syb*_*0rg 10 c audio memory-management deep-copy portaudio
在这里,我试图为连续录制的音频系统编写一些代码.然后,当某个幅度阈值被破坏时,我试图将音频记录一段时间.
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include <time.h>
#include <portaudio.h>
#include <sndfile.h>
#define FRAMES_PER_BUFFER (1024)
#define SAMPLE_SIZE (4)
typedef struct
{
uint16_t formatType;
uint16_t numberOfChannels;
uint32_t sampleRate;
float* recordedSamples;
} AudioData;
AudioData initAudioData(uint32_t sampleRate, uint16_t channels, int type)
{
AudioData data;
data.formatType = type;
data.numberOfChannels = channels;
data.sampleRate = sampleRate;
return data;
}
float avg(float *data)
{
int elems = sizeof(data) / sizeof(data[0]);
float sum = 0;
for (int i = 0; i < elems; i++)
{
sum += fabs(*(data + i));
}
return (float) sum / elems;
}
int main(void)
{
AudioData data = initAudioData(44100, 2, paFloat32);
PaStream *stream = NULL;
PaError err = paNoError;
int size = FRAMES_PER_BUFFER * data.numberOfChannels * SAMPLE_SIZE;
float *sampleBlock = malloc(size);
float *recordedSamples = NULL;
time_t talking = 0;
time_t silence = 0;
if((err = Pa_Initialize())) goto done;
PaStreamParameters inputParameters =
{
.device = Pa_GetDefaultInputDevice(),
.channelCount = data.numberOfChannels,
.sampleFormat = data.formatType,
.suggestedLatency = Pa_GetDeviceInfo(Pa_GetDefaultInputDevice())->defaultHighInputLatency,
.hostApiSpecificStreamInfo = NULL
};
if((err = Pa_OpenStream(&stream, &inputParameters, NULL, data.sampleRate, FRAMES_PER_BUFFER, paClipOff, NULL, NULL))) goto done;
if((err = Pa_StartStream(stream))) goto done;
for(int i = 0;;)
{
err = Pa_ReadStream(stream, sampleBlock, FRAMES_PER_BUFFER);
if(avg(sampleBlock) > 0.000550) // talking
{
printf("You're talking! %d\n", i);
i++;
time(&talking);
recordedSamples = realloc(recordedSamples, size * i);
if (recordedSamples) memcpy(recordedSamples + ((i - 1) * size), sampleBlock, size); // problem here writing to memory at i = 16?
else free(recordedSamples);
}
else //silence
{
double test = difftime(time(&silence), talking);
printf("Time diff: %g\n", test);
if (test >= 1.5)
{
// TODO: finish code processing audio snippet
talking = 0;
free(recordedSamples); // problem freeing memory?
}
}
}
done:
free(sampleBlock);
Pa_Terminate();
return err;
}
但是,代码有点挑剔.有时当我在Xcode中运行我的程序时,我得到以下输出:
Run Code Online (Sandbox Code Playgroud)Time diff: 1.4218e+09 You're talking! 0 You're talking! 1 You're talking! 2 You're talking! 3 You're talking! 4 You're talking! 5 You're talking! 6 You're talking! 7 You're talking! 8 You're talking! 9 You're talking! 10 You're talking! 11 You're talking! 12 You're talking! 13 You're talking! 14 You're talking! 15 (lldb)
Xcode指向这一行是问题所在:
Run Code Online (Sandbox Code Playgroud)if (recordedSamples) memcpy(recordedSamples + ((i - 1) * size), sampleBlock, size); // problem here writing to memory at i = 16?
其他时候我运行代码,我收到此错误:
Run Code Online (Sandbox Code Playgroud)Time diff: 1.4218e+09 You're talking! 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 0 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 1 Time diff: 2 Time diff: 1.4218e+09 CTestEnvironment(55085,0x7fff7938e300) malloc: *** error for object 0x10081ea00: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug
这两个错误都让我感到困惑......有什么建议吗？
您正在写出已分配缓冲区的范围:
recordedSamples = realloc(recordedSamples, size * i);
memcpy(recordedSamples + ((i - 1) * size), sampleBlock, size);
realloc()这里分配一定数量的字节size * i.生成的指针存储在recordedSamples其中,具有类型float*.
在memcpy()随后试图将数据写入recordedSamples + ((i - 1) * size.指针算术用于确定应写入的位置.由于recordedSamples是类型float*,recordedSample + X指向X浮点值(不是X字节)的偏移量.
换句话说,recordedSamples + ((i - 1) * size指向((i - 1) * size * sizeof(float)后面的内存位置字节recordedSamples.这通常不在分配的缓冲区内,因为浮点数大于单个字节.
要解决这个问题,最大的问题是if size是多少字节还是多个浮点数.这取决于您正在使用的API函数,我没有详细研究过它.
如果它是一个floats,那么你必须调整对基本内存管理函数的调用malloc,realloc并且memcpy,因为全部操作字节.而不是malloc(size)你会打电话malloc(size * sizeof(float)).
如果size确实是一些字节,那么在进行带字节偏移的指针算法之前制作recordedSamplesa char*或者至少强制转换它会更合乎逻辑memcpy((char*)recordedSamples + ...).