KR20090085346A - Display for pip, soc and dmb using the same - Google Patents

Abstract

A PIP support display device, a system on chip using the same and a DMB terminal are provided to improve the reliability of a product. A receiver(110) receives transmission streams of plural channels. A decoder(120) outputs plural image frame data and an STC(System Time Clock) for a main channel transmission stream. A frame memory(130) is comprised of sub frame memories for storing a plurality of image frame data according to each channel. In case a CTS(Composition Time Stamp) of the image frame data stored in each sub frame memory satisfies the STC, an image frame data output unit(140) outputs corresponding image frame data.

Description

Display device supporting PIP, system on chip and DMB terminal using same {display for PIP, SoC and DMB using the same}

The present invention relates to a PIP support display device, a system on chip and a DMB terminal using the same, and more specifically, a display device supporting picture in picture (PIP) in a display device supporting only one PCR (Program Clock Reference). And it relates to a system-on-chip and DMB terminal using the same.

PIP (Picture in Picture) refers to a screen that has the function to display a small screen at the same time separately from the screen seen on the television receiver screen, and is similar to a window of a personal computer (PC). It is called PIP) function. In televisions having such a function, the background of the background is called the mother screen (main screen), and the smaller screen is called a PIP (sub screen). This feature allows you to see the contents of another channel at the same time while watching a program, but the drawback is that part of the screen is hidden. It is also a kind of PIP to display a general screen broadcast with a 4: 3 aspect ratio on a small screen on a large television having a 16: 9 aspect ratio.

Such a PIP may provide convenience by displaying several channels simultaneously to a user in consideration of the present time in which various broadcast channels exist and the future of continuous broadcast channels. In other words, when broadcasting a desired program on several channels at the same time, the user can selectively watch only one channel broadcast program, and can satisfy the user's desire by providing another sub channel broadcast program as a sub screen. This helps to improve the reliability of the whole product.

In general, PIP-enabled displays are applied to medium and large size televisions that are not portable as in home televisions. In order to support PIP, it is necessary to simultaneously receive and process multiple channel transport streams. Therefore, as many tuners plus the number of main screens are added to the desired number of PIPs, a corresponding baseband part is required to secure a certain amount of space. Because.

In addition, a program clock reference (PCR) for each transport stream for each channel must be supported, which means that a device supporting PCR as many as the number of screens to be displayed must be added to the display device separately.

However, a portable or small display device such as a digital multimedia broadcasting (DMB) terminal does not support a plurality of PCRs. Accordingly, PIP support in portable or small displays is currently insignificant. Therefore, there is an urgent need for a solution.

The present invention was created to improve the above problems, and an object of the present invention is to support a smooth PIP function in a display device supporting only one PCR.

In addition, by providing a system on a chip that supports a smooth PIP function in a display device that supports only one PCR, it is another object to enable the support of the PIP function in a portable or small display device such as a DMB terminal.

In order to achieve the above object, the present invention includes a receiver for receiving a transport stream of a plurality of channels; A decoding unit for decoding the received plurality of transport streams and outputting a plurality of image frame information and a system time clock (STC) for the main channel transport stream; A frame memory unit arranged in a number corresponding to the output plurality of image frame information and configured to store the plurality of image frame information for each channel; And a picture frame information output unit for outputting corresponding picture frame information when the composition time stamp (CTS) of the picture frame information stored in each subframe memory satisfies the STC. present.

Here, the decoding unit separates the received plurality of transport streams into selective audio data and a plurality of video data, and restores and outputs an STC, which is a reference of the system, from a PCR (Program Clock Reference) of the main channel transport stream. A system decoder; A bit stream buffer unit disposed in a number corresponding to the plurality of video data and configured to store the plurality of video data for each channel; And a video decoder for decoding the video data stored in the bit stream buffer unit to output image frame information. In this case, the video decoder unit may output the video data of the bit stream buffer unit when the frame memory unit is empty. It is desirable to load.

Preferably, the image frame information output unit checks whether the frame memory unit is stored for each display clock.

On the other hand, CTS (New_Sub_CTS) of the transport stream (sub-channel transport stream) excluding the main channel is the following equation

New_Sub_CTS = C_Sub_CTS-(F_Sub_CTS-F_STC_Time)

C_Sub_CTS: CTS of data in current subchannel transport stream

F_Sub_CTS: CTS of data in first subchannel transport stream

F_STC_Time: STC when F_Sub_CTS is applied

It is preferred to be defined by.

In addition, the present invention includes a decoding unit for decoding the received transport stream of the plurality of channels and outputs a plurality of image frame information and the STC for the main channel transport stream; A frame memory unit arranged in a number corresponding to the plurality of output image frame information and configured to store the plurality of image frame information for each channel; And an image frame information output unit for outputting corresponding image frame information when the CTS of the image frame information stored in each subframe memory satisfies the STC. do.

Furthermore, a receiver for receiving a transport stream of a plurality of channels; A decoder configured to decode the received plurality of transport streams and output a plurality of video frame information and STCs for a main channel transport stream, and a number corresponding to the output plurality of video frame information, the plurality of video frames A PIP including a frame memory unit configured to store information for each channel, and an image frame information output unit configured to output corresponding image frame information when the CTS of the image frame information stored in each subframe memory satisfies the STC. Support system on chip; And a PIP support digital multimedia broadcasting (DMB) terminal supporting only one PCR including a display unit displaying the output image frame information.

As described above, the PIP support display device according to the present invention, the system on chip and the DMB terminal using the same can improve the reliability of the entire product by providing a smooth PIP function in a display device supporting only one PCR.

Hereinafter, a scheme for implementing PIP in a display device supporting only one PCR will be described in detail.

1 is a block diagram schematically showing the configuration of a display device supporting only one PCR.

Referring to FIG. 1, a broadcast signal is received through an antenna, and a specific program or channel is selected through a tuner 11 and transmitted to the system decoder 12 in the form of a transport stream (TS). Since the present invention relates to a PIP function of displaying a plurality of screens on one screen, the tuner 11 is made of at least two, and at the rear end thereof, a device such as a baseband unit is provided. Is added. The number of the tuner and the baseband unit varies depending on the number of screens to be displayed by the PIP function. In general, since the current PIP supports two main screens, one main screen serving as a background and one subscreen displayed on a part of the main screen, the following description will focus on implementing the PIP with two screens.

Since the tuner 11 and the baseband (not shown) must simultaneously process two broadcast channel transport streams, the tuner 11 and the baseband (not shown) must be allocated to each of the broadcast channel transport streams two by two. The system decoder 12 collects program guide information from the transport stream TS, filters audio and video data corresponding to a program selected by the viewer, and delivers the audio to the audio decoder 13 and the video decoder 16, respectively. Depending on its speed, one can perform the function. At this time, the format of the data transmitted to the audio decoder 13 and the video decoder 16 includes information useful for decoding such as time stamps (DTS, CTS in the case of MPEG-4) according to the MPEG version. In addition, the system decoder 12 restores an STC (System Time Clock), which is a standard of a system, from a PCR (Program Clock Reference), which is information contained in a transport stream (TS). To pass). The STC may be used as a driving clock of the STC counter on which the audio decoder 13 and the video decoder 16 match and decode the time stamp. However, since it is assumed that PIP is implemented with two screens, and only two channel transport streams are received, only one PCR is supported. Therefore, only one of the PCRs included in the two transport streams should be selected and used. In general, the STC is restored by using the PCR of the main transport stream applied to the main screen, and the processing of the sub transport stream applied to the sub screen having no STC will be described later. The audio data output from the system decoder 12 needs to support only one audio output even during the PIP implementation, and the output will be the audio output to the main screen (audioally displayed through the speaker 14). Although no consideration is required, the processing for the sub transport stream, which will be described later, is related even when the user requests audio output for the sub screen instead of the main screen.

The video decoder 16 decodes the video data output from the system decoder 12 to output image frame information to be displayed on the actual screen, and the output image frame information is stored in the frame memory 17.

The video post-processing unit 18 converts the image frame information decoded by the video decoder 16 and stored in the frame memory 17 to fit the screen configuration of the display device 19 and displays the image on the screen. do. Examples of image conversion include screen size conversion, aspect ratio conversion, and display scan method conversion.

Looking at the above example, there is only one component corresponding to the PCR included in the transport stream of the main channel corresponding to the main screen, that is, only one PCR, so that the example of implementing the PIP in such a configuration Let's look through FIG.

In FIG. 2, only audio processing is shown except for audio processing.

The system decoder 22 receives a transport stream of a plurality of channels (two channels in this embodiment), separates the audio data and the video data, and restores the STC with reference to a PCR of a predetermined transport stream. The transport stream comprising the PCR will be the main transport stream (the transport stream of the main channel).

The bit stream buffer 25 stores the video data output from the system decoder 22. In this embodiment, the main video data and the sub screen (corresponding to the main channel) corresponding to the main screen (sub channel) Sub video data are stored alternately as M: 0, S: 0, M: 1, S: 1, .... The bit stream buffer 25 manages access unit information (AUI), takes a queue-type storage method, and outputs the data in an input order. Of course, the manner in which the main video data and the sub video data are alternately stored must be promised to each other at the system decoder 22 and the later video decoder 26.

The video decoder 26 outputs image frame information generated by decoding the main video data and the sub video data stored in the bit stream buffer 25. In general, image frame information may refer to post-processed data. However, in the present invention, decoded video data is referred to as image frame information in order to distinguish it from video data that has passed through the system decoder 22.

The image frame information is stored in the frame memory 27. Like the bit stream buffer 25, the main image frame information for the main video data and the sub image frame information for the sub video data are alternately stored. It also takes the same queue format as the bit stream buffer 25. The main video frame information stored in the frame memory 27 is compared with the composition time stamp (CTS) included in the main video frame information and the STC output from the system decoder 22, and the CTS satisfies the STC. If there is a difference, the difference is delayed by the difference and then output to the display device 29. The comparison between the CTS and the STC is performed by the image frame information output unit 28. The image frame information output from the image frame information output unit 28 may be directly displayed through a predetermined display unit, or may be displayed in a state in which an aspect ratio is adjusted through a video post-processing unit.

However, in the present embodiment, since the CTS for the subchannel does not have an STC as a reference for comparison, the subchannel is output after being delayed by giving a random but consistent delay value. However, even in such a case, not only the sub picture corresponding to the sub channel is not normally output, but also the main screen is not output at a normal timing, so that lip-sync of audio-video cannot be matched. Since the main image frame information corresponding to the main screen and the sub image frame information corresponding to the sub screen are alternately stored in the single frame memory, if the main image frame is connected to the STC of the image frame information output unit 28, As a result of the comparison, when 30 ms is required and 20 ms delay is applied to the sub image frame, the main screen and the sub screen output to the image frame information output unit 28 are 50 ms in which delays of the main and sub image frames are added together. This is because a delay occurs. On the contrary, the audio decoder (not shown) outputs audio data with reference to the STC, so that the audio decoder deviates from the main screen, thereby reducing the reliability of the user. This occurs in the case where the audio data corresponds to the sub channel, but as a solution to this, the delay of the audio decoder output may be set in consideration of both the main screen and the sub screen delay. However, in this case, since a time difference occurs that the difference between the actual broadcast time is recognized, it may be another factor that lowers the reliability of the user, which is not preferable.

Therefore, the present invention proposes the following scheme for efficient PIP implementation in a display device supporting only one PCR.

3 is a block diagram illustrating a PIP support display device according to an exemplary embodiment of the present invention. Referring to FIG. 3, the PIP support display device includes: a receiver 110 receiving a plurality of channels of transport streams; A decoding unit (120) for decoding the received plurality of transport streams and outputting a plurality of image frame information and a system time clock (STC) for the main channel transport stream; A frame memory unit (130) arranged in a number corresponding to the output plurality of image frame information and configured to store the plurality of image frame information for each channel; And an image frame information output unit 140 for outputting corresponding image frame information when the composition time stamp (CTS) of the image frame information stored in each subframe memory satisfies the STC.

The receiver 110 receives a transport stream of a plurality of channels, and is provided with a device such as a tuner (not shown) corresponding to the number of channels to be received, that is, displayed on the screen.

The decoding unit 120 filters the audio data and the video data for each of the transport streams of the plurality of channels received through the receiving unit 110, decodes each of the video data, and outputs the image frame information as the main channel. The STC is restored and output by referring to the PCR included in the main transport stream, which is the transport stream. The decoding unit 120 is a configuration excluding an audio decoder, and detailed description of the audio decoder is omitted.

The frame memory unit 130 is a set of subframe memories provided with the number of pieces of image frame information output from the decoding unit 120 so that image frame information of one channel is stored separately from image frame information of another channel. to be. Therefore, only the image frame information corresponding to one channel is stored in the sub frame memory. Each sub frame memory is output in the order of input to the memory of the queue type.

The image frame information output unit 140 checks each sub frame memory of the frame memory unit 130 and, when there is image frame information, decodes the CTS included in the image frame information in the decoding unit 120. When the CTS satisfies the STC, the image frame information is output when the CTS satisfies the STC. The output information is processed directly or by a video post-processing unit (not shown), and the user is displayed through a display device (not shown). Is displayed. If the CTS does not satisfy the STC, the CTS delays the difference and outputs the delay. The image frame information stored in each subframe memory includes a CTS. Since the STC becomes the STC for the main screen, the image frame information except for the CTS of the image frame information for the main screen (sub image frame information) CTS has no object of comparison. Therefore, as described with reference to FIG. 2, a consistent delay value is assigned to the CTS of the sub-picture frame information to be processed. Since the delay value does not take into account the STC corresponding to the sub picture frame information, the delay time may show an error of a certain time from the actual broadcast time. However, unlike in FIG. 2, the delay value corresponds to the number of sub frame memories corresponding to the number of channels. By storing image frame information corresponding to a channel, the delay value of one channel does not affect the delay value of another channel. Therefore, the main screen is processed irrespective of the delay applied to other sub screens, so that audio and video outputs are normally performed, and outputs showing disparity or interruption due to a consistent delay value arbitrarily assigned only to the sub screens are generated. do. If the audio output for the sub picture is to be performed, the audio output for the main picture is stopped and the audio decoder outputs the sub audio data corresponding to the sub picture by applying the arbitrarily given consistent delay value. Make sure the output is done. Of course, in this case, the parallax or disconnection with the real broadcast may appear by not referring to its own STC value.

The image frame information output unit 140 checks whether the frame memory unit, more specifically, each sub frame memory is stored. The check interval is sufficient for each display clock. In the sleep state, it is desirable to prevent unnecessary power consumption.

In summary, the PIP-supported display device according to the present embodiment includes a plurality of subframe memories corresponding to each of the plurality of channel image frame information output from the decoding unit, so that delay values of one channel are different from each other. Do not affect the delay value. Also, by restoring the STC as a reference to correspond to the main screen, at least the main screen is normally displayed as in a normal television. As a result, a display device supporting only one PCR can support a PIP function capable of displaying a normal main channel.

On the other hand, the decoding unit 120 is preferably configured as shown in FIG. In this embodiment, since the audio decoder is not considered, the decoding unit 120 largely includes a system decoder 121 for filtering audio data and video data from the transport stream, and a video decoder 125 for decoding the video data. Will be done. In addition, since the inflow of video data into the video decoder 125 should be performed according to whether there is content stored in the frame memory unit, a bit stream buffer unit 123 for storing video data output from the system decoder 121 is additionally provided. Required.

The system decoder 121 separates a plurality of channel transport streams received through the receiver 110 into selective audio data and a plurality of video data, and references the system from a PCR (Program Clock Reference) of the main channel transport stream. The STC is restored and output. Since the present invention is directed to a display device that supports only one PCR, the STC restored by the system decoder 121 becomes a value corresponding to one PCR, and the transport stream of the main channel among the transport channels of the plurality of channels is selected. It is preferable to make it a target.

The bit stream buffer unit 123 includes as many sub bit stream buffers as the number corresponding to video data output from the system decoder 121 so that video data corresponding to one channel is stored in one sub bit stream buffer. . Although the bit stream buffer unit 123 may be configured as one sub bit stream buffer, the plurality of channels may be alternately stored as shown in FIG. 2, but as the number of channels to be implemented as PIP increases, problems in processing speed may occur. There is a possibility to occur. Therefore, it is desirable to construct a plurality of sub-bit stream buffers, and to make each of them correspond to the sub-frame memory to achieve consistent data processing. For example, the sub bit stream buffer 0 and the sub frame memory 0 may store information on the main screen (video data and video frame information).

The video decoder 125 decodes the video data stored in the bit stream buffer unit to output image frame information. The video decoder unit 125 performs the bit stream buffer when the frame memory unit 130 is empty. It should be configured to import the video data of the unit 123. If not, overflow may occur.

4 illustrates a number of sub storage units (sub bit stream buffer, sub corresponding to the number of channels for which both the bit stream buffer unit and the frame memory unit are to be represented as PIP in a display device supporting only one PCR. Frame memory) to smoothly implement a large number of PIPs.

In the above embodiment, as an alternative to the PCR for the subchannel, that is, the STC cannot be considered, a method of providing a randomly consistent delay value has been disclosed. Thus, even if it is possible to implement PIP without any difficulty, it is never preferable. Is clear. First of all, a separate component for giving a consistent delay value should be added, and the configuration for not comparing with the STC does not pass through the image frame information output unit 140 of FIG. need. Through this, even if it is possible to provide a sub-channel (sub screen) without any inconvenience to the user, it is inevitable to have a time difference with the real broadcast, and in general, by applying a consistent delay value to the CTS that changes frequently, the screen is cut off. Loss can occur, which can be a factor in reducing user confidence in the long run.

Therefore, there is a need for improvement. In the following, the STC for the main channel can be compared with the CTS of the subchannel, that is, the function of the image frame information output unit of FIG. 3 can be applied to the subchannel to simplify the configuration. And we will look at how to enable the normal output for the sub-channel.

In general, the PCR of the subchannel transport stream, that is, the PCR of the sub transport stream, is left with a constant offset from the main transport stream as shown in FIG. 5. The CTS value of the video data may be adjusted and compared with the reconstructed STC by referring to the PCR of the main transport stream.

That is, the CTS (New_Sub_CTS) of the transport stream (sub channel transport stream) excluding the main channel is defined by Equation 1 below to enable comparison with the STC of the main channel.

New_Sub_CTS = C_Sub_CTS-(F_Sub_CTS-F_STC_Time)

C_Sub_CTS: CTS of data in current subchannel transport stream

F_Sub_CTS: CTS of data in first subchannel transport stream

F_STC_Time: STC when F_Sub_CTS is applied

Although the PCR for the subchannel is not referenced even when the first subchannel transport stream is received, the decoding unit extracts the CTS while decoding the data in the subchannel transport stream. At this time, the CTS value does not correspond to the sub-STC restored by the PCR of the original sub-channel, but will be close to it. The offset (= (F_Sub_CTS-F_STC_Time)) for the subchannel is obtained by comparing with the STC. Then, if the offset is subtracted from the CTS of the data in the currently received sub transport stream, the value New_Sub_CTS becomes close to the CTS of the data in the main transport stream. This means that the New_Sub_CTS can be compared with the STC of the main transport stream. The presence of the STC to be compared makes the display of the sub screen normally.

The New_Sub_CTS is output and displayed when the image frame information output unit 140 is compared with the STC and satisfies the STC. Accordingly, the sub channel information does not need to be avoided even in the video frame information output unit, and the main screen and the sub screen can be output in a simpler configuration. Since New_Sub_CTS can be applied to sub audio data of a sub channel, the screen output including the normal audio output is possible even if the user wants to output the sub channel instead of the main channel.

Meanwhile, the embodiment described above may be integrated into one system chip (SoC).

That is, the decoding unit for decoding the transport stream of the plurality of channels received in one one-chip system to output a plurality of image frame information and the STC of the main channel transport stream; A frame memory unit arranged in a number corresponding to the output plurality of image frame information and configured to store the plurality of image frame information for each channel; And when the CTS of the image frame information stored in each subframe memory satisfies the STC, by integrating all of the image frame information output units for outputting the corresponding image frame information, it is desirable to improve design convenience and reduce production cost. .

At the present time, a method for integrating a plurality of tuners is not sufficient, and thus a receiver is not added. However, this may be added according to future technology development. In addition, in the case of the one-chip system, it is preferable to limit the two or four screens including the main screen to implement the PIP to reduce the cost of the one-chip system itself. In particular, in the case of a portable or small display device such as a digital multimedia broadcasting (DMB) terminal, since the screen size is basically small, it is difficult to recognize when the screen size exceeds 4 split screens or PIPs. .

In addition, since a portable display device such as a DMB terminal mostly supports only one PCR, it may be desirable to arrange the one-chip system using the embodiments of FIGS. 3 and 4 or the same.

That is, the receiving unit for receiving the transport stream of the multi-channel DMB terminal; A decoder configured to decode the received plurality of transport streams and output a plurality of video frame information and STCs of a main channel transport stream, and a number corresponding to the output plurality of video frame information, the plurality of video frame information PIP including a frame memory unit including a sub frame memory for storing channels for each channel, and an image frame information output unit for outputting corresponding image frame information when the CTS of the image frame information stored in each sub frame memory satisfies the STC. System-on-chip; And a display unit for displaying the output image frame information, so that the PIP can be implemented with a simple configuration.

On the other hand, the above has mainly dealt with the PIP, it is possible to apply the PIP support configuration according to the present invention even in the case of a split screen different from the PIP concept.

Although the technical spirit of the present invention has been described in detail according to the above-described preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

The present invention can be applied to a case where a PIP or a split screen is to be supported in a display device supporting only one PCR, and in particular, it may be advantageous to apply to a small or portable display device such as a DMB terminal.

1 is a block diagram schematically showing the configuration of a display device supporting only one PCR.

Figure 2 is a block diagram showing a PIP implementation apparatus in a display device that supports only one PCR.

3 is a block diagram showing a PIP-enabled display device according to an embodiment of the present invention.

4 is a block diagram illustrating in detail the decoding unit of FIG. 3.

5 is a graph showing a relationship between a main stream and a sub stream;

* Description of the symbols for the main parts of the drawings *

110 Receiver 120 Decode

130 ... frame memory section 140 ... video frame information output section

Claims (7)

A receiving unit for receiving a transport stream of a plurality of channels; A decoding unit for decoding the received plurality of transport streams and outputting a plurality of image frame information and a system time clock (STC) for the main channel transport stream; A frame memory unit arranged in a number corresponding to the output plurality of image frame information and configured to store the plurality of image frame information for each channel; And And a picture frame information output unit for outputting the corresponding picture frame information when the composition time stamp (CTS) of the picture frame information stored in each subframe memory satisfies the STC. . The method according to claim 1, The decoding unit A system decoder for separating the received plurality of transport streams into selective audio data and a plurality of video data, and restoring and outputting an STC which is a system reference from a PCR (Program Clock Reference) of the main channel transport stream; A bit stream buffer unit disposed in a number corresponding to the plurality of video data and configured to store the plurality of video data for each channel; And And a video decoder which decodes the video data stored in the bit stream buffer unit and outputs image frame information. The method according to claim 2, And the video decoder unit loads the video data of the bit stream buffer unit when the frame memory unit is empty. The method according to claim 1, The image frame information output unit And a display device for checking whether or not the frame memory unit is stored for each display clock. The method according to any one of claims 1 to 4, The CTS (New_Sub_CTS) of the transport stream (sub channel transport stream) except for the main channel is represented by the following equation. New_Sub_CTS = C_Sub_CTS-(F_Sub_CTS-F_STC_Time) C_Sub_CTS: CTS of data in current subchannel transport stream F_Sub_CTS: CTS of data in first subchannel transport stream F_STC_Time: STC when F_Sub_CTS is applied PIP support display device, characterized in that defined by. A decoding unit to decode the received transport streams of the plurality of channels and output a plurality of image frame information and STCs for the main channel transport stream; A frame memory unit arranged in a number corresponding to the output plurality of image frame information and configured to store the plurality of image frame information for each channel; And And a video frame information output unit for outputting the corresponding video frame information when the CTS of the image frame information stored in each subframe memory satisfies the STC. A receiving unit for receiving a transport stream of a plurality of channels; A decoding unit configured to decode the received plurality of channel transport streams and output a plurality of image frame information and STCs for a main channel transport stream; And a frame memory unit configured to store information for each channel, and a video frame information output unit for outputting corresponding image frame information when the CTS of the image frame information stored in each sub frame memory satisfies the STC. PIP support system on chip; And And a display unit for displaying the output image frame information. A digital multimedia broadcasting (DMB) terminal supporting a PIP including only one PCR.

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