Musipedia
Search principles
Musipedia offers two search methods: either based on the melodic contour or on pitch and rhythm.
The contour search is based on an edit distance. Therefore, not only entries are found, which correspond exactly to the melodic contour input, but also the most similar among the non-identical melodies. The similarity is measured on the basis of the necessary edit operations ( insert, replace or delete a character ), which would convert the Parsons code of the query in the Parsons Code of the search result. Since only the melodic contour, melodies can find you even if you are not sure about the key, the rhythm or the exact intervals.
The pitch and rhythm - search, which is used as default, also has a certain robustness, because it does not depend on the absolute pitch and exact tempo, but only of the intervals and the rhythm. The melody can be entered in several ways, such as with a keyboard on the computer screen. The search engine then decomposes the request into short segments, converts each segment in a set of points in two-dimensional space of time and pitch up and finally compares each of these sets of points on the basis of Earth Mover 's Distance with the sets of points that describe the segments of the melody database. As with the contour Search only small changes to the query also correspondingly small changes in the search results, which makes fault-tolerant searching.
Both search methods are accelerated with indexes that are based on Vantage objects. Instead of calculating the distance between the query and each database entry, only the distances between the query and a small number Vantage objects are determined when searching. The distance to each object in the database is already available for each of these objects in advance Vantage calculated. Since the triangle inequality applies to the edit distance as well as the transport distance used by Musipedia, the search algorithm, only the objects with similar distances must be observed the Vantage objects in a second step.
Demarcation audio search engines
The Musipedia search engine works fundamentally different from a search engine such as Shazam. The latter can be short waveform data (a few seconds of a recording) identify, even if they were transmitted over a poor quality telephone connection. Used Shazam audio fingerprinting. With audio fingerprinting can identify recordings, using a search engine such as Musipedia contrast, pieces of music, containing a given melody. Shazam is exactly the recording, which contains a given cut, but no other recordings of the same piece of music.