解码G711从C ++转换为C＃

Question

i try to decoding G711 packet i find this code in c++ but i do not know how to convert this code to c#

this the code

gint16 alaw_exp_table[256] = {
      -5504, -5248, -6016, -5760, -4480, -4224, -4992, -4736,
      -7552, -7296, -8064, -7808, -6528, -6272, -7040, -6784,
      -2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368,
      -3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392,
     -22016,-20992,-24064,-23040,-17920,-16896,-19968,-18944,
     -30208,-29184,-32256,-31232,-26112,-25088,-28160,-27136,
     -11008,-10496,-12032,-11520, -8960, -8448, -9984, -9472,
     -15104,-14592,-16128,-15616,-13056,-12544,-14080,-13568,
       -344,  -328,  -376,  -360,  -280,  -264,  -312,  -296,
       -472,  -456,  -504,  -488,  -408,  -392,  -440,  -424,
        -88,   -72,  -120,  -104,   -24,    -8,   -56,   -40,
       -216,  -200,  -248,  -232,  -152,  -136,  -184,  -168,
      -1376, -1312, -1504, -1440, -1120, -1056, -1248, -1184,
      -1888, -1824, -2016, -1952, -1632, -1568, -1760, -1696,
       -688,  -656,  -752,  -720,  -560,  -528,  -624,  -592,
       -944,  -912, -1008,  -976,  -816,  -784,  -880,  -848,
       5504,  5248,  6016,  5760,  4480,  4224,  4992,  4736,
       7552,  7296,  8064,  7808,  6528,  6272,  7040,  6784,
       2752,  2624,  3008,  2880,  2240,  2112,  2496,  2368,
       3776,  3648,  4032,  3904,  3264,  3136,  3520,  3392,
      22016, 20992, 24064, 23040, 17920, 16896, 19968, 18944,
      30208, 29184, 32256, 31232, 26112, 25088, 28160, 27136,
      11008, 10496, 12032, 11520,  8960,  8448,  9984,  9472,
      15104, 14592, 16128, 15616, 13056, 12544, 14080, 13568,
        344,   328,   376,   360,   280,   264,   312,   296,
        472,   456,   504,   488,   408,   392,   440,   424,
         88,    72,   120,   104,    24,     8,    56,    40,
        216,   200,   248,   232,   152,   136,   184,   168,
       1376,  1312,  1504,  1440,  1120,  1056,  1248,  1184,
       1888,  1824,  2016,  1952,  1632,  1568,  1760,  1696,
        688,   656,   752,   720,   560,   528,   624,   592,
        944,   912,  1008,   976,   816,   784,   880,   848};



#include <glib.h>
#include "G711adecode.h"
#include "G711atable.h"

int
decodeG711a(void *input, int inputSizeBytes, void *output, int *outputSizeBytes)
{
  guint8 *dataIn = (guint8 *)input;
  gint16 *dataOut = (gint16 *)output;
  int i;

  for (i=0; i<inputSizeBytes; i++)
  {
    dataOut[i] = alaw_exp_table[dataIn[i]];
  }
  *outputSizeBytes = inputSizeBytes * 2;
  return 0;
}

can any body help me ?

thanks in advance

Answer 1

This is a short[] .
You can translate it like any other array:

short[] x = { 1,2,3 };

Answer 2

Looks like this is a fairly simple lossy encoding of a short array. Since G711 is an audio codec, that makes sense. Just iterate over the input byte array, and put the values from the lookup table in the output short array.

private short[] alaw_exp_table = {/* same data as the C code */};

public short[] decodeG711a(byte[] input)
{
    short[] result = new short[input.Length];

    for (int i = 0; i < input.Length; i++)
    {
        result[i] = alaw_exp_table[input[i]];
    }

    return result;
}