annotate feature-description-example.n3 @ 269:39fb206b1153 piper-nopiper

Filter out Xing/LAME info frames, rather than letting them go to the mp3 decoder as if they were audio frames. Fixes the 1152-sample zero pad at start of some decoded mp3 files (distinct from decoder delay). The logic here is based on the madplay code.
author Chris Cannam
date Thu, 24 Nov 2016 13:32:04 +0000
parents 581b1b150a4d
children
rev   line source
Chris@0 1
Chris@0 2 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
Chris@0 3 @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
Chris@0 4 @prefix dc: <http://purl.org/dc/elements/1.1/> .
Chris@0 5 @prefix mo: <http://purl.org/ontology/mo/> .
Chris@0 6 @prefix af: <http://purl.org/ontology/af/> .
Chris@0 7 @prefix event: <http://purl.org/NET/c4dm/event.owl#> .
Chris@0 8 @prefix tl: <http://purl.org/NET/c4dm/timeline.owl#> .
Chris@0 9 @prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
Chris@0 10 @prefix : <#> .
Chris@0 11
Chris@0 12
Chris@0 13 # Describe the signal we're annotating, and associate it with a
Chris@0 14 # timeline (the timeline is named as :base_timeline but never given
Chris@0 15 # any attributes in this document). Any feature that is associated
Chris@0 16 # with the same timeline will be taken as derived from this signal.
Chris@0 17
Chris@0 18 :audio_signal a mo:Signal ;
Chris@0 19 mo:available_as <file:///path/to/myfile.wav> ;
Chris@0 20 mo:time :signal_interval .
Chris@0 21
Chris@0 22 :signal_interval a tl:Interval ;
Chris@0 23 tl:onTimeLine :base_timeline ;
Chris@0 24 tl:beginsAt "PT0"^^xsd:duration .
Chris@0 25
Chris@0 26
Chris@0 27 # A sparse feature event.
Chris@0 28
Chris@0 29 :event0 a af:Onset ;
Chris@0 30 event:time :time0 .
Chris@0 31
Chris@0 32 :time0 a tl:Instant ;
Chris@0 33 tl:onTimeLine :base_timeline ;
Chris@0 34 tl:at "PT0.185759637S"^^xsd:duration .
Chris@0 35
Chris@0 36 # Alternatively we could write that with a blank node.
Chris@0 37
Chris@0 38 :event1 a af:Onset ;
Chris@0 39 event:time [
Chris@0 40 a tl:Instant ;
Chris@0 41 tl:onTimeLine :base_timeline ;
Chris@0 42 tl:at "PT0.510839002S"^^xsd:duration ;
Chris@0 43 ] .
Chris@0 44
Chris@0 45
Chris@0 46 # For a dense feature, we need an appropriately sampled, windowed timeline.
Chris@0 47
Chris@0 48 :feature_timeline a tl:DiscreteTimeLine .
Chris@0 49
Chris@0 50 :feature_timeline_map a tl:UniformSamplingWindowingMap ;
Chris@0 51 tl:rangeTimeLine :feature_timeline ;
Chris@0 52 tl:domainTimeLine :base_timeline ;
Chris@0 53 tl:sampleRate "44100"^^xsd:int ;
Chris@0 54 tl:windowLength "1024"^^xsd:int ;
Chris@0 55 tl:hopSize "512"^^xsd:int .
Chris@0 56
Chris@0 57
Chris@0 58 # ... and an interval, defined in terms of hops (the discrete steps of
Chris@0 59 # the windowed timeline).
Chris@0 60
Chris@0 61 :feature_interval a tl:Interval ;
Chris@0 62 tl:onTimeLine :feature_timeline ;
Chris@0 63 tl:beginsAt "0"^^xsd:int ;
Chris@0 64 tl:duration "5634"^^xsd:int .
Chris@0 65
Chris@0 66
Chris@0 67 # Then our feature is a signal that is on the interval we just
Chris@0 68 # described. We associate it explicitly with the original audio
Chris@0 69 # signal, although presumably we could leave the association implicit,
Chris@0 70 # to be derived from the relationships between timelines, just as it
Chris@0 71 # is for the sparse features above.
Chris@0 72
Chris@0 73 :audio_signal af:signal_feature :feature1 .
Chris@0 74
Chris@0 75 :feature_signal_type rdfs:subClassOf af:DetectionFunction ;
Chris@0 76 dc:title "Detection Function from Simple Percussion Onset Detector" .
Chris@0 77
Chris@0 78 :feature1 a :feature_signal_type ;
Chris@0 79 mo:time :feature_interval ;
Chris@0 80 af:dimensions "12 12345" ;
Chris@0 81 af:value "0 0 0 0 0 0 0 1 2 3 1 24 236 123213 (etc)" .
Chris@0 82