how to fill the "data field" of wavfile - c++

Question

Hi i am trying to record from a board and i have successfully record 4 seconds. Problem is when i try to record for more time, i got an error telling me that there not enough memory. my target is to record a 5 minutes file. Until now i have create a buffer named snIn[256] where are the samples. i send it to a big buffer of [16K * 4sec] and when it is full, i create the wav file.
#include "SAI_InOut.hpp"
#include "F746_GUI.hpp"
#include "Delay.hpp"
#include "WaveformDisplay.hpp"
#include "SDFileSystem.h"
#include "wavfile.h"
using namespace Mikami;
#define RES_STR_SIZE 0x20
#define WAVFILE_SAMPLES_PER_SECOND 16000
#define REC_TIME 4
//Create an SDFileSystem object
SDFileSystem sd("sd");
bool flag = 1;
int count = 0;
char *res_buf;
int rp = 0;
const int NUM_SAMPLES = WAVFILE_SAMPLES_PER_SECOND * REC_TIME;
Array<int16_t> my_buffer(NUM_SAMPLES);
int j = 0;
static const char *target_filename = "/sd/rectest.wav";
const int SEG_SIZE = 256;
int sent_array = 0;
int rec(const char *filename, Array<int16_t> my_buffer)
{
j = 0;
flag = 0;
sent_array = 0;
WavFileResult result;
wavfile_info_t info;
wavfile_data_t data;
WAVFILE_INFO_AUDIO_FORMAT(&info) = 1;
WAVFILE_INFO_NUM_CHANNELS(&info) = 1;
WAVFILE_INFO_SAMPLE_RATE(&info) = WAVFILE_SAMPLES_PER_SECOND;
WAVFILE_INFO_BITS_PER_SAMPLE(&info) = 16;
WAVFILE_INFO_BYTE_RATE(&info) = WAVFILE_INFO_NUM_CHANNELS(&info) * WAVFILE_INFO_SAMPLE_RATE(&info) * (WAVFILE_INFO_BITS_PER_SAMPLE(&info) / 8);
WAVFILE_INFO_BLOCK_ALIGN(&info) = 2;
WAVFILE *wf = wavfile_open(filename, WavFileModeWrite, &result);
if (result != WavFileResultOK) {
wavfile_result_string(result, res_buf, RES_STR_SIZE);
printf("%s", res_buf);
return result;
} else printf ("Open file success \r\n");
rp = 0;
WAVFILE_DATA_NUM_CHANNELS(&data) = 1;
result = wavfile_write_info(wf, &info);
if (result != WavFileResultOK) {
wavfile_result_string(result, res_buf, RES_STR_SIZE);
printf("%s", res_buf);
return result; } else printf ("Write info success \r\n");
while ( rp < NUM_SAMPLES ) {
WAVFILE_DATA_CHANNEL_DATA(&data, 0) = my_buffer[rp];
result = wavfile_write_data(wf, &data);
rp += 1;
}
if (result != WavFileResultOK) {
wavfile_result_string(result, res_buf, RES_STR_SIZE);
printf("%s", res_buf);
return result; } else printf ("Write Data file success \r\n");
result = wavfile_close(wf);
if (result != WavFileResultOK) {
wavfile_result_string(result, res_buf , RES_STR_SIZE);
printf("%s", res_buf);
return result; } else printf ("Close file success \r\n");
//UnMount the filesystem
sd.unmount();
printf("Success rec !\r\n");
return 0;
}
int main()
{
//Mount the filesystem
sd.mount();
const float MAX_DELAY = 0.5f; // 最大遅延，単位：秒
const int FS = I2S_AUDIOFREQ_16K; // 標本化周波数: 16 kHz
const uint32_t MAX_ARRAY_SIZE = (uint32_t)(MAX_DELAY*FS);
SaiIO mySai(SaiIO::BOTH, 256, FS, INPUT_DEVICE_DIGITAL_MICROPHONE_2);
Label myLabel(185, 10, "Delay System", Label::CENTER, Font16);
// ButtonGroup: "ON", "OFF"
const uint16_t BG_LEFT = 370;
const uint16_t BG_WIDTH = 100;
const uint16_t BG_HEIGHT = 45;
ButtonGroup onOff(BG_LEFT, 40, BG_WIDTH/2, BG_HEIGHT,
2, (string[]){"ON", "OFF"}, 0, 0, 2, 1);
const uint16_t SB_LEFT = BG_LEFT - 320;
const uint16_t SB_WIDTH = 270;
const uint16_t SB_Y0 = 240;
char str[20];
sprintf(str, " %3.1f [s]", MAX_DELAY);
SeekBar barDelay(SB_LEFT, SB_Y0, SB_WIDTH,
0, MAX_ARRAY_SIZE, 0, "0", "", str);
NumericLabel<float> labelDelay(SB_LEFT+SB_WIDTH/2, SB_Y0-40, "DELEY: %4.2f", 0, Label::CENTER);
DelaySystem delaySystem(MAX_ARRAY_SIZE);
WaveformDisplay displayIn(*GuiBase::GetLcdPtr(), SB_LEFT+7, 70, 256, 9,LCD_COLOR_WHITE, LCD_COLOR_CYAN,GuiBase::ENUM_BACK);
Label inLabel(SB_LEFT-30, 65, "IN");
WaveformDisplay displayOut(*GuiBase::GetLcdPtr(), SB_LEFT+7, 130, 256, 9,LCD_COLOR_WHITE, LCD_COLOR_CYAN,GuiBase::ENUM_BACK);
Label outLabel(SB_LEFT-30, 125, "OUT");
int runStop = 1;
Array<int16_t> snIn(mySai.GetLength());
Array<int16_t> snOut(mySai.GetLength());
mySai.RecordIn();
mySai.PlayOut();
mySai.PauseOut();
while (true)
{
// On/OFF
int num;
if (onOff.GetTouchedNumber(num))
if (runStop != num)
{
if (num == 0) mySai.ResumeOut();
else mySai.PauseOut();
runStop = num;
}
if (mySai.IsCompleted())
{
for (int n=0; n<mySai.GetLength() ; n++)
{
int16_t xL, xR;
mySai.Input(xL,xR);
int16_t xn = xL + xR;
snIn[n] = xn;
my_buffer[j] = xn;
j++;
if (j == NUM_SAMPLES && flag == 1) {
rec (target_filename , my_buffer); }
int16_t yn = delaySystem.Execute(xn);
mySai.Output(yn, yn);
snOut[n] = yn;
}
mySai.Reset();
displayIn.Execute(snIn);
}
}
}
I thought about a possible solution, to fill directly the "data field" of the wavefile with the snIn[256] buffer (instead of using my_buffer) again and again and at the end close the wavfile. Please let me know what you think about that and other solutions

Answer 1

things to note: 1) while a write operation is being performed, more data is still coming in.
At the very least I would double buffer that data, so can be writing one buffer while the other one fills.
Usually this means using an interrupt to collect the samples (into which ever buffer is currently being filed.)
the foreground program waits for the current buffer to be 'full', then initiates write operation.,
then waits again for a buffer to be 'full'
The interrupt function tracks which buffer is being filled and the current index into that buffer. When a buffer is full, set a 'global' status to let the foreground program know which buffer is ready to be written.
The foreground program writes the buffer, then resets the status for that buffer.