KR20110029043A - Method for channel controlling in mage displa device - Google Patents

Abstract

PURPOSE: A method for controlling a channel in mage display device is provided to promptly cope with a problem related to a data reception error by automatically detecting a PID(Packet IDentifier). CONSTITUTION: A TP(Transport) parser(12) extracts audio, video and additional PID(Packet IDeitifier) of a selected channel through a tuner(10), and audio/video decoders(14,18) decode a voice signal stream/video signal stream compressed by the extracted audio/video PID. If a predetermined audio/video PID exists, a microcomputer(24) sets up a corresponding audio/video PID at the TP parser. The microcomputer receives the feedback for the decoded audio/video signal.

Description

Channel control method in video display device {Method for channel controlling in mage displa device}

The present invention relates to a TV, and more particularly, to a channel control apparatus and method for a digital TV.

In general, digital satellite broadcasting requires multiplexing of TV signals. When multiplexing such TV signals (audio / video signals), each of the video audio is divided into a string of appropriate lengths called packets. The video and audio packets are appropriately switched by attaching additional information such as a header and transmitted to the repeater (communication satellite) in a time division transmission method.

The packet transmitted through the repeater (communication satellite) is restored to the original signal through the subscriber's Digital Brodcasting System (DBS) receiver, thereby enabling viewing of the channel transmitted from the broadcasting station. At this time, the broadcasting station converts the video, audio and transmission data signals into a scrambled digital signal according to the Moving Picture Experts Group (MPEG) standard. It consists of a stream to make one TV signal stream.

The packet stream is a signal composed of 188 bytes, and the signal may be divided into a header and a payload portion. The header part includes information indicating the start of a signal and a PID (packet identifier) number indicating what signal is a signal contained in the payload unit.

The payload portion contains image information, audio information or additional information to be transmitted. The PID (packet identifier) number provides a means for demultiplexing a time multiplexed signal. The PID identifier determines whether the current packet is a video packet, an audio packet, or an additional information (SI) packet. Can be identified.

The video and audio standard is a standard for compressed video and audio signal sequences. Video, audio, and other additional information are time-multiplexed and carried in multiple transport stream packets, which are also distinguished by PID numbers. That is, the PID number is an identification number indicating whether the current packet is a video packet, an audio packet, or additional information (PSI). In the US digital TV standard, PSIP (Program And System Information Protocol) is included in the additional information. do.

As described above, DTV broadcasting receives TS and checks PID. Air broadcasting uses PID information of TVCT table as first priority and cable broadcasting uses PID information of CVCT table as first priority. At this time, if the TVCT / CVCT table does not exist, an error occurs during video or audio decoding, and it stops in a state in which no action is taken.

The present invention is to solve the above problems and to provide a video display device and a control method for solving the problems of data errors occurring on the field.

The present invention for achieving the above object is a tuner for selecting a channel according to the channel increase and decrease key input by the user; A TP (Transport) parser for extracting audio, video, and additional information PIDs of selected channels through the tuner; A memory for storing audio, video, and additional information PIDs extracted by the TP parser; An audio / video decoder which receives and decodes the audio signal sequence / video signal sequence compressed by the extracted audio / video PID; It is determined whether the audio / video PID of the selected channel is previously stored in the memory, and if the pre-stored audio / video PID exists, the corresponding audio / video PID is set in the TP parser and decoded by the audio / video decoder. And a micom configured to control whether to reset the audio / video PID by receiving a feedback of an audio / video signal.

As described above, the present invention has an effect of quickly and accurately coping with a problem of data reception error by automatically searching for a PID.

Hereinafter, an operation of an image display device according to the present invention will be described in detail with reference to the accompanying drawings. 1 is a block diagram of a video display device to which the present invention is applied.

1 is a block diagram of a video display device to which the present invention is applied. Referring to FIG. 1, a tuner 10 receiving a VSB (Quadrature Side Band) or QAM (Quadrature Amplitude Modulation) signal received from an antenna and outputting a transport signal sequence, and a transport signal sequence output through the tuner 10 A TP parser 12 for receiving the demultiplexed signal, an audio decoder 14 for receiving and decoding the demultiplexed voice signal through the TP parser 12, and the audio decoder 14 of the audio decoder 14; It includes an audio processor 16 for converting the output signal into an analog signal to be output through the speaker.

In addition, the video decoder 18 receives and decodes the demultiplexed video signal through the TP parser 12, a user interface 22 for outputting a signal desired by the user, and additional information from the TP parser 3. Extract and process a microcomputer 10 for outputting a control signal according to a user request applied by the user interface 9, a memory 11 for storing additional information under the control of the microcomputer 10, and And a switching unit 7 for selectively outputting the output of the video decoder 6 or the OSD processor 12 according to the control signal of the microcomputer 10, and a screen selected by receiving the signal selected by the switching unit 7. It consists of an NTSC encoder 8 for converting into a video signal displayable on the image.

The digital TV configured as described above operates as follows.

The tuner 2 receives and detects a VSB or QAM signal from the antenna 1, corrects an error, and outputs a transport signal sequence. The TP parser 3 receives the transport signal sequence and performs demultiplexing. do. Here, the demultiplexing means detecting a PID number and dividing the video signal sequence into a video signal sequence, an audio signal sequence, and an additional information signal sequence. The audio signal sequence is applied to the audio decoder 14, and the video signal sequence is applied to the video decoder 18. The additional information signal string is applied to the microcomputer 24.

The audio decoder 14 expands the voice signal string compressed in the Dolby AC3 format and outputs the audio signal to the audio processor 16. The audio processor 16 converts the digital voice signal into an analog voice signal and converts the left and right speakers. Is output via The video decoder 18 extends the video signal sequence compressed with MPEG-3 and outputs the video signal to the video processor 20.

The microcomputer 24 extracts and processes the output from the TP parser 12 and outputs a control signal to correspond to user-specific requests applied through the user interface 22 such as a remote controller or a key operation.

FIG. 2 is a format diagram of a transport packet in a transport stream, and FIG. 3 is an exemplary format diagram of a packet having a program association table (PAT) and a packet having a specific program map table (PMT) among transport packets. . First, as shown in FIG. 2, a transport packet in an MPEG-2 transport stream is 188 bytes, and is composed of a packet header HEADER and a packet payload. The packet header is 4 bytes, and if there is no adaptation field (ADAPTATION_FIELD) in the packet payload, the packet payload is 184 bytes. The header includes 13 bits of Program Identification Information (PID).

The packet containing the data for the stream corresponding to the desired channel will have its own PID. However, the transport decoder 112 does not recognize the PID that must be read from the newly input transport stream. The transport decoder must first extract and confirm program description information (PSI) from the transport stream in order to recognize such a PID. That is, the transport decoder 112 must first wait for a transport packet (PID = 0x0000) P1 having a Program Association Table (PAT). The PAT is provided with information (ie PID of the corresponding transport packet) indicating a transport packet having a program map table (PMT) for each program.

The PMT is provided with information (i.e., PID of the corresponding transport packet) indicating in which transport packet the video and audio bit strings constituting the program are carried. As such, the transport decoder 112 first waits for a transport packet P1 having a PAT, receives the input packet, and analyzes the received packet. The transport decoder 112 includes a PMT of a corresponding desired program (program number = 1 in the example of FIG. 4). The PID of the transport packet (PID = PMT PID1 in the example of FIG. 3) is checked, and the transport packet P2 having the PID is waited.

Thereafter, the transport packet P2 having such a PMT is read to identify the PID of the desired transport packet. Thereafter, the transport packet for the elementary stream PES of the desired program having the PID is recognized and the elementary stream is recognized. Will be supplied to the decoder.

In particular, the video display device according to an embodiment of the present invention preferentially refers to TVCT as the first priority in the case of airwaves when checking PIDs, but does not execute video playback when there is no PID identified during video playback. At this time, the PID information existing in the PMT is acquired to perform video or audio reproduction.

4 to 5 are flowcharts of an image reproducing operation according to an exemplary embodiment of the present invention. The above-described configuration will be described in detail with reference to FIGS. 4 to 5.

The microcomputer 24 receives a request signal for a channel change such as a screen change request through the user interface 22 and outputs it to the decoder (step 405). The decoder receives the screen change request signal received from the controller 24. In step 410, a request signal for searching for TVCT received according to the PSIP standard is transmitted to the transport stream and the PID is confirmed. (Step 415). The PID is then separated into audio data and video data. And stores the data in the memory unit 26 and performs audio or video decoding with the stored data (step 420) to output the corresponding video or audio. The memory unit 26 stores the data and decodes the data even though the data is not normal. Therefore, as shown in FIG. 5, an operation for decoding error data is performed.

The microcomputer 24 performs video decoding to output an image. (Step 505) Check whether an error occurs while performing the decoding (step 510). If an error occurs in the decoding step, the information on the PID checked by the TVCT or CVCT is performed. Detect errors on

Accordingly, the microcomputer 24 searches for the same PID in the PMT (step 515), checks the corresponding PID (step 520), and re-decodes the video using the PID information read from the PMT (step 525). To print.

1 is a block diagram of a video display device to which an embodiment of the present invention is applied.

2 is a format diagram of a transport packet in a transport stream;

3 is an exemplary format diagram of a packet having a program association table (PAT) and a packet having a specific program map table (PMT) among transport packets.

4 is a flowchart illustrating channel data acquisition operations according to an embodiment of the present invention.

5 is a flowchart illustrating an image output operation according to an exemplary embodiment of the present invention.

Claims (5)

A tuner for selecting a channel according to a channel up / down key input by a user; A TP (Transport) parser for extracting audio, video, and additional information PIDs of selected channels through the tuner; A memory for storing audio, video, and additional information PIDs extracted by the TP parser; An audio / video decoder which receives and decodes the audio signal sequence / video signal sequence compressed by the extracted audio / video PID; It is determined whether the audio / video PID of the selected channel is previously stored in the memory, and if the pre-stored audio / video PID exists, the corresponding audio / video PID is set in the TP parser and decoded by the audio / video decoder. And a microcomputer to control whether to reset the audio / video PID by receiving a feedback of an audio / video signal. The video display device of claim 1, wherein the microcomputer receives the audio signal sequence / video signal sequence and re-requests the decoding by requesting the PID from the PMT when an error occurs in the stored PID during decoding. Selecting a predetermined channel by a user request; Determining whether audio PID and video PID of the selected channel are previously stored in the memory; Setting the stored audio PID and the video PID to the TP parser if the audio PID and the video PID of the selected channel are already stored; Receiving audio and video PIDs set in the TP parser and decoding the audio and video signals to be output; And terminating the routine when the decoded audio and video signals are normally output. The method of claim 3, further comprising: extracting a PAT / PMT (Program Association Table / Program Map Table) from the transport stream when packet data of the PID is not retrieved; And updating the pre-stored PSI contents through the extracted PAT / PMT. The method of claim 3, wherein the PAT / PMT is extracted from the transport stream at a predetermined period to update the pre-stored data.

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