psiroki

Fairly Decent Image Codec — Encoding Specification

This document defines the Fairly Decent Image Codec which aims to be byte‑aligned and simple to encode or decode (sacrificing a bit of compression).
All opcodes are one full byte, and additional payload bytes follow as specified.

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1. Overview

TODO: file header.

psiroki

// avrdude ... -U lfuse:w:0x6a:m
// 1.2 MHz (9.6 MHz oscillator divided by 8)
// Brown-out detection at 2.7 V (I guess the blue leds wouldn't work anyway)
#define F_CPU 1200000UL
#define MCU attiny13
#include <avr/io.h>
#include <avr/pgmspace.h>

void turnAllOff() {
	PORTB = 0;

psiroki

#include <math.h>

#define SWAP(a,b) tempr=(a);(a)=(b);(b)=tempr

/*
 * Discrete Fast Fourier Transform based on the algorithm in
 * Numerical Recipes in C, slighly modified by removing the
 * insane 1 based array access.
 *
 * Takes the data pointer which contains nn pairs of doubles,