Audio to ASCII conversion program for 12-pwmsound #567

ABelliqueux · 2025-05-06T12:52:37Z

ABelliqueux
May 6, 2025

Hi,

The sample 12-pwmsound readme mentions a 'little program' to convert raw audio to ASCII :

You can provide 16 bit Stereo sound on your own (e.g. by exporting it as 16 bit signed raw data without header from Audacity and converting it into ASCII with a little program).

Does anyone know what/where this program is ?

Would https://github.com/rzavalet/wav2ascii work ?

Answered by rsta2

May 6, 2025

This small program should do it:

#include <stdio.h> 

int main (void)
{
	FILE *fin = fopen ("sound.raw", "rb");
	if (fin == NULL)
	{
		return 1;
	}

	unsigned offset = 0;
	short value;
	while (fread (&value, sizeof value, 1, fin) == 1)
	{
		printf ("%d", (int) value);

		if (offset++ % 24 == 23)
		{
			printf (",\n");
		}
		else
		{
			printf (",");
		}
	}

	fclose (fin);

	return 0;
}

It expects the 16-bit signed audio samples in the file sound.raw (without header) and writes them to stdout. You must prepare a header file from this, like shown in the sample's README.

View full answer

rsta2 · 2025-05-06T15:38:51Z

rsta2
May 6, 2025
Maintainer

This small program should do it:

#include <stdio.h> 

int main (void)
{
	FILE *fin = fopen ("sound.raw", "rb");
	if (fin == NULL)
	{
		return 1;
	}

	unsigned offset = 0;
	short value;
	while (fread (&value, sizeof value, 1, fin) == 1)
	{
		printf ("%d", (int) value);

		if (offset++ % 24 == 23)
		{
			printf (",\n");
		}
		else
		{
			printf (",");
		}
	}

	fclose (fin);

	return 0;
}

It expects the 16-bit signed audio samples in the file sound.raw (without header) and writes them to stdout. You must prepare a header file from this, like shown in the sample's README.

7 replies

ABelliqueux May 7, 2025
Author

Ok, will do. I'm testing with various audio settings right now, and it works fine with 16 bit signed raw data without header, as mentionned in the readme, but if I try to export audio from Audacity as mono 8bit signed raw data without header (as in your sample code), the sound is distorted/wrong (and I still have to signed short instead of unsigned chars for Sound[] ).

If I try to export it as mono 8bit unsigned raw data, I get signed values.

Here are partial sample outputs :

8bit Signed Mono Raw No-Header :

signed short Sound[] =		  
{
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,-256,-1,-1,-1,255,0,0,0,0,0,0,0,-1,-1,-1,-1,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
255,0,-256,-1,-1,-1,-1,-1,-1,-1,0,0,0,0,0,0,-256,-1,0,0,0,0,0,0,
0,0,0,0,0,0,0,0,0,-256,-1,-1,-1,-1,-1,-1,-256,-1,-1,-1,-1,0,0,0,
0,0,0,0,0,0,0,-256,255,-256,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,255,
0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,-256,-1,-1,-1,-1,-1,
-1,255,0,0,0,0,0,0,-1,-1,-1,-1,-1,-1,-1,-256,255,-1,-1,-1,-1,-1,-1,255,
0,0,0,0,0,0,0,0,-256,-1,-1,-1,-1,0,0,0,0,0,0,0,257,257,257,514,
514,514,257,0,-1,-258,-515,-772,-772,-772,-772,-772,-1029,-1286,-1799,-2057,-2314,-2571,-2571,-2315,-1801,-1287,-1029,-516,
-515,-515,-771,-1028,-1542,-1800,-2314,-2827,-3341,-4111,-4626,-5396,-5910,-6425,-6426,-6683,-6170,-5400,-4629,-3857,-3343,-2828,-2828,-2828,
-2828,-2572,-1802,-775,510,1796,3338,4367,5139,5140,4114,3086,1545,516,-512,-771,-772,-772,-259,-1,-1,-1,-258,-771,
[...]

8bit Unsigned Mono Raw No-Header :

// should be unsigned char ?
signed short Sound[] =
{
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,32640,32639,32639,32639,-32641,-32640,-32640,-32640,-32640,-32640,-32640,-32640,32639,32639,32639,32639,
-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,-32640,32639,32639,32639,32639,32639,32639,32639,32639,32639,32639,
-32641,-32640,32640,32639,32639,32639,32639,32639,32639,32639,-32640,-32640,-32640,-32640,-32640,-32640,32640,32639,-32640,-32640,-32640,-32640,-32640,-32640,
[...]

Any clue as to what's going on ?

rsta2 May 7, 2025
Maintainer

Yes, the given small program is for 16-bit signed samples only.

ABelliqueux May 7, 2025
Author

Allright, I was able to get it to work with your clue 😉

I used unsigned char instead of short for value, and cast it as a short instead of an int after that.

ABelliqueux May 8, 2025
Author

Ok, PR is here #570 but it added a bunch of commits I did not wan to submit 🤔
I suspect it's because I did not use the develop branch.
Should I close this PR and re-submit from the develop branch ?

rsta2 May 8, 2025
Maintainer

I merged it already. Yes, one has to branch of from develop to suppress these commits.

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Audio to ASCII conversion program for 12-pwmsound #567

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Audio to ASCII conversion program for 12-pwmsound #567

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ABelliqueux May 6, 2025

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rsta2 May 6, 2025 Maintainer

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