diff Example VamPy plugins/PyZeroCrossing.py @ 37:27bab3a16c9a vampy2final

new branch Vampy2final

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Example VamPy plugins/PyZeroCrossing.py	Mon Oct 05 11:28:00 2009 +0000
@@ -0,0 +1,162 @@
+'''PyZeroCrossing.py - Example plugin demonstrates
+how to write a Vampy plugin in pure Python without
+using Numpy or the extensions provided by the embedded 
+vampy module. 
+
+This plugin is compatible with provious versions of vampy, 
+apart from moving the inputSampleRate
+argument from initialise to __init__()
+
+Outputs: 
+1) Zero crossing counts
+2) Zero crossing locations
+
+Centre for Digital Music, Queen Mary University of London.
+Copyright (C) 2009 Gyorgy Fazekas, QMUL. (See Vamp sources 
+for licence information.)
+
+'''
+
+class PyZeroCrossing: 
+	
+	def __init__(self,inputSampleRate): 
+		self.m_inputSampleRate = inputSampleRate 
+		self.m_stepSize = 0
+		self.m_blockSize = 0
+		self.m_channels = 0
+		self.previousSample = 0.0
+		self.threshold = 0.005
+		self.counter = 0
+		
+	def initialise(self,channels,stepSize,blockSize):
+		self.m_channels = channels
+		self.m_stepSize = stepSize		
+		self.m_blockSize = blockSize
+		return True
+	
+	def getMaker(self):
+		return 'Vampy Example Plugins'
+	
+	def getName(self):
+		return 'Vampy Zero Crossings'
+		
+	def getIdentifier(self):
+		return 'vampy-zc2'
+	
+	def getMaxChannelCount(self):
+		return 1
+		
+	def getInputDomain(self):
+		return 'TimeDomain'
+			
+	def getOutputDescriptors(self):
+		
+		#descriptors can be returned as python dictionaries
+		output0={
+		'identifier':'vampy-counts',
+		'name':'Number of Zero Crossings',
+		'description':'Number of zero crossings per audio frame',
+		'unit':' ',
+		'hasFixedBinCount':True,
+		'binCount':1,
+		#'binNames':['1 Hz',1.5,'2 Hz',3,'4 Hz'],
+		'hasKnownExtents':False,
+		#'minValue':0.0,
+		#'maxValue':0.0,
+		'isQuantized':True,
+		'quantizeStep':1.0,
+		'sampleType':'OneSamplePerStep'
+		#'sampleRate':48000.0
+		}
+
+		output1={
+		'identifier':'vampy-crossings',
+		'name':'Zero Crossing Locations',
+		'description':'The locations of zero crossing points',
+		'unit':'discrete',
+		'hasFixedBinCount':True,
+		'binCount':0,
+		'sampleType':'VariableSampleRate'
+		}
+
+		return [output0,output1]
+
+
+	def getParameterDescriptors(self):
+		paramlist1={
+		'identifier':'threshold',
+		'name':'Noise threshold',
+		'description':'',
+		'unit':'v',
+		'minValue':0.0,
+		'maxValue':0.5,
+		'defaultValue':0.005,
+		'isQuantized':False
+		}
+		return [paramlist1]
+
+
+	def setParameter(self,paramid,newval):
+		if paramid == 'threshold' :
+			self.threshold = newval
+		return
+
+		
+	def getParameter(self,paramid):
+		if paramid == 'threshold' :
+			return self.threshold
+		else:
+			return 0.0
+
+
+	# legacy process type: the input is a python list of samples
+	def process(self,inbuf,timestamp):
+		crossing = False
+		prev = self.previousSample
+		count = 0.0;
+		channel = inbuf[0]
+
+		#we have two outputs defined thus we have to declare
+		#them as empty dictionaries in our output list
+		#in order to be able to return variable rate outputs
+		output0=[]
+		output1=[]
+
+		if sum([abs(s) for s in channel]) > self.threshold : 
+
+			for x in range(len(channel)-1) :
+				crossing = False
+				sample = channel[x]
+				if sample <= 0.0 : 
+					if prev > 0.0 : crossing = True
+				else :
+					if sample > 0.0 :
+						if prev <= 0.0 : crossing = True		
+			
+				if crossing == True : 
+					count = count + 1
+					feature1={
+					'hasTimestamp':True,	
+					'timeStamp':long(timestamp + x),				
+					'values':[count],			
+					'label':str(count),				
+					}				
+					output1.append(feature1)
+			
+				prev = sample	
+			self.previousSample = prev
+
+		else :
+			count = 0.0
+			self.previousSample = channel[len(channel)-1]
+
+		feature0={
+		'hasTimestamp':False,		
+		'values':[count],
+		'label':str(count)				
+		}
+		output0.append(feature0)
+		
+		#return a LIST of list of dictionaries
+		return [output0,output1]
+