JP4056057B2 - Method and apparatus for retrieving and recording media signal - Google Patents

Description

Prior Application This application is a continuation-in-part of US Provisional Application No. 60/274904 filed March 9,2001.

TECHNICAL FIELD The present invention relates to a method and system for recording a time-limited signal sequence in a media channel that may contain undesirable signal components. For example, the present invention can be used to record music in a radio broadcast.

Background and Summary of the Invention Since radio and television technology was first developed, it has become common to record both radio and television music and other broadcasts. Examples of this are songs, movies and music events. Recording is for both storing specific identified broadcasts so that they can be enjoyed repeatedly and not limited to listening / watching only during the broadcast time. To be done. For example, one problem with recording music from radio broadcasts is that in most cases the listener does not know which song will be broadcast. In many cases, a song has already been played for some time before it can be recognized as a song to be recorded from the beginning. In addition to this, if you do not know the airtime, you spend time on paying attention to the radio for a particular song or watching to watch a movie.

  As the price of music and movies on CDs, DVDs and other recording media has increased, new less expensive alternatives have been developed that enable entertainment such as these. The Internet now has a major role in spreading music in different file formats more or less legally or illegally. In particular, music and movies are replicated and made available to the general public on the Internet, for example in MP3 format. Interest in free music is shown, for example, by a number of users on a home page on a search engine that gives the availability of free music, an example of this is Napster.com.

  A large percentage of people who listen to music have limited knowledge of the artists they are listening to and only listen to radio stations mixed with artists that they do not always know. Consumers are shown to be more interested in music from a specific genre than music in a specific artist, as well as increased interest in music CDs for mixed groups / artists.

  Patent application DE 19810114 searches for a pre-stored piece of music called a key, finds one that matches the music broadcast by the selected radio channel, and selects if these keys match the broadcasted song Describes a method for automatically recording recorded songs. For each song to be searched and recorded, a start key in the form of the first part of the song and an end key in the form of the end part of the song are stored in a memory on the radio. These in the preselected key are compared to all broadcasted by a number of radio channels and if the key is found, the part in between is recorded. You can also search for specific types of music by storing category keys for matching and recording specific music categories such as pop music, rock music, classical music, or other types of music.

  One drawback of this method of recording music is that only pre-selected music, for example in the form of a portion called a music key pre-stored on a CD, is matched to a radio channel to record the desired music. It can be done. It is possible to extract one or more keys from any song being played on the radio and continuously match the radio channel to automatically obtain a full-length version of that song I can't. Another drawback is that it records everything between the keys so that it cannot record music completely without unwanted signal components, which is undesirable such as noise from conversations and bad broadcasts. It means that a signal component is included in the song. It is common for radio speakers or commercials to interfere with music in radio broadcasts.

  The present invention searches for the desired source material in a media channel that contains undesired signal components and records the above-mentioned problems when the same source material is broadcast at least twice in either the same channel or a different channel. It is intended to be solved by providing procedures and equipment. One source material can be a song, a movie, or anything else that is considered time-limited and separate from other materials. In particular, if necessary, for at least one media channel, the signal is continuously stored primarily in memory at the receiving member. The next step may include identifying and selecting the desired source material by an activation member connected to the receiving member. From this desired source material, a section or a representation of a section may be obtained as a search key. The apparatus may automatically select a search key in one variation of implementing the invention. Next, a media signal located around the search key is stored in a memory. The search key is compared with other stored media signals or media signals currently being broadcast. If a second example of the search key is detected, then the signal sections connected to these search keys are compared. Signal sequences that are found to be substantially identical by comparison are identified as belonging to the same source material. Identifying a common segment between the first signal segment and the second signal segment makes it possible to find the beginning and end of the common segment, and thus the beginning and end of the whole or part of the source material. Make it possible to find. These common segments may be stored for later use.

  The next step may be an iteration of search key detection, storage in memory, and comparison between media signals as described above, where signal segments identified as originating from the same source material are The common segment found can be supplemented. This can result in a longer, more complete and higher quality source material segment than can be initially obtained.

  The iteration may be stopped by a threshold for stopping, whereby an acceptable long common segment of sufficient quality is identified and stored in a final memory portion for later performance.

  The present invention provides the user with a unique new way of continuously obtaining records of source materials such as music and movies. When the present invention is used for radio broadcasting, the present invention can continuously record all the songs repeated on the radio and store them in a playlist for later use. In addition, if the user of the device hears a song he wishes to record, the user need only press a button to automatically obtain a full length record of the song. The present invention can distinguish between music on the radio, commercials and conversations.

DETAILED DESCRIPTION The following is a procedure and apparatus for searching for a desired source material in a media channel containing unwanted signal components and recording if the same source material is broadcast at least twice in either the same channel or a different channel followed by. The method identifies the desired source material and undesirable materials such as speech, commercials and strains. Examples of source material can be music, movies, and the like. Searching and recording hit songs in radio broadcasts is used as an illustrative example in this application. It should be understood that the present invention is not limited to hit song identification and recording, but may be used for movies, music videos, and other types of source material as well. Said searching and recording can be performed by an iterative procedure including finding, comparing and storing signal segments identified by a search key derived from the source material to be recorded.

  By using the method and apparatus according to the present invention, the user can choose to record the source material that is currently being broadcast to the receiving member by the media channel at any instant. In one method of implementing the present invention, the user also automatically has source material recorded from the media channel. The device automatically identifies the beginning and end of a complete source material or portion of source material and saves these sections for later use.

  An example of source material can be a hit song broadcast to a radio receiver over a radio channel. By using the method, the listener can, after a while, obtain a high quality full length version of the hit song stored on the device without manual manipulation. At any time during the performance of the song, the user can start recording a complete version of the song by simply pressing a button. By using the method of the present invention, the device can also automatically extract music in radio broadcasts and record each song separately. Thus, the user of the device can continuously update the list of separate songs played by the radio. The present invention provides users of the present invention with at least two unique ways of obtaining music. One way is by pressing a button while listening to the desired song, and the other way is by having the device automatically record the song as a whole and store them in a playlist. is there.

  The media channel temporarily stores media signals, such as radio and television broadcasts, that are sent to a receiver such as a radio, television, PC, or similar device in one or more buffer memories. In the buffer memory of the device of the present invention, the older stored media signal may be continuously replaced by the latest broadcast media signal of one or many channels. The media signal is accessible to a user who can activate the device.

  Continuous recording of media signals and primary storage to this one or more memory locations, eg, 5 days primary storage adjusted, to notify complete source material recording as described in detail below. be able to. The recording is also possible when the user determines the recording rate in broadcasting the source material.

  If the user or device indicates that a particular source material should be recorded, the section of the media signal or a representation of the section at this point may be selected as a search key. The search key may be a derivative of the complete source material.

  The device may store a sufficiently long section of the recorded media signal around the search key, and for a hit song, the sufficient length can be 5 minutes before and after the activation time. . This procedure activates the pre-recording function that gives the user a full broadcast of the source material broadcast at that time, presses a button, turns the wheel, or handles or any other member in the receiver You may carry out by activating. The activation may be performed automatically by the device. This automated activation may be triggered randomly or periodically, or may be triggered by certain recognizable features of the broadcast. In the example of music in a radio broadcast, this allows the device to automatically construct a list of music played on the radio. The music may be stored in much the same way as in a normal CD player, giving the user the possibility to listen to one song after the next song.

  The required length of the section recorded before and after the activation can be determined by estimating the likely length of the source material of that type. For hit songs, 5 minutes before and after the activation will be sufficient in most cases. Media signal broadcasts of source material stored in memory may not be free of unwanted signal components. For example, in radio broadcasts, it is very common for music to be disturbed by conversation at least at the beginning or end of a song. Sometimes a disc jockey may break during the performance of a song, and even if one piece of music is usually played on the radio, a large portion of it is broadcast without interruption.

  Another problem is that where the source material starts and ends in the stored record is unknown. The present invention provides a solution to how to find the beginning and end of source material in a continuous media signal, for example, the beginning and end of a song in a continuous radio broadcast. If the device automatically activates, it may be possible to continuously record music repeated on the radio and automatically save songs from the radio.

  FIG. 1 illustrates a procedure for forming a search key 100 for a section of source material or a representation of that section. The media signal 10 may be a piece of music 12 that may include, for example, unwanted signal components 102, 104 and other unwanted segments 103, 105 before and after the song 12. The desired source material 12 is marked with a thick line in FIG. The segment 12 has a start 13 and an end 14. A search key 100 may be formed that detects previous and future broadcasts of the same source material, eg, the same music. The detection may be performed by matching and comparing the search key with a segment of a media signal stored in the buffer memory or broadcast later. Detection of previous or future broadcasts of the desired source material may be performed by direct matching of the search key. Identify sections of the broadcast that may contain the source material, then check these sections in one or many steps in one or many steps, and these are actually from the desired source material It may be performed by a procedure for testing whether or not. Preferably, the media signal 10 is longer than the desired source material 12 to ensure that the entire source material 12 is recorded last.

  When storing a portion of the media signal for later comparison, the media signal 10 should extend the time period before and after the search key sufficient to accommodate the complete source material. As an example, most common music is less than 5 minutes and record activation occurs at any time during the performance of the music, so save 5 minutes before and 5 minutes after the activation time, It is desirable to ensure that the entire music is recorded. In this method, the media signal 10 may be about 10 minutes. Of course, any time period can be selected as desired.

  If a second substantially identical example of the search key 100 is detected, the signal section connected to the search key is compared at this time. Signal segments that are found to be practically identical in themselves by comparison are identified as originating from the same source material 12. Identifying the common segment between the first signal segment and the second signal segment makes it possible to find the start and end of the common part and thus find the start and end of the whole or part of the source material Make it possible.

  As will be described below, the iterative process of the present invention reduces the degraded segments 102, 104 and duplicates these segments replicated from other broadcasts of the same source material that were broadcast in the past or in the future. Minimize by gradual replacement with not clean segments. An important assumption of the present invention is that the desired source material is substantially the same for all broadcasts of the same source material, and that the reception of a song is nearly the same at any time transmitted to the radio It is. Undesirable signal segments such as speech, commercials, and distortion usually differ each time the same song is played.

  FIG. 2 includes a portion that is substantially identical to section 10 by using matching of search key 100 and second example 200 that is the same or close to the search key, and thus from the same source material. A procedure for detecting a second section of the media signal 20 that is believed to have occurred is shown. It should be noted that the media signal 20 has a shorter degraded segment 202 having a beginning 24 and an end 26 at the beginning of the desired source material 22. However, the signal 20 has a degraded S-multiple segment 204 that is relatively long compared to the segment 104 of the signal 10. The portion of the two media signals that are the same is the time between 107 and 109, which may be stored as a common segment. One purpose of the iterative process of the present invention is to utilize a relatively short distorted segment 202 but ignore the relatively long segment 204.

  Preferably, as described above, the media signal is temporarily stored in the buffer memory in a continuous manner. Extending the test beyond the scope of the search key, possibly in other ways, with the media signal 20 detected by recognizing that the search key 100 is identical or close to the second example of this search key To test further for similarity. If there is sufficient evidence that they originated from the same source material, the segment 20 may be duplicated in memory or the beginning and end points may be stored in the memory. This may be done by duplicating and a sufficiently long signal segment after the second example 200 of the search key. This prevents signal sections that can be used for other processing to obtain a replica of the desired source material from disappearing when the buffer memory is again filled with new media signals. In one embodiment of the invention, instead of moving the media signal between memories, the device may store the media signal for a predetermined time without overwriting its original location.

  As a result of confirmation of the search key and storage of the media signal, two media signals, ie media signals 10 and 20, are stored. The media signal 20 is compared to the initially stored media signal 10. The same or nearly identical parts of the two media signals 10 and 20 are treated as if they are free of unwanted signal components and thus represent at least part of the desired source signal. This portion may be, for example, part or all of a desired song without any disturbing conversations or commercials. In this case, segment 106 of signal 10 is identical to segment 206 of signal 20. The common segment may be saved for later use, eg, listening. Assume that the segments before and after the segments 106, 206 where the media signals 10, 20 do not match, i.e. are not identical, represent undesirable signal components. In particular, segments 106 may be stored and added in memory by future iterations until the entire desired source material 12 is stored in the final memory or until a threshold for stopping is reached. In this manner, a segment 106 of source material 12 is made available for playing, and segment 106 has an identified end 109 and an identified beginning 107.

  Only the shorter section 106 of the desired source material 12 will be identified the first time the section 106 is stored to identify only the same or near-identical portions of the media signal. If the user is lucky, he or she can obtain the entire source material, for example the entire song, the first time the second example of the search key is found.

  In one simpler way of implementing the invention, the device works only once through the process. The first common segment that comprises the search key is used to identify the beginning and end of the source material. This process has been described above in FIGS. A simpler version of the present invention only gives the user of the device the final identified common segment as the final version, thus giving the user less chance of finding the entire source material. .

  In order to increase the chances of finding the entire source material, for example the entire song 12 on the radio, the above procedure is repeated many times. Accordingly, the steps of detecting a media signal, storing the detected media signal in a memory, and comparing the media signals to find a matching common segment may continue. One purpose is to add more matched sections to the signal segment 106 stored in the final memory, thereby pairing the same media signal that complements the previously confirmed signal segment 106 to increase the It is to detect a common segment. This iteration leads to a longer common segment stored in the final memory.

  3 matches the search key 112 of the media signal 70, the search key 114 in the segment 703 of the media signal 80, and the search key 116 in the segment 705 of the media signal 90 with the source material 110 that is almost complete and undegraded. Explain how to grow by an iterative process. Media signal 70 includes a desired source material 702 having a beginning 704 and an end 706. Note that media signals 70, 80, and 90 include the same source material, and search keys 112, 114, and 116 are identical or nearly identical. Since section 120 of signal 80 is identical to section 122 of signal 90, section 118 may be added to the common segment stored in the final memory. Similarly, since section 126 of media signal 90 is identical to section 128 of media signal 70, section 124 may be added to the common segment stored in the final memory. If the start point 130 and end point 132 represent the beginning and end of the common segment, the segment 110 covers almost the entire source material 702. The only missing segments are the segment 133 at the beginning 704 and the end 706 of the signal segment 702. The procedure may continue iterating in the method until the entire source material is recorded.

  In order to avoid the iterative search procedure including the comparing and adding procedure going forever, a threshold for stopping may be set. This threshold may be a predetermined number of iteration steps for the iterative search procedure. Another alternative may be to use known and identifiable characteristics of the media signal regarding the stopping of the process. The stopping of the iteration may be triggered when the length of a number of added common segments falls below a certain value, which indicates that there is no more to find the complete source material . The iteration may be set to stop if no additional common segment is added despite a certain number of confirmations of the same source material.

  If a common segment is found first, the common segment is stored in the final memory and ready to be played by the user. This gives the user the option of enjoying the common segment repeatably, for example, enjoying a song repeatably by connecting a music player to the final memory. Each song may be added over time with new parts of the song, thus giving the listener a longer and more complete version of the desired music.

  In another simpler way of carrying out the invention, the apparatus works through the above-described iterative process as shown in FIGS. 1 and 2, and works through the above-described iterative process as in FIG. Instead, the device uses only the longest common segment, which is the longest confirmed portion of the source material, as the final version. This simpler version of the invention gives the user of the device less chance to find the entire source material, but the device is easier to develop.

  FIG. 4 shows an example of forming a number of search keys 300, 310, 320 in the media signal 30. This method is particularly useful when the media signal contains a large amount of unwanted signal components. The method increases the chance that at least one of the search keys 300, 310, 320 does not contain unwanted signal components.

  In the illustrated example, only the search key 310 does not contain unwanted signal components, and if the source material 31 is later found or rebroadcast in the memory, it can match the same search key. Search keys 300 and 320 will not match in later media signals because the unwanted signal components are not expected to repeat exactly the same in later broadcasts. The procedure may be designed to compensate for the identified common segment by detecting additional pairs of the same signal segment and adding these additional common segments to the common segment in the memory.

  This method improves the chance of finding and verifying intact portions of the desired source material in memory or next broadcast. This also finds an acceptable length in the desired source material 31 and speeds up the obtaining process. The entire procedure may be repeated in iterative steps as described above.

  FIG. 5 shows a procedure for forming a number of search keys 500, 510, 520 in the segment 501 of the media signal 50 after matching and detecting the initial search key 400 of the media signal 40. The procedure follows a comparison of the three search keys 510, 500 and 520 and the media signal 60. The search key 520 is substantially identical to the search key 620 and thus indicates a match between Qian segments. As described above, the media signals 40, 50, 60 contain the same source material, but these three different media signals have different amounts of undesirable signal components such as speech and commercials that interfere with the source material. Have This provides an opportunity to compare three stored versions 40, 50, 60 that include at least a portion of the same source material. Since the search key 400 and the search key 500 match, the first common segment 402 may be stored in the final memory. The above iteration can add common segments before and after common segment 402 as other common segments are found by using the search key.

  Because search key 400 and search key 500 match, it is assumed that media signal 40 originated at least in part from the same source material as media signal 50. The difference is that both signals have different amounts of unwanted signal components. An important feature is that because search key 520 and search key 620 match, media signals 40, 50 are assumed to have a common part with media signal 60, and they are assumed to originate from the same source material. . This means that the signal segment 602 of the media signal 60 is substantially identical to the segment 404 of the media signal 40 and this common segment can be added to the common segment in the final memory. The entire procedure may be repeated in an iterative step as described above.

  One purpose of the iterative method of the present invention is to obtain a full length version of the source material in the final memory that does not have any undesired signal components such as speech, commercials, distortions and the like.

  In an alternative embodiment of the present invention, the method identifies a source material, such as a hit on the radio, with the aid of a search key that is a selected section of the source material or a representation of this section. For example, the search key may represent a very short section of the desired hit song or a representation of this section. The desired source material may be recognized by ascertaining similarities between the search key and a media signal.

  There are a number of possible methods that can be used to determine the degree of similarity between the search key and a section of the media signal. For example, a section of a media signal may use a correlation that is rolled with other sections of the same media signal to obtain a value that represents the degree of similarity between these two included sections. As this value gets larger, there is a higher degree of similarity, and therefore it is more likely that they originated from the same source material.

  In general, an exact match in which the section under investigation is from the same time period of the same source material that exactly obtained the search key is more distinct with having a much higher value in the match than the surrounding erroneous time period. A long pattern of sections included in the correlation process. Therefore, it is advantageous to use longer sections in the correlation process. However, longer sections require greater processing power, so there is a practical limit on how long a section can be used.

  Other methods can be used to determine the similarity between sections of the media signal. In a method called cancellation, the search key is a section of the media signal with respect to correlation and compares it with other sections of the media signal. The search key and media signal sections to be compared for similarity are first normalized in gain so that they have approximately the same gain. The samples from one section are then subtracted from the samples from the other sections and the absolute values of these differences are summed to obtain the final cancellation value. If the sections are exactly the same, the resulting value is zero. In actual use, an exact match will show a very low cancellation value. If the sections are the same, the sections cancel each other, and if the sections are very similar, the sections cancel each other, so this method is called cancellation.

  With respect to cancellation, as with correlation, the longer the section included in the process, the more accurate the match is usually clearer.

  Both methods, correlation and cancellation described above benefit from the use of longer sections in the process. Because there is a practical limit on the length of the section that can be used, for example due to processing power limitations, we have obtained a modified version of both correlation and cancellation. These methods simply do not include all samples in the process, but instead consist of taking every Nth sample, where N can be any number greater than or equal to one. N need not be a fixed value, but may vary between steps within the calculation of a processing value. The method involving every Nth sample of the media signal can be used in most other methods of recognizing the similarity between the search key and a section of the media signal. The step sequence need not be the same between process values. The same steps should be used in the search key and section under investigation within each processing value calculation. These newly devised methods are named deformation correlation and deformation cancellation.

  These variants can give very clear results when searching for matches and when searching for the beginning and end of the source material, but the penalty for not using all samples in the process is accurate. The average noise level away from a good match may not be higher than when all samples are included.

  In one method of implementing the present invention, the apparatus solves the problem of comparing media signals transmitted at different gains by normalizing these individual gains as part of the comparison process. Gain normalization may be performed as part of the process of recording the media signal. Gain if the comparison method used to determine the degree of similarity between the search key and the media signal is the correlation method or any other method whose result depends on the gain in the signal chain Measurements can be normalized using methods that compensate for the change. In the audio case, there are several possible ways to use an audio compressor of the type often used by radio stations, to prevent transmitter overload and at the same time make the sound as loud as possible.

  One particular method of the present invention that has many advantages is to normalize the calculated similarity value with the absolute value of the sample in the section of interest. This can effectively cancel the effects of variable signal gain if, for example, the disc jockey plays the same song at two different times with different gain settings in the mixing console.

  When using correlation or modified correlation as a method to determine the degree of similarity between the search key section and the section of the media signal, it is necessary to know in advance how high the correlation value in an exact match should be expected. Can be used to know. By reviewing nearly identical media signals because they originated from the same source material, it is possible to know in advance how similar the expected sections in an exact match look. The exact match must be very similar to the search key section. Thus, the expected correlation value in an exact match can be calculated in advance by simply correlating the search key section with itself and normalizing the result with the help of a moving average of the search key section. . This value was arbitrarily called the T value. When searching for a correlation value that can be the result of a possible exact match, one search criterion can be that the correlation value is close to the expected T value.

  Another use for the T value is when trying to determine the quality of a record of the same source material. If several signal segments that are determined to originate from the same source material are found, the T-value can be used to indicate something about their relative quality with respect to noise, interference and distortion. Instead of just calculating the T value for the media signal in an exact match, calculate a continuous T value over part or all of the section. This section is then correlated with other sections from the same source material, and the resulting correlation values and corresponding T values are compared. Note that the signal segments to be compared should be aligned in time and normalized in gain, and the number of samples in the T-value calculation should be the same as the number in the correlation. If the sections are identical, the earlier calculated T value should be exactly the same as the later calculated correlation value. Any deviation from the expected T value may be due to some undesired signal changes, since both sections are presumed to originate from the same source material. As the deviation from the expected T value increases, the difference between the sections is likely to increase. If the correlation value is close to the T value, it can be assumed that the two sections are of high quality, since it is unlikely that similar random disturbances contaminated both sections.

  You can compare many sections and get an indication of these relative qualities. For three sections, sections 1 and 2 may be compared, then 1 and 2, and finally 2 and 3 may be compared. Using this method of determining the quality of a section of a media signal, a criterion can be obtained regarding when a section is found to be good enough, and can also be used to select a section of similar quality. The latter may be important when combining pieces from different records of the same source material together to make a longer continuous section of the source material. When playing the combined longer sections, the user can be prevented from suddenly realizing a jump in quality.

  When using cancellation as a method of determining similarity between sections of a media signal, the expected value of the match may approach zero. The degree of similarity determines how far the cancellation value is from zero. Cancellation can be used to determine when sections are similar, and the method can be used to determine the relative quality between sections if determined to have originated from the same source material. Two or more sections from the same part of the same source material will be contaminated by noise and other disturbances, and more cancellation values will be accurately aligned in time, with the sections normalized in gain, Expected to deviate from zero.

  In one alternative, searching and matching sections of the media signal is performed only on the available data and / or a subset of this data broadcast. This can be done in many ways. In any case, when the device forms a search key, it uses only a small piece of the specimen that builds the material. Another method is for the device to record the media signal in two or more separate files, one or more search files, and one or more files for later use, eg performance. . The search file can be a recording of the media signal with a narrower bandwidth, or it can be a file that includes only specific frequency intervals. The search file may be a representation of the recorded media signal. The search file can be used to form the search key and to search for a second event of the search key. The search file can also be used to find the beginning and end of the source material. For music broadcast on the radio, the search file can be a separate record of the media signal at a lower sample rate, eg, 6 kz. This search file can be used to form the search key and find other events of the search key, and also find the beginning and end of the source material. This start and end information can be used to find the start and end of the source material in a complete quality record. One reason for using a separate search file is to reduce the processing power required.

  In another method of implementing the invention, the device forms a search key and looks for this search key in a file stored on the hard drive. Only when the processor speed is fast enough, the factor limiting the speed of the device is the speed of accessing the stored media signal in the hard drive. The underside is that the hard drive must be continuously accessed and therefore uses power continuously. In another method of implementing the present invention, the apparatus may continuously form a plurality of search keys as the media signal is broadcast, and search for many search keys simultaneously. This reduces the need to access information from the final hard drive, thus saving power on the device, since the search can be performed entirely in the device's RAM memory. For example, by loading an hour of music or search files from a hard drive or broadcast into RAM memory and searching the RAM memory for a number of search keys, the hard drive is given rest and the device is powered by battery power. And can be differentiated faster.

  In another method of implementing the present invention, the apparatus searches for and matches signal sections in a hierarchical method, an initial selection of a number of possible matches, and from the possible matches using a more accurate method. To find an exact match. For example, one way to do this is to first calculate each correlation between the search key and the media signal, identify sections of the media signal that have a sufficiently high correlation with the search key, and then other more accurate It may be possible to test the identified section in a simple manner. This other method may be to use a larger search key or some completely different method.

  The search key used to look for a replica of the source material can be configured in different ways. In one method of implementing the present invention, the search key used is shortened, such as a 0.1-2 second long section of the media signal. In other ways of implementing the invention, the search key may be a representation of a section, for example by using a mathematical transformation on this section, or by extracting some descriptive features. In other ways of implementing the invention, the search key can be made much longer and used in combination with compression or by using a program or algorithm, for example to describe a media signal. Different types of search keys can be used in combination to better search for the desired media signal.

  Instead of just using the instantaneous amplitude value of the media signal in the sample, compression process, the music may be indexed and a short signal segment may be stored, said segment identifying a segment from other music It has several features. For example, a song may have a unique drum segment, store only a portion of this drum segment, and compare to other media signals until the same drum segment is located. Whenever this drum segment is played again, the segment is stored in an indexed memory so that only the indexed portion of the memory need be searched without having to search the entire memory. To do. The drum segments are transformed by mathematical algorithms in a way that reduces the required storage requirements or facilitates matching.

  In another method of carrying out the present invention, the searching step and the step of comparing the stored search key with the current media signal or recorded broadcast is performed by continuously searching at a specific frequency. May be. For example, the search key may not include the entire frequency register, but may include only certain predetermined frequencies. When using music in radio broadcasting, the search key may include only frequencies 30-31 Hz and 13000-13100 Hz. A 30-31 Hz signal can be used to identify the same drum sound in a particular length of song in a particular time interval. Similarly, a 1300-13100 Hz signal can be used to identify the same guitar sound at a specific time interval and length. Thus, the search procedure may be performed by searching only for radio broadcast 30-31 Hz signals. If a matching feature at 30-31 Hz frequency is found in the memory, the 13000-13100 Hz frequency is searched and compared. If the media signal has the same guitar sound at 13000-13100 Hz frequency, it is assumed to be the same media signal.

  Comparing only a specific part of the frequency register results in a better capacity usage compared to searching the entire frequency range. Also, the beginning and end of the source material can be found by comparing few frequencies. The signal segments to be compared are considered to be the same as long as the frequencies to which the signal segments compare are substantially the same.

  The search process may search for a code that identifies the broadcasted source material embedded in the media signal. For example, in digital radio broadcasting, there is a possibility of transmitting a code for identifying music that is currently being played. Some CDs include a code that identifies the artist and song for each track. This encoded information may be used by a procedure to find a copy of a song, locating its beginning and end, and removing unwanted signal components.

  In order to be able to quickly find the source material, like finding a song in an already recorded radio broadcast, the memory capacity of the receiving device must be a stored broadcast of at least 2-3 hours. For music in the standard MP3 format, this is about 100-200 MB of stored music. The memory can also be very large, for example so that it can contain many different media channels over a much longer time period. The memory may also contain previous records of source material found by the device.

  The search process may be triggered by him when the user notices the recorded source material or by the device itself. If the device is not in use by a manually triggered search request, a search key can be formed automatically, a search can be performed, and a common segment library or list stored in memory can be built. The list of these common segments repeated in the media signal can be used for feature search or later performance by the user. This automatic search is particularly useful when the radio station plays only a limited number of songs, such as the top 40 radio stations. For stations with a wide variety of music, it is necessary to search and find repeated songs, but as soon as a song is repeated, the device recognizes and stores it. If the user wants to record a song, the device may have already made several iterations over a long period of time, and the entire song is available to the listener without having to wait to complete for all of the iterations. It may be possible. Initiating the search process from among already identified and stored source materials makes the search much faster because the desired source material may already have been previously identified and stored by the device. be able to.

  In certain versions of the invention below, the device tests and verifies that the search key contains sufficient information to use. For example, if the device itself automatically generates a search key, it is not a good use if it is in the midst of a silent part of the broadcast. This may also happen if the search request is triggered manually. By slightly changing the method for obtaining the search key, the search key can be formed as unique as possible. This can lead to a greater chance of finding the search key match.

  One way to improve the quality of the search key is most unique in the sense that it is best suited to test several possible search keys near the time of activation and use them to find the desired matching signal segment. Select a search key that seems to be. If the search key is triggered in a silent part of the broadcast, another way to improve the quality of the search key is to move the search key acquisition instantly before or after the silent part. This allows the device to obtain a search key that contains more information.

  Compare a search key with other sections of the media signal and if the likelihood that they are from the same part of the same source material is high as indicated by some set criteria, perform the second step of the identification process be able to. If this is actually an exact match, move the time that is before and after the match in both sections that the signals are still very similar and therefore still appear to be from the same source material, It can be estimated by making a new comparison. At some point in the section where the similarity is below a certain level, it can be assumed that the end point of the portion of the similar section has been reached. In a similar manner, other end points can be searched.

  The search for the end point can be performed in a number of ways. The section can be tested by moving the test continuously along the section until a lower similarity level is reached, which is considered acceptable and determined to be an end point. Jump at a specific time away from the latest comparison point, test again, test this new point that can reduce the pop size and reverse the jump direction if still similar enough, and step size Reduce again. If the sections are considered sufficiently similar here, the new step direction is changed, and if the sections are not considered sufficiently similar, the step direction is not changed. The iterative process continues until a predetermined minimum step size is reached, which is the point considered as the end point. Other end points can be obtained in the same way.

In order to compare sections that originated from different media players and may have been obtained at different points in time, a particular speed change is considered between them. Therefore, if we jump some time away from the initial comparison point to a section, we cannot deduce that the comparison between the two sections may show the strongest similarity at this new point exactly. Jump one time before this point in one of the sections, and from this point, compare to a point well after the theoretical point and note where the highest similarity is achieved. More mathematically, a time t _JAMP jump in one selection and a t _JUMP-M jump in another selection, where M denotes a number of samples in other sections. Next, the portion around t _JUMP-M in the later section is compared with the same length portion of the other sections around t _JUMP . M is then decreased and the process is repeated until M reaches a certain value, often -M, and the process is stopped.

If the degree of similarity at this point is sufficiently high by making an estimate on the device tolerances and other variables involved that can affect the speed of recording, the section at that point still originated from the same source material A period around the expected match position in t _JUMP that is still allowed to be close enough can be determined. The above can be shown to give us other ways to increase the likelihood that a section at a particular point originated from the same source material. Of course, the first method is to calculate the degree of similarity by a method, and if that value is better than a certain set level, it is considered an exact match. A second way to further ensure that the sections are from the same source material at this point is to show how close to the logical point when the actual highest similarity is achieved. For example, we started earlier that the comparison process should start 1000 samples before the expected point and continue to 1000 samples after this point, and an exact match must appear in 10 samples before and after the logical point. It may be assumed that Now we can calculate all 2000 possible comparisons and show that the highest value is obtained at this point.

  If this value is within 10 samples of the theoretical point, it is likely that the section at this point originated from the same source material. The probability that two unrelated sections show the highest similarity within this 20-sample region is 20/2000 = 0.01. It can be seen that the longer the search area around the theoretical point, the more can trust the maximum similarity point within the limits.

  After jumping through many steps and finding a sufficient degree of similarity within the set limits, the limits can be narrowed for further jumps. This sets a narrower limit around this offset if it is determined what the expected offset is due to the fact that the offset from the expected point may be similar from step to step can do. It is unlikely that device tolerances and other factors that can affect the recording speed of a section will change significantly within a short time period. Together these two methods, a method of measuring the degree of similarity, and a method that only allows the highest similarity point within a certain time limit around the expected point in time, together Or only one can be used.

  In some versions of the invention below, the method also includes a counter that counts the number when the same source material is detected in part or in whole. One method may count the number of times when the second example of the search key is identified. In one application, if a song is played more times, the quality of the final recording of the song is higher and the likelihood that almost the entire song has been recorded is higher.

  In one version of the invention, the count is used to generate a source material list arranged according to how many times source material has been played in a particular time period on one or more media channels. You can also With respect to radio, the method can be used to form a list of the most played music last week at a particular or multiple radio stations and ranked according to how often the music was played.

  In some versions of the invention, the method may generate a list based on user selections and preferences. The user may recognize a source material when it is played, activate the device, and automatically save the source material in a list of listener choices. This may be one or more lists for different source material styles or users, i.e. for radio, for example a hard rock list, a pop music list, and a friend of the main user of the device The third list may be used.

  In some versions of the invention, the user may classify media channels so that source material played in the same format media channel is stored in the same list or library. With respect to radio, for example, some libraries may contain hard rock from radio stations that the user knows will play that type of music, while other libraries may also relate to soft music from that type of radio station. Good, etc.

  The device identifies, in certain versions implementing the present invention, certain source materials that are not played frequently and removes such source materials from the list. For example, if the time period between each time the source material is played exceeds a specified time, the source material may be considered less popular and removed from the top list.

  As previously indicated, the method can remove certain undesirable signal components, such as commercials. For example, the method may remove common segments that are shorter than a specific time period, such as 30 seconds or 1 minute, because most commercials are shorter than the desired source material. The device may recognize unwanted signal components and store them in a separate list.

  The method may remove signal segments that are found to be identical over a longer period of time. For example, if a radio broadcast is identical to other broadcasts for more than 5 to 10 minutes, it is probably a rebroadcast of a complete program rather than a single song, and therefore a user who wants to record a separate song I am not interested. These time parameters may be adjustable to the user so that he can use the device tail w to record both a separate source material and a collection of source materials.

  In some versions of the invention, the device may be able to generate a list of materials that the user desires not to be exposed. This can be done, for example, when the user presses an activation button when an undesirable material is played. In the case of radio, this list can include commercials, conversations, jingles, and the like. These signal components can be stored in an undesired list and this list can be used to block these segments from the list of desired materials. The user can also mark the source material in the desired list as undesirable and prevent them from being played or given to the user.

  In one method of implementing the present invention, the user is not exposed directly to the broadcast, but is exposed to a slightly delayed version, and the device removes any unwanted signal components before they reach the user, thus removing these gaps. Be able to have time to fill with the content of wear. This may be done by automatically searching the broadcast for unwanted signal components, changing the delay if an unwanted signal component is detected, and jumping to it. This can, for example, finally create a gap that is large enough to fill from the previously recorded desired material, and when these performances are finished, the source can be switched to an earlier program.

  The device may automatically change media channels such as radio stations when certain conditions are met. For example, the device may change radio stations after a specific time period, such as every 5 minutes or every 24 hours. The radio station can also be changed if a new song is not found after a certain time. Changes to new media channels can increase the number of pieces of source material that can be found. Program the device to find a predetermined number of source materials, such as 20, in one media channel, then change the media channel and a predetermined number of different sources in the second media channel You may find material. The device changes the media channel if the device cannot find any new source material after a certain time period, such as when the device fails to find a new source material at 48 hours. May be. The device may change the media signal when no recognizable media signal is found, such as when the broadcast is in a bad condition.

  The device may store signals from many media channels in a buffer memory. Exploring many media channels can increase the chances of finally getting the entire desired source material, eg, the entire song.

  In certain methods using the present invention, the apparatus can resume the iterative process and achieve a higher quality record of the source material. For example, when recording music from a radio broadcast, too short pieces of the desired song may be obtained or may have a lower quality than desired. The device or the user using the activation member may in this case start the process of obtaining a new search key from a common segment of the source material already recorded, which may be desired in memory or broadcast. Guides a new search for source materials.

  In another version of the invention, the device connects to an external system that names the desired source material. This can be done by the device sending a portion of the desired source material or a search key from the desired source material to the external device to obtain a regeneration identifying the source material. When the broadcast is used in music in radio broadcast, the device connects to the system and sends a recorded piece of music for identification. The identification system can send a music title, artist or group back to the device. This allows the user not only to listen to music, but also to obtain a title and to know what artist or group is performing. This identification can be done automatically or by triggering by the user.

  The quality of the media section recorded from the same part of the same source material, ie the proximity to the source material, can be improved by using two or more records of the same source material. If the device finds, for example, three media signals that contain the same source material, the undesired signal component is the same as the section with the undesired signal component, and thus there is no undesired signal component. May be removed by replacing with corresponding sections from the two media signals. In particular, if a particular section of the first media signal has a low similarity with the same section of the second media signal, but there is a high similarity between the second section and the third section, the method comprises: It may be designed to replace the section of the first media signal with a corresponding section of the second or third media signal.

  The search key may operate similarly to identifying only segments where the search key is higher than a certain predetermined value similarity. If the similarity value is set too high, there is a risk that segments originating from the same source material will be missed by the search key. If the similarity value is set too low, it may select inappropriate signal segments from the correct source material or incompletely broadcast signal segments.

  Of course, instead of simply maximizing sound quality, the device selects segments with similar values of similarity to prevent certain sound sections from being extremely clear and other sections from becoming so clear. It may be set. That is, the entire song can have an evenly distributed distortion level with an acceptable small size.

  One method used in certain versions of the present invention to increase the quality of the media signal is to add time aligned records from the same source material together sample by sample and add the resulting amplitude value to this additional process. Divide by. The desired signal information is not affected because it is the same in all recordings. Undesirable signal components such as noise and distortion are not affected as well as the desired signal information. Noise and other similar forms of undesirable information are considered more or less random in nature, so when adding two signals having the same average noise level, the average noise level does not double. If the amplitude of the desired signal portion is restored by dividing the amplitude value by the number of recordings participating in this process, the average noise level will be lower than the average noise level of the original recording.

  If the noise level in a record of the same source material differs from a certain level, it is actually better to choose the best record and not try to improve the quality by adding the records. Other types of undesirable signals and similar signals other than noise can also be reduced in this manner.

  If there are only two records of the same source material and they differ considerably in quality, it is difficult to say which of these is the best or which are of the same quality. The solution to this situation is to add the records and divide the resulting amplitude by two. One of the records can be substantially better than the other, and the best is to choose this record, but if not, the processed version is the best choice.

  If the section of source material originates from a radio broadcast or other perishable broadcast channel, a possible quality indication can be obtained from the signal strength at the receiver. Weaker reception is generally more noisy and distorted. It can also be used to measure other parameters of the received signal and give a quality indication of the resulting signal material.

  In one version of the invention below, the iterative method of the invention adds a new unobstructed source material segment to the source material segment stored in memory. The device matches two segments that should be joined together by deriving a mathematical calculation of the similarity of the two segments, eg, the beginning of the first segment exactly matches the beginning of the second segment As a result, the two segments can be placed exactly in time. The device may test for different overlaps and when the similarity is the highest, the device merges the two segments and the user adds the first segment to the second segment. Don't notice.

  In some versions of the invention below, the device automatically checks whether the signal segment was broadcast in reverse phase. An out-of-phase signal segment may have a negative similarity or correlation with a signal segment played in the opposite phase, even if it originates from the same part of the same source material. The apparatus may check both positive and negative similarities of the search key and allow use of anti-phase signal segments. In some versions of the invention below, if the device detects a phase reversal of one of the media signals, the device will do this before combining the two media signals into one. It may be automatically adjusted by changing one of the phases.

  Two sections to be merged into one may not have these sampled points aligned, and as a result, when merged, there may be discontinuities at the contacts in the final merged section . In order to make the transition between the two sections to be merged together as smooth as possible, gradually expand or compress one or both signals of the sections with a limited time close to the contact, It may be possible that coalescence between sections can occur without discontinuities. Another way to solve this discontinuity problem is to mathematically shift the sampling points of one or both of the sections so that the transition does not show discontinuities.

  The media signal can be a radio broadcast, a television broadcast, a broadcast over a computer network, a computer file, in a device that already stores the file, and so on.

  The media channel can be a radio and television network, a mobile phone network, a computer network, and so on.

  The receiving member may be a radio device, a television device, a VCR, a personal computer, a mobile phone, or other device that receives media signals.

  The activation member can be a button, lever device, computer program, algorithm, handle, or equivalent member. Voice control, infrared or Bluetooth connection, wireless connection, or a combination thereof may be used.

  All of the above members may be used and may be programmed, automated, or time-controlled activation members.

  Undesirable signal components in the broadcast may be speech from radio speakers, DJs, VJs, television people, readers, news, or equivalent. Undesirable signal components in the broadcast may occur, for example, due to the weakness of the broadcast, or for other reasons where the legality is interrupted or disturbed.

  The source material can be music, movies, commercials, TV programs, news, speech, sound effects, film effects, and so on.

  The detection member can be formed by an LP filter, HP filter, BP filter, BS filter, or an active or digital filter structure that performs frequency filtering, or a computer program, processor, or algorithm.

  The iterative member may be, for example, a computer program or algorithm.

  The final memory may be an internal memory in the media signal player. The final memory may be a CD-R, mini-disc, floppy (registered trademark) disk, hard disk drive, cassette recorder, multimedia card, compact flash (registered trademark) card, or other external or internal memory, or It is good also as a combination. The final memory may be part of external or internal memory, or part of buffer memory.

  The performance member may be a CD player, mini-disc player, cassette deck, stereo device, radio, television, VCR, MP3 player, PC, PDA, or any other device that performs media.

  The above-described procedures and apparatus for achieving the above-described goals of the present invention can include both software and hardware, or a combination of both.

  Although the invention has been described in accordance with the preferred configurations and examples, it should be understood that specific substitutions and modifications thereto may be made without departing from the spirit and scope of the claims.

Fig. 4 illustrates a procedure for forming a search key for a section of music or a representation of a section stored in memory, for example to compare and match the same music on a radio channel. An example of a procedure related to music recognition using a stored search key is shown. How a more complete piece of music can be detected by multiple iterations of detection, comparison and storage of substantially identical music, eg by continuously matching the search key with pieces of music broadcast over a radio channel, for example An example of how to form is shown. Illustrates the procedure for generating more search keys. An example of a procedure related to formation of an additional search key after matching with the first search key and detection is shown.

Claims (28)

In a method for identifying a desired segment of a media signal that includes undesirable signal components at a receiving device ,
Stores media signals (10, 20, 30, 40, 50, 60, 70, 80, 90) including undesired signal components (102, 103, 104, 105, 202, 204) received by the receiving device. Steps,
Selecting a first search key (100, 112, 400) in the media signal;
Searching for a second search key (114, 200, 500, 510, 520) substantially identical to the first search key;
The first segment (106, 128, 402, 404, 702) of the media signal generated before and after the generation of the first search key is changed into the second segment (120, 206, 501), and
Identifying a first common segment (106, 206, 702, 703) between the first segment and the second segment , comprising: A method of identification in a receiving device . The method of identifying at a receiving device a desired segment of a media signal comprising an undesirable signal component according to claim 1, wherein the step of searching for a third search key (116, 620) substantially identical to the first search key. When,
Comparing a third segment (122, 126, 602) of the media signal that occurs before and after generation of the third search key with the first segment and the second segment;
Identifying a second common segment (702, 705) between the first segment and a third segment and a third common segment (120, 122) between the second segment and the third segment; A method of identifying a desired segment of a media signal that includes an undesirable signal component at a receiving device . 3. A method for identifying a desired segment of a media signal including unwanted signal components at a receiving device according to claim 2, wherein said first common segment is linked to said second common segment to form a media signal segment (110). A method for identifying a desired segment of a media signal including an undesirable signal component at a receiving device, further comprising the step of: The method of identifying at a receiving device a desired segment of a media signal that includes an unwanted signal component as recited in claim 1, further comprising manually activating the device by using a first activation member. A method for identifying a desired segment of a media signal including an undesirable signal component at a receiving device . The method of claim 1 further comprising the step of automatically activating the device to identify a desired segment of a media signal that includes the unwanted signal component. A method for identifying a desired segment of a media signal including at a receiving device . The method of identifying at a receiving device a desired segment of a media signal that includes an unwanted signal component according to claim 1, wherein forming the first and second search keys comprises:
Storing the first and second search keys;
Searching with said first and second search keys further comprising identifying a desired segment of a media signal including undesired signal components at a receiving device . The method of identifying at a receiving device a desired segment of a media signal that includes an undesirable signal component according to claim 1, further comprising calculating a similarity factor between the first search key and the second search key. A method for identifying a desired segment of a media signal including an undesirable signal component at a receiving device . The method of identifying at a receiving device a desired segment of a media signal that includes an undesirable signal component according to claim 1, wherein the device uses every nth sample of the media signal when forming a search key ;
Using the same every n th sample of the media signal while searching with the sample search key;
Providing a parameter having one or more values to identify a desired segment of a media signal that includes an undesirable signal component at a receiving device . 2. The method of claim 1, further comprising the step of normalizing a signal gain of the media signal in the receiving apparatus for identifying a desired segment of the media signal including the unwanted signal component. A method for identifying a desired segment of a media signal comprising : 3. The method of identifying a desired segment of a media signal that includes an undesirable signal component according to claim 2 at a receiving device , comprising: selecting a longest common segment of the first common segment, the second common segment, and a third common segment. A method for identifying a desired segment of a media signal including an undesirable signal component at a receiving device, further comprising: A method of identifying at a receiving device a desired segment of a media signal that includes an unwanted signal component as recited in claim 1, forming a number of copies of the media signal or a representation of the media signal; Storing a duplicate or representation further comprising identifying a desired segment of a media signal including an undesirable signal component at a receiving device . A method for identifying the reception device segments desirable media signal containing undesirable signal components according to claim 1, characterized by further comprising the step of counting the number of times the identified common segment is received, preferably A method of identifying a desired segment of a media signal that includes no signal component at a receiving device . The method of identifying at a receiving device a desired segment of a media signal that includes an undesirable signal component as recited in claim 1, wherein the number of times the second search key is substantially identical to the first search key. A method of identifying a desired segment of a media signal that includes an undesirable signal component at a receiving device . A method for identifying the reception device segments desirable media signal containing undesirable signal components according to claim 1, characterized by further comprising the step of generating a first list of common segments, the undesired signal components A method for identifying a desired segment of a media signal including at a receiving device . 15. The method of identifying a desired segment of a media signal including an undesirable signal component at a receiving device as recited in claim 14, wherein the unwanted common segment is activated by a second activation member at the device, and the unwanted common segment is activated. A method of identifying a desired segment of a media signal including an undesirable signal component at a receiving device, further comprising the step of identifying by storing in a second list. 15. The method of identifying at a receiving device a desired segment of a media signal that includes an undesirable signal component according to claim 14, wherein a common segment shorter than a predetermined time period is selected and the shorter common segment is included in a third list. A method of identifying a desired segment of a media signal including an undesirable signal component at a receiving device, further comprising the step of storing. 17. The method of identifying at a receiving device a desired segment of a media signal that includes an undesirable signal component according to claim 16, further comprising the step of removing a common segment in the third list from the first list. A method for identifying a desired segment of a media signal that includes undesirable signal components at a receiving device . 16. The method of identifying at a receiving device a desired segment of a media signal that includes an undesirable signal component according to claim 15, further comprising the step of removing a common segment in the second list from the first list. A method for identifying a desired segment of a media signal that includes undesirable signal components at a receiving device . The method of identifying at a receiving device a desired segment of a media signal that includes an undesirable signal component according to claim 1, wherein a common segment longer than a first predetermined time period is selected and a second predetermined A method for identifying a desired segment of a media signal that includes undesirable signal components at a receiving device, further comprising removing from the first list the selected common segment that is longer than a time period. The method of identifying a desired segment of a media signal including an undesirable signal component at a receiving device according to claim 1, wherein a first signal strength at an input of the receiving device in a time period of receiving the first common segment is Comparing with a second signal strength at the input of the receiving device in a time period for receiving a second common segment, selecting the first segment if the first signal strength is greater than the second signal strength, and Selecting a second segment if the second signal strength is greater than the first signal strength , and identifying a desired segment of the media signal including an undesirable signal component at the receiving device . 3. The method of identifying a desired segment of a media signal including an undesirable signal component at a receiving device according to claim 2, wherein a first similarity between the first segment and the second segment in the first common segment is determined. Determining a second similarity between the second segment and the third segment in the second common segment;
The first common segment is selected when the first similarity exhibits a higher degree of similarity than the second similarity, and the second similarity is higher than the first similarity. Selecting the second common segment when indicating similarity, and receiving the media signal at the receiving device. The method of identifying at a receiving device a desired segment of a media signal that includes unwanted signal components according to claim 1, wherein the common segment is based on how often the common segment is identified over a predetermined time period. A method for identifying a desired segment of a media signal including an undesirable signal component at a receiving device, further comprising: generating a fourth list of: The method of identifying at a receiving device a desired segment of a media signal that includes undesirable signal components as recited in claim 1, wherein a fifth list of common segments is generated based on how long the common segment has been last identified. A method for identifying a desired segment of a media signal including an undesirable signal component at a receiving device, further comprising the step of: The method of identifying a desired segment of a media signal including an undesirable signal component at a receiving device according to claim 1, wherein the media channel is changed when a predetermined time has elapsed and no new common segment has been identified. A method for identifying a desired segment of a media signal including an undesirable signal component at a receiving device, further comprising the step of: The method of identifying at a receiving device a desired segment of a media signal that includes an undesirable signal component according to claim 1, wherein a predetermined time has elapsed since the receiving device last changed a media channel: A method for identifying a desired segment of a media signal including an undesirable signal component at a receiving device, further comprising changing the media channel. The method of identifying at a receiving device a desired segment of a media signal that includes an undesirable signal component as recited in claim 1, further comprising changing the media channel when a certain number of new common segments are identified. A method for identifying a desired segment of a media signal including an undesirable signal component at a receiving device . The method of identifying at a receiving device a desired segment of a media signal that includes an undesirable signal component according to claim 1, wherein searching for a plurality of search keys substantially identical to the first search key; Identifying a desired segment of the media signal that includes the undesired signal component at the receiving device, further comprising identifying a fourth signal segment that is substantially identical to the selected signal segment. The method of identifying at a receiving device a desired segment of a media signal that includes an unwanted signal component according to claim 1, further comprising the step of normalizing a signal gain of the media signal, wherein the normalization factor is a selected section. A method for identifying a desired segment of a media signal containing an undesirable signal component at a receiving device, characterized in that it is obtained from a sum of absolute values of samples in

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