def lpcc(self, lpcorder=None, cepsorder=None):
'''
Function: lpcc
Summary: Computes the linear predictive cepstral compoents. Note: Returned values are in the frequency domain. LPCC is computed through LPC.
Examples: audiofile = AudioFile.open('file.wav',16000)
frames = audiofile.frames(512,np.hamming)
for frame in frames:
frame.lpcc()
Attributes:
@param (self):
@param (lpcorder) default=None: The input order to compute the LPC coefficents.
@param (cepsorder) default=None: The output order to compute the LPCC coefficents.
Returns: A list of LPCC components with size order +1 or len(seq), depending on if cepsorder is None
'''
coefs, err_term = LinearPredictiveAnalysis.lpc(self, lpcorder)
return LinearPredictiveAnalysis.lpcc(coefs, err_term, cepsorder)
def lsp(self,order=None,rectify=True):
'''
Function: lsp
Summary: Computes Line spectrum pairs ( also called line spectral frequencies [lsf]). Does not use any fancy algorithm except np.roots to solve
for the zeros of the given polynom A(z) = 0.5(P(z) + Q(z))
Examples: audiofile = AudioFile.open('file.wav',16000)
frames = audiofile.frames(512,np.hamming)
for frame in frames:
frame.lsp()
Attributes:
@param (self):
@param (order) default=None:Order of lpc coefficients. Return array has size order + 1. Default is the length of the current frame
@param (rectify) default=True: Specifies if the return values are only positive. If rectify is False it also returns the (symmetric) negative values
Returns: A list of size order/ len(frames) (if nothing is specifed), which represents the line spectrum pairs.
'''
coefs, _ = LinearPredictiveAnalysis.lpc(self, order)
return LinearPredictiveAnalysis.lsp(coefs,rectify)
def lpc(self, order=None):
'''
Function: lpc
Summary: Computes for each given sequence the LPC ( Linear predictive components ) sequence.
Examples: audiofile = AudioFile.open('file.wav',16000)
frames = audiofile.frames(512,np.hamming)
for frame in frames:
frame.lpc()
Attributes:
@param (seq):A sequence of time-domain frames, usually obtained by .frames()
@param (order) default=None: Size of the returning cepstral components. If None is given,
we use len(seq) as default, otherwise order +1
Returns: A list of lpc coefficents
'''
# Only return the coefficients not the error term (in [1])
return LinearPredictiveAnalysis.lpc(self, order)[0]
