KR101495881B1 - Adaptive method of providing fast synchronization of audio signals for seamless link in a heterogeneous audio broadcast receiver, and computer-readable recording medium for the same - Google Patents

Abstract

The present invention generally relates to a technology of adaptively fast processing a sound source synchronization procedure for a seamless link in a heterogeneous audio broadcast receiver. More specifically, the present invention relates to a technology of seamlessly processing an audio signal to receive broadcast, in which, when a broadcasting receiving module is rapidly switched while the broadcasting program is maintained during the listening of broadcasting due to a broadcasting coverage or a shadow area in the heterogeneous audio broadcast receiver having different broadcasting receiving modules, the sound source synchronization procedure, which must be performed to seamlessly link audio so that a user can be satisfied with the audio, is adaptively fast processed without preventing the audio from being temporarily disconnected or repeated or to prevent an audio volume from being rapidly increased or decreased. Accordingly, the seamless link can be effectively accomplished even in a low-specification receiver. According to the present invention, when a switching operation is performed between broadcast receiving paths in the heterogeneous audio broadcast receiver, time to compute the sound source synchronization algorithm is reduced, so that the seamless link can be accomplished without burden even in the low-specification process employed through a system-on-chip scheme. Accordingly, the user satisfaction for the heterogeneous audio broadcast receiver can be improved.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adaptive fast processing method for seamless synchronization in a heterogeneous audio broadcast receiving apparatus and a computer readable recording medium therefor. recording medium for the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention generally relates to a technique for adaptively and rapidly processing a sound source synchronization process for a seamless link in a heterogeneous audio broadcast receiving apparatus. More particularly, the present invention relates to a heterogeneous audio broadcast receiving apparatus having a different type of broadcast receiving module, and more particularly, to a broadcast receiving apparatus capable of rapidly switching a broadcasting receiving module while maintaining the same broadcasting program while listening to broadcasting, The sound source synchronization process that must be performed in order to seamlessly link the audio to satisfy the user without causing the sudden increase or decrease of the audio volume or the phenomenon of the audio interruption or repetition of the audio in the case of the audio interruption So that the seamless link can be effectively achieved even in a low-end receiving apparatus.

In order to achieve a seamless link of a broadcast receiving path in a heterogeneous audio broadcast receiving apparatus, a process of synchronizing these audio streams is required. When the sound source synchronization algorithm is implemented in a low - end embedded system, it takes a considerable time to acquire the synchronous result value because the processor processing capability is insufficient. Accordingly, the present invention relates to a technique for shortening the time for obtaining the synchronization result value, and is applicable to various types of heterodyne audio broadcasting receiving apparatuses, for example, a DAB / DAB + / DMB-A digital radio or a FM analog radio dual- can do.

Efforts are being made to digitally convert existing analog audio broadcasts worldwide. The main motivation to switch to digital broadcasting is improving sound quality, saving frequency resources, and expanding various broadcasting services. However, in spite of these many advantages, digital conversion is proceeding progressively because huge facility investment should be preceded in order to convert to digital broadcasting. In fact, in most countries as of 2014, broadcasting services are being performed with existing analog audio broadcasting and digital audio broadcasting mixed.

Comparing the advantages and disadvantages of analog broadcasting and digital broadcasting, existing analog broadcasting shows strength in terms of broadcasting reception coverage and digital audio broadcasting shows strength in terms of audio quality. Therefore, in recent years, there is a need for a heterogeneous audio broadcast receiving apparatus that simultaneously receives analog / digital audio broadcasts in order to take advantage of all of these advantages. The heterogeneous audio broadcast receiving apparatus automatically links the broadcast reception path between the digital and analog to the advantageous according to the broadcast reception environment for the same broadcast program to link (link) the audio.

This heterogeneous audio broadcasting environment will be described using DAB and FM as an example. In a heterogeneous audio broadcast receiving environment, a broadcasting station generally simultaneously transmits the same broadcasting to FM and DAB for broadening coverage coverage, and FIG. 1 conceptually shows such a situation. Through the method of FIG. 1, a user generally enjoys high-quality audio of a DAB digital broadcast and then enters an area where the DAB digital broadcast can not be received, thereby switching to an FM analog broadcast to continuously listen to the audio. This can reduce coverage areas and broaden coverage areas.

However, the difference between the signal transmission method, the difference according to the arrival time of the radio wave, and the difference in the processing delay within the receiving apparatus are reflected in a complex manner. Amplitude) of the audio signal and the time synchronization (timing) of the audio signal do not match exactly. If the receiver only performs automatic switching without solving this problem, the listener will feel nervous.

Therefore, there is a need for a technique for allowing audio broadcasts to be disconnected in a heterogeneous audio broadcast receiving apparatus or to smoothly connect the volume without suddenly changing the volume. Such a technical problem is generally referred to as a seamless link. Various sound source synchronization algorithms have been conventionally proposed in order to achieve a level of seamless link satisfying a user in a heterogeneous audio broadcasting apparatus.

However, the conventional sound source synchronization algorithm is a method of dividing time into individual samples and processing each sample individually, which requires a tremendous processing in a mathematical operation process. Accordingly, in the conventional sound source synchronization algorithm, it takes a long time to calculate the synchronization of the sound source according to the processor operation processing capability of the embedded system.

In the field of audio broadcasting, real-time processing is very important. When the quality of voice synchronization is increased, the amount of processing computation is increased. Therefore, it takes much time to satisfy the real time property. If the calculation amount is reduced to satisfy real- It will be done. Recently, an audio broadcast receiving apparatus implemented as an embedded system is generally implemented as a system-on-chip having an ARM core having an operating frequency of about 220 MHz. In the heterogeneous heterogeneous audio broadcasting receiving apparatus, the sound source synchronization process can not be processed smoothly, resulting in a user's dissatisfaction.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a technique for effectively performing seamless switching seamlessly between different broadcast receiving paths in a heterogeneous audio broadcast receiving apparatus. Typical analog audio broadcasts include AM / FM, and digital audio broadcasts include DAB, DAB +, DRM, and IBOC (HD Radio). Therefore, the present invention can be effectively applied to a heterogeneous audio broadcasting receiving apparatus in which broadcast media are multiplexed and broadcast.

1. Korean Patent Application No. 10-2003-7013838 "Packetized Video Data Processing Method, Image Data Decoding Method, and Video Broadcasting Method"

2. Korean Patent Application No. 10-2009-0018651 "Broadcast signal receiving method and broadcast signal receiving apparatus"

3. Korean Patent Application No. 10-2012-0091955 entitled " Broadcasting Data Continuous Decoding Output Device of Digital Audio Broadcasting "

4. Korean Patent Application No. 10-2006-7003596 entitled " Method and Related Apparatus for seamlessly transferring broadcast and multicast content across cell boundaries and / or between different transmission schemes "

5. Korean Patent Application No. 10-2000-7005332 entitled "Method and Apparatus for Performing Seamless Switching Between Two Digital Video Signals"

6. European Patent Application 98301501.7 "Apparatus for receiving audio broadcast signals"

7. European Patent Application 01103896.5 "Receiver for receiving broadcast signals, comprising two tuners, receiving a broadcast signal transmitted on two different broadcast frequencies or using two different broadcast systems"

8. European patent application 09178508.9 "Audio processing device and method for processing audio signals"

SUMMARY OF THE INVENTION It is an object of the present invention to provide a technology for adaptively and high-speed processing of a sound source synchronization process for a seamless link in a heterogeneous audio broadcast receiving apparatus. In particular, in the heterogeneous audio broadcast receiving apparatus having different broadcast receiving modules, when the broadcast receiving module is rapidly switched while maintaining the same broadcast program during the broadcast listening due to problems such as broadcast coverage and shadow areas, The sound source synchronization process to be performed in order to seamlessly link the audio to satisfy the user without causing a sudden increase or decrease of the audio volume, And to provide a technology that can effectively achieve seamless link even in low-end receiving apparatuses.

According to another aspect of the present invention, there is provided a method for adaptively fast processing a sound source synchronization for a seamless link between audio sample streams in a heterogeneous audio broadcast receiving apparatus, the method comprising: a first step of starting a sound source synchronization process for a specific audio program; A second step of identifying a sound source synchronization operation environment for an audio program based on whether previous sound source synchronization result information for the audio program exists in the storage medium of the heterogeneous audio broadcast receiving apparatus; A correlation calculation interval for the sound source synchronization process is set differently according to the identified sound source synchronization operation environment, and when the previous sound source synchronization result information is present in the storage medium, the correlation calculation interval is set to be shorter step; A fourth step of performing correlation computation between audio sample streams corresponding to the set correlation computation period to estimate at least one of a timing deviation and an amplitude deviation; A fifth step of switching a broadcast reception path for an audio program in a state where sound source synchronization is matched by controlling at least one of buffering delay and sample scaling for an audio sample stream based on the estimation; And storing at least one of the estimated timing deviation and the amplitude deviation in a storage medium by combining the at least one of the estimated timing deviation and the amplitude deviation with the content identification information of the audio program as the sound source synchronization result information for the audio program.

The second step of the present invention comprises the steps of: setting a sound source synchronization operation environment as a first operation environment when previous sound source synchronization result information for an audio program exists in a temporary storage medium of a heterogeneous audio broadcast receiving apparatus; Setting a sound source synchronization operation environment to a second operation environment when the previous sound source synchronization result information for the audio program does not exist in the temporary storage medium and exists in a storage medium for storage of the heterogeneous audio broadcast receiving apparatus; Setting a sound source synchronization operating environment to a third operating environment when the previous sound source synchronization result information for the audio program is not present in any of the temporary storage storage medium and the storage storage medium, Setting a correlation computation period in a first operating environment to a first predetermined value; Setting a correlation computation period in a second operating environment to a second predetermined value that is greater than a first value; And setting a correlation computation interval in a third operating environment to a third predetermined value that is greater than a second value.

In a sixth step, the sound synchronization result information is combined with the content identification information of the audio program and stored in the temporary storage medium of the heterogeneous audio broadcast receiving apparatus. And storing the combination of the sound source synchronization result information stored in the temporary storage medium and the content identification information of the audio program in the storage medium for storage when the heterogeneous audio broadcast receiving apparatus is powered off.

In operation 61, starting a storage process of a storage medium for temporary storage of sound source synchronization result information (hereinafter, referred to as 'current sound source synchronization result information'); Checking whether or not previous sound source synchronization result information for the content identification information exists in the temporary storage medium; Storing the current sound source synchronization result information in a temporary storage medium if the previous sound source synchronization result information does not exist; If the previous sound source synchronization result information exists, the sound source correlation ratio of the current sound source synchronization result information and the previous sound source synchronization result information is compared. If the sound source correlation ratio is larger than the current sound source synchronization result information, And storing the result information in a temporary storage medium.

In the present invention, the content identification information includes at least one of a service identifier and a broadcast identifier for an audio program.

Meanwhile, a computer-readable recording medium according to the present invention records a program for executing a sound source synchronization adaptive fast processing method for a seamless link in a heterogeneous audio broadcast receiving apparatus as described above.

According to the present invention, when switching between broadcast reception paths in a heterogeneous audio broadcast receiving apparatus, it is possible to achieve a seamless link even in a low-end processor currently adopted as a system-on-chip system in a current embedded system by shortening a calculation time of a sound source synchronization algorithm Thus, there is an advantage in that the satisfaction of use of the heterogeneous audio broadcast receiving apparatus can be improved.

FIG. 1 is a diagram conceptually showing a broadcasting station expanding broadcast coverage by broadcasting the same broadcast to DAB digital broadcasting and FM analog broadcasting in a heterogeneous audio broadcasting environment; FIG.
2 is a diagram schematically illustrating a timing deviation of an audio sample stream in a heterogeneous audio broadcast receiving apparatus,
3 is a block diagram conceptually showing a process of processing an audio signal while achieving a seamless link between audio sample streams in a heterogeneous audio broadcast receiving apparatus to which the present invention is applicable;
FIG. 4 is a block diagram conceptually illustrating a process of estimating a timing deviation by a TA estimator through correlation calculation between audio sample streams in a heterogeneous audio broadcast receiving apparatus to which the present invention is applicable; FIG.
5 is a diagram showing an example in which, in the TA estimator, a correlator calculates a cross-correlation degree when a sample block selector selects a correlation diagram block as a C block of a DAB audio sample;
6 is a diagram showing an example of a cross-correlation diagram outputted by a correlator in the present invention,
FIG. 7 is a flowchart showing an overall process of a sound source synchronization adaptive fast processing method for a seamless link according to the present invention;
8 is a flowchart illustrating a process of updating a sound source synchronization result in a storage space according to the present invention;
FIG. 9 is a block diagram of a heterogeneous audio broadcast receiving apparatus according to an exemplary embodiment of the present invention. FIG. 9 is a block diagram of a heterogeneous audio broadcast receiving apparatus according to an embodiment of the present invention. A conceptual diagram of the process of becoming.

Hereinafter, the present invention will be described in detail with reference to the drawings.

2 is a diagram conceptually showing a timing deviation between an audio sample stream (DAB audio samples and FM audio samples) in a heterogeneous audio broadcast receiving apparatus. FIG. Is a block diagram conceptually illustrating a process of processing an audio signal while achieving a seamless link between audio sample streams at a receiver.

Even if the same audio broadcast is simultaneously transmitted to the DAB and the FM in the broadcasting station, a timing deviation as shown in FIG. 2 occurs in the audio sample stream in the heterogeneous audio broadcasting receiving apparatus. In general, the analog broadcasting signal FM is converted into a digital broadcasting signal (digital broadcasting signal) by a combination of the difference between analog and digital signal transmission processes, the difference according to the arrival time of the radio waves, DAB).

This timing deviation is likely to occur, and it is common for time synchronization between DAB audio samples and FM audio samples not to be precisely matched due to such timing deviations. Therefore, if switching between the DAB and the FM is performed without eliminating the timing deviation, the audio is temporarily disconnected or repetitively occurs at the switching time point, and the user feels inconvenience.

In addition, although not shown in FIG. 2, there is a problem that the size (amplitude) of a voice signal between the DAB digital broadcasting and the FM analog broadcasting does not exactly match in the receiving apparatus for the same broadcast audio. This is referred to as amplitude deviation. When switching between DAB and FM without resolving such amplitude deviation, a sudden increase or decrease in audio volume occurs at the switching time point, and the user feels uncomfortable.

Accordingly, in a heterogeneous audio broadcast receiving apparatus, when a broadcast reception path is changed between DAB and FM, a sound source synchronization process is performed to eliminate a timing deviation and an amplitude deviation to achieve a seamless link. At this time, since the operation can not be performed on the entire section of the audio sample stream, a search interval (for example, 7 seconds) is set to perform the sound source synchronization process.

3 is a diagram conceptually illustrating a process of processing an audio signal in a heterogeneous audio broadcast receiving apparatus to which the present invention is applicable. The present invention relates to a technique for achieving a seamless link between audio sample streams in an apparatus equipped with different types of audio broadcast receiving modules, as well as DAB-FM as well as various heterogeneous types such as DAB-AM, DRM-FM / AM, IBOC- The same can be applied to the audio broadcast receiving apparatus. In the present specification, the technique of the present invention will be described based on a DAB-FM heterogeneous audio broadcast receiving apparatus on the basis of the description.

Digital audio samples (samples 1 and 2) according to DAB digital broadcasting and FM analog broadcasting are input to the application processor 100 through the DAB tuner 111 and the FM tuner 112 in the heterogeneous audio broadcasting receiving apparatus, respectively. The application processor 100 performs audio signal processing on these digital audio samples, selects audio data to be finally output as audio through a predetermined evaluation, and the selected audio data is transmitted through the DA converter 160 And output to the speaker SPK. At this time, when the broadcast reception path is changed, the application processor 100 achieves the seamless link by eliminating the timing deviation and the amplitude deviation.

3, the application processor 100 includes first and second sample buffers 121 and 122, a TA (Timing and Amplitude Estimator) 130, first and second sample scalers 141 and 142, Quality analyzer 150 and achieves seamless switching between DAB audio samples (sample 1) received via DAB digital broadcasting and FM audio samples (sample 2) received via FM analog broadcasting.

The digital audio samples input to the application processor 100 are input to the TA estimator 130 via the respective sample buffers 121 and 122. The TA estimator 130 estimates a timing difference and an amplitude difference between these digital audio sample streams. The first and second sample buffers 121 and 122 compensate timing deviations between the sample streams by reflecting the estimation result of the TA estimator 130. The first and second sample scalers 141 and 142 compensate for the amplitude deviation between the sample streams by reflecting the estimation result of the TA estimator 130.

The signal quality analyzer 150 (also referred to as a demodulator) uses the signal quality information (e.g., CNR (Carrier Noise Ratio), RSSI (received signal strength), BER (bit error rate), etc.) transmitted from the DAB tuner 111 and the FM tuner 112 ) Determines which of the two sample streams (sample 1, sample 2) to export to the final output stage. The selected sample stream is delivered to the listener via the DA converter 160 and the speaker SPK.

The technical configuration shown in FIG. 3 shows an example of a heterogeneous audio broadcast receiving apparatus suitable for applying the technical idea of the present invention. The technical content of [Fig. 3] is disclosed in the applicant's Korean Patent Application No. 10-2014-0044549, entitled "Method for seamlessly processing audio signals in a heterogeneous audio broadcast receiving apparatus and a computer readable recording medium therefor "

4 is a block diagram conceptually illustrating a process of estimating a timing deviation by the TA estimator 130 through correlation calculation between audio sample streams in a heterogeneous audio broadcast receiving apparatus to which the present invention is applicable. The TA estimator 130 includes a correlation block selector 131, a delay buffer 132, a correlator 133, a maximum energy detector 134, and an operation interval setting unit 135. The process performed by the TA estimator 130 to estimate the timing deviation will now be described in detail.

First, the sample block selector 131 selects a sample block (i.e., a correlation correlation block) of a predetermined size (e.g., 4096 samples) to which the correlation operation is to be applied from the DAB audio sample stream (sample 1). One example for the sample block selector 131 to select the correlation computation block from the DAB audio sample stream is to search for a maximum correlation block. That is, after calculating the partial averages for the DAB audio samples, an optimal correlation sample block is searched for from the DAB audio sample stream based on the partial averages. As the silence interval is included in the audio sample stream, the correlation characteristic degrades. Therefore, the optimal correlation block corresponds to a sample block whose silence interval is excluded as much as possible in the DAB audio sample stream.

The delay buffer 132 temporarily stores the FM audio sample stream (sample 2) in the buffering memory while the sample block selector 131 selects the correlation computation block from the DAB audio sample stream. When a correlation operation block is selected from the DAB audio samples, the correlator 133 correlates correlation data between the correlation operation block of the DAB audio samples and the FM audio sample stream over a predetermined interval (i.e., (cross-correlation).

5 shows an example in which the correlator 133 calculates the cross correlation degree when the sample block selector 131 selects the correlation correlation calculation block from the DAB audio sample stream, for example, as a 'C' block in the TA estimator 130 Fig. At this time, the correlator 133 performs a cross-correlation operation on the selected correlation calculation block (i.e., block C) and the FM audio sample stream over a predetermined correlation calculation interval.

On the other hand, preferably, the starting position of the cross correlation operation is determined in the FM audio sample stream according to the position of the correlation operation block in the DAB audio sample stream. This is because, based on general experience, it is assumed that a voice signal of FM, which is an analog broadcast signal, comes in before a DAB voice signal which is a digital broadcast signal. If a broadcast reception environment in which the DAB speech signal is first received is assumed, the correlation calculation period is set to the block A 'to the block F', and the calculation is performed.

Finally, the maximum energy searcher 134 searches for a point at which the cross-correlation value is at its maximum, and estimates the timing deviation between the DAB audio sample and the FM audio sample based on the result. As the correlator 133 calculates the cross correlation degree, a kind of energy value is derived. The maximum energy searcher 134 estimates the timing deviation by searching for a position where the maximum value appears among the energy values.

6 is a diagram showing an example of a cross-correlation diagram output by the correlator 133 in the present invention. The cross-correlation diagram output by the correlator 133 has a point indicating a maximum value, which is searched by the maximum energy searcher 134. The TA estimator 130 estimates the timing deviation between the two audio samples based on the maximum correlation energy location searched by the maximum energy searcher 134 and the application processor 100 determines the first and second By controlling the buffering delay time for one or more of the sample buffers 121 and 122, a seamless link can be achieved.

On the other hand, the amplitude deviation between the DAB audio sample and the FM audio sample can be estimated by calculating the ratio of the total average of both audio samples, i.e., the cumulative average of the sample streams. The configuration for estimating the amplitude deviation from both audio sample streams is not shown in FIG.

At this time, an example of an operation performed by the TA estimator 130 may be expressed by Equation (1).

On the other hand, the calculation interval setter 135 sets the range of the audio samples, that is, the correlation degree calculation interval shown in FIG. 5, when the correlator 133 calculates the cross-correlation degree. The setting of the correlation calculation interval is interlocked with the search interval described above with reference to FIG. 2. Generally, if the correlation calculation interval is increased, the search interval is also increased. On the contrary, if the correlation interval is decreased, .

The longer the correlation computation interval, the greater the number of audio samples and thus the computational complexity and the time required for the sound source synchronization process. Assuming that the sampling frequency is 48 KHz, as the correlation calculation interval increases by 1 second, the number of processed audio samples increases by 48,000, which has a great influence on the calculation amount. However, as the correlation calculation interval is decreased, the estimation result of the timing deviation becomes inaccurate generally, so that the synchronization performance of the sound source is decreased. Therefore, the correlation calculation time can not be reduced.

In the present invention, the operation interval setter 135 typically sets the correlation operation interval to a suitably set value (e.g., 7 seconds) in advance. Then, only when the special condition that the sound source synchronization performance is not to be satisfied is satisfied, the correlation calculation period is set to a much reduced value (for example, 1 second or several tens of msec) to control the seamless link to be processed quickly. The processing operation of the operation region setting unit 135 will be described in detail with reference to [FIG. 7] to [FIG. 9].

FIG. 7 is a flowchart conceptually illustrating an overall process of a sound source synchronization adaptive fast processing method for a seamless link according to the present invention. The basic idea of the present invention, reflected in FIG. 7, is to improve the synchronizing speed of a sound source that the user actually senses by operating the sound source synchronization processing conditions differently according to the operating environment in which the seamless link occurs.

Step S110: A DAB audio sample stream (sample 1) and an FM audio sample stream (sample 2) are transmitted through the DAB tuner 111 and the FM tuner 112, as shown in FIG. 3, .

Step S120: Due to problems such as broadcast coverage and shadow areas, there is a situation in which the broadcast reception path must be changed suddenly while listening to a specific audio program. In order to achieve a seamless link, a sound source synchronization Process.

Step S130: The sound source synchronization operation environment for the audio program is identified and the correlation calculation interval is set accordingly. As described above, the correlation calculation section directly affects the operation amount of the sound source synchronization process. According to the present invention, as described later with reference to FIG. 9, the sound source synchronization operation environment for the audio program is identified, and the correlation calculation interval is set to be increased or decreased according to the identified sound source synchronization operation environment.

Steps (S140, S150, S160): The correlation (cross-correlation) between the DAB audio sample and the FM audio sample is calculated as described above with reference to FIGS. 4 and 5, And estimates the timing deviation. In addition, the amplitude deviation can be estimated by calculating the ratio to the cumulative average of both audio sample streams. Then, the buffering delay is controlled according to the synchronization deviation, and the sample scaling is controlled according to the amplitude deviation to switch the broadcast reception path while blending DAB audio and FM audio in synchronization with the sound source synchronization.

Step S170: After performing the seamless link through the previous process, the sound source synchronization result (e.g., timing deviation, amplitude deviation) is combined with the audio program and stored in a volatile storage medium such as a RAM . At this time, as the information for identifying the audio program, a service ID (Service ID) inserted and transmitted in the DAB broadcast stream can be preferably utilized. Because audio broadcasting has a continuous property, it is stored in a broadcasting program for reference in the subsequent sound source synchronization process, assuming that the characteristics related to sound source synchronization, that is, timing deviation and amplitude deviation, will not change significantly.

Step S180: When powering off the heterogeneous audio broadcast receiving apparatus, the result of synchronization of the sound source stored in the nonvolatile storage medium is combined with the corresponding audio program and stored in a nonvolatile storage medium for storage, for example, a flash memory. The user may turn on the different audio broadcast receiving apparatus again before the end of the broadcast program.

FIG. 8 is a flowchart illustrating a process of updating a synchronization result of a sound source in a seamless space in a seamless link process according to an embodiment of the present invention. Although FIG. 8 describes the step S 170 of temporarily storing the synchronization result of the sound source in the volatile storage medium, the present invention is also applicable to the step S 180 of storing the result of synchronization of the sound source in the nonvolatile storage medium Is not excluded.

Step S171: The process of storing the combination of the sound source synchronization result (e.g., timing deviation, amplitude deviation) and the audio program identification information (e.g., Service ID) in the volatile storage medium for temporary storage after the seamless link is performed do.

Step S172: First, using the audio program identification information, it is checked whether or not the previous sound source synchronization result for the audio program is stored in the volatile storage medium.

Steps S173 and S174: If it is determined that the previous sound source synchronization result for the audio program does not exist, that is, if the sound source synchronization process is performed for the audio program for the first time, the process proceeds to step S174, And stores the synchronization result in a volatile storage medium.

Step S175: As a result of the check, if there is already a previous sound source synchronization result for the audio program, preferably these sound source synchronization results are compared and a more accurate result is maintained in the volatile storage medium. In the present invention, a correlation ratio between audio sample streams is used as a criterion for evaluating a sound source synchronization result. Conceptually, the correlation ratio is a value of 1 or less, which indicates the ratio of the total variation generated in the sample 1 to the sample 2, and the larger the value, the greater the correlation between the audio samples. The correlation ratio is denoted by the symbol 侶, and the formula for calculating the correlation ratio between the two samples is omitted here because it is already presented in statistical analysis.

Because of the noise on the transmission path and various factors inside the receiving device, the quality of the analog broadcasting channel fluctuates at that time. In the digital broadcasting channel, audio data errors occasionally occur due to various factors. Therefore, even if the same audio broadcast is received, the sample 1 received through the digital broadcast channel at the receiving end and the sample 2 received through the analog broadcast channel are different from each other. However, the degree of the difference varies from moment to moment.

Therefore, in the present invention, the correlation ratio between both audio sample streams is calculated. If the correlation ratio is larger, it is determined that both audio samples are more similar, that is, the original audio broadcasting data transmitted from the broadcasting station is accurately reflected. It is also expected that the timing and amplitude deviations estimated by the TA estimator 130 will be more accurate in the situation where both audio sample streams more accurately reflect the original audio broadcast.

Step S176: If the result of the comparison shows that the new sound source synchronization result is better, i.e., the sound source correlation ratio derived in the new sound source synchronization process is higher than the original sound source correlation result of the previously stored sound source synchronization result, S174) and stores the new sound source synchronization result in the volatile storage medium.

On the other hand, the embodiment of FIG. 8 evaluates the previous sound source synchronization results for the same audio program, and stores them in a more accurate manner. As described above, since the audio broadcasting has a continuous property, it is assumed that the timing deviation and the amplitude deviation are constant within one broadcast program, and the accurate synchronization of the sound source synchronization results is stored. As another example, if it is assumed that the timing deviation and the amplitude deviation in one broadcast program change to some extent, the latest sound source synchronization result may be stored in the volatile storage medium without being compared with the previous sound source synchronization result .

FIG. 9 is a block diagram of a heterogeneous audio broadcast receiving apparatus according to an exemplary embodiment of the present invention. FIG. 9 is a block diagram of a heterogeneous audio broadcast receiving apparatus according to an embodiment of the present invention. Which is a conceptual diagram of the process. In order to achieve seamless linking as described above with reference to FIG. 4, the delay time of the sample buffer must be controlled by estimating a timing deviation between audio sample streams. In the present invention, a technique for setting a correlation calculation interval in response to an operation condition in a correlation calculation performed to estimate the timing deviation is disclosed.

Step S131: Obtain identification information (e.g., Service ID) of a corresponding audio program for which the sound source synchronization process is performed.

Step S 132: The above identification information is inquired for a volatile storage medium (for example, RAM) as a temporary storage space and a non-volatile storage medium (flash memory) as a storage storage space. . This is to identify the operating environment for the sound source synchronization process to be performed at this time based on the search result.

Steps S133 and S134: First, a case where a previous sound source synchronization result for the audio program exists in the volatile storage medium will be described. This means that the heterogeneous audio broadcast receiving apparatus has recently performed the psychic time link for the same audio program while maintaining the power-on state, thereby obtaining the sound source synchronization result (timing deviation, amplitude deviation).

Since the audio program is the same and the state of the heterogeneous audio broadcast receiving apparatus remains the same, it is also possible to assume that the result of synchronization of the sound source is not significantly different from the result of synchronization of the previous sound source. Accordingly, the correlation calculating section to be applied to the TA estimator 130 is set to a very short value, that is, the shortest value (e.g., 0.05 second). At this time, the shortest value can be set in advance to a specific time, and can be set in conjunction with the value of the timing deviation read from the volatile storage medium.

Steps S135 and S136: Secondly, a case in which the previous synchronization of the sound source for the audio program is not present in the volatile storage medium but exists only in the non-volatile storage medium as the storage apparatus will be described. This is because when the operating power is applied in a state in which the effective sound source synchronization result previously generated in the heterogeneous audio broadcasting receiving apparatus is stored, for example, when the heterogeneous audio broadcasting receiving apparatus is turned off once and then turned on again while the same audio program is being continued it means.

The result of synchronization of the previous sound source is valid because the audio program is the same. However, since the state of the different type audio broadcast receiving apparatus is changed, there is a possibility that the result of synchronization of the sound source is slightly different from the previous result. Accordingly, the correlation calculation section to be applied to the TA estimator 130 is set to a value slightly larger than the preceding shortest value, that is, an intermediate value (e.g., 1 second). The intermediate value applied at this time can also be set in advance to a specific time or can be set in conjunction with the value of the timing deviation read from the nonvolatile storage medium.

Step S137: Third, a case in which there is no previous sound source synchronization result for the audio program is examined. (For example, 7 seconds) to the TA estimator 130. In this case, it is assumed that the sound source synchronization process is performed for the audio program for the first time in the heterogeneous audio broadcast receiving apparatus. . That is, the correlation calculation section is set to a time sufficient for the heterogeneous audio broadcast receiving apparatus to be able to afford.

In the case where there is no record in which the sound source synchronization process has been performed previously for the audio program, the heterogeneous audio broadcast receiving apparatus according to the present invention basically sets the correlation calculation period to a sufficiently long value, If the synchronization result of the previous sound source is stored in the medium, the correlation operation interval is set to be somewhat shorter, and if the sound source synchronization result is stored in the volatile storage medium, the correlation operation interval is set to be the shortest.

According to the results of the internal experiment of the applicant, in the embedded system having the operating frequency of 220 MHz, when the correlation calculation interval is set to the default value (7 seconds), the middle value (1 second) and the shortest value (0.05 second) The time required was 40 seconds, 5.7 seconds, and 0.3 seconds, respectively. Therefore, according to the present invention, when a user uses a heterogeneous audio broadcasting receiving apparatus, the system performance for performing a seamless link is gradually improved, and the satisfaction is increased.

Meanwhile, although the above description has been made on the basis of an audio program, it may be discriminated on a broadcasting company basis according to an implementation example. The same broadcaster is to identify by broadcasting company on the assumption that it will show the same timing deviation and amplitude deviation. That is, when the above process is implemented, it may be based on the identification information of the audio program or the identification information of the broadcasting company. Accordingly, the term " content identification information " can be used to cover them.

Although the storage medium for temporary storage is assumed to be a volatile storage medium (e.g., RAM) and the storage medium is assumed to be a nonvolatile storage medium (e.g., flash memory), it is also possible to implement a medium different from the storage medium . In addition, the present invention is not limited to a storage medium built in a heterogeneous audio broadcast receiving apparatus, and an implementation method using an external storage medium such as a web disk or a cloud disk is not excluded from the scope of the present invention.

The present invention can also be embodied in the form of computer readable code on a computer readable recording medium. At this time, the computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored.

Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage, and the like, and may be implemented in the form of a carrier wave . The computer-readable recording medium can also be stored and executed by a computer-readable code in a distributed manner on a networked computer system. And functional programs, codes, and code segments for implementing the present invention can be easily deduced by programmers skilled in the art to which the present invention belongs.

As described above, the embodiments of the present invention have been disclosed in the present specification and drawings, and although specific terms have been used, they have been used only in a general sense to easily describe the technical contents of the present invention and to facilitate understanding of the invention. And is not intended to limit the scope of the invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

100: Application processor
111: DAB tuner
112: FM tuner
121, 122: sample buffer
130, 230, 330: TA estimator
131: Sample block selector
132: delay buffer
133: Correlator
134: Maximum Energy Explorer
135: operation interval setting unit
141, 142: sample scalar
150: Signal quality analyzer
160: DA converter

Claims (6)

An adaptive fast processing method for a sound source synchronization for a seamless link between audio sample streams in a heterogeneous audio broadcast receiving apparatus,
A first step of starting a sound source synchronization process for a specific audio program;
A second step of identifying a sound source synchronization operation environment for the audio program based on whether previous sound source synchronization result information for the audio program exists in a storage medium of the heterogeneous audio broadcast receiving apparatus;
Wherein the correlation calculation interval for the sound source synchronization process is differentiated according to the identified sound source synchronization operation environment, and when the previous sound source synchronization result information exists in the storage medium, the correlation calculation interval is set shorter A third step of setting;
A fourth step of performing correlation computation between audio sample streams corresponding to the set correlation computation period to estimate at least one of a timing deviation and an amplitude deviation;
A fifth step of switching a broadcast reception path for the audio program in synchronization with sound source synchronization by controlling at least one of buffering delay and sample scaling for the audio sample stream based on the estimation;
A sixth step of combining at least one of the estimated timing deviation and the amplitude deviation with the content identification information of the audio program as sound source synchronization result information for the audio program and storing the result in the storage medium;
And an adaptive fast processing method for a seamless synchronization in a sound source synchronization in a heterogeneous audio broadcast receiving apparatus.
The method according to claim 1,
The second step comprises:
Setting the sound source synchronization operating environment to a first operating environment when previous sound source synchronization result information on the audio program exists in a temporary storage medium of the heterogeneous audio broadcasting receiver;
When the previous sound source synchronization result information for the audio program is not present in the temporary storage medium and exists in the storage medium for storage of the heterogeneous audio broadcasting receiver, the sound source synchronization operation environment is set as the second operation environment ;
Setting the sound source synchronization operating environment to a third operating environment when previous sound source synchronization result information for the audio program is not present in any of the temporary storage medium and the storage storage medium;
And,
In the third step,
Setting the correlation computing period to a first predetermined value in the first operating environment;
Setting the correlation computation period in a second operating environment to a second predetermined value that is greater than the first value;
Setting the correlation computing period to a third predetermined value that is greater than the second value in the third operating environment;
Wherein the adaptive fast processing method is applied to a seamless link in a heterogeneous audio broadcast receiving apparatus.
The method of claim 2,
In the sixth step,
61. The method of claim 61, further comprising the step of: combining the sound source synchronization result information with content identification information of the audio program and storing the information in the temporary storage medium of the heterogeneous audio broadcasting receiver;
62) storing the combination of the sound source synchronization result information stored in the temporary storage medium and the content identification information of the audio program in a storage medium for storage when the heterogeneous audio broadcasting receiver is powered off;
Wherein the adaptive fast processing method is applied to a seamless link in a heterogeneous audio broadcast receiving apparatus.
The method of claim 3,
In operation 61,
Starting a storage process of the temporary storage medium for the sound source synchronization result information (hereinafter, referred to as 'current sound source synchronization result information');
Checking whether there is previous sound source synchronization result information for the content identification information in the temporary storage medium;
Storing the current sound source synchronization result information in the temporary storage medium if the previous sound source synchronization result information does not exist as a result of the checking;
Wherein if the previous sound source synchronization result information is present as a result of the checking, the sound source correlation ratio of the current sound source synchronization result information and the previous sound source synchronization result information is compared, and if the sound source correlation ratio Storing the current sound source synchronization result information in the temporary storage medium;
Wherein the adaptive fast processing method is applied to a seamless link in a heterogeneous audio broadcast receiving apparatus.
The method of claim 4,
Wherein the content identification information comprises at least one of a service identifier and a broadcast identifier for the audio program.
A computer-readable recording medium on which is recorded a program for causing a computer to execute a sound source synchronization adaptive fast processing method for a seamless link in a heterogeneous audio broadcast receiving apparatus according to any one of claims 1 to 5.

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