我试图使用libsndfile库在音频文件之间读/写信息。
我设法阅读了原始文件，用＆＃34; watermark＆＃34;写了一份副本。值。
我现在尝试做的就是打印任何值不为0的索引。
然而，当我调用printBuffer（）函数时，它会返回全0，即使在调试模式下，我可以看到缓冲区中的值不是零/更改每次迭代。
我是否错误地调用了缓冲区数组？
我还是C新手，所以如果您有任何建议，我们将不胜感激。
谢谢。
代码：
#define _CRT_SECURE_NO_DEPRECATE
#include <stdio.h>
#include <stdlib.h>
#include <sndfile.h>
#include <time.h>
#define MAX_CHANNEL 2
#define BUF_SIZE 1024
int numItems(int frames, int channels);
void printInfo(int frames, int channels, int sampleRate);
void watermark(double *buffer, int count, int channels);
void watermark2(double *buffer, int count);
void readFile(int fileNumber);
void printBuffer(double *buffer, size_t count);
int main(void)
{
int chosenFile, answer;
printf("Please select the file you want to read\n");
printf("1. File1\n");
printf("2. File2\n");
printf("3. File3\n");
printf("4. File4\n");
printf("5. File5\n");
scanf("%d", &chosenFile);
processFile(chosenFile);
/*
Put boolean here to check whether to process the original file or the new one
*/
printf("Would you like to read the new file?\n");
printf("1. Yes\n");
printf("2. No\n");
scanf("%d", &answer);
if (answer == 1)
{
readFile(chosenFile);
}
}
int processFile(int fileNumber)
{
/*READING FILE*/
static double buffer[BUF_SIZE];
SF_INFO info;
SNDFILE *infile,*outfile;
int readCount, i;
/*
Put boolean here to check whether it should read the original files, or the new output files
*/
char *Files[] = { "File1.wav", "File2.wav", "File3.wav"
, "File4.wav", "DFile5.wav" };
char *Files2[] = { "File1Output.wav", "File2Output.wav", "File3Output.wav"
, "File4Output.wav", "File5Output.wav" };
char *inputFile = Files[fileNumber - 1];
if (!(infile = sf_open(inputFile, SFM_READ, &info)))
{
printf("Not able to open input file %s.\n", inputFile);
puts(sf_strerror(NULL));
return 1;
};
printf("You have opened: %s\n", Files[fileNumber - 1]);
printInfo( info.frames, info.channels, info.samplerate);
int num = numItems(info.frames, info.channels);
printf("Buffer(frames*channels): %d \n", num);
/*WRITING FILE*/
char *outputFile = Files2[fileNumber - 1];
printf("Your file has been saved in the following location: %s\n", outputFile);
if (!(outfile = sf_open(outputFile, SFM_WRITE, &info)))
{
printf("Not able to open output file %s.\n", outputFile);
puts(sf_strerror(NULL));
return 1;
};
/*
Actual buffer size is numItems, somehow can't declare buffer as buffer[numItems]
BUF_SIZE is set to 1024, which means that it reads the data in chunks of 1024 frames
it will keep writing in 1024 chuncks until all numItems have been written (numItems/BUF_SIZE)
Needs to be on a while loop otherwise it will only write the first 1024 frames of the file
*/
while ((readCount = sf_read_double(infile, buffer, BUF_SIZE)))
{
watermark(buffer, readCount, info.channels);
sf_write_double(outfile, buffer, readCount);
};
for (i = 0; i < sizeof(buffer) / sizeof *buffer; i++)
{
printBuffer(buffer, sizeof(buffer)/sizeof *buffer);
}
/*
Can only close SF_open once both reading/writing has been done
if you close infile after the read, it's not able to copy the audio
data from infile to write into outfile
*/
sf_close(infile);
sf_close(outfile);
return;
}
void readFile(int fileNumber)
{
SF_INFO info;
SNDFILE *infile;
char *Files[] = { "File1Output.wav", "File2Output.wav", "File3Output.wav"
, "File4Output.wav", "File5Output.wav" };
char *inputFile = Files[fileNumber - 1];
infile = sf_open(inputFile, SFM_READ, &info);
printf("You have opened: %s\n", Files[fileNumber - 1]);
printInfo(info.frames, info.channels, info.samplerate);
sf_close(infile);
return;
}
int numItems(int frames, int channels)
{
int numItems = frames * channels;
return numItems;
}
void printInfo(int frames, int channels, int sampleRate)
{
printf("Number of Frames = %d\n", frames);
printf("Number of Channels = %d\n", channels);
printf("Sample Rate = %d\n", sampleRate);
}
void watermark(double *buffer, int count, int channels)
{
double value[MAX_CHANNEL] = { 0.0, 0.0 };
int i, j;
if (channels > 1)
{
/*
Sets j to be the first channel and while i is less than 1024/5, i += channels
buffer[3] value is multiplied by 0, and set to 0
this mutes that particular index value or frame
this keeps going until i>=1024/5 and then the next channel is chosen where j = 2
buffer[4] value is multiplied by 0 and set to 0
this keeps going until i>=1024/5 where it calls back to the while loop in processFile
*/
for (j = 0; j < channels; j++)
{
for (i = j; i < count / 5; i += channels)
{
buffer[i] *= value[j];
}
}
}
else
{
/*
If audio file has 1 channel, buffer[i] is set to 0 for all values < 1024/5 frames
and it goes back to normal until the next 1024 frames where the first 1024/5 frames.
*/
for (i = 0; i < count / 5; i++)
{
buffer[i] *= value[0];
}
}
return;
}
void printBuffer(double *buffer, size_t count)
{
int i;
for (i = 0; i < count; i++)
{
if (i != 0)
printf("%d\n", buffer[i]);
}
}
/*
- *DONE* - Need to create function that will read the newly outputted file
- Find where the watermarks have been left on the audio
- Compare buffer[] values between original file and new outputted file
*/
答案 0 :(得分：0)
while ((readCount = sf_read_double(infile, buffer, BUF_SIZE)))
{
watermark(buffer, readCount, info.channels);
sf_write_double(outfile, buffer, readCount);
};
在这里，你一次又一次地使用缓冲区来读取一些数据，给它添加水印并将其写出来。只有完成后，才能从缓冲区中打印出最后剩余的数据：
for (i = 0; i < sizeof(buffer) / sizeof *buffer; i++)
{
printBuffer(buffer, sizeof(buffer)/sizeof *buffer);
}
所以，用
#define MAX_CHANNEL 2
#define BUF_SIZE 1024
和一个16位44100立体声的波形文件，你只会看到最后5.8ms的声音数据，这可能几乎是静音，如果你有像音乐这样的普通音频或者几乎没有噪音的高质量录音。 / p>
另外：根据最后一个块读取，你看到文件的尾部，然后是尾部之前的一些部分，就像你看到最后的3.2ms然后是之前的2.6ms，它没有被覆盖最后一次看书。
/ edit：好的，可能我的数字错了，数据类型是双等等，但概念错误是一样的。
/编辑2：看看Jonathan Leffler的评论，我看到还有更多错误...... - 我建议启用所有编译器警告，并尝试理解（并修复）它们。