add horizontal strip encoding type

encoder/src/dec.rs

@@ -1,9 +1,30 @@
 use crate::*;
 
+pub fn bg_strips_horizontal(_prev_frame: &Frame, encoded: &[u8], reader: &mut usize) -> Frame {
+	*reader += 1;
+	let bg = encoded[0] >> 7;
+	let fg = 1 - bg;
+	let mut frame = [[bg; HEIGHT]; WIDTH];
+	let count = (encoded[0] & 0x7f) as usize;
+	*reader += count * 2;
+	for i in 0..count {
+		let upper = (encoded[i * 2 + 1] as u16) << 8;
+		let lower = encoded[i * 2 + 2] as u16;
+		let y_x_w: u16 = upper | lower;
+		let y = (y_x_w >> 11) as usize;
+		let x_start = ((y_x_w >> 5) & 0x3f) as usize;
+		let w = (y_x_w & 0x1f) as usize;
+		for x in x_start..(x_start + w) {
+			frame[x][y] = fg;
+		}
+	}
+	frame
+}
+
 pub fn rle_diff_horizontal(prev_frame: &Frame, encoded: &[u8], reader: &mut usize) -> Frame {
 	let (runs, decoded) = rle_255_decode_until(encoded, FRAME_SIZE);
 	*reader += runs;
-	let mut frame = prev_frame.clone();
+	let mut frame = *prev_frame;
 	let mut i = 0;
 	for y in 0..HEIGHT {
 		for x in 0..WIDTH {
@@ -17,11 +38,15 @@ pub fn rle_diff_horizontal(prev_frame: &Frame, encoded: &[u8], reader: &mut usiz
 pub fn rle_diff_vertical(prev_frame: &Frame, encoded: &[u8], reader: &mut usize) -> Frame {
 	let (runs, decoded) = rle_255_decode_until(encoded, FRAME_SIZE);
 	*reader += runs;
-	let mut frame = prev_frame.clone();
+	let mut frame = *prev_frame;
+	let mut dbg_frame = FRAME_0;
 	let mut i = 0;
 	for x in 0..WIDTH {
 		for y in 0..HEIGHT {
 			frame[x][y] ^= decoded[i];
+			frame[x][y] &= 1;
+			dbg_frame[x][y] ^= decoded[i];
+			dbg_frame[x][y] &= 1;
 			i += 1;
 		}
 	}

encoder/src/enc.rs

@@ -1,5 +1,58 @@
 use crate::*;
 
+pub fn bg_strips_horizontal(_prev_frame: &Frame, frame: &Frame) -> EncodedFrame {
+	let bg = most_common_pixel(frame);
+	fn pack_strip(x: usize, y: usize, width: usize) -> [u8; 2] {
+		// Y is 0..31 so will only need 5 bits
+		// x is 0..42 so needs 6 bits
+		// 5 bits remain for width
+		// y: 1111100000000000
+		let mut y_x_w: u16 = (y as u16) << 11;
+		// x: 0000011111100000
+		y_x_w |= (x as u16) << 5;
+		// w: 0000000000011111
+		y_x_w |= width as u16;
+		[(y_x_w >> 8) as u8, (y_x_w as u8)]
+	}
+
+	let mut strips = Vec::new();
+	'outer: for y in 0..HEIGHT {
+		let mut strip_start = 0;
+		let mut in_strip = false;
+		for x in 0..WIDTH {
+			let pixel = frame[x][y];
+			if !in_strip && pixel != bg {
+				in_strip = true;
+				strip_start = x;
+			}
+			if in_strip {
+				if pixel == bg {
+					strips.push((strip_start, y, x - strip_start));
+					in_strip = false;
+				} else if x - strip_start == 31 {
+					strips.push((strip_start, y, x - strip_start));
+					strip_start = x;
+				}
+				if strips.len() == 127 {
+					break 'outer;
+				}
+			}
+		}
+		if in_strip {
+			strips.push((strip_start, y, WIDTH - strip_start));
+		}
+	}
+	let mut frame_bytes = Vec::with_capacity(1 + strips.len() * 2);
+	frame_bytes.push(bg << 7 | (strips.len() as u8));
+	for (x, y, width) in strips {
+		frame_bytes.extend_from_slice(&pack_strip(x, y, width));
+	}
+	EncodedFrame {
+		encoding: Encoding::BGStripsH,
+		data: frame_bytes,
+	}
+}
+
 pub fn rle_diff_horizontal(prev_frame: &Frame, frame: &Frame) -> EncodedFrame {
 	let mut pixels = Vec::new();
 	for y in 0..HEIGHT {

encoder/src/main.rs

@@ -7,7 +7,7 @@ mod util;
 pub use util::*;
 
 const INSPECT_ENC: bool = false;
-const INSPECT_DEC: bool = true;
+const INSPECT_DEC: bool = false;
 
 fn main() {
 	let frames = get_all_frames("../video/frames/");
@@ -25,7 +25,10 @@ fn main() {
 		let decoder = get_matching_decoder(frame_type);
 		last_frame = decoder(&last_frame, &encoded[reader..], &mut reader);
 		if INSPECT_DEC {
-			println!("\n{frame_type:?}");
+			println!(
+				"\n{frame_type:?}, error: {}",
+				frame_error(&frames[frame_index], &last_frame)
+			);
 			render_images(&frames[frame_index], &last_frame);
 			wait_for_input();
 			frame_index += 1;
@@ -52,11 +55,12 @@ fn encode(frames: &[Frame]) -> Vec<u8> {
 		enc::rle_vertical,
 		enc::rle_diff_horizontal,
 		enc::rle_diff_vertical,
+		enc::bg_strips_horizontal,
 	];
 	let max_error = 0;
 
 	let mut last_frame = FRAME_0;
-	for frame in frames {
+	for (i, frame) in frames.iter().enumerate() {
 		let mut options = Vec::new();
 		for encode in &encodings {
 			let encoded = encode(&last_frame, frame);
@@ -65,6 +69,11 @@ fn encode(frames: &[Frame]) -> Vec<u8> {
 			let error = frame_error(frame, &decoded);
 			if error <= max_error {
 				options.push(encoded);
+			} else {
+				// dbg!(&encoded);
+				// println!("{:?}, error: {error}, frame: {i}", encoded.encoding);
+				// render_images(&frame, &decoded);
+				// panic!("loss in compression");
 			}
 		}
 		options.sort_by_key(|b| b.data.len());
@@ -81,7 +90,7 @@ fn encode(frames: &[Frame]) -> Vec<u8> {
 		}
 		let best_encoding = best_encoding.into_bytes();
 		out.extend_from_slice(&best_encoding);
-		last_frame = frame.clone();
+		last_frame = *frame;
 	}
 	out
 }
@@ -96,15 +105,15 @@ enum Encoding {
 	RLEDiffHorizontal,
 	RLEDiffVertical,
 	BGStripsH,
-	BGStripsV,
-	QuadTree,
-	DrawCommands,
-	CellDiff8H,
-	CellDiff8V,
-	CellDiff4HH,
-	CellDiff4HV,
-	CellDiff4VH,
-	CellDiff4VV,
+	// BGStripsV,
+	// QuadTree,
+	// DrawCommands,
+	// CellDiff8H,
+	// CellDiff8V,
+	// CellDiff4HH,
+	// CellDiff4HV,
+	// CellDiff4VH,
+	// CellDiff4VV,
 }
 
 fn get_matching_decoder(encoding: Encoding) -> FrameDecoder {
@@ -115,22 +124,23 @@ fn get_matching_decoder(encoding: Encoding) -> FrameDecoder {
 		Encoding::RLEVertical => dec::rle_vertical,
 		Encoding::RLEDiffHorizontal => dec::rle_diff_horizontal,
 		Encoding::RLEDiffVertical => dec::rle_diff_vertical,
-		Encoding::BGStripsH => todo!(),
-		Encoding::BGStripsV => todo!(),
-		Encoding::QuadTree => todo!(),
-		Encoding::DrawCommands => todo!(),
-		Encoding::CellDiff8H => todo!(),
-		Encoding::CellDiff8V => todo!(),
-		Encoding::CellDiff4HH => todo!(),
-		Encoding::CellDiff4HV => todo!(),
-		Encoding::CellDiff4VH => todo!(),
-		Encoding::CellDiff4VV => todo!(),
+		Encoding::BGStripsH => dec::bg_strips_horizontal,
+		// Encoding::BGStripsV => todo!(),
+		// Encoding::QuadTree => todo!(),
+		// Encoding::DrawCommands => todo!(),
+		// Encoding::CellDiff8H => todo!(),
+		// Encoding::CellDiff8V => todo!(),
+		// Encoding::CellDiff4HH => todo!(),
+		// Encoding::CellDiff4HV => todo!(),
+		// Encoding::CellDiff4VH => todo!(),
+		// Encoding::CellDiff4VV => todo!(),
 	}
 }
 
 type FrameEncoder = fn(previous_frame: &Frame, new_frame: &Frame) -> EncodedFrame;
 type FrameDecoder = fn(previous_frame: &Frame, encoded_bytes: &[u8], reader: &mut usize) -> Frame;
 
+#[derive(Debug)]
 struct EncodedFrame {
 	encoding: Encoding,
 	data: Vec<u8>,

encoder/src/util.rs

@@ -1,6 +1,6 @@
 use std::{
 	fs::{self, File},
-	io::BufReader,
+	io::{stdin, BufReader},
 };
 
 use image::{self, DynamicImage, GenericImageView, ImageFormat, Rgba};
@@ -14,7 +14,7 @@ pub const FRAME_0: Frame = [[0; HEIGHT]; WIDTH];
 pub const FRAME_1: Frame = [[1; HEIGHT]; WIDTH];
 
 pub fn wait_for_input() {
-	std::io::stdin().read_line(&mut String::new()).unwrap();
+	stdin().read_line(&mut String::new()).unwrap();
 }
 
 fn convert_pixel(rgba: Rgba<u8>) -> u8 {
@@ -55,6 +55,23 @@ pub fn frame_error(real: &Frame, decoded: &Frame) -> usize {
 	error
 }
 
+pub fn most_common_pixel(frame: &Frame) -> u8 {
+	let mut white_pixels = 0;
+	let mut black_pixels = 0;
+	for col in frame {
+		for &p in col {
+			let p = p as u32;
+			white_pixels += p;
+			black_pixels += 1 - p;
+		}
+	}
+	if white_pixels > black_pixels {
+		1
+	} else {
+		0
+	}
+}
+
 fn render_pixel_pair(img: &Frame, x: usize, y: usize) {
 	let char = match (img[x][y * 2], img[x][y * 2 + 1]) {
 		(0, 0) => " ",
@@ -77,14 +94,15 @@ pub fn render_image(img: &Frame) {
 
 pub fn render_images(left: &Frame, right: &Frame) {
 	for y in 0..(HEIGHT / 2) {
+		print!("|");
 		for x in 0..WIDTH {
 			render_pixel_pair(left, x, y);
 		}
-		print!("   ");
+		print!("|");
 		for x in 0..WIDTH {
 			render_pixel_pair(right, x, y);
 		}
-		println!();
+		println!("|");
 	}
 }
 
@@ -95,7 +113,7 @@ pub fn rle_255_encode(raw: &[u8]) -> Vec<u8> {
 	for &val in raw {
 		if val != last_val || run == 255 {
 			encoded.push(run);
-			if run == 255 {
+			if run == 255 && val == last_val {
 				encoded.push(0);
 			}
 			run = 1;