JP3549461B2 - Channel selection method for digital broadcast receiver - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for selecting a digital broadcast receiver, and more particularly to a method for selecting a carrier and a transponder, obtaining identification information of video and audio from broadcast radio waves, and outputting video and audio. .
[0002]
[Prior art]
In digital broadcasting, the contents of one or a plurality of broadcast programs are compressed by an MPEG2 encoder, and the video and audio of the broadcast programs are numbered by arbitrary identification information called PID, respectively, and transport packets (TP ) Is packetized into one packet of 188 bytes and transmitted in a time-division manner. This set of TPs is called a transport stream (TS).
[0003]
In order to view a desired broadcast program, a transport packet (TP) in which one or a plurality of broadcast programs are multiplexed is used to convert video and audio transport packets to be viewed, and video and audio constituting the broadcast program. It is necessary to extract a transport packet (TP) of program specification information, called PSI, which contains information indicating the relevance of the PID, which is the identification information of the PID.
[0004]
Information indicating a currently transmitted broadcast program is referred to as a PAT (Program Association Table), and information indicating the relationship between PIDs, which are identification information of video and audio for each broadcast program, is referred to as a PMT (Program MapTable).
[0005]
The PAT contains all the currently transmitted broadcast programs. One broadcast program is identified by a program number, and has a one-to-one relationship with the PMT that contains detailed information of the broadcast program. Yes, it is.
[0006]
Inside the PMT, ES PID (Elementary) such as video identification information (Video Stream PID), audio identification information (Audio Stream PID), and time reference information identification information (PCR PID) related to the corresponding broadcast program. PID).
[0007]
Therefore, to watch a broadcast program, first, a PAT, which is PSI information, is acquired, a PMT corresponding to a broadcast program to be viewed is received, video identification information (Video stream PID), and audio identification information (Audio Stream). PID) and identification information (PCR PID) of a PCR (Program Clock Reference) that stores time information serving as a reference time for reproducing video and audio.
[0008]
Also, at the time when the reproduction of the video and audio of the broadcast program obtained from the PSI is started, the output of the video and audio is not performed at the same time, so that the video and audio are not synchronized.
[0009]
Therefore, in order to synchronize the video and the audio, the value of the PCR, which is the reference time, is synchronized with the oscillation speed of the PLL clock of the receiver, and then the reproduction time of the video stream and the audio stream respectively. The PTS (Presentation Time Stamp) is synchronized with the value counted up by the PLL clock of the receiver.
[0010]
Furthermore, in recent digital broadcasting, there is a case where a different video format is transmitted for each broadcast program. In this case, the digital broadcast receiver detects the video format and sets the video display circuit of the receiver. Must be adjusted to the received video format. In order to acquire the video format, it is necessary to refer to the contents of the Sequence Header added to the video stream at regular intervals.
[0011]
The channel selection time in a digital broadcast receiver is mainly the time from setting of the tuner unit to tuning, PAT / PMT reception wait time, video format information detection time, and A / V synchronization (lip sync). Processing).
[0012]
Of the time elements of these channel selection processes, the time excluding the time from the setting of the tuner unit to the tuning is the necessary information for receiving the information necessary for each process from the transport stream (TS). Greatly depends on the time of the retransmission cycle.
[0013]
In other words, the time required for the tuning process (tuning time)
Tuning time = tuning time of tuner section + PAT retransmission cycle + PMT retransmission cycle + Sequence Header retransmission cycle This is given by the above equation, but as shown by the above equation, it largely depends on the time of the retransmission cycle of necessary information.
[0014]
As an example of a retransmission cycle of each information, the United States ATSC standard (United States Advanced Television Committee) defines the retransmission time of each information as follows.
PAT retransmission cycle = 100 ms
PMT retransmission cycle = 400 ms
Sequence Header transmission cycle = 500 ms
With a receiver that conforms to this broadcasting standard, it can be easily estimated that it takes about one second from the PSI reception processing until video and audio are output.
[0015]
[Problems to be solved by the invention]
However, according to the conventional channel selection method, until the identification information of the video (Video Stream PID) and the identification information of the audio (Audio Stream PID) are obtained, the reception of the PAT, the reception of the PMT, and the reception of the PMT are waited. Since the reception processing of the PAT and the PMT starts after the reception of the channel is completed, the time required for acquiring the PAT and the PMT is large in the entire channel selection time.
[0016]
Further, according to the conventional tuning method, the sequential processing is performed while waiting until necessary information can be obtained, so that the efficiency of the tuning processing cannot be increased.
[0017]
SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to provide a tuning method that speeds up tuning processing and improves responsiveness of a user operation.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, a method for selecting a channel in a digital broadcast receiver according to the present invention uses a channel number of a desired broadcast program, a program number, or information for identifying a broadcast program. And an A / V identification information predicting step for obtaining identification information (Video Stream PID), audio identification information (Audio Stream PID) and identification information (PCR PID) of time reference information included in the information. The video identification information (Video Stream PID), audio identification information (Audio Stream PID), and time reference information identification information (PCR PID) obtained in the above A / V identification information prediction process are provisionally determined identification information. The preparation for reproducing the video and audio is performed in parallel with the reception processing of the information (PAT) indicating the broadcast program and the reception processing of the information (PMT) indicating the relevance of the PID which is the identification information of the video and audio for each broadcast program. A / V provisional reproduction process, which performs video format detection, PCR reproduction processing, and A / V synchronization processing in advance. An A / V identification information comparing step of comparing the identification information obtained in the A / V identification information prediction step with the identification information obtained from the PAT and the PMT is provided. After confirming that the identification information predicted in the prediction process is correct, a video and a sound which are already prepared in the A / V provisional reproduction process are immediately output.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a digital broadcast receiver to which an embodiment of a tuning method according to the present invention is applied.
[0020]
In FIG. 1, reference numeral 10 denotes a receiving antenna, 11 denotes a remote control light receiving unit, 12 denotes a video output terminal, 13 denotes an audio output terminal, 100 denotes a tuner unit, and 101 denotes a signal input from the tuner unit 100 as a digital signal (TS). A digital demodulation / error correction unit for demodulating and error correcting to 102; a channel selection instruction unit 102 for receiving a channel selection instruction from a user; 103 a demultiplexer for separating a digital signal into video data, audio data, and PSI data; Reference numeral 104 denotes a video decoder for decoding video data into a video signal; 105, an audio decoder for decoding audio data into an audio signal; 106, a PSI analysis unit for expanding and analyzing PSI information; 107, a channel selection instruction unit 102 and a PSI analysis unit The video PI to operate and output the demultiplexer 103 according to the information from 107 Channel selection control unit for switching and audio PID, 108 is a video display control section for controlling the output of the video signal, 109 is an audio output control unit which controls the output of the audio signal.
[0021]
FIG. 2 is a flowchart showing the flow of the channel selection processing according to the present embodiment, and the channel selection method of the present embodiment will be described along this processing flow.
[0022]
First, a tuning process is started by an instruction from the tuning instruction unit 102 (step S200).
[0023]
Next, in the process of stopping the A / V output in step S201, the video and audio information may be changed in the middle by the channel selection operation, and the video and audio may be disturbed. Stop outputting the audio signal.
[0024]
Next, in the tuner setting and tuning process (tuner setting, carrier detection process) in step S202, a frequency to be set for tuning is obtained based on the channel number specified by the channel selection instruction unit 102, and the tuner unit 100 is sent to the tuner unit 100. The frequency is set, and the process waits until the tuner unit 100 detects that it has tuned to the broadcast radio wave.
[0025]
As the tuner unit 100 tunes, the received signal is decoded into digital data by the digital demodulation / error correction unit 101, and the digital signal starts flowing to the demultiplexer 103.
[0026]
As a result, in the PAT receiving process of step S203, an instruction for PAT receiving processing is issued. Next, in the PAT analyzing process of step S204, the PSI analyzing unit 106 expands and analyzes the received PSI information, and PID is required.
[0027]
In the PMT receiving process of step S205 following step S204, the tuning control unit 107 instructs the PSI analyzing unit 106 to perform a PMT receiving process, and the PMT received by the PSI analyzing unit 106 is transmitted to the next step S206. In the PMT analysis step S206, the data is expanded and analyzed to obtain the PID of the audio stream, the PID of the video stream, and the identification information (PCR PID) of the time reference information.
[0028]
On the other hand, in parallel with the above-described processing from the PAT receiving step (step S203) to the PMT analyzing step (step S206), the next A / V identification information prediction step (step S207) and the A / V temporary reproduction step (step S208) ) Are performed simultaneously.
[0029]
That is, in the A / V identification information prediction process in step S207, prediction processing of Audio Stream PID, Videos Stream PID, and PCR PID is performed based on the channel number specified by the channel selection instruction unit 102, and ES PID ( Elementary PID).
[0030]
In the A / V provisional reproduction process of step S208 following step S207, the obtained ES PID (Elementary PID) is registered in the demultiplexer 103, and the video or audio bit stream data on which the PID filtering has been performed by the demultiplexer 103 is , Respectively, to the video decoder 104 and the audio decoder 105.
[0031]
When the bit stream data starts flowing to the video decoder 104 and the audio decoder 105, the acquisition of the video format information, the adjustment of the setting value of the video display system, and the A / V synchronization process are performed. However, at this time, the output from the video display control unit 108 and the audio output control unit 109 to the output terminals 12 and 13 is not performed.
[0032]
When the A / V provisional reproduction process (S208) and the PMT analysis process (S206) are completed, the ES obtained by the PMT analysis process (Step S206) in the A / V identification information comparison process of Step S209. The PID (Elementary PID) is compared with the ES PID (Elementary PID) obtained by the A / V identification information prediction process (Step S207), and the result of the A / V identification information prediction process (Step S207) is correct. It is determined whether or not.
[0033]
As a result of the comparison of the ES PID (Elementary PID) in the A / V identification information comparison process (Step S209), when the results match, it can be determined that the result of the A / V identification information prediction process (Step S207) has been correctly predicted. As described above, if the result of the comparison of the ES PID (Elementary PID) in the A / V identification information comparison process (Step S209) shows that the two match, the A / V temporary reproduction process (Step S208) preliminarily compares the video with the video. Since preparation for audio output is ready, the process immediately proceeds to the A / V output start process in step S211 and immediately outputs a video signal to the video output terminal 12 and an audio signal to the audio output terminal 13, respectively.
[0034]
If the result of the comparison of the ES PID (Elementary PID) in the A / V identification information comparison process (step S209) does not match, the result of the A / V identification information prediction process (step S207) can be correctly predicted. It is determined that there is not, and the process proceeds to the A / V reproduction preparation process of step S210. In the A / V reproduction preparation process (step S210), the ES PID (Elementary PID) obtained in the PMT analysis process (step S206) is registered in the demultiplexer 103, and the PID filtering is performed by the demultiplexer 103 on the video or audio. Since the bit stream data starts flowing to the video decoder 104 and the audio decoder 105, acquisition of video format information, adjustment of set values of a video display system, and A / V synchronization processing are performed. After waiting for the completion of the A / V reproduction preparation process (step S210), in the A / V output start process of step S211 the video signal is sent to the video output terminal 12 and the audio signal is sent to the audio output terminal 13. Are respectively output.
[0035]
Thus, the tuning process is completed in step S212.
[0036]
Next, an example of a prediction method performed in the A / V identification information prediction process (step S207) of FIG. 2 will be described.
[0037]
ATSC DIGITAL TELEVISION STANDARD A / 53 The video and audio PIDs are obtained by the channel number specified at the time of channel selection, based on the example defined in “5.3 The program paradigm”.
[0038]
According to ATSC DIGITAL TELEVISION STANDARD A / 53 "5.3 The program paradigm", there are the following examples of PMT PID, VIDEO PID, AUDIO PID, and PCR PID.
[0039]
First, base PID = program number≪4 PMT PID = base PID + 0 × 0000
VIDEO PID = base PID + 0 × 0001
PCR PID = base PID + 0 × 0001
AUDIO PID = base PID + 0x0004
According to this example, if the broadcast signal conforms to the ATSC, various PIDs can be predicted by obtaining the Program Number without obtaining the PAT / PMT.
[0040]
According to this prediction method, when the channel number for identifying the broadcast program of the U.S. terrestrial broadcast (DTV) is "35.03", in the DTV, "35" identifies the RF frequency at which the broadcast wave is carried. Channel number to be used for setting the tuner section.
[0041]
“03” is “Program Number” and is used as a number for identifying a broadcast program carried in the same RF frequency band. Based on the Program Number “03”, various identification information can be predicted as follows according to the range of the ATSC standard.
[0042]
PMT PID = 0x0030
VIDEO PID = 0x0031
・ PCR PID = 0 × 0031
AUDIO PID = 0x0034
Although this prediction method has been described as a specific example in the case where the present invention is applied to U.S. terrestrial information (DTV), the prediction method is not limited to this example and is within a range not departing from the spirit of the present invention. Therefore, the prediction method should be changed according to the digital broadcasting standard to which the present invention is applied.
[0043]
FIG. 3 is a flowchart showing a conventional general tuning method without using the tuning method of the above-described embodiment. Steps S301 to S306 in FIG. 3 are the same as steps S201 to S206 in FIG. 2, step S307 in FIG. 3 is the same as step S210 in FIG. 2, steps S308 and S309 in FIG. This is the same as S212. That is, the conventional general channel selection method shown in FIG. 3 is different from the channel selection method of the embodiment of the present invention in that steps S207, S208, and S209 shown in FIG.
[0044]
FIG. 4 is a time chart showing a comparison between the tuning time according to the conventional method and the tuning time according to the tuning method of the embodiment of the present invention.
[0045]
In FIG. 4, 400 to 404 indicate elapsed times according to the conventional tuning method, and 500 to 506 indicate elapsed times according to the tuning method according to the embodiment of the present invention.
[0046]
As can be seen from FIG. 4, the progress of the tuning process has almost the same number of steps in all of 300 to 304 and 400 to 406. However, in the tuning method of the present invention, the display system, Since the output preparation of the audio system can be performed in advance, the channel selection processing can be completed in a time obtained by adding the step 505 to the steps 400 to 402 of the conventional channel selection method.
[0047]
【The invention's effect】
As described above, according to the present invention, in a digital broadcast receiver, channel selection processing can be efficiently performed in a shorter time, and responsiveness of a user operation can be improved.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a digital broadcast receiver to which a tuning method according to an embodiment of the present invention is applied.
FIG. 2 is a flowchart illustrating a flow of a tuning process according to an embodiment of the present invention.
FIG. 3 is a flowchart showing a flow of a conventional general tuning process.
FIG. 4 is a time chart showing a comparison between a conventional tuning process time and a tuning process time according to an embodiment of the present invention.
[Explanation of symbols]
Reference Signs List 10 receiving antenna 11 remote control light receiving section 12 video output terminal 13 audio output terminal 100 tuner section 101 digital demodulation / error correction section 102 tuning selection section 103 demultiplexer 104 video decoder 105 audio decoder 106 PSI analysis section 107 tuning control section 108 video Display control unit 109 Audio output control unit S200 Tuning process start S201 A / V output stop process S202 Tuner setting and tuning process S203 PAT reception process S204 PAT analysis process S205 PMT reception process S206 PMT analysis process S207 A / V identification information prediction process S208 A / V provisional reproduction process S209 A / V identification information comparison process S210 A / V reproduction preparation process S211 A / V output start process S212 Tuning process completion S300 Tuning process start S301 A / V output stop Step S302 Tuner setting and tuning step S303 PAT reception step S304 PAT analysis step S305 PMT reception step S306 PMT analysis step S307 A / V reproduction preparation step S308 A / V output start step S309 Tuning processing completion 400 Tuning processing start 401 PAT reception Step 402 PMT reception step 403 A / V reproduction preparation step 404 Tuning processing completion 500 Tuning processing start 501 PAT reception step 502 PMT reception step 503 A / V identification information prediction step 504 A / V provisional reproduction step 505 A / V identification Information comparison process 506 Tuning process completed

Claims (1)

A desired broadcast program is detected from a digital broadcast wave obtained by multiplexing at least one broadcast program, and video identification information (Video Stream PID), audio identification information (Audio Stream PID), and identification information (PCR PID) of time reference information are detected. A channel selection method for reproducing video and audio,
Using the channel number or program number of the desired broadcast program or information for identifying the broadcast program, video identification information (Video Stream PID) and audio identification information (Audio Stream PID) included in the received digital broadcast wave and a / V identification information prediction process for obtaining the identification information of the time reference information (PCR PID) and,
The video identification information ( Video Stream PID ), audio identification information ( Audio Stream PID ) and time reference information identification information ( PCR PID ) obtained by the A / V identification information prediction process are used as provisionally determined identification information. An A / V provisional playback process that precedes video and audio playback preparation,
The operation of the A / V identification information prediction step and the A / V provisional reproduction step is performed in parallel with the operation of a step of obtaining information of a broadcast program included in a digital broadcast wave,
The A / V identification information prediction process includes the video identification information ( Video Stream PID ), audio identification information ( Audio Stream PID ), time reference information identification information ( PCR PID ), and digital broadcast waves. The result of comparing the video identification information ( Video Stream PID ), the audio identification information ( Audio Stream PID ), and the time reference information identification information ( PCR PID ) obtained in the process of acquiring the broadcast program information , and comparing the results. If the two pieces of identification information match each other, video and audio are immediately output based on the playback preparation performed in the A / V provisional playback process, and as a result of the comparison, if the two pieces of identification information do not match, identification information of the image identification information obtained by the process of acquiring the information of the broadcast program included in the digital broadcast (video Stream PID) and voice identification information (audio Stream PID) and time reference information (PCR PID) DOO, the channel selection method for a digital broadcast receiver and outputs video, audio performs playback preparation of the video and audio.

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