Frequently Asked Questions (FAQ)
Click here to read a press release about the Melody Comparison and Rhythm Comparison "copyright checker" tools.
How does Dr. Lustig’s Melody Comparison tool work?
The Melody Comparison tool compares the similarity % of two series of pitches. First, it uses a key-finding algorithm to determine the key of each series, and transposes them to the same key for comparison. Then it uses state-of-the-art comparison technology (Levenshtein distance) to determine their similarity percentage.
Why can’t I hum the melody or upload the audio?
The current technology for accurately converting audio inputs to meaningful music-symbolic data just isn’t good enough yet to get reliable results as an audio copyright checker or mp3 copyright checker. For that reason, your input option for the Melody Comparison tool is a virtual piano.
Why is it giving me a range (e.g. “20-70% similar”) instead of an exact percentage?
Some melodies have multiple possible keys. This usually happens for inputs that are short, such as 3 to 4 notes - they are “underdefined” and thus have multiple possible solutions. Depending on the solution, there are different results for similarity between the two melodies.
What is a problematic similarity percentage between two melodies? How much is TOO much?
There is no easy answer to this question because it depends entirely on the case and context. For example, two songs’ melodies might both go A-B-C at one point—which is technically a 100% pitch similarity—but if those three notes are the only commonality between the two songs, and they occur with different rhythms, the similarity may not be particularly significant. Further complicating the case is the idea of “prior art”: the musicologist can demonstrate that the pattern A-B-C has occurred in a lot of prior music that predates both the plaintiff and defendant, and therefore is not protectable in the first place.
On the other hand, sometimes two songs can be in different genres and sound quite different, and yet expert forensic musicology analysis can shine a light on the hidden similarity, helping to reveal and demonstrate that highly distinct/original aspects have been copied from the plaintiff’s melody.
Why does the score only show sharp notes (no flat notes)?
You may have noticed that in the Melody Comparison tool, black keys on the piano are notated as # only (such as A# instead of Bb). This is for a few reasons. Non-musicians can get overwhelmed by enharmonic equivalence, and the concept of sharp is easier to understand than flat (C, C#, D, D# etc. is easier to understand than C, Db, D, Eb etc.). Also, music producers who learn about notes from digital audio workstations (DAWs) are often presented with a sharp-only piano roll (no flats), so they have heard of A# but not Bb. Finally, it is impossible to determine from the piano input alone, if a G# or an Ab was intended.
Click here to read a press release about the Melody Comparison and Rhythm Comparison "copyright checker" tools.
How does Dr. Lustig’s Melody Comparison tool work?
The Melody Comparison tool compares the similarity % of two series of pitches. First, it uses a key-finding algorithm to determine the key of each series, and transposes them to the same key for comparison. Then it uses state-of-the-art comparison technology (Levenshtein distance) to determine their similarity percentage.
Why can’t I hum the melody or upload the audio?
The current technology for accurately converting audio inputs to meaningful music-symbolic data just isn’t good enough yet to get reliable results as an audio copyright checker or mp3 copyright checker. For that reason, your input option for the Melody Comparison tool is a virtual piano.
Why is it giving me a range (e.g. “20-70% similar”) instead of an exact percentage?
Some melodies have multiple possible keys. This usually happens for inputs that are short, such as 3 to 4 notes - they are “underdefined” and thus have multiple possible solutions. Depending on the solution, there are different results for similarity between the two melodies.
What is a problematic similarity percentage between two melodies? How much is TOO much?
There is no easy answer to this question because it depends entirely on the case and context. For example, two songs’ melodies might both go A-B-C at one point—which is technically a 100% pitch similarity—but if those three notes are the only commonality between the two songs, and they occur with different rhythms, the similarity may not be particularly significant. Further complicating the case is the idea of “prior art”: the musicologist can demonstrate that the pattern A-B-C has occurred in a lot of prior music that predates both the plaintiff and defendant, and therefore is not protectable in the first place.
On the other hand, sometimes two songs can be in different genres and sound quite different, and yet expert forensic musicology analysis can shine a light on the hidden similarity, helping to reveal and demonstrate that highly distinct/original aspects have been copied from the plaintiff’s melody.
Why does the score only show sharp notes (no flat notes)?
You may have noticed that in the Melody Comparison tool, black keys on the piano are notated as # only (such as A# instead of Bb). This is for a few reasons. Non-musicians can get overwhelmed by enharmonic equivalence, and the concept of sharp is easier to understand than flat (C, C#, D, D# etc. is easier to understand than C, Db, D, Eb etc.). Also, music producers who learn about notes from digital audio workstations (DAWs) are often presented with a sharp-only piano roll (no flats), so they have heard of A# but not Bb. Finally, it is impossible to determine from the piano input alone, if a G# or an Ab was intended.
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Disclaimer: the results of this tool do not constitute official legal or musicological advice. Data from this page such as the “percent similarity” metric cannot be used in legal documents and does not constitute an endorsed statement by Dr. Ethan Lustig. These tools are previews and not official analyses of similarity. For a real expert interpretation, contact Dr. Ethan Lustig.
