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Chris Cannam, 2014-07-16 06:52 PM


Piano Evaluation for Level Normalisation

Lack of normalisation for Vamp plugin inputs is a problem when analysing quiet recordings (see #1028).

Testing using a small set of piano recordings, quickly evaluating performance across the first 30 seconds under a number of different normalisation / level management regimes.

Input files

Filename Signal max approx
31.wav 0.57
MAPS_MUS-bach_846_AkPnBcht.wav 0.12
MAPS_MUS-chpn_op7_1_ENSTDkAm.wav 0.33
MAPS_MUS-scn15_7_SptkBGAm.wav 0.13
mz_333_1MINp_align.wav 0.10

The plugin has one internal threshold parameter, which can be lowered to find quieter notes (at the expense of course of more false positives). We don't really want to expose this (or any continuous controls) as a parameter. But we need to have approximately predictable input levels, for this threshold to be meaningful.

Methods

Name Hg revision Description
as-is d721a17f3e14 No normalisation
norm d721a17f3e14 Normalise to 0.50 max before running plugin (can't do this in plugin)
to-date d9b688700819 Track max signal level so far, adjust each sample so that max is at 0.50

Results

Reporting only the note onset F-measure for the first 30 seconds of each piece.

Filename as-is norm to-date
31.wav 33 50 40
MAPS_MUS-bach_846_AkPnBcht.wav 15 87 62
MAPS_MUS-chpn_op7_1_ENSTDkAm.wav 31 33 31
MAPS_MUS-scn15_7_SptkBGAm.wav 16 73 61
mz_333_1MINp_align.wav 3 66 58