intro.doc

speech signal process tools

       INTRODUCTION TO ESPS                                           page 13


       The psps (1-ESPS) listing for a file processed as above will show  the
       item symbolically, i.e.:

           . . .
           filt_type: BAND_PASS
           . . .


       Also, programs that read a file with such a generic  item  defined  in
       the  header  can refer to the contents symbolically, as in the follow-
       ing:

           struct header *hd;
           short filter_class;
           . . .
           filter_class = *(short *) get_genhd("filt_type", hd);
           . . .
           switch (fitler_class) {
                   case LOW_PASS:
                       . . .
                       break;
                   case HIGH_PASS:
                       . . .
                       break;
                   case BAND_PASS:
                       . . .
                       break;
                   case MISC:
                       . . .
                       break;
                   default:
                       ERROR_EXIT("invalid filter type encountered");
           }


       Note that one can also add generic header items to existing  files  by
       means of the user-level program addgen (1-ESPS).

       7 .2 .  ESPS Record Structures

       The ESPS header is followed by a set  of  fixed-length  data  records.
       When  any  record  is read into memory (through use of an ESPS library
       routine), it is stored as a C structure  that  is  documented  in  the
       relevant Section 5 manual page of the ESPS Manual.  As is the case for
       file headers, programmers need not be concerned with the actual format
       of  ESPS data records.  For example, suppose that the variable scbkrec
       is pointer to a SCBK file record (each record contains a scalar quant-
       ization  codebook  plus  related  design information).  Then the final
       distortion value for that codebook and the population of the ith code-
       word are referred to as

           scbkrec->final_dist



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       INTRODUCTION TO ESPS                                           page 14


       and

           scbkrec->final_pop[i]

       respectively (see SCBK (5-ESPS)).

       This symbolic form of reference for ESPS data records also applies  to
       FEA  files.  For  example,  if  anarec  is a pointer to a FEA_ANA file
       record, the ith filter pole in that record is referred to as

           anarec->filt_poles[i]

       (see FEA_ANA (5-ESPS). As mentioned earlier, users  can  define  their
       own FEA file sub-types and extend existing subtypes. New fields in FEA
       file records are defined through use of  add_fea_fld  (3-ESPS),  which
       creates  a new field with a given name size, numerical type, etc.  The
       new fields are accessed by means of  of  get_fea_ptr  (3-ESPS),  which
       returns a pointer to a field with a given name from a given record.

       7 .3 .  The ESPS Library

       To support the writing of  new  user-level  ESPS  programs,  the  ESPS
       library  contains  various  routines  for processing ESPS headers, for
       processing ESPS data records, and for performing various  signal  pro-
       cessing  functions.   At  present,  there are over 110 routines in the
       library.

       A full ESPS lint library is included so  that  ESPS  programs  can  be
       fully  checked  with  the  standard UNIX lint(1) utility for C program
       checking.  As a further aid to programmers, echeck (3-ESPS)  looks  up
       entries  in  the  ESPS  lint  library  and  prints  the proper calling
       sequence.  For emacs users, a mock-lisp file provides for  echeck  use
       from  within  emacs.   The  scripts  emake (1-ESPS), ecc (1-ESPS), and
       elint (1-ESPS) facilitate compiling and checking programs  under  ESPS
       (for details, see.[5])

       Here are a few examples of functions in the ESPS library:

       7 .3 .1 .  Signal Processing Support Library Functions

        analyze  compute prediction error filter and reflection coefficients
        block-filterfilter a data array
        convolv  convolution of polynomials or auto-correlations
        covar    compute reflection coefficients with covariance method
        fdbk_laticfeedback filtering with lattice form
        feedbk_filfeedback filtering with transversal form
        gauss    compute Gaussian random numbers
        get_auto compute auto-correlation coefficients
        get_burg compute reflection coefficients with Burg or modified
                 Burg method
        get_fft  compute fast Fourier transform
        hamm_dec decode (8,4) Hamming code
        hamm_enc encode with (8,4) Hamming code


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       INTRODUCTION TO ESPS                                           page 15


        interp_filtperform interpolation filtering
        is_dist_tdcompute Itakura-Saito distortion
        pc_to_lsfconvert prediction coefficients to line spectrum frequencies
        rand_intnrsample without replacement from uniformly
                 distributed integers
        refl_to_filtconvert reflection coefficients to filter coefficients
        remove_dcremove DC, using exponential weighting
        vqdesign design a full-search vector quantization codebook


       7 .3 .2 .  File Support Library Functions

        add_comment  adds a string to the comment field of an ESPS header
        add_fea_fld  add a new field to data record in a FEA file
        add_genhd    adds a generic header item to a ESPS header
        add_source_fileadd the header of a source file to an ESPS header
        copy_header  copies an ESPS header to a new header
        genhd_list   returns a list of defined generic header items
        get_cmd_line returns pointer to string containing program's command line
        get_fea_fld  returns pointer to named field in a FEA record
        get_genhd    returns pointer to named generic header item
        get_spec_rec get next spectral record from ESPS SPEC file
        get_sym      get a parameter value after read_params called
        new_header   create new ESPS file header
        print_fea_recprints a FEA file record
        put_fea_rec  writes a FEA file record
        put_sym      put value in ESPS common file
        range_switch parse the argument to a command-line range switch
        read_header  read an ESPS file header
        read_params  read the parameters in ESPS parameter or common file
        skiprec      skip records in ESPS file
        write_header write an ESPS file header


       8 .  EXAMPLE USER-LEVEL ESPS PROGRAMS

       This section lists some user-level ESPS programs of general  interest.
       Note  that the entire ESPS Manual is stored on-line.  The manual pages
       can be viewed with the eman (1-ESPS) command, which is an ESPS version
       of  the  UNIX  man  command. Eman includes the -k option to search the
       manual for programs whose one-line descriptions include a  given  key-
       word.

       8 .1 .  Conversion and Related Support Programs

        addfea   adds a FEA file field from ASCII data
        addfeahd adds a FEA file header to binary data
        addgen   adds generic header item to ESPS file header
        atofilt  convert ASCII file to FILT file
        atosps   converts ASCII output to ESPS file (see spstoa)
        bhd      behead an ESPS file
        eitem    prints item from ESPS file header
        ils_sps  converts ILS sampled data file to ESPS SD file


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       INTRODUCTION TO ESPS                                           page 16


        pplain   print values from ESPS files in "plain" ASCII format
        spstoa   convert ESPS file to machine-independent ASCII format
        testsd   make SD file with sine wave, pulses, Gaussian noise, or from ASCII data


       8 .2 .  Signal I/O and Processing

        addsd    adds SD files with scaling
        ana      perform speech analysis from SD file
        me_spec  compute spectra (FEA_SPEC file) from FEA_ANA file
        distort  compute distortion measures between ESPS files
        classify classify records in FEA files
        fea_statscompute statistics from FEA files
        fft      produces FEA_SPEC file by doing fft on SD file
        filter   performs digital filtering on SD file
        lloydcbk design a scalar quantizer using Lloyd's algorithm
        notch_filtdesign a notch filter
        play     play portions of SD files
        playtest step through an "A-B" listening test with control options
        randplay create play scripts for randomized "A-B" listening comparisons
        record   digitize data using Masscomp EF-12M
        refcof   compute reflection coefficients from sampled data (FEA_ANA output)
        rem_dc   remove DC component from SD file
        sdcomp   listening program for detailed comparison of two sampled data files
        spectranstransform FEA_ANA from one spectral representation to another
        stats    computes statistics from ESPS files
        synt     synthesize speech from ANA file
        testsd   make SD file with sine wave, pulses, Gaussian noise, or from ASCII data
        vqdes    design a vector quantization codebook from a FEA file
        vq       encode FEA file with a vector quantization codebook
        wmse_filtdesign FIR filter using weighted mean square error criterion
        iir_filt design recursive filter


       8 .3 .  File Manipulation and Plotting

        aplot    plot an array of ASCII data
        comment  displays or adds comments in the header of an ESPS file
        copysd   copy selected portions of SD files to a new file
        fea_edit edit a FEA file in ASCII form
        genplot  plot elements from any ESPS file in precise, multiline format
        histogramsort data into bins for plotting histograms
                 (screen, Imagen, or Tektronix)
        mlplot   plot SD file in precise, multiline format
                 (screen, Imagen, or Tektronix)
        plotsd   plot sampled data (screen, Imagen, or Tektronix)
        plotspec plot spectra from FEA_SPEC file (screen, Imagen, or Tektronix)
        psps     print ESPS file headers and records
        range    select a range from a graphics plot
        select   select FEA records that satisfy queries
        scatplot make a scatter plot




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       INTRODUCTION TO ESPS                                           page 17


       9 .  FUTURE CHANGES

       Everything discussed in the foregoing is  available  in  ESPS  Version
       3.3.   In  this section, we mention some of the things that will added
       in later versions.

       Current ESPS FEA files are restricted to  fixed  length  records,  one
       record  type  per file, with record fields containing only the machine
       primitive data types (integer,  float,  double,  character).   All  of
       these restrictions should be relaxed.

       We will provide support for engineering units, so  that  plotting  and
       printing  programs  can  display  data in terms of externally relevant
       units (volts, pressure, etc.).

       We will provide some additional facilities to  support  ESPS  program-
       ming.   For  example,  there  will be a program for the semi-automatic
       generation of new FEA file sub-types, and there will be a program  for
       the automatic generation of C skeletons for user-level programs.

       The ESPS parameter file format  might  be  simplified  so  that  users
       didn't  have  to  specify  types (they don't on command lines).  Also,
       ESPS user-level programs will be modified to take all parameters  from
       the  parameter  file  (with  possible  command-line overrides) so that
       every program can be run interactively  using  eparam  (1-ESPS)  (some
       programs in Version 3.3 require command line arguments for some or all
       parameters).

       Another significant enhancement  will  be  provided  by  an  interface
       between  ESPS  and a UNIX relational data base system.  This interface
       will create data base records from ESPS file headers so that the  data
       base system can be used to manage sets of ESPS files.

       10 .  REFERENCES

       1.   Entropic Signal Processing System Version 3.0 User's Manual.

       2.   "Data Files in the Entropic Processing System," , ETM-S-86-13.

       3.   "Parameter and Common  Files  in  ESPS,"  ,  ETM-S-86-12:jtb  1.2
            11/12/86.

       4.   "Guidelines for Implementing ESPS Feature File Subtypes," ,  ETM-
            S-86-25.

       5.   "Entropic Signal Processing  System  Programming  Guidelines,"  ,
            ETM-S-86-14 .

       6.   "ESPS APPLICATIONS NOTE: Filtering Sampled Data," .

       7.   "ESPS APPLICATIONS NOTE:  File  Headers  and  Record  Keeping  in
            ESPS," .



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