.\" Copyright (c) 1987 Entropic Speech, Inc.; All rights reserved.\" @(#)scbk.5t	1.2 7/15/87 ESI.TH SCBK 5\-ESPS 7/15/87.ds ]W "\fI\s+4\ze\h'0.05'e\s-4\v'-0.4m'\fP\(*p\v'0.4m'\ Entropic Speech, Inc..SH NAMEESPS SCBK Scalar Quantization Codebook\- (.scbk).SH SYNOPSIS.B #include <sps/header.h>.br.B #include <sps/scbk.h>.SH DESCRIPTIONA SCBK file consists of a header that is followed by one data record..PPThe header has the following layout as defined by.I <sps/header.h>The header items common to all ESPS data files are described in\fIESPS\fR(5\-ESPS).   The type specific header structure for SCBK filesis shown below..PP.nf.br/* SCBK  Scalar Quantization Codebook specific header */.br.spstruct scbk_header {.TSl1 l1 l1 l.	long	num_items;	/\(** number of items processed \(**/	short	distortion;	/\(** distortion measure used \(**/	unsigned short	num_cdwds;	/\(** number of codewords \(**/	float	convergence;	/\(** convergence threshold \(**/	short	codebook_type;	/\(** type of codebook \(**/	short	element_num;	/\(** element number \(**/	short	spares[SCBK_SPARES];	/\(** spares \(**/.TE};.fi.sp.PPThe following items are in the SCBK file specific header structure..IP num_itemsThe number of data items that were used in designing the codebook..IP distortionThe type of distortion measure that was used in clustering the data.Legal values are defined in <sps/header.h>..IP num_cdwdsThe number of codewords in the codebook..IP convergenceThe convergence threshold used in the design of the codebook..IP codebook_typeThe name of the parameter that the codebook represents.Legal values are defined in <sps/header.h>..IP element_numThe codebook was designed for this element of the specified .I codebook_type.0 means element zero, 1 means element one, and so on.Two negative values have special meaning:-1 means all elements of the specified .I codebook_typeareused, and -2 means that no record of element value is being kept. .IP spares[SPARES]There are SCBK_SPARES spare shorts..PPThe one data record follows the header.The data structure is shown below in C syntax..PPThis data structure is defined in\fI<sps/scbk.h>\fR.A function is available to allocate memory for this data structure andto fill in the type fields in the common part of the header..spstruct qtable_entry {.TSl1 l1 l1 l. float	enc;	/\(** upper limit on encoding range \(**/ float	dec;	/\(** value to decode \(**/ unsigned short	code;	/\(** bit pattern \(**/};.TE.spstruct scbk_data {.TSl1 l1 l1 l. float	final_dist;	/\(** final distortion \(**/ float	cdwd_dist[\fInum_cdwds\fR];	/\(** individual codeword distortions \(**/ long	final_pop[\fInum_cdwds\fR];	/\(** codeword populations \(**/ struct qtable_entry	qtable[\fInum_cdwds\fR];	/\(** codewords \(**/};    .TE.PPThe.I SCBKdata record starts with the.I final_distvalue.This isthe average distortion that results from representing the training data by the finalcodebook.This data value is followed by an .I num_cdwds elementarray of.I final_popvalues.Each element of this array contains the number of data items thatare associated with the corresponding codeword.For example, final_pop[0] contains the number of data items that wereclosest to the first codeword (codeword[0]), final_pop[1] contains the number of items thatwere closest to the second, and so on.Nextthere is an .I num_cdwdselement array of.I cdwd_distvalues.Each element of this array contains the average distortion associated withthe corresponding codeword. That is,cdwd_dist[0] contains the average distortion that results from representing thefinal_pop[0] data items by codeword[0].Finally, there are .I num_cdwdsstructures.I qtable_entry.These structures are ordered from the smallest .I qtable.encvalue to the largest..I qtable.encis the largest value that gets decoded as .I qtable.dec.The bit pattern stored in .I qtable.codeis the pattern used to represent .I qtable.decodeby Rosetta..SH RECORD ELEMENT FILE STRUCTURE.PPThe order of record elements is not the same on the file itself as it isin the structure defined above.    The mapping is given by the tablebelow.  This information should not be used by programs that use thedata record access functions.  This information is provided for use onlywith generic ESPS programs (see \fIstats\fR(1\-ESPS))..sp.TScenter,tab(;),box;c | c | cl | l | l.Record Item;Starting Element Number;Number of Elements_final_dist;1;1cdwd_dist;2;\fInum_cdwds\fRqtable->enc;\fInum_cdwds\fR+2;\fInum_cdwds\fRqtable->dec;(\fInum_cdwds\fR*2)+2;\fInum_cdwds\fRfinal_pop;(\fInum_cdwds\fR*3)+2;\fInum_cdwds\fRqtable->code;(\fInum_cdwds\fR*4)+2;\fInum_cdwds\fR.TE.SH FILES.nf/usr/include/sps/header.h/usr/include/sps/scbk.h.fi.SH SEE ALSOallo_scbk_rec(3\-ESPSu), get_scbk_rec(3\-ESPSu), put_scbk_rec(3\-ESPSu),read_header(3\-ESPS), write_header(3\-ESPS),ESPS(5\-ESPS).SH AUTHORDavid Burton