transmits the encoded signal to a receiving interface device; And Including a channel state monitor for receiving the channel state information including the transmission rate and Bit Error Ratio (BER) information from the receiving interface device, And the data cropper crops the data of the edge portion of the video data according to the channel state information.

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