音频demo：将PCM数据与g726数据的相互转换

1、README

前言

本demo是将使用了开源项目EasyAACEncoder里的src/g726.cpp(demo中的已重命名为g726.c)和src/g726.h将16位小字节序的pcm数据和g726进行相互转换。

注：相关测试文件已存放在demo的audio目录下，目前发现pcm转换得到的g726文件用软件Audacity播放不正常（没找到g726，所以选的VOX ADPCM），而将所得到的g726再转换回pcm却播放正常，网上说需要支持g726解码的播放器才能播放，用ffmpeg播放也出错，所以看到本注释时的g726都是播放不了的。

a. 编译

$ make clean && make # 或者`make DEBUG=1`打开调试打印信息，又或者指定`CC=your-crosscompile-gcc`进行编译交叉编译

b. 使用

$ ./pcm_g726_convert
Usage:./pcm_g726_convert -t pcm_2_g726 -i ./audio/test_8khz_16bit_mono_128kbps.pcm -r 16000 -o out_8khz_16kbps.g726./pcm_g726_convert -t pcm_2_g726 -i ./audio/test_8khz_16bit_mono_128kbps.pcm -r 24000 -o out_8khz_24kbps.g726./pcm_g726_convert -t pcm_2_g726 -i ./audio/test_8khz_16bit_mono_128kbps.pcm -r 32000 -o out_8khz_32kbps.g726./pcm_g726_convert -t pcm_2_g726 -i ./audio/test_8khz_16bit_mono_128kbps.pcm -r 40000 -o out_8khz_40kbps.g726./pcm_g726_convert -t g726_2_pcm -i ./audio/test_8khz_16kbps.g726 -r 16000 -o out_8khz_16bit_mono_128kbps-1.pcm./pcm_g726_convert -t g726_2_pcm -i ./audio/test_8khz_24kbps.g726 -r 24000 -o out_8khz_16bit_mono_128kbps-2.pcm./pcm_g726_convert -t g726_2_pcm -i ./audio/test_8khz_32kbps.g726 -r 32000 -o out_8khz_16bit_mono_128kbps-3.pcm./pcm_g726_convert -t g726_2_pcm -i ./audio/test_8khz_40kbps.g726 -r 40000 -o out_8khz_16bit_mono_128kbps-4.pcm

c. 参考文章

音频采样及编解码——LPCM 、ADPCM、G711、G726、AAC_夜风的博客-CSDN博客_adpcm
g726转pcm_ybn187的专栏-CSDN博客_g726转pcm
g726算法的一些总结_那年晴天的博客-CSDN博客

d. demo目录架构

$ tree
.
├── audio
│   ├── test_8khz_16bit_mono_128kbps.pcm
│   ├── test_8khz_16kbps.g726
│   ├── test_8khz_24kbps.g726
│   ├── test_8khz_32kbps.g726
│   └── test_8khz_40kbps.g726
├── docs
│   ├── g726算法的一些总结_那年晴天的博客-CSDN博客.mhtml
│   ├── g726转pcm_ybn187的专栏-CSDN博客_g726转pcm.mhtml
│   └── 音频采样及编解码——LPCM 、ADPCM、G711、G726、AAC_夜风的博客-CSDN博客_adpcm.mhtml
├── g726.c
├── g726.h
├── main.c
├── Makefile
└── README.md

2、主要代码片段

g726.c

/*Copyright (c) 2013-2016 EasyDarwin.ORG.  All rights reserved.Github: https://github.com/EasyDarwinWEChat: EasyDarwinWebsite: http://www.easydarwin.org
*/#include <stdio.h>
#include <math.h>
#include <stdlib.h>
#include "g726.h"static const int qtab_726_16[1] =
{261
};static const int qtab_726_24[3] =
{8, 218, 331
};static const int qtab_726_32[7] =
{-124, 80, 178, 246, 300, 349, 400
};static const int qtab_726_40[15] =
{-122, -16,  68, 139, 198, 250, 298, 339,378, 413, 445, 475, 502, 528, 553
};static __inline int top_bit(unsigned int bits)
{
#if defined(__i386__)  ||  defined(__x86_64__)int res;__asm__ (" xorl %[res],%[res];\n"" decl %[res];\n"" bsrl %[bits],%[res]\n": [res] "=&r" (res): [bits] "rm" (bits));return res;
#elif defined(__ppc__)  ||   defined(__powerpc__)int res;__asm__ ("cntlzw %[res],%[bits];\n": [res] "=&r" (res): [bits] "r" (bits));return 31 - res;
#elif defined(_M_IX86) // Visual Studio x86__asm{xor eax, eaxdec eaxbsr eax, bits}
#elseint res;if (bits == 0)return -1;res = 0;if (bits & 0xFFFF0000){bits &= 0xFFFF0000;res += 16;}if (bits & 0xFF00FF00){bits &= 0xFF00FF00;res += 8;}if (bits & 0xF0F0F0F0){bits &= 0xF0F0F0F0;res += 4;}if (bits & 0xCCCCCCCC){bits &= 0xCCCCCCCC;res += 2;}if (bits & 0xAAAAAAAA){bits &= 0xAAAAAAAA;res += 1;}return res;
#endif
}static bitstream_state_t *bitstream_init(bitstream_state_t *s)
{if (s == NULL)return NULL;s->bitstream = 0;s->residue = 0;return s;
}/** Given a raw sample, 'd', of the difference signal and a* quantization step size scale factor, 'y', this routine returns the* ADPCM codeword to which that sample gets quantized.  The step* size scale factor division operation is done in the log base 2 domain* as a subtraction.*/
static short quantize(int d,                  /* Raw difference signal sample */int y,                  /* Step size multiplier */const int table[],     /* quantization table */int quantizer_states)   /* table size of short integers */
{short dqm;    /* Magnitude of 'd' */short exp;    /* Integer part of base 2 log of 'd' */short mant;   /* Fractional part of base 2 log */short dl;     /* Log of magnitude of 'd' */short dln;    /* Step size scale factor normalized log */int i;int size;/** LOG** Compute base 2 log of 'd', and store in 'dl'.*/dqm = (short) abs(d);exp = (short) (top_bit(dqm >> 1) + 1);/* Fractional portion. */mant = ((dqm << 7) >> exp) & 0x7F;dl = (exp << 7) + mant;/** SUBTB** "Divide" by step size multiplier.*/dln = dl - (short) (y >> 2);/** QUAN** Search for codword i for 'dln'.*/size = (quantizer_states - 1) >> 1;for (i = 0;  i < size;  i++){if (dln < table[i])break;}if (d < 0){/* Take 1's complement of i */return (short) ((size << 1) + 1 - i);}if (i == 0  &&  (quantizer_states & 1)){/* Zero is only valid if there are an even number of states, sotake the 1's complement if the code is zero. */return (short) quantizer_states;}return (short) i;
}
/*- End of function --------------------------------------------------------*//*
* returns the integer product of the 14-bit integer "an" and
* "floating point" representation (4-bit exponent, 6-bit mantessa) "srn".
*/
static short fmult(short an, short srn)
{short anmag;short anexp;short anmant;short wanexp;short wanmant;short retval;anmag = (an > 0)  ?  an  :  ((-an) & 0x1FFF);anexp = (short) (top_bit(anmag) - 5);anmant = (anmag == 0)  ?  32  :  (anexp >= 0)  ?  (anmag >> anexp)  :  (anmag << -anexp);wanexp = anexp + ((srn >> 6) & 0xF) - 13;wanmant = (anmant*(srn & 0x3F) + 0x30) >> 4;retval = (wanexp >= 0)  ?  ((wanmant << wanexp) & 0x7FFF)  :  (wanmant >> -wanexp);return (((an ^ srn) < 0)  ?  -retval  :  retval);
}/*
* Compute the estimated signal from the 6-zero predictor.
*/
static __inline short predictor_zero(g726_state_t *s)
{int i;int sezi;sezi = fmult(s->b[0] >> 2, s->dq[0]);/* ACCUM */for (i = 1;  i < 6;  i++)sezi += fmult(s->b[i] >> 2, s->dq[i]);return (short) sezi;
}
/*- End of function --------------------------------------------------------*//*
* Computes the estimated signal from the 2-pole predictor.
*/
static __inline short predictor_pole(g726_state_t *s)
{return (fmult(s->a[1] >> 2, s->sr[1]) + fmult(s->a[0] >> 2, s->sr[0]));
}/*
* Computes the quantization step size of the adaptive quantizer.
*/
static int step_size(g726_state_t *s)
{int y;int dif;int al;if (s->ap >= 256)return s->yu;y = s->yl >> 6;dif = s->yu - y;al = s->ap >> 2;if (dif > 0)y += (dif*al) >> 6;else if (dif < 0)y += (dif*al + 0x3F) >> 6;return y;
}
/*- End of function --------------------------------------------------------*//*
* Returns reconstructed difference signal 'dq' obtained from
* codeword 'i' and quantization step size scale factor 'y'.
* Multiplication is performed in log base 2 domain as addition.
*/
static short reconstruct(int sign,    /* 0 for non-negative value */int dqln,    /* G.72x codeword */int y)       /* Step size multiplier */
{short dql;    /* Log of 'dq' magnitude */short dex;    /* Integer part of log */short dqt;short dq;     /* Reconstructed difference signal sample */dql = (short) (dqln + (y >> 2));  /* ADDA */if (dql < 0)return ((sign)  ?  -0x8000  :  0);/* ANTILOG */dex = (dql >> 7) & 15;dqt = 128 + (dql & 127);dq = (dqt << 7) >> (14 - dex);return ((sign)  ?  (dq - 0x8000)  :  dq);
}
/*- End of function --------------------------------------------------------*//*
* updates the state variables for each output code
*/
static void update(g726_state_t *s,int y,       /* quantizer step size */int wi,      /* scale factor multiplier */int fi,      /* for long/short term energies */int dq,      /* quantized prediction difference */int sr,      /* reconstructed signal */int dqsez)   /* difference from 2-pole predictor */
{short mag;short exp;short a2p;        /* LIMC */short a1ul;       /* UPA1 */short pks1;       /* UPA2 */short fa1;short ylint;short dqthr;short ylfrac;short thr;short pk0;int i;int tr;a2p = 0;/* Needed in updating predictor poles */pk0 = (dqsez < 0)  ?  1  :  0;/* prediction difference magnitude */mag = (short) (dq & 0x7FFF);/* TRANS */ylint = (short) (s->yl >> 15);            /* exponent part of yl */ylfrac = (short) ((s->yl >> 10) & 0x1F);  /* fractional part of yl *//* Limit threshold to 31 << 10 */thr = (ylint > 9)  ?  (31 << 10)  :  ((32 + ylfrac) << ylint);dqthr = (thr + (thr >> 1)) >> 1;            /* dqthr = 0.75 * thr */if (!s->td)                                 /* signal supposed voice */tr = 0;else if (mag <= dqthr)                      /* supposed data, but small mag */tr = 0;                             /* treated as voice */else                                        /* signal is data (modem) */tr = 1;/** Quantizer scale factor adaptation.*//* FUNCTW & FILTD & DELAY *//* update non-steady state step size multiplier */s->yu = (short) (y + ((wi - y) >> 5));/* LIMB */if (s->yu < 544)s->yu = 544;else if (s->yu > 5120)s->yu = 5120;/* FILTE & DELAY *//* update steady state step size multiplier */s->yl += s->yu + ((-s->yl) >> 6);/** Adaptive predictor coefficients.*/if (tr){/* Reset the a's and b's for a modem signal */s->a[0] = 0;s->a[1] = 0;s->b[0] = 0;s->b[1] = 0;s->b[2] = 0;s->b[3] = 0;s->b[4] = 0;s->b[5] = 0;}else{/* Update the a's and b's *//* UPA2 */pks1 = pk0 ^ s->pk[0];/* Update predictor pole a[1] */a2p = s->a[1] - (s->a[1] >> 7);if (dqsez != 0){fa1 = (pks1)  ?  s->a[0]  :  -s->a[0];/* a2p = function of fa1 */if (fa1 < -8191)a2p -= 0x100;else if (fa1 > 8191)a2p += 0xFF;elsea2p += fa1 >> 5;if (pk0 ^ s->pk[1]){/* LIMC */if (a2p <= -12160)a2p = -12288;else if (a2p >= 12416)a2p = 12288;elsea2p -= 0x80;}else if (a2p <= -12416)a2p = -12288;else if (a2p >= 12160)a2p = 12288;elsea2p += 0x80;}/* TRIGB & DELAY */s->a[1] = a2p;/* UPA1 *//* Update predictor pole a[0] */s->a[0] -= s->a[0] >> 8;if (dqsez != 0){if (pks1 == 0)s->a[0] += 192;elses->a[0] -= 192;}/* LIMD */a1ul = 15360 - a2p;if (s->a[0] < -a1ul)s->a[0] = -a1ul;else if (s->a[0] > a1ul)s->a[0] = a1ul;/* UPB : update predictor zeros b[6] */for (i = 0;  i < 6;  i++){/* Distinguish 40Kbps mode from the others */s->b[i] -= s->b[i] >> ((s->bits_per_sample == 5)  ?  9  :  8);if (dq & 0x7FFF){/* XOR */if ((dq ^ s->dq[i]) >= 0)s->b[i] += 128;elses->b[i] -= 128;}}}for (i = 5;  i > 0;  i--)s->dq[i] = s->dq[i - 1];/* FLOAT A : convert dq[0] to 4-bit exp, 6-bit mantissa f.p. */if (mag == 0){s->dq[0] = (dq >= 0)  ?  0x20  :  0xFC20;}else{exp = (short) (top_bit(mag) + 1);s->dq[0] = (dq >= 0)?  ((exp << 6) + ((mag << 6) >> exp)):  ((exp << 6) + ((mag << 6) >> exp) - 0x400);}s->sr[1] = s->sr[0];/* FLOAT B : convert sr to 4-bit exp., 6-bit mantissa f.p. */if (sr == 0){s->sr[0] = 0x20;}else if (sr > 0){exp = (short) (top_bit(sr) + 1);s->sr[0] = (short) ((exp << 6) + ((sr << 6) >> exp));}else if (sr > -32768){mag = (short) -sr;exp = (short) (top_bit(mag) + 1);s->sr[0] =  (exp << 6) + ((mag << 6) >> exp) - 0x400;}else{s->sr[0] = (short) 0xFC20;}/* DELAY A */s->pk[1] = s->pk[0];s->pk[0] = pk0;/* TONE */if (tr)                 /* this sample has been treated as data */s->td = 0;      /* next one will be treated as voice */else if (a2p < -11776)  /* small sample-to-sample correlation */s->td = 1;       /* signal may be data */else                    /* signal is voice */s->td = 0;/* Adaptation speed control. *//* FILTA */s->dms += ((short) fi - s->dms) >> 5;/* FILTB */s->dml += (((short) (fi << 2) - s->dml) >> 7);if (tr)s->ap = 256;else if (y < 1536)                      /* SUBTC */s->ap += (0x200 - s->ap) >> 4;else if (s->td)s->ap += (0x200 - s->ap) >> 4;else if (abs((s->dms << 2) - s->dml) >= (s->dml >> 3))s->ap += (0x200 - s->ap) >> 4;elses->ap += (-s->ap) >> 4;
}/*
* Decodes a 2-bit CCITT G.726_16 ADPCM code and returns
* the resulting 16-bit linear PCM, A-law or u-law sample value.
*/
static short g726_16_decoder(g726_state_t *s, unsigned char code)
{short sezi;short sei;short se;short sr;short dq;short dqsez;int y;/* Mask to get proper bits */code &= 0x03;sezi = predictor_zero(s);sei = sezi + predictor_pole(s);y = step_size(s);dq = reconstruct(code & 2, g726_16_dqlntab[code], y);/* Reconstruct the signal */se = sei >> 1;sr = (dq < 0)  ?  (se - (dq & 0x3FFF))  :  (se + dq);/* Pole prediction difference */dqsez = sr + (sezi >> 1) - se;update(s, y, g726_16_witab[code], g726_16_fitab[code], dq, sr, dqsez);return (sr << 2);
}
/*- End of function --------------------------------------------------------*//** Encodes a linear PCM, A-law or u-law input sample and returns its 3-bit code.*/
static unsigned char g726_16_encoder(g726_state_t *s, short amp)
{int y;short sei;short sezi;short se;short d;short sr;short dqsez;short dq;short i;sezi = predictor_zero(s);sei = sezi + predictor_pole(s);se = sei >> 1;d = amp - se;/* Quantize prediction difference */y = step_size(s);i = quantize(d, y, qtab_726_16, 4);dq = reconstruct(i & 2, g726_16_dqlntab[i], y);/* Reconstruct the signal */sr = (dq < 0)  ?  (se - (dq & 0x3FFF))  :  (se + dq);/* Pole prediction difference */dqsez = sr + (sezi >> 1) - se;update(s, y, g726_16_witab[i], g726_16_fitab[i], dq, sr, dqsez);return (unsigned char) i;
}/*
* Decodes a 3-bit CCITT G.726_24 ADPCM code and returns
* the resulting 16-bit linear PCM, A-law or u-law sample value.
*/
static short g726_24_decoder(g726_state_t *s, unsigned char code)
{short sezi;short sei;short se;short sr;short dq;short dqsez;int y;/* Mask to get proper bits */code &= 0x07;sezi = predictor_zero(s);sei = sezi + predictor_pole(s);y = step_size(s);dq = reconstruct(code & 4, g726_24_dqlntab[code], y);/* Reconstruct the signal */se = sei >> 1;sr = (dq < 0)  ?  (se - (dq & 0x3FFF))  :  (se + dq);/* Pole prediction difference */dqsez = sr + (sezi >> 1) - se;update(s, y, g726_24_witab[code], g726_24_fitab[code], dq, sr, dqsez);return (sr << 2);
}
/*- End of function --------------------------------------------------------*//** Encodes a linear PCM, A-law or u-law input sample and returns its 3-bit code.*/
static unsigned char g726_24_encoder(g726_state_t *s, short amp)
{short sei;short sezi;short se;short d;short sr;short dqsez;short dq;short i;int y;sezi = predictor_zero(s);sei = sezi + predictor_pole(s);se = sei >> 1;d = amp - se;/* Quantize prediction difference */y = step_size(s);i = quantize(d, y, qtab_726_24, 7);dq = reconstruct(i & 4, g726_24_dqlntab[i], y);/* Reconstruct the signal */sr = (dq < 0)  ?  (se - (dq & 0x3FFF))  :  (se + dq);/* Pole prediction difference */dqsez = sr + (sezi >> 1) - se;update(s, y, g726_24_witab[i], g726_24_fitab[i], dq, sr, dqsez);return (unsigned char) i;
}/*
* Decodes a 4-bit CCITT G.726_32 ADPCM code and returns
* the resulting 16-bit linear PCM, A-law or u-law sample value.
*/
static short g726_32_decoder(g726_state_t *s, unsigned char code)
{short sezi;short sei;short se;short sr;short dq;short dqsez;int y;/* Mask to get proper bits */code &= 0x0F;sezi = predictor_zero(s);sei = sezi + predictor_pole(s);y = step_size(s);dq = reconstruct(code & 8, g726_32_dqlntab[code], y);/* Reconstruct the signal */se = sei >> 1;sr = (dq < 0)  ?  (se - (dq & 0x3FFF))  :  (se + dq);/* Pole prediction difference */dqsez = sr + (sezi >> 1) - se;update(s, y, g726_32_witab[code], g726_32_fitab[code], dq, sr, dqsez);return (sr << 2);
}
/*- End of function --------------------------------------------------------*//** Encodes a linear input sample and returns its 4-bit code.*/
static unsigned char g726_32_encoder(g726_state_t *s, short amp)
{short sei;short sezi;short se;short d;short sr;short dqsez;short dq;short i;int y;sezi = predictor_zero(s);sei = sezi + predictor_pole(s);se = sei >> 1;d = amp - se;/* Quantize the prediction difference */y = step_size(s);i = quantize(d, y, qtab_726_32, 15);dq = reconstruct(i & 8, g726_32_dqlntab[i], y);/* Reconstruct the signal */sr = (dq < 0)  ?  (se - (dq & 0x3FFF))  :  (se + dq);/* Pole prediction difference */dqsez = sr + (sezi >> 1) - se;update(s, y, g726_32_witab[i], g726_32_fitab[i], dq, sr, dqsez);return (unsigned char) i;
}/*
* Decodes a 5-bit CCITT G.726 40Kbps code and returns
* the resulting 16-bit linear PCM, A-law or u-law sample value.
*/
static short g726_40_decoder(g726_state_t *s, unsigned char code)
{short sezi;short sei;short se;short sr;short dq;short dqsez;int y;/* Mask to get proper bits */code &= 0x1F;sezi = predictor_zero(s);sei = sezi + predictor_pole(s);y = step_size(s);dq = reconstruct(code & 0x10, g726_40_dqlntab[code], y);/* Reconstruct the signal */se = sei >> 1;sr = (dq < 0)  ?  (se - (dq & 0x7FFF))  :  (se + dq);/* Pole prediction difference */dqsez = sr + (sezi >> 1) - se;update(s, y, g726_40_witab[code], g726_40_fitab[code], dq, sr, dqsez);return (sr << 2);
}
/*- End of function --------------------------------------------------------*//** Encodes a 16-bit linear PCM, A-law or u-law input sample and retuens* the resulting 5-bit CCITT G.726 40Kbps code.*/
static unsigned char g726_40_encoder(g726_state_t *s, short amp)
{short sei;short sezi;short se;short d;short sr;short dqsez;short dq;short i;int y;sezi = predictor_zero(s);sei = sezi + predictor_pole(s);se = sei >> 1;d = amp - se;/* Quantize prediction difference */y = step_size(s);i = quantize(d, y, qtab_726_40, 31);dq = reconstruct(i & 0x10, g726_40_dqlntab[i], y);/* Reconstruct the signal */sr = (dq < 0)  ?  (se - (dq & 0x7FFF))  :  (se + dq);/* Pole prediction difference */dqsez = sr + (sezi >> 1) - se;update(s, y, g726_40_witab[i], g726_40_fitab[i], dq, sr, dqsez);return (unsigned char) i;
}g726_state_t *g726_init(g726_state_t *s, int bit_rate)
{int i;if (bit_rate != 16000  &&  bit_rate != 24000  &&  bit_rate != 32000  &&  bit_rate != 40000)return NULL;s->yl = 34816;s->yu = 544;s->dms = 0;s->dml = 0;s->ap = 0;s->rate = bit_rate;for (i = 0; i < 2; i++){s->a[i] = 0;s->pk[i] = 0;s->sr[i] = 32;}for (i = 0; i < 6; i++){s->b[i] = 0;s->dq[i] = 32;}s->td = 0;switch (bit_rate){case 16000:s->enc_func = g726_16_encoder;s->dec_func = g726_16_decoder;s->bits_per_sample = 2;break;case 24000:s->enc_func = g726_24_encoder;s->dec_func = g726_24_decoder;s->bits_per_sample = 3;break;case 32000:default:s->enc_func = g726_32_encoder;s->dec_func = g726_32_decoder;s->bits_per_sample = 4;break;case 40000:s->enc_func = g726_40_encoder;s->dec_func = g726_40_decoder;s->bits_per_sample = 5;break;}bitstream_init(&s->bs);return s;
}int g726_decode(g726_state_t *s,short amp[],const unsigned char g726_data[],int g726_bytes)
{int i;int samples;unsigned char code;int sl;for (samples = i = 0;  ;  ){if (s->bs.residue < s->bits_per_sample){if (i >= g726_bytes)break;s->bs.bitstream = (s->bs.bitstream << 8) | g726_data[i++];s->bs.residue += 8;}code = (unsigned char) ((s->bs.bitstream >> (s->bs.residue - s->bits_per_sample)) & ((1 << s->bits_per_sample) - 1));s->bs.residue -= s->bits_per_sample;sl = s->dec_func(s, code);amp[samples++] = (short) sl;}return samples;
}int g726_encode(g726_state_t *s,unsigned char g726_data[],const short amp[],int len)
{int i;int g726_bytes;short sl;unsigned char code;for (g726_bytes = i = 0;  i < len;  i++){sl = amp[i] >> 2;code = s->enc_func(s, sl);s->bs.bitstream = (s->bs.bitstream << s->bits_per_sample) | code;s->bs.residue += s->bits_per_sample;if (s->bs.residue >= 8){g726_data[g726_bytes++] = (unsigned char) ((s->bs.bitstream >> (s->bs.residue - 8)) & 0xFF);s->bs.residue -= 8;}}return g726_bytes;
}

main.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <getopt.h>#include "g726.h"// 编译时Makefile里控制
#ifdef ENABLE_DEBUG#define DEBUG(fmt, args...)     printf(fmt, ##args)
#else#define DEBUG(fmt, args...)
#endif#define BUF_SIZE 	2048	void print_Usage(char *processName)
{printf("Usage: \n""   %s -t pcm_2_g726 -i ./audio/test_8khz_16bit_mono_128kbps.pcm -r 16000 -o out_8khz_16kbps.g726\n""   %s -t pcm_2_g726 -i ./audio/test_8khz_16bit_mono_128kbps.pcm -r 24000 -o out_8khz_24kbps.g726\n""   %s -t pcm_2_g726 -i ./audio/test_8khz_16bit_mono_128kbps.pcm -r 32000 -o out_8khz_32kbps.g726\n""   %s -t pcm_2_g726 -i ./audio/test_8khz_16bit_mono_128kbps.pcm -r 40000 -o out_8khz_40kbps.g726\n""   %s -t g726_2_pcm -i ./audio/test_8khz_16kbps.g726 -r 16000 -o out_8khz_16bit_mono_128kbps-1.pcm\n""   %s -t g726_2_pcm -i ./audio/test_8khz_24kbps.g726 -r 24000 -o out_8khz_16bit_mono_128kbps-2.pcm\n""   %s -t g726_2_pcm -i ./audio/test_8khz_32kbps.g726 -r 32000 -o out_8khz_16bit_mono_128kbps-3.pcm\n""   %s -t g726_2_pcm -i ./audio/test_8khz_40kbps.g726 -r 40000 -o out_8khz_16bit_mono_128kbps-4.pcm\n",processName, processName, processName, processName, processName, processName, processName, processName);
}int main(int argc, char *argv[])
{unsigned int bitRates = 0;unsigned char *inBuf = (unsigned char *)malloc(BUF_SIZE);unsigned char *outBuf = (unsigned char *)malloc(BUF_SIZE);char convertType[128];char inputFileName[128];char outputFileName[128];FILE *fpInput = NULL;FILE *fpOutput = NULL;g726_state_t *g726Handler = NULL; // g726操作句柄if(argc == 1){print_Usage(argv[0]);return -1;}// 解析命令行参数 -- start --char option = 0;int option_index = 0;const char *short_options = "ht:i:o:r:";struct option long_options[] ={{"help",         no_argument,       NULL, 'h'},{"convert_type", required_argument, NULL, 't'},{"input_file", 	 required_argument, NULL, 'i'},{"output_file",  required_argument, NULL, 'o'},{"bit_rates",    required_argument, NULL, 'r'},{NULL,           0,                 NULL,  0 },};  while((option = getopt_long_only(argc, argv, short_options, long_options, &option_index)) != -1) {switch(option){case 'h':print_Usage(argv[0]);return 0;case 't':strncpy(convertType, optarg, 128);break;case 'i':strncpy(inputFileName, optarg, 128);break;case 'o':strncpy(outputFileName, optarg, 128);break;case 'r':bitRates = atoi(optarg);break;defalut:printf("Unknown argument!\n");break;}}// 解析命令行参数 -- end --printf("\n**************************************\n""convert type: %s\n""input file name: %s\n""output file name: %s\n""g726 bit rates: %d bps\n""**************************************\n\n",!strcmp(convertType, "pcm_2_g726") ? "pcm -> g726" : "g726 -> pcm",inputFileName, outputFileName, bitRates);fpInput  = fopen(inputFileName, "rb");fpOutput = fopen(outputFileName, "wb");if(!fpInput || !fpOutput){printf("Open Input/Output file failed!\n");return -1;}// step 1: 先分配内存空间给操作句柄g726Handler = (g726_state_t *)malloc(sizeof(g726_state_t));if(g726Handler == NULL){printf("Alloc memory for g726 handler failed!\n");return -1;}// step 2: 根据比特率（码率）进行初始化得到句柄g726Handler = g726_init(g726Handler, bitRates);// 按一"帧"160个采样点进行操作#define SAMPLES_PER_FRAME 	(160)if(strcmp(convertType, "pcm_2_g726") == 0) // encode{int readBytes = -1;int ret = -1;while(1){readBytes = fread(inBuf, 1, SAMPLES_PER_FRAME*(16/8), fpInput);if(readBytes <= 0)break;/* 参数：句柄、g726缓存（传出）、pcm缓存（传入）、pcm的采样点个数；* 返回值：编码得到的g726数据长度*/ret = g726_encode(g726Handler, (unsigned char*)outBuf, (const short*)inBuf, readBytes/2); // 记得读到的字节数要除以2DEBUG("[g726_encode]  read pcm bytes: %d  ->  encode g726 bytes: %d\n", readBytes, ret);if(ret != readBytes * bitRates / 128000){printf("PCM encode to G726 failed!\n");printf("\033[31mFailed!\033[0m\n");break;}fwrite(outBuf, 1, ret, fpOutput);}}else if(strcmp(convertType, "g726_2_pcm") == 0) // decode{int readBytes = -1;int ret = -1;while(1){readBytes = fread(inBuf, 1, SAMPLES_PER_FRAME * (16/8) * bitRates / 128000, fpInput);if(readBytes <= 0)break;/* 参数：句柄、pcm缓存（传出）、g726缓存（传入）、g726数据长度；* 返回值：pcm的采样点个数，注意不是字节数！！！所以字节数是要x2*/ret = g726_decode(g726Handler, (short*)outBuf, inBuf, readBytes);DEBUG("[g726_decode] read g726 bytes: %d  ->  decode pcm bytes: %d\n", readBytes, ret*2);if(ret*2 * bitRates / 128000 != readBytes){printf("G726 decode to PCM failed!\n");printf("\033[31mFailed!\033[0m\n");break;}fwrite(outBuf, 2, ret, fpOutput);}}else{printf("Unknown convert type!\n");printf("\033[31mFailed!\033[0m\n");return -1;}printf("\033[32msuccess!\033[0m\n");// step : 释放句柄的内存free(g726Handler);free(inBuf);free(outBuf);fclose(fpInput);fclose(fpOutput);return 0;
}