3 files changed, 54 insertions, 0 deletions
diff --git a/evc/src/codec/decode.rs b/evc/src/codec/decode.rs
new file mode 100644
index 0000000..9dc6a69
--- /dev/null
+++ b/evc/src/codec/decode.rs
@@ -0,0 +1,18 @@
+use crate::{
+    block::{Block, BlockInner},
+    frame::Frame,
+    view::View,
+};
+
+pub fn decode_block(block: &Block, mut target: View<&mut Frame>, prev: View<&Frame>) {
+    match &block.inner {
+        BlockInner::Literal(pixels) => target.set_pixels(pixels),
+        BlockInner::Split(box [a, b]) => {
+            let [at, bt] = target.split_mut_unsafe();
+            let [ap, bp] = prev.split();
+            decode_block(a, at, ap);
+            decode_block(b, bt, bp);
+        }
+        BlockInner::Reference { translation: _ } => target.copy_from(&prev),
+    }
+}
diff --git a/evc/src/codec/encode.rs b/evc/src/codec/encode.rs
new file mode 100644
index 0000000..cf407fa
--- /dev/null
+++ b/evc/src/codec/encode.rs
@@ -0,0 +1,34 @@
+use crate::{
+    block::{Block, BlockInner},
+    frame::Frame,
+    view::View,
+};
+
+pub fn encode_block(view: View<&Frame>, prev: View<&Frame>) -> Block {
+    let diff = View::diff(&view, &prev) / view.area() as f64;
+    // eprintln!("{:?} {diff}", view.size);
+    let inner = if diff < 0.9 {
+        BlockInner::Reference {
+            translation: (0, 0),
+        }
+    } else {
+        if view.size.0 < 32 {
+            BlockInner::Literal(view.pixels())
+        } else {
+            let [av, bv] = view.split();
+            let [ap, bp] = prev.split();
+            let a = encode_block(av, ap);
+            let b = encode_block(bv, bp);
+            if a.is_literal() && b.is_literal() {
+                BlockInner::Literal(view.pixels())
+            } else {
+                BlockInner::Split(Box::new([a, b]))
+            }
+        }
+    };
+
+    Block {
+        size: view.size,
+        inner,
+    }
+}
diff --git a/evc/src/codec/mod.rs b/evc/src/codec/mod.rs
new file mode 100644
index 0000000..1c80d24
--- /dev/null
+++ b/evc/src/codec/mod.rs
@@ -0,0 +1,2 @@
+pub mod decode;
+pub mod encode;