In audio applications on electronic devices, rewinding/winding has become a required feature. In applications such as the RealPlayer, a user is capable of moving forward and backwards through various audio tracks. This feature can be used for a variety of purposes, such as to revisit a portion of an audio book where the user was distracted, or to skip ahead to a desired location within the audio content.
Winding and rewinding is conventionally performed based upon a certain time duration. Such systems can automatically move backwards or forwards in a track by a predetermined period of time with each “touch,” or the length of time can be dependent upon the length of time that a user presses a “forward” or “rewind” button or icon. It is also possible for the position in an audio track to be selected arbitrarily, where audio playback always starts from a selected location in the audio regardless of the track's content. In other words, in these systems, the playback position is not dependent on the audio content of a signal.
To demonstrate this issue, it is helpful to look at the effect of rewinding on both music content and speech content. If music content is rewinded back by, for example, twenty seconds, playback will then start in the middle of the music, without control of the exact starting position. Generally, this is not considered to be a significant issue because a music signal is usually considered to be a continuous signal. As a result of this fact, the user will usually not lose track of the music signal, even when playback is started in the middle of a music section.
If the audio comprises spoken speech, words, sentences, paragraphs or chapters, on the other hand, the situation is quite different. If such audio content is played starting in the middle of a word, sentence, paragraph or chapter, the entire meaning of the speech may be lost, as a person may not be able to infer the spoken text that exists before the playback starting point. This problem occurs frequently when traditional winding method is used, i.e., when a winding button is pressed and the playing position of the audio track is moved by an arbitrary time interval. In conventional winding systems, there is no control mechanism that can ensure that audio playing will start at the beginning of a word, sentence, paragraph or chapter, and such a system would be highly desirable by the user.
Audio content can include a type of indexing feature that is defined by the producer of the content. For example, the Victor Reader Classic talking book player includes keys that allow the user to easily move from one book element to another, permitting the user to quickly go to desired information. In such systems, a user is capable of moving by chapter, section, page, paragraph, book, or other elements that are defined by the book's producer. However, such a system only permits the user to wind or rewind to a limited set of predefined locations.
With music content, a user may often select only certain tracks within a music track collection for playback or play the entire track collection from start to finish. In such situations, the need for winding is not necessary, although basic winding functionality is usually still implemented in such music-specific applications. However, when the audio content includes speech, winding and rewinding is substantially more important, because the user is not simply listening to tracks or songs but is instead interested in “textual context.” For example, when a user is listening to an audio book, he or she may want to listen to specific chapters, paragraphs, sentences or even words in order to obtain the necessary or desired context of the respective section.
Another method of navigating through audio content is to divide the content into individual tracks to enable a listener to easily navigate through the document. Individual tracks are easy to access by moving back and forth between tracks. With this technique, the listener can efficiently access a desired section. For example, a listener can first browse various section headings that correspond to various tracks in order to find the section he or she wants to listen to. The user can then use the section numbers included with the section headings to travel to the desired section; the section number announced at the start of each section indicates if the desired section is before or after the current track. Once again, however, the user's options for winding and rewinding are limited. Using such a “track” system, for example, a user may not be able to rewind the audio to hear only a few seconds of sound that he or she may have missed during the original playing. Instead, the user would have to go back to, at a minimum, the beginning of the track, regardless of whether the beginning of the track was a few seconds or several minutes backwards in time. The user's only other option would be to attempt to manually wind or rewind the audio content, which leads to the problem of broken words, sentences, etc. discussed above.
It would therefore be desirable to provide a system and method for permitting the winding and rewinding of audio content that addresses the above-identified difficulties.