记录到WAV文件中
Record into WAV file
自从我发布这个问题以来,我一直在尝试用原始PCM数据自己编写一个有效的WAV文件。我已经设法编写了FLAC转换器(经过测试并工作),但它没有对我一直在编写的WAV文件进行编码。
我不确定我做错了什么。我一直在互联网上搜索其他人的源代码,并将其与我自己的源代码进行比较,但我仍然无法使其发挥作用。
以下是精简后的源代码(很抱歉,它仍然有点长,需要一些代码才能自己记录到.wav
):
// Compile with "g++ test.ccp -o test -lasound"
// Use the newer ALSA API
#define ALSA_PCM_NEW_HW_PARAMS_API
#include <alsa/asoundlib.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>
struct WaveHeader
{
char RIFF_marker[4];
uint32_t file_size;
char filetype_header[4];
char format_marker[4];
uint32_t data_header_length;
uint16_t format_type;
uint16_t number_of_channels;
uint32_t sample_rate;
uint32_t bytes_per_second;
uint16_t bytes_per_frame;
uint16_t bits_per_sample;
};
struct WaveHeader *genericWAVHeader(uint32_t sample_rate, uint16_t bit_depth, uint16_t channels)
{
struct WaveHeader *hdr;
hdr = (WaveHeader*) malloc(sizeof(*hdr));
if (!hdr)
return NULL;
memcpy(&hdr->RIFF_marker, "RIFF", 4);
memcpy(&hdr->filetype_header, "WAVE", 4);
memcpy(&hdr->format_marker, "fmt ", 4);
hdr->data_header_length = 16;
hdr->format_type = 1;
hdr->number_of_channels = channels;
hdr->sample_rate = sample_rate;
hdr->bytes_per_second = sample_rate * channels * bit_depth / 8;
hdr->bytes_per_frame = channels * bit_depth / 8;
hdr->bits_per_sample = bit_depth;
return hdr;
}
int writeWAVHeader(int fd, struct WaveHeader *hdr)
{
if (!hdr)
return -1;
write(fd, &hdr->RIFF_marker, 4);
write(fd, &hdr->file_size, 4);
write(fd, &hdr->filetype_header, 4);
write(fd, &hdr->format_marker, 4);
write(fd, &hdr->data_header_length, 4);
write(fd, &hdr->format_type, 2);
write(fd, &hdr->number_of_channels, 2);
write(fd, &hdr->sample_rate, 4);
write(fd, &hdr->bytes_per_second, 4);
write(fd, &hdr->bytes_per_frame, 2);
write(fd, &hdr->bits_per_sample, 2);
write(fd, "data", 4);
uint32_t data_size = hdr->file_size + 8 - 44;
write(fd, &data_size, 4);
return 0;
}
int recordWAV(const char *fileName, struct WaveHeader *hdr, uint32_t duration)
{
int err;
int size;
snd_pcm_t *handle;
snd_pcm_hw_params_t *params;
unsigned int sampleRate = hdr->sample_rate;
int dir;
snd_pcm_uframes_t frames = 32;
char *device = (char*) "plughw:1,0";
char *buffer;
int filedesc;
printf("Capture device is %sn", device);
/* Open PCM device for recording (capture). */
err = snd_pcm_open(&handle, device, SND_PCM_STREAM_CAPTURE, 0);
if (err)
{
fprintf(stderr, "Unable to open PCM device: %sn", snd_strerror(err));
return err;
}
/* Allocate a hardware parameters object. */
snd_pcm_hw_params_alloca(¶ms);
/* Fill it in with default values. */
snd_pcm_hw_params_any(handle, params);
/* ### Set the desired hardware parameters. ### */
/* Interleaved mode */
err = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
if (err)
{
fprintf(stderr, "Error setting interleaved mode: %sn", snd_strerror(err));
snd_pcm_close(handle);
return err;
}
/* Signed 16-bit little-endian format */
if (hdr->bits_per_sample == 16) err = snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16_LE);
else err = snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_U8);
if (err)
{
fprintf(stderr, "Error setting format: %sn", snd_strerror(err));
snd_pcm_close(handle);
return err;
}
/* Two channels (stereo) */
err = snd_pcm_hw_params_set_channels(handle, params, hdr->number_of_channels);
if (err)
{
fprintf(stderr, "Error setting channels: %sn", snd_strerror(err));
snd_pcm_close(handle);
return err;
}
/* 44100 bits/second sampling rate (CD quality) */
sampleRate = hdr->sample_rate;
err = snd_pcm_hw_params_set_rate_near(handle, params, &sampleRate, &dir);
if (err)
{
fprintf(stderr, "Error setting sampling rate (%d): %sn", sampleRate, snd_strerror(err));
snd_pcm_close(handle);
return err;
}
hdr->sample_rate = sampleRate;
/* Set period size*/
err = snd_pcm_hw_params_set_period_size_near(handle, params, &frames, &dir);
if (err)
{
fprintf(stderr, "Error setting period size: %sn", snd_strerror(err));
snd_pcm_close(handle);
return err;
}
/* Write the parameters to the driver */
err = snd_pcm_hw_params(handle, params);
if (err < 0)
{
fprintf(stderr, "Unable to set HW parameters: %sn", snd_strerror(err));
snd_pcm_close(handle);
return err;
}
/* Use a buffer large enough to hold one period */
err = snd_pcm_hw_params_get_period_size(params, &frames, &dir);
if (err)
{
fprintf(stderr, "Error retrieving period size: %sn", snd_strerror(err));
snd_pcm_close(handle);
return err;
}
size = frames * hdr->bits_per_sample / 8 * hdr->number_of_channels; /* 2 bytes/sample, 2 channels */
buffer = (char *) malloc(size);
if (!buffer)
{
fprintf(stdout, "Buffer error.n");
snd_pcm_close(handle);
return -1;
}
err = snd_pcm_hw_params_get_period_time(params, &sampleRate, &dir);
if (err)
{
fprintf(stderr, "Error retrieving period time: %sn", snd_strerror(err));
snd_pcm_close(handle);
free(buffer);
return err;
}
uint32_t pcm_data_size = hdr->sample_rate * hdr->bytes_per_frame * duration / 1000;
hdr->file_size = pcm_data_size + 44 - 8;
filedesc = open(fileName, O_WRONLY | O_CREAT, 0644);
err = writeWAVHeader(filedesc, hdr);
if (err)
{
fprintf(stderr, "Error writing .wav header.");
snd_pcm_close(handle);
free(buffer);
close(filedesc);
return err;
}
fprintf(stdout, "Channels: %dn", hdr->number_of_channels);
for(int i = duration * 1000 / sampleRate; i > 0; i--)
{
err = snd_pcm_readi(handle, buffer, frames);
if (err == -EPIPE) fprintf(stderr, "Overrun occurred: %dn", err);
if (err) err = snd_pcm_recover(handle, err, 0);
// Still an error, need to exit.
if (err)
{
fprintf(stderr, "Error occured while recording: %sn", snd_strerror(err));
snd_pcm_close(handle);
free(buffer);
close(filedesc);
return err;
}
write(filedesc, buffer, size);
}
close(filedesc);
snd_pcm_drain(handle);
snd_pcm_close(handle);
free(buffer);
printf("Finished writing to %sn", fileName);
return 0;
}
int main(int argc, char *argv[]) {
if(argc != 2)
{
fprintf(stderr, "Usage: %s (record duration)n", argv[0]);
return -1;
}
int err;
struct WaveHeader *hdr;
// Creates a temporary file in /tmp
char wavFile[L_tmpnam + 5];
char *tempFilenameStub = tmpnam(NULL);
sprintf(wavFile, "%s.wav", tempFilenameStub);
hdr = genericWAVHeader(44000, 16, 2);
if (!hdr)
{
fprintf(stderr, "Error allocating WAV header.n");
return -1;
}
err = recordWAV(wavFile, hdr, 1000 * strtod(argv[1], NULL));
if (err)
{
fprintf(stderr, "Error recording WAV file: %dn", err);
return err;
}
free(hdr);
return 0;
}
程序运行时我得到的输出:
$ ./capture 5
Capture device is plughw:1,0
Channels: 2
Error occured while recording: Channel number out of range
Error recording WAV file: -44
有什么建议吗?我一直在想这个有一段时间了。
snd_
*函数返回的错误代码为负数。有一些函数可以返回正值来指示成功(例如,snd_pcm_readi
返回帧数)。
试试这个:
printf("Channels: %dn", hdr->number_of_channels);
for (i = 0; i < 2*16000/128; i++)
{
printf("n Recording %d",i);
err = snd_pcm_readi(handle, buffer, frames);
write(filedesc, buffer, size);
}
相关文章:
- 尝试使用来自 Win32 WASAPI C++的"捕获流"创建 wav 文件
- 如何从wav文件中获取采样率?
- 写入 wav 文件时定期创建静音
- 在不打开应用程序的情况下在MinGW c++中播放声音(.wav)文件
- 如何使用curl c ++源代码发布wav文件数据,如何使用c ++使用--data-binary?
- 为什么 XAudio2 仅在系统暂停时播放.wav文件?
- 处理文件期间输出失真.wav
- webRTC : 如何通过从WAV文件获得的样本将webRTC的VAD应用于音频
- WAV文件停止功能
- 如何从特定点播放.WAV文件(例如30秒)
- 通过C(或C )中的WAV文件循环
- 开放式阅读WAV文件lib
- 使用C++ / Python的wav文件的FFT
- 在mbed中打开的wav文件数量是否有限制
- 音频编程 SDL - 如何使用 wav 文件在命令行中指定频率切割
- 无法使用两种不同的频率填充 *.wav 文件的缓冲区
- 禁用在使用QAudioRecorder时创建wav文件
- 无论如何,我可以从WAV文件中打印Sox即可打印幅度值
- WAV文件的数据在-1和1之间,C ,SNDFILE
- 在黑莓10(原生)上分割音频文件(wav)