Tempo has several plausible levels
An onset pattern can fit 60, 120 or 240 BPM depending on the beat level. This tool searches a limited pulse range and reports the strongest repeating energy lag. Sparse melodies and rubato may have no reliable pulse.
A phrase may not establish a key
Duration-weighted pitch classes are compared with major and minor profiles. A scale fragment or modulation can favor the wrong tonic. Listen for the cadence and inspect the harmony before assigning a key signature.
The MIDI conversion remains useful even when these estimates are inconclusive: the note events preserve measured timing and can be edited independently.
Compare pulse against a known passage
The example melody repeats note attacks every 0.6 seconds, so 100 BPM is a useful expected pulse. That does not mean every five-second recording has a reliable tempo. A held flute note may provide a clear pitch and almost no rhythmic evidence; a tremolo can produce several pulses inside one musical beat.
Count along with the original and test a metronome at the estimate, then at half or double that value when musically plausible. If the downbeats drift, the performance may vary in tempo or the detector may be following a subdivision. The MIDI export does not automatically quantize the phrase to the reported estimate.
Use the key suggestion to ask a better question
A phrase containing C, E, G and A can fit several tonal contexts. If the melody resolves to A over an A-minor harmony, a C-major suggestion may describe its pitch collection without identifying its tonal center. Inspect the longest notes, the final cadence and the accompaniment yourself. The tool compares duration-weighted pitch classes against major/minor profiles; it does not analyze chord progressions or identify every modulation.