Silvet Note Transcription

h1. 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.

Recording 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: