mlib_signalcepstralinit_s16(3mlib) [opensolaris man page]

mlib_SignalCepstralInit_S16(3MLIB)			    mediaLib Library Functions				mlib_SignalCepstralInit_S16(3MLIB)

NAME

       mlib_SignalCepstralInit_S16, mlib_SignalCepstralInit_F32 - initialization for cepstral analysis

SYNOPSIS

       cc [ flag... ] file... -lmlib [ library... ]
       #include <mlib.h>

       mlib_status mlib_SignalCepstralInit_S16(void *state, mlib_s32 order);

       mlib_status mlib_SignalCepstralInit_F32(void *state, mlib_s32 order);

DESCRIPTION

       Each of these functions initializes the internal state structure for cepstral analysis.

       The  init function performs internal state structure allocation and global initialization. Per function call initialization is done in each
       function, so the same internal state structure can be reused for multiplefunction calls.

PARAMETERS

       Each of the functions takes the following arguments:

       order	The order of the input signal vector and the cepstral coefficients, where length = 2**order.

       state	Pointer to the internal state structure.

RETURN VALUES

       Each of the functions returns MLIB_SUCCESS if successful. Otherwise it returns MLIB_FAILURE.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       mlib_SignalCepstral_S16(3MLIB),	mlib_SignalCepstral_S16_Adp(3MLIB),  mlib_SignalCepstral_F32(3MLIB),   mlib_SignalCepstralFree_S16(3MLIB),
       mlib_SignalCepstralFree_F32(3MLIB), attributes(5)

SunOS 5.11							    2 Mar 2007					mlib_SignalCepstralInit_S16(3MLIB)

mlib_SignalCepstral_S16(3MLIB)				    mediaLib Library Functions				    mlib_SignalCepstral_S16(3MLIB)

NAME

       mlib_SignalCepstral_S16 - perform cepstral analysis

SYNOPSIS

       cc [ flag... ] file... -lmlib [ library... ]
       #include <mlib.h>

       mlib_status mlib_SignalCepstral_S16(mlib_s16 *cepst, mlib_s32 cscale, const mlib_s16 *signal, void *state);

DESCRIPTION

       The  mlib_SignalCepstral_S16()  function  performs cepstral analysis.  The user supplied scaling factor will be used and the output will be
       saturated if necessary.

       The basic operations to compute the cepstrum is shown below.

	     +-----------+	+--------+	 +-----------+
	     |	Fourier  |	|	 |	 |  Inverse  |
       ----->|		 |----->| log|*| |------>|  Fourier  |----->
	x(n) | Transform | X(k) |	 | X'(k) | Transform | c(n)
	     +-----------+	+--------+	 +-----------+

       where x(n) is the input signal and c(n) is its cepstrum. In mathematics, they are

	      N-1		 2*PI*k*n
       X(k) = SUM x(n) * exp(-j*----------)
	      n=0		    N

       X'(k) = log|X(k)|

	       1  N-1		     2*PI*k*n
       c(n) = --- SUM X'(k) * exp(j*----------)
	       N  n=0			N

       Since X'(k) is real and even (symmetric), i.e.

       X'(k) = X'(N - k)

       the c(n) is real and the equation becomes Cosine transform.

	       1  N-1		   2*PI*k*n
       c(n) = --- SUM X'(k) * cos(----------)
	       N  n=0		      N

       The cepstral coefficients in LPC is a special case of the above.

       See Digital Signal Processing by Alan V. Oppenheim and Ronald W. Schafer, Prentice Hall, 1974.

       See Fundamentals of Speech Recognition by Lawrence Rabinerand Biing-Hwang Juang, Prentice Hall, 1993.

PARAMETERS

       The function takes the following arguments:

       cepst	       The cepstral coefficients.

       cscale	       The scaling factor of cepstral coefficients, where actual_data = output_data * 2**(-scaling_factor).

       signal	       The input signal vector, the signal samples are in Q15 format.

       state	       Pointer to the internal state structure.

RETURN VALUES

       The function returns MLIB_SUCCESS if successful. Otherwise it returns MLIB_FAILURE.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Evolving			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |MT-Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       mlib_SignalCepstralInit_S16(3MLIB), mlib_SignalCepstral_S16_Adp(3MLIB), mlib_SignalCepstralFree_S16(3MLIB), attributes(5)

SunOS 5.10							    10 Nov 2004 				    mlib_SignalCepstral_S16(3MLIB)