pcm数据相关转换

/******************************************************************** function: g.711 decoder and encoder ********************************************************************/ //hyy add 2010.4.9 begin #include#include#includetypedef unsigned short uint16;

typedef unsigned int uint32;

#pragma pack(push, 1)

// pcm文件头

typedef struct

{

uint32 ChunkID; //00H 4 char "RIFF"标志

uint32 ChunkSize; //04H 4 long int 文件长度文总长-8

uint32 Format; //08H 4 char "WAVE"标志

uint32 SubChunk1ID; //0CH 4 char "fmt "标志

uint32 SubChunk1Size; //10H 4 0x10000000H(PCM)过渡字节(不定)

uint16 AudioFormat; //14H 2 int 格式类别（0x01H为PCM形式的声音数据) 0x0100H

uint16 NumChannels; //16H 2 int 通道数，单声道为1，双声道为2

uint32 SampleRate; //18H 4 int 采样率（每秒样本数），表示每个通道的播放速度，

uint32 ByteRate; //1CH 4 long int 波形音频数据传送速率，其值Channels×SamplesPerSec×BitsPerSample/8

uint16 BlockAlign; //20H 2 int 数据块的调整数（按字节算的），其值为Channels×BitsPerSample/8

uint16 BitsPerSample; //22H 2 每样本的数据位数，表示每个声道中各个样本的数据位数。如果有多个声道，对每个声道而言，样本大小都一样。

uint32 DataTag; //24H 4 char 数据标记符＂data＂

uint32 DataLen; //28H 4 long int 语音数据的长度(文长-44)

}PCM_HEAD, *PPCM_HEAD;

// a-law文件头

typedef struct

{

uint32 ChunkID; //00H 4 char "RIFF"标志

uint32 ChunkSize; //04H 4 long int 文件长度文总长-8

uint32 Format; //08H 4 char "WAVE"标志

uint32 SubChunk1ID; //0CH 4 char "fmt "标志

uint32 SubChunk1Size; //10H 4 0x12000000H(ALAW)

uint16 AudioFormat; //14H 2 int 格式类别 0x0600H

uint16 NumChannels; //16H 2 int 通道数，单声道为1，双声道为2

uint32 SampleRate; //18H 4 int 采样率（每秒样本数），表示每个通道的播放速度，

uint32 ByteRate; //1CH 4 long int 波形音频数据传送速率，其值Channels×SamplesPerSec×BitsPerSample/8

uint16 BlockAlign; //20H 2 int 数据块的调整数（按字节算的），其值为Channels×BitsPerSample/8

//uint16 BitsPerSample; //22H 2 每样本的数据位数，表示每个声道中各个样本的数据位数。如果有多个声道，对每个声道而言，样本大小都一样。

uint32 BitsPerSample; //22H 2 每样本的数据位数，表示每个声道中各个样本的数据位数。如果有多个声道，对每个声道而言，样本大小都一样。

uint32 WaveFact; //26H 4 char "fact"标志

uint32 Temp1; //2AH 4 0x04000000H

uint32 Temp2; //2EH 4 0x00530700H

uint32 DataTag; //32H 4 char 数据标记符＂data＂

uint32 DataLen; //36H 4 long int 语音数据的长度(文长-58)

}ALAW_HEAD, *PALAW_HEAD;

#pragma pack(pop)

//hyy add 2010.4.9 end

#define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */

#define QUANT_MASK (0xf) /* Quantization field mask. */

#define NSEGS (8) /* Number of A-law segments. */

#define SEG_SHIFT (4) /* Left shift for segment number. */

#define SEG_MASK (0x70) /* Segment field mask. */

#define BIAS (0x84) /* Bias for linear code. */

#define CLIP 8159

static const short seg_aend[8] = {0x1F, 0x3F, 0x7F, 0xFF,

0x1FF, 0x3FF, 0x7FF, 0xFFF};

static const short seg_uend[8] = {0x3F, 0x7F, 0xFF, 0x1FF,

0x3FF, 0x7FF, 0xFFF, 0x1FFF};

/*********** 本程序是采用查表的方式来近似ln的算法 *************/

//short alaw2linear(unsigned char a_val),ulaw2linear(unsigned char u_val);

//char linear2alaw(short pcm_val),linear2ulaw(short pcm_val);

/*************** 检查输入信号在哪个压缩区间 *********************/

static short search( short val, short *table, short size)

{

short i;

for (i = 0; i < size; i++)

{

if (val <= *table++) //找出一个与输入信号最相近的值（大于）

{

return (i);

}

return (size);

}

/********************* PCM 2 a-law 的压缩 ****************************/

char linear2alaw(short pcm_val) /* 2's complement (16-bit range) */

{

short mask;

short seg;

unsigned char aval;

pcm_val = pcm_val >> 3;

if (pcm_val >= 0)

{

mask = 0xD5; /* sign (7th) bit = 1 */

}

else

{

mask = 0x55; /* sign bit = 0 */

pcm_val = -pcm_val - 1;

}

/* Convert the scaled magnitude to segment number. */

seg = search(pcm_val, (short *)seg_aend, (short)8);

/* Combine the sign, segment, and quantization bits. */

if (seg >= 8) /* out of range, return maximum value. */

{

return (unsigned char) (0x7F ^ mask);

}

else

{

aval = (unsigned char) seg << SEG_SHIFT;

if (seg < 2)

{

aval |= (pcm_val >> 1) & QUANT_MASK;

}

else

{

aval |= (pcm_val >> seg) & QUANT_MASK;

}

return (aval ^ mask);

}

/***************** a-law 2 PCM *******************/

* alaw2linear() - Convert an A-law value to 16-bit linear PCM

short alaw2linear(unsigned char a_val)

{

short t;

short seg;

a_val ^= 0x55;

t = (a_val & QUANT_MASK) << 4;

seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;

switch (seg)

{

case 0:

t += 8;

break;

case 1:

t += 0x108;

break;

default:

t += 0x108;

t <<= seg - 1;

break;

}

return ((a_val & SIGN_BIT) ? t : -t);

}

/*********************** pcm 2 u law *************************/

char linear2ulaw(short pcm_val) /* 2's complement (16-bit range) */

{

short mask;

short seg;

unsigned char uval;

/* Get the sign and the magnitude of the value. */

pcm_val = pcm_val >> 2;

if (pcm_val < 0)

{

pcm_val = -pcm_val;

mask = 0x7F;

}

else

{

mask = 0xFF;

}

if ( pcm_val > CLIP )

{

pcm_val = CLIP; /* clip the magnitude */

}

pcm_val += (BIAS >> 2);

/* Convert the scaled magnitude to segment number. */

seg = search(pcm_val, (short *)seg_uend, (short)8);

* Combine the sign, segment, quantization bits;

* and complement the code word.

if (seg >= 8) /* out of range, return maximum value. */

{

return (unsigned char) (0x7F ^ mask);

}

else

{

uval = (unsigned char) (seg << 4) | ((pcm_val >> (seg + 1)) & 0xF);

return (uval ^ mask);

}

* ulaw2linear() - Convert a u-law value to 16-bit linear PCM

* First, a biased linear code is derived from the code word. An unbiased

* output can then be obtained by subtracting 33 from the biased code.

* Note that this function expects to be passed the complement of the

* original code word. This is in keeping with ISDN conventions.

short ulaw2linear(unsigned char u_val)

{

short t;

/* Complement to obtain normal u-law value. */

u_val = ~u_val;

* Extract and bias the quantization bits. Then

* shift up by the segment number and subtract out the bias.

t = ((u_val & QUANT_MASK) << 3) + BIAS;

t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;

return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));

}

void print_error()

{

printf("input Error!\n");

printf("input argv[1] in filename\n");

printf("input argv[2] 0=pcm:wav -> a-lam:wav\n");

printf(" 1=a-lam -> a-lam:wav\n");

printf(" 2=a-lam -> pcm:wav\n");

printf(" 3=pcm -> pcm:wav\n");

printf(" 4=pcm -> a-lam:wav\n");

printf(" 5=a-lam:wav -> pcm:wav\n");

printf("input argv[3] out filename\n");

printf("input argv[4] filehead len\n");

}

void init_pcm_head(PPCM_HEAD head)

{

head->ChunkID = 0x46464952;

//head->ChunkSize = 0xa17fe4;

head->Format = 0x45564157;

head->SubChunk1ID = 0x20746d66;

head->SubChunk1Size = 0x10;

head->AudioFormat = 0x1;

head->NumChannels = 0x2;

head->SampleRate = 0xac44;

head->ByteRate = 0x2b110;

head->BlockAlign = 0x4;

head->BitsPerSample = 0x10;

head->DataTag = 0x61746164;

//head->DataLen = 0xa17fc0;

}

void init_alaw_head(PALAW_HEAD head)

{

head->ChunkID = 0x46464952;

//head->ChunkSize = 0x50c012;

head->Format = 0x45564157;

head->SubChunk1ID = 0x20746d66;

head->SubChunk1Size = 0x12;//0x10;

head->AudioFormat = 0x6;

head->NumChannels = 0x1;//0x2;

head->SampleRate = 0x3E80;//0x1f40;//0xac44; // 采样率

head->ByteRate = 0x3E80;//0x1f40;//0x2b110; // 波形传送速率

head->BlockAlign = 0x01;//0x4; // 调整数

head->BitsPerSample = 0x08;//0x10; // 量化数

head->WaveFact = 0x74636166;

head->Temp1 = 0x4;

//head->Temp2 = 0x75300;

head->DataTag = 0x61746164;

//head->DataLen = 0x50bfe0;

}

int main(int argc, char * argv[])

{

FILE *fpin = NULL;

FILE *fpout = NULL;

PCM_HEAD pcm_head;

ALAW_HEAD alaw_head;

char format[5] = ".wav";

char filename[50];

char c;

short pcm_val;

struct stat st;

int move_len = 0;

if (argc != 5 || ('0' > argv[2][0] || argv[2][0] > '5'))

{

print_error();

return -1;

}

move_len = atol(argv[4]);

if ('0' == argv[2][0]) // pcm:wav -> a-lam:wav

{

fpin = fopen(argv[1], "r");

if (NULL == fpin)

{

printf("OpenFile Error!\n");

return -1;

}

memset(filename, 0, sizeof (filename));

if (NULL != strstr(argv[3], format))

{

sprintf(filename, "%s", argv[3]);

}

else

{

sprintf(filename, "%s%s", argv[3], format);

}

fpout = fopen(filename, "w+");

if (NULL == fpout)

{

fclose(fpin);

printf("OpenFile Error!\n");

return -1;

}

if (1 != fread(&pcm_head, sizeof(PCM_HEAD), 1, fpin))

{

printf("ReadFile Error!\n");

goto END;

}

if (pcm_head.AudioFormat != 0x1)

{

printf("AudioFormat Error!\n");

goto END;

}

memset(&alaw_head, 0, sizeof (ALAW_HEAD));

alaw_head.ChunkID = pcm_head.ChunkID;

alaw_head.ChunkSize = (pcm_head.ChunkSize - 36) / 2 + 50;

alaw_head.Format = pcm_head.Format;

alaw_head.SubChunk1ID = pcm_head.SubChunk1ID;

alaw_head.SubChunk1Size = pcm_head.SubChunk1Size;//0x00000012;

alaw_head.AudioFormat = 0x0006;

alaw_head.NumChannels = pcm_head.NumChannels;

alaw_head.SampleRate = pcm_head.SampleRate;

alaw_head.ByteRate = pcm_head.ByteRate;

alaw_head.BlockAlign = pcm_head.BlockAlign;

alaw_head.BitsPerSample = pcm_head.BitsPerSample;

alaw_head.WaveFact = 0x74636166; // 值要倒过来 "fact"

alaw_head.Temp1 = 0x00000004;

alaw_head.Temp2 = (pcm_head.ChunkSize - 36) / 2;//0x00075300;

alaw_head.DataTag = pcm_head.DataTag;

alaw_head.DataLen = (pcm_head.ChunkSize - 36) / 2;

fwrite(&alaw_head, sizeof(ALAW_HEAD), 1, fpout);

while (1 == fread(&pcm_val, sizeof(short), 1, fpin))

{

c = linear2alaw(pcm_val);

fputc(c, fpout);

}

else if ('5' == argv[2][0]) // a-lam:wav -> pcm:wav

{

fpin = fopen(argv[1], "r");

if (NULL == fpin)

{

printf("OpenFile Error!\n");

return -1;

}

memset(filename, 0, sizeof (filename));

if (NULL != strstr(argv[3], format))

{

sprintf(filename, "%s", argv[3]);

}

else

{

sprintf(filename, "%s%s", argv[3], format);

}

fpout = fopen(filename, "w+");

if (NULL == fpout)

{

fclose(fpin);

printf("OpenFile Error!\n");

return -1;

}

if (1 != fread(&alaw_head, sizeof(ALAW_HEAD), 1, fpin))

{

printf("ReadFile Error!\n");

goto END;

}

if (alaw_head.AudioFormat != 0x6)

{

printf("AudioFormat Error!\n");

goto END;

}

memset(&pcm_head, 0, sizeof (PCM_HEAD));

pcm_head.ChunkID = alaw_head.ChunkID;

pcm_head.ChunkSize = alaw_head.DataLen * 2 + 36;

pcm_head.Format = alaw_head.Format;

pcm_head.SubChunk1ID = alaw_head.SubChunk1ID;

pcm_head.SubChunk1Size = alaw_head.SubChunk1Size;//0x00000012;

pcm_head.AudioFormat = 0x0001;

pcm_head.NumChannels = alaw_head.NumChannels;

pcm_head.SampleRate = alaw_head.SampleRate;

pcm_head.ByteRate = alaw_head.ByteRate;

pcm_head.BlockAlign = alaw_head.BlockAlign;

pcm_head.BitsPerSample = alaw_head.BitsPerSample;

pcm_head.DataTag = alaw_head.DataTag;

pcm_head.DataLen = alaw_head.DataLen * 2;

fwrite(&pcm_head, sizeof(PCM_HEAD), 1, fpout);

while (1 == fread(&c, sizeof(char), 1, fpin))

{

pcm_val = alaw2linear(c);

fwrite(&pcm_val, sizeof(short), 1, fpout);

}

else

{

if (NULL != strstr(argv[1], format))

{

printf("FileFormat Error!\n");

return -1;

}

if (stat(argv[1], &st) != 0)

{

printf("Read FileSize Error!\n");

return -1;

}

fpin = fopen(argv[1], "r");

if (NULL == fpin)

{

printf("OpenFile Error!\n");

return -1;

}

memset(filename, 0, sizeof (filename));

if (NULL != strstr(argv[3], format))

{

sprintf(filename, "%s", argv[3]);

}

else

{

sprintf(filename, "%s%s", argv[3], format);

}

fpout = fopen(filename, "w+");

if (NULL == fpout)

{

fclose(fpin);

printf("OpenFile Error!\n");

return -1;

}

if (move_len)

{

fseek(fpin, move_len, SEEK_SET);

}

if ('1' == argv[2][0]) // a-lam -> a-lam:wav

{

init_alaw_head(&alaw_head);

alaw_head.ChunkSize = (st.st_size - move_len) + 50;

alaw_head.Temp2 = (st.st_size - move_len);

alaw_head.DataLen = (st.st_size - move_len);

fwrite(&alaw_head, sizeof(ALAW_HEAD), 1, fpout);

while (1 == fread(&c, sizeof(char), 1, fpin))

{

fputc(c, fpout);

}

else if ('2' == argv[2][0]) // a-lam -> pcm:wav

{

init_pcm_head(&pcm_head);

pcm_head.ChunkSize = (st.st_size - move_len) * 2 + 36;

pcm_head.DataLen = (st.st_size - move_len) * 2;

fwrite(&pcm_head, sizeof(PCM_HEAD), 1, fpout);

while (1 == fread(&c, sizeof(char), 1, fpin))

{

pcm_val = alaw2linear(c);

fwrite(&pcm_val, sizeof(short), 1, fpout);

}

else if ('3' == argv[2][0]) // pcm -> pcm:wav

{

init_pcm_head(&pcm_head);

pcm_head.ChunkSize = (st.st_size - move_len) + 36;

pcm_head.DataLen = (st.st_size - move_len);

fwrite(&pcm_head, sizeof(PCM_HEAD), 1, fpout);

while (1 == fread(&pcm_val, sizeof(short), 1, fpin))

{

fwrite(&pcm_val, sizeof(short), 1, fpout);

}

else if ('4' == argv[2][0]) // pcm -> a-lam:wav

{

init_alaw_head(&alaw_head);

alaw_head.ChunkSize = (st.st_size - move_len) / 2 + 50;

alaw_head.Temp2 = (st.st_size - move_len) / 2;

alaw_head.DataLen = (st.st_size - move_len) / 2;

fwrite(&alaw_head, sizeof(ALAW_HEAD), 1, fpout);

while (1 == fread(&pcm_val, sizeof(short), 1, fpin))

{

c = linear2alaw(pcm_val);

fputc(c, fpout);

}

printf("OK!\n");

END:

fclose(fpin);

fclose(fpout);

return 1;

}

最后编辑于：2017.12.04 23:27:58

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pcm数据相关转换

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