WAVE音乐格式解析（讲解加代码）

之前一直想用单片机的adc播放音乐，一直有这个念头，网上找了很多的代码都很复杂，就想自己写一个兼容性高的，一眼就能看懂的WAVE解析的代码。以前基本功太差，现在感觉天清了雨晴了，我又觉得我行了！(狗头)

熬了两宿，对着两幅图把之前立的flag给补上了一部分。今天真的是写的太烦了，下边付了一份自己写的代码，代码目前的状态也就是能用吧！不稳定，bug超多，file safe啥的也没做，以后闲的蛋疼的时候在慢慢改。

代码先奉上，讲解日后心情好的时候补上。

 wave.c

#include <stdio.h>
#include<stdlib.h>
#include <string.h>
#include "wave.h"void printf_c(void * data,unsigned char num)
{unsigned int i = 0;char name[num];memcpy(name,data,num);for(i=0;i<num;i++)printf("%c",name[i]);printf("\n");
}int wave_asf(wave *ral_wave)
{unsigned int read_len = 0;unsigned int read_len_sizeof = 0;unsigned int ChunkID = 0;unsigned int local_offset = 0;unsigned char * extern_data;Wave_RIFF *baseframe;Wave_Base *miniframe;Wave_FMT *wavefmt;WAVE_DATA *wavedata;baseframe = (Wave_RIFF*)calloc(sizeof(Wave_RIFF),sizeof(char));miniframe = (Wave_Base*)calloc(sizeof(Wave_Base),sizeof(char));wavefmt   = (Wave_FMT*) calloc(sizeof(Wave_FMT),sizeof(char));wavedata  = (WAVE_DATA*)calloc(sizeof(WAVE_DATA),sizeof(char));read_len = fread(baseframe, 1, sizeof(Wave_RIFF), ral_wave->fp);if(read_len<sizeof(Wave_RIFF))printf("read file false!\n");local_offset = local_offset + read_len;bit8to32(&ChunkID,baseframe->ChunkID);if(ChunkID != RIFF_id)printf("file no wave!\n");while(TURE){memset(miniframe,0,sizeof(Wave_Base));ChunkID = 0;// 获取chunk_idread_len = fread(miniframe, 1, sizeof(Wave_Base), ral_wave->fp);if(read_len<sizeof(Wave_Base))printf("read file false!\n");local_offset = local_offset + read_len;bit8to32(&ChunkID,miniframe->ChunkID);switch(ChunkID){case fmt_id:read_len = fread(&read_len_sizeof, 1,sizeof(int) , ral_wave->fp);local_offset = local_offset + read_len;read_len = fread(wavefmt, 1,read_len_sizeof , ral_wave->fp);local_offset = local_offset + read_len;ral_wave->AudioFormate  = wavefmt->AudioFormate;ral_wave->BitePerSample = wavefmt->BitePerSample;ral_wave->BlockAilgn    = wavefmt->BlockAilgn;ral_wave->ByteRate      = wavefmt->ByteRate;ral_wave->NumChannels   = wavefmt->NumChannels;ral_wave->SampleRate    = wavefmt->SampleRate;ral_wave->ChunkSize     = read_len_sizeof;break;case data_id:read_len = fread(wavedata, 1,sizeof(WAVE_DATA) , ral_wave->fp);local_offset = local_offset + read_len;ral_wave->Subchunck2Size = wavedata->Subchunck2Size;goto out_while;default:read_len = fread(&read_len_sizeof, 1,sizeof(int) , ral_wave->fp);local_offset = local_offset + read_len;extern_data = (unsigned char*)calloc(read_len_sizeof,sizeof(char));read_len = fread(extern_data, 1,read_len_sizeof , ral_wave->fp);local_offset = local_offset + read_len;// 文件指针后移free(extern_data);break;}}
out_while:free(baseframe);free(miniframe);free(wavefmt);free(wavedata);ral_wave->DataOffset = 	local_offset;printf("ral_wave->DataOffset %x\n",ral_wave->DataOffset);printf("hello world~\n");return 0;
}int channel_select(wave *ral_wave)
{switch(ral_wave->AudioFormate){case 1:return 1;break;case 2:// 不支持其他break;default:// 不支持其他break;}return 0;
}// 声道，采样率分离
void channal_sbisample(wave *ral_wave)
{unsigned int read_len;
//	printf("ral_wave->ByteRate %d\n",ral_wave->ByteRate);
//	printf("ral_wave->BitePerSample %d\n",ral_wave->BitePerSample);
//	printf("ral_wave->BlockAilgn %d\n",ral_wave->BlockAilgn);
//	printf("ral_wave->NumChannels %d\n",ral_wave->NumChannels);
//	printf("ral_wave->SampleRate %d\n",ral_wave->SampleRate);// ByteRate == SampleRate * NumChannels * BitsPerSample/8// BlockAlign == NumChannels * BitsPerSample/8if(ral_wave->NumChannels == 1){switch(ral_wave->BitePerSample){case 8:printf("channel 1,8 bit\n");break;case 16:printf("channel 1,16 bit\n");break;default:printf("chanel 1 error!\n");break;}}else if(ral_wave->NumChannels == 2){switch(ral_wave->BitePerSample){case 8:printf("channel 2,8 bit\n");break;case 16:printf("channel 2,16 bit\n");c2b16 loca_c2b16;read_len = fread(&loca_c2b16, 1,sizeof(c2b16) , ral_wave->fp);printf("%d %d  read_len %d\n",sizeof(c2b16),sizeof(short),read_len);printf("loca_c2b16.L_c2b16 %x,loca_c2b16.R_c2b16 %x\n",loca_c2b16.L_c2b16,loca_c2b16.R_c2b16);ral_wave->DataOffset = ral_wave->DataOffset + read_len;printf("ral_wave->DataOffset %x\n",ral_wave->DataOffset);// 直接写道到DAC？break;default:printf("chanel 2 error!\n");break;}}else{printf("error!\n");}
}int main(void)
{wave *do_wave;do_wave = (wave*)calloc(sizeof(wave),sizeof(char));do_wave->fp = fopen("D:\\wave\\test.wav", "r");wave_asf(do_wave);if(channel_select(do_wave)!=1)return 0;for(int i = 0;i<1000;i++)channal_sbisample(do_wave);fclose(do_wave->fp);free(do_wave);return 0;
}

 wave.h

/** wave.h**  Created on: 2021年7月22日*      Author: uida0349*/#ifndef WAVE_H_
#define WAVE_H_#define TURE  1
#define FALSE 0// 将四个8bit的拼接成32bit的
#define bit8to32(a,b)    {*a = b[3];*a = ((*a)<<8)|b[2];*a = ((*a)<<8)|b[1];*a = ((*a)<<8)|b[0];}/*** 此处用于存储WAV的id信息* */
enum WAV_ID{RIFF_id = 0x46464952,fmt_id  = 0x20746d66,data_id = 0x61746164,
};typedef struct wave_base{//char           ExtentsID[4];unsigned char  ChunkID[4];
}Wave_Base;
typedef struct wave_riff{//char           ExtentsID[4];unsigned char  ChunkID[4];unsigned int   ChunkSize;unsigned char  Format[4];
}Wave_RIFF;
typedef struct wave_fmt{// fmt Bolckunsigned short AudioFormate;unsigned short NumChannels;unsigned int   SampleRate;unsigned int   ByteRate;unsigned short BlockAilgn;unsigned short BitePerSample;
}Wave_FMT;
typedef struct wave_data{// data Blockunsigned int   Subchunck2Size;
}WAVE_DATA;
typedef struct wave_Extents{char           ExtentsID[4];unsigned int   ExtentsSize;unsigned int   ExtentsDataLength;void *         ExtentsData;
}Extents_data;typedef struct wave_demo{FILE           *fp;// RIFF Bolckchar           ChunkID[4];unsigned int   ChunkSize;char           Format[4];// fmt Bolckchar           Subchunk1ID[4];unsigned int   Subchunk1Size;unsigned short AudioFormate;unsigned short NumChannels;unsigned int   SampleRate;unsigned int   ByteRate;unsigned short BlockAilgn;unsigned short BitePerSample;// extents BlockExtents_data   *ExtentsFrames;// data Blockchar           Subchunck2ID[4];unsigned int   Subchunck2Size;// data offsetunsigned int   DataOffset;
}wave;// 存储单声道8bit的数据
typedef unsigned char c1b8;
// 存储单声道16bit的数据
typedef unsigned short c1b16;
// 存储双声道8bit的数据
typedef struct {unsigned char L_c2b8;unsigned char R_c2b8;
}c2b8;// 存储双声道16bit的数据
typedef struct {unsigned short L_c2b16;unsigned short R_c2b16;
}c2b16;
#endif /* WAVE_H_ */

下一步的计划，一直到单片机里边，再加个timer，调度啥的，争取早点实现单片机片上DAC播放WAVE的想法。