Moved resample to third_party directory

git-svn-id: http://svn.pjsip.org/repos/pjproject/branches/split-3rd-party@1170 74dad513-b988-da41-8d7b-12977e46ad98

1 files changed, 159 insertions, 0 deletions

diff --git a/third_party/resample/src/filterkit.h b/third_party/resample/src/filterkit.h
new file mode 100644
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+++ b/third_party/resample/src/filterkit.h
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+/*:filterkit.h */
+
+#include	"stdefs.h"
+
+/*
+ * LpFilter() - Calculates the filter coeffs for a Kaiser-windowed low-pass
+ *                   filter with a given roll-off frequency.  These coeffs
+ *                   are stored into a array of doubles.
+ * writeFilter() - Writes a filter to a file.
+ * makeFilter() - Calls LpFilter() to create a filter, then scales the double
+ *                   coeffs into an array of half words.
+ * readFilter() - Reads a filter from a file.
+ * FilterUp() - Applies a filter to a given sample when up-converting.
+ * FilterUD() - Applies a filter to a given sample when up- or down-
+ *                   converting.
+ * initZerox() - Initialization routine for the zerox() function.  Must
+ *                   be called before zerox() is called.  This routine loads
+ *                   the correct filter so zerox() can use it.
+ * zerox() - Given a pointer into a sample, finds a zero-crossing on the
+ *                   interval [pointer-1:pointer+2] by iteration.
+ * Query() - Ask the user for a yes/no question with prompt, default, 
+ *                   and optional help.
+ * GetUShort() - Ask the user for a unsigned short with prompt, default,
+ *                   and optional help.
+ * GetDouble() - Ask the user for a double with prompt, default, and
+ *                   optional help.
+ * GetString() - Ask the user for a string with prompt, default, and
+ *                   optional help.
+ */
+
+void LpFilter(double c[], int N, double frq, double Beta, int Num);
+/*
+ * reference: "Digital Filters, 2nd edition"
+ *            R.W. Hamming, pp. 178-179
+ *
+ * LpFilter() computes the coeffs of a Kaiser-windowed low pass filter with
+ *    the following characteristics:
+ *
+ *       c[]  = array in which to store computed coeffs
+ *       frq  = roll-off frequency of filter
+ *       N    = Half the window length in number of coeffs
+ *       Beta = parameter of Kaiser window
+ *       Num  = number of coeffs before 1/frq
+ *
+ * Beta trades the rejection of the lowpass filter against the transition
+ *    width from passband to stopband.  Larger Beta means a slower
+ *    transition and greater stopband rejection.  See Rabiner and Gold
+ *    (Theory and Application of DSP) under Kaiser windows for more about
+ *    Beta.  The following table from Rabiner and Gold gives some feel
+ *    for the effect of Beta:
+ *
+ * All ripples in dB, width of transition band = D*N where N = window length
+ *
+ *               BETA    D       PB RIP   SB RIP
+ *               2.120   1.50  +-0.27      -30
+ *               3.384   2.23    0.0864    -40
+ *               4.538   2.93    0.0274    -50
+ *               5.658   3.62    0.00868   -60
+ *               6.764   4.32    0.00275   -70
+ *               7.865   5.0     0.000868  -80
+ *               8.960   5.7     0.000275  -90
+ *               10.056  6.4     0.000087  -100
+ */
+
+int writeFilter(HWORD Imp[], HWORD ImpD[], UHWORD LpScl, UHWORD Nmult, UHWORD Nwing);
+/*
+ * Write a filter to a file
+ *    Filter file format:
+ *       file name: "F" Nmult "T" Nhc ".filter"
+ *       1st line:  the string "ScaleFactor" followed by its value.
+ *       2nd line:  the string "Length" followed by Nwing's value.
+ *       3rd line:  the string "Coeffs:" on a separate line.
+ *       following lines:  Nwing number of 16-bit impulse response values
+ *          in the right wing of the impulse response (the Imp[] array).
+ *         (Nwing is equal to Npc*(Nmult+1)/2+1, where Npc is defined in the
+ *         file "resample.h".)  Each coefficient is on a separate line.
+ *       next line:  the string "Differences:" on a separate line.
+ *       following lines:  Nwing number of 16-bit impulse-response
+ *          successive differences:  ImpD[i] = Imp[i+1] - Imp[i].
+ * ERROR codes:
+ *   0 - no error
+ *   1 - could not open file
+ */
+
+int makeFilter(HWORD Imp[], HWORD ImpD[], UHWORD *LpScl, UHWORD Nwing,
+	       double Froll, double Beta);
+/*
+ * makeFilter
+ * ERROR return codes:
+ *    0 - no error
+ *    1 - Nwing too large (Nwing is > MAXNWING)
+ *    2 - Froll is not in interval [0:1)
+ *    3 - Beta is < 1.0
+ *    4 - LpScl will not fit in 16-bits
+ */
+
+int readFilter(char *filterFile,
+	       HWORD **ImpP, HWORD **ImpDP, UHWORD *LpScl, 
+	       UHWORD *Nmult, UHWORD *Nwing);
+/*
+ * Read-in a filter
+ *    Filter file format:
+ *       Default file name: "F" Nmult "T" Nhc ".filter"
+ *       1st line:  the string "ScaleFactor" followed by its value.
+ *       2nd line:  the string "Length" followed by Nwing's value.
+ *       3rd line:  the string "Coeffs:" on separate line.
+ *       Nwing number of 16-bit impulse response values in the right
+ *          wing of the impulse response.  (Length=Npc*(Nmult+1)/2+1,
+ *          where originally Npc=2^9, and Nmult=13.)   Each on separate line.
+ *       The string "Differences:" on separate line.
+ *       Nwing number of 16-bit impulse-response successive differences:
+ *          ImpDiff[i] = Imp[i+1] - Imp[i].
+ *
+ * ERROR return codes:
+ *    0 - no error
+ *    1 - file not found
+ *    2 - invalid ScaleFactor in file
+ *    3 - invalid Length in file
+ */
+
+WORD FilterUp(HWORD Imp[], HWORD ImpD[], UHWORD Nwing, BOOL Interp,
+	      HWORD *Xp, HWORD Inc, HWORD Ph);
+
+WORD FilterUD(HWORD Imp[], HWORD ImpD[], UHWORD Nwing, BOOL Interp,
+	      HWORD *Xp, HWORD Ph, HWORD Inc, UHWORD dhb);
+
+int initZerox(UHWORD tempNmult);
+/*
+ * initZerox
+ * ERROR return values:
+ *   0 - no error
+ *   1 - Nmult is even (should be odd)
+ *   2 - filter file not found
+ *   3 - invalid ScaleFactor in input file
+ *   4 - invalid Length in file
+ */
+
+/*
+ * zerox
+ *    Given a pointer into a sound sample, this function uses a low-pass
+ * filter to estimate the x coordinate of the zero-crossing which must ocurr
+ * between Data[0] and Data[1].  This value is returned as the value of the
+ * function.  A return value of -100 indicates there was no zero-crossing in
+ * the x interval [-1,2].  Factor is the resampling factor: Rate(out) /
+ * Rate(in).  Nmult (which determines which filter is used) is passed the
+ * zerox's initialization routine: initZerox(Nmult)
+ */
+double zerox(HWORD *Data, double Factor);
+
+BOOL Query(char *prompt, BOOL deflt, char *help);
+
+unsigned short GetUShort(char *title, unsigned short deflt, char *help);
+
+double GetDouble(char *title, double deflt, char *help);
+
+char *GetString(char *prompt, char *deflt, char *help);
+
+#define GetUHWORD(x,y,z) GetUShort(x,y,z)
+