Tempo and beat analysis is the basis of rhythm perception and music understanding. Although most humans can easily follow the beat of music by tapping their feet or clapping their hands, detecting a musical beat automatically remains a difficult task.
Various media editing and playback tools utilize automatic beat detection. For example, currently available movie editing tools permit a user to extract important video shots from a movie and to align transitions between these shots with the beat of a piece of music. Various photo viewing and presentation tools allow a user to put together a slideshow of photos set to music. Some of these photo presentation tools can align the transition between photos in the slideshow with the beat of the music. Other music playback media tools provide visualizations on a computer screen while playing back music. Music visualizations can be any sort of visual design such as circles, lines, flames, fountains, smoke, etc., that change in appearance while music is being played back. Transitions in the appearance of a music visualization that are linked to the beat of the music provide a more interesting experience for the user than if such transitions occur randomly.
The burgeoning use of computers to store, access, edit and playback various media through such media tools makes the task of music beat analysis and detection increasingly important. Accurate and efficient beat analysis and detection algorithms are therefore becoming basic components for various media editing and playback tools that perform tasks such as those mentioned above. However, prior methods and systems of beat analysis and detection have several disadvantages. One disadvantage is that most prior beat analysis and detection methods require that assumptions be made about the time signature and hierarchical meter of the music. For example, a typical assumption made in prior methods is that the time signature of the music is 4/4. Another disadvantage with prior methods/systems is that not all of the detected beats in such systems are in sync with the actual beat phase of the music. Often, there are detected beats that are out of sync or locked in a false beat phase. Furthermore, prior methods and systems do not offer a way to rectify the beats that are out of sync with the true beat phase of the music.
Accordingly, a need exists for improved beat analysis and detection that does not require assumptions regarding musical time signature and hierarchical meter, and that overcomes various disadvantages with prior methods such as those mentioned above.