aftersol / simplified-qoi-codec

An QOI codec that doesn't requires any other dependencies

Simplified QOI Codec Library

A one header file library for encoding and decoding QOI files.

Features

• A much simpler and abstracted code
• No 400MB limit found in reference QOI implementation
• No extra memory allocation while running this codec¹
• Programmed in freestanding C useful in embedded systems

How to Install Library

Place the qoi.h file into your project folder preferably in your project's include folder

Define the following below before you include qoi.h library in one of your source code file

#define  SIMPLIFIED_QOI_IMPLEMENTATION
#include "sQOI.h"

Minimal implementation

Encoder

/* 	
	Assume you open the file and
	allocated enough memory for the encoder
	before this code
*/

qoi_desc_t desc;
qoi_enc_t enc;
uint8_t* pixel_seek;

qoi_desc_init(&desc);
qoi_set_dimensions(&desc, width, height);
qoi_set_channels(&desc, channels);
qoi_set_colorspace(&desc, colorspace);

write_qoi_header(&desc, qoi_file);  

pixel_seek = file_buffer;
qoi_enc_init(&desc, &enc, qoi_file);

while(!qoi_enc_done(&enc))
{
	qoi_encode_chunk(&desc, &enc, pixel_seek);
	pixel_seek += desc.channels;
}

/* 
	Write the QOI file after encoding
	or do something else after encoding
*/

Decoder

/* After reading a QOI file and placed in buffer */

qoi_desc_t desc;
qoi_dec_t dec;
qoi_pixel_t px;

uint8_t *bytes;
size_t rawImageLength, seek;

qoi_desc_init(&desc);

if (!read_qoi_header(&desc, qoi_bytes))
{
	printf("The file you opened is not a QOIF file\n");
	return;
}

raw_image_length = (size_t)desc.width * (size_t)desc.height * (size_t)desc.channels;

seek = 0;
if (raw_image_length == 0)
	return;

qoi_dec_init(&desc, &dec, qoi_bytes, buffer_size);
/* Creates a blank image for the decoder to work on */
bytes = (unsigned char*)malloc(raw_image_length * sizeof(unsigned char) + 4);

if (!bytes)
	return;

/* Keep decoding the pixels until
all pixels are done decompressing */
while (!qoi_dec_done(&dec))
{
	px = qoi_decode_chunk(&dec);
	/* Do something with the pixel values below */
	bytes[seek] = px.red;
	bytes[seek + 1] = px.green;
	bytes[seek + 2] = px.blue;
	
	if (desc.channels > 3) 
		bytes[seek + 3] = px.alpha;
	
	seek += desc.channels;
}

/* Use the pixels however you want after this code */

How to Run Example Programs

Encoder

qoi_enc <input file> <width> <height> <channels> <colorspace> <output file>

Input file must be raw RGB or RGBA file

Decoder

This program only outputs raw RGB or RGBA files depending on the amount of channels in a QOI file

qoi_dec <input file> <output file>

Software Requirements

• C99 compiler or C++ compiler
• CMake 3.1

References

Thank you to the authors of the source code being used for inspiration for this source code

Official QOI References

• QOI Reference Implementation (phoboslab)
• QOI Specification

Other QOI Programs

• Mini-QOI (sharaiwi) (decoder only)
• QOI Explained (YouTube: Reducible)
• floooh's QOI Viewer
• FFmpeg
  • Encoder
  • Decoder

Footnotes

1. You must provide a pointer to an existing array to run this codec ↩

simplified-qoi-codec's Issues

Error in byte swapping

Hi,

While checking your code, I have found that sQOI.h#L198 is shifting value twice with >> 24:

((value >> 24) & 0xFF | (value << 8) & 0xFF0000 | (value >> 8) & 0xFF00 | (value >> 24) & 0xFF000000);

The last bit shifting should be << 24 instead. Finally, for clarity reasons, it would be great if the 2nd and 3rd expressions between | were swapped. This would be like the following:

((value >> 24) & 0xFF | (value >> 8) & 0xFF00 | (value << 8) & 0xFF0000 | (value << 24) & 0xFF000000);

Licensing

Is this code provided with a license? I was unable to locate one in the repo.