shazam音乐检索算法 附完整c代码详解编程语言

#include <stdio.h> 
#include <stdlib.h> 
#include <math.h> 
#include <time.h> 
#include "fft.h" 
//ref:https://raw.githubusercontent.com/cxong/tinydir/master/tinydir.h 
#include "tinydir.h" 
#include "timing.h" 
#define DR_WAV_IMPLEMENTATION 
//ref:https://raw.githubusercontent.com/mackron/dr_libs/master/dr_wav.h 
#include "dr_wav.h" 
int16_t *wavRead_int16(char *filename, uint32_t *sampleRate, uint64_t *totalSampleCount) { 
unsigned int channels; 
int16_t *buffer = drwav_open_and_read_file_s16(filename, &channels, sampleRate, totalSampleCount); 
if (buffer == 0) { 
fprintf(stderr, "ERROR/n"); 
exit(1); 
} 
if (channels == 2) { 
int16_t *bufferSave = buffer; 
for (int i = 0; i < *totalSampleCount; i += 2) { 
*bufferSave++ = (int16_t) ((buffer[i] + buffer[i + 1]) >> 1); 
} 
*totalSampleCount = *totalSampleCount >> 1; 
} 
return buffer; 
} 
unsigned long hash(unsigned char *str) { 
unsigned long hash = 5381; 
int c; 
while (c = *str++) 
hash = ((hash << 5) + hash) + c; 
return hash; 
} 
int generateHashes(char *input_file, int **hashtable, int songid, size_t N, int freqbandWidth, int maxElems) { 
printf("reading %s /n", input_file); 
uint32_t sampleRate = 0; 
uint64_t samplesize = 0; 
int16_t *pcmdata = wavRead_int16(input_file, &sampleRate, &samplesize); 
float *inputBuffer = (float *) calloc(sizeof(float), N); 
fft_complex *outBuffer = (fft_complex *) calloc(sizeof(fft_complex), N); 
int sect = 0; 
int cnt = 0; 
int numHashes = 0; 
for (int i = 0; i < samplesize; i++) { 
if (sect < N) { 
inputBuffer[sect] = (float) pcmdata[i]; 
sect++; 
} else { 
sect = 0; 
i -= 1; 
cnt++; 
fft_plan plan = fft_plan_dft_r2c_1d(N, inputBuffer, outBuffer, 0); 
fft_execute(plan); 
fft_destroy_plan(plan); 
int freq1 = 0, freq2 = 0, freq3 = 0, freq4 = 0, freq5 = 0; 
int pt1 = 0, pt2 = 0, pt3 = 0, pt4 = 0, pt5 = 0; 
int freqbandWidth2 = freqbandWidth * 2; 
int freqbandWidth3 = freqbandWidth * 3; 
int freqbandWidth4 = freqbandWidth * 4; 
int freqbandWidth5 = freqbandWidth * 5; 
int freqbandWidth6 = freqbandWidth * 6; 
for (int k = freqbandWidth; k < freqbandWidth6; k++) { 
int freq = (outBuffer[k].real > 0) ? (int) outBuffer[k].real : (int) (0 - outBuffer[k].real); 
int Magnitude = (int) (log10f((freq + 1)) * 1000); 
if (k >= freqbandWidth && k < freqbandWidth2 && Magnitude > freq1) { 
freq1 = Magnitude; 
pt1 = k; 
} else if (k >= freqbandWidth2 && k < freqbandWidth3 && Magnitude > freq2) { 
freq2 = Magnitude; 
pt2 = k; 
} else if (k >= freqbandWidth3 && k < freqbandWidth4 && Magnitude > freq3) { 
freq3 = Magnitude; 
pt3 = k; 
} else if (k >= freqbandWidth4 && k < freqbandWidth5 && Magnitude > freq4) { 
freq4 = Magnitude; 
pt4 = k; 
} else if (k >= freqbandWidth5 && k < freqbandWidth6 && Magnitude > freq5) { 
freq5 = Magnitude; 
pt5 = k; 
} 
} 
char buffer[50]; 
sprintf(buffer, "%d%d%d%d%d", pt1, pt2, pt3, pt4, pt5); 
unsigned long hashresult = hash(buffer) % maxElems; 
int key = (int) hashresult; 
if (key < 0) 
printf("Invalid key %d/n", key); 
hashtable[key][songid]++; 
numHashes++; 
} 
} 
free(pcmdata); 
free(inputBuffer); 
free(outBuffer); 
return numHashes; 
} 
int main(int argc, char *argv[]) { 
printf("Audio Processing/n"); 
printf("shazam audio hash/n"); 
printf("blog: http://cpuimage.cnblogs.com//n"); 
int N = 512; 
int freqbandWidth = 50; 
int maxSongs = 10; 
size_t maxElems = 200000; 
int **hashTable; 
int i = 0, n = 0; 
float count = 0; 
int numsongs = 0; 
char filenames[maxSongs + 1][_TINYDIR_FILENAME_MAX]; 
int filesizes[maxSongs + 1]; 
int songScores[maxSongs + 1]; 
float songMatch[maxSongs + 1]; 
printf("running... /n"); 
if (argc < 2) { 
printf("no excerpt file to open /n"); 
exit(1); 
} 
double start_total = now(); 
hashTable = (int **) calloc(maxElems, sizeof(int *)); 
for (i = 0; i < maxElems; i++) 
hashTable[i] = (int *) calloc(maxSongs + 1, sizeof(int)); 
printf("Generating hashes for original files.. /n"); 
tinydir_dir dir; 
tinydir_open(&dir, "data"); 
while (dir.has_next) { 
tinydir_file file; 
tinydir_readfile(&dir, &file); 
if (file.is_reg) { 
numsongs++; 
double startTime = now(); 
filesizes[numsongs] = generateHashes(file.path, hashTable, numsongs, N, freqbandWidth, maxElems); 
size_t time_interval = (size_t) (calcElapsed(startTime, now()) * 1000); 
songScores[numsongs] = 0; 
printf("%d:%d hashes for %s/n", numsongs, filesizes[numsongs], file.path); 
printf("Time taken: %d seconds %d milliseconds/n", time_interval / 1000, time_interval % 1000); 
strcpy(filenames[numsongs], file.name); 
} 
tinydir_next(&dir); 
} 
tinydir_close(&dir); 
printf("Generating hashes for recorded file.. /n"); 
generateHashes(argv[1], hashTable, 0, N, freqbandWidth, maxElems); 
printf("Calculating score.. /n"); 
for (i = 0; i < maxElems; i++) { 
if (hashTable[i][0] > 0) { 
for (n = 1; n <= maxSongs; n++) { 
if (hashTable[i][n] >= hashTable[i][0]) 
songScores[n] = songScores[n] + hashTable[i][0]; 
else 
songScores[n] = songScores[n] + hashTable[i][n];; 
} 
} 
} 
for (i = 1; i <= numsongs; i++) { 
songMatch[i] = ((float) songScores[i]) / ((float) filesizes[i]); 
printf("Score for %s = %f/n", filenames[i], songMatch[i]); 
if (songMatch[i] > count) { 
count = songMatch[i]; 
n = i; 
} 
} 
printf("Best Score: %s/n", filenames[n]); 
for (i = 0; i < maxElems; i++) 
free(hashTable[i]); 
free(hashTable); 
size_t msec = (size_t) (calcElapsed(start_total, now()) * 1000); 
printf("Total time taken: %d seconds %d milliseconds/n", msec / 1000, msec % 1000); 
return 0; 
}