M10.4: multithreaded AVIF encoding (ravif threading, speed 8): ~4x faster export

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Cargo.lock

@@ -2239,6 +2239,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8ea1f30cedd69f0a2954655f7188c6a834246d2bcf1e315e2ac40c4b24dc9519"
 dependencies = [
  "cfg-if",
+ "rayon",
 ]
 
 [[package]]
@@ -3261,6 +3262,7 @@ dependencies = [
  "loop9",
  "quick-error 2.0.1",
  "rav1e",
+ "rayon",
  "rgb",
 ]
 

Cargo.toml

@@ -50,7 +50,7 @@ tiff = "0.11"
 image-webp = "0.2"
 moxcms = { version = "0.9", default-features = false, features = ["lut"] }
 jxl-oxide = { version = "0.12", default-features = false }
-ravif = { version = "0.13", default-features = false }
+ravif = { version = "0.13", default-features = false, features = ["threading"] } # no "asm": it needs nasm (non-Rust)
 
 # ui
 egui = "0.36"

crates/engine/src/export.rs

@@ -207,7 +207,7 @@ pub fn encode_image(img: &Rgba8, o: &ExportOptions) -> Result<Vec<u8>, String> {
         ExportFormat::Png => encode::encode_png(&e, &meta),
         ExportFormat::Tiff => encode::encode_tiff(&e, TiffCompression::Deflate, &meta),
         ExportFormat::Webp => encode::encode_webp_lossless(&e, &meta),
-        ExportFormat::Avif => encode::encode_avif(&e, o.quality, 6, &meta),
+        ExportFormat::Avif => encode::encode_avif(&e, o.quality, 8, &meta),
     };
     r.map_err(|e| e.to_string())
 }