add maybe-rayon and "threading" feature

Cargo.toml

@@ -45,7 +45,7 @@ log = { version = "0.4.28" }
 num-rational = { version = "0.4.2", default-features = false }
 num-traits = "0.2.19"
 pastey = "0.2.1"
-rayon = "1.11.0"
+rayon = { package = "maybe-rayon", version = "0.1", default-features = false }
 serde = { version = "1.0.228", features = ["derive"], optional = true }
 serde_json = { version = "1.0.145", optional = true }
 thiserror = "2.0.17"
@@ -64,7 +64,7 @@ cc = { version = "1.2.47", features = ["parallel"], optional = true }
 nasm-rs = { version = "0.3.1", features = ["parallel"], optional = true }
 
 [features]
-default = ["asm", "binary"]
+default = ["asm", "binary", "threading"]
 # Enable platform-specific SIMD for enhanced performance
 asm = ["cc", "libc", "nasm-rs"]
 # Statically compile only the SIMD for the targeted CPU (e.g. only AVX512 for znver4)
@@ -80,6 +80,8 @@ serialize = ["serde", "serde_json"]
 tracing = ["dep:tracing", "tracing-perfetto", "tracing-subscriber"]
 bench-internals = []
 vapoursynth = ["av-decoders/vapoursynth"]
+# Disabling this will remove `rayon` from the dependency tree
+threading = ["rayon/threads"]
 
 [lints.clippy]
 # Correctness/Safety

README.md

@@ -106,7 +106,7 @@ cd av-scenechange
 cargo build --release
 
 # Build without assembly optimizations (no NASM required)
-cargo build --release --no-default-features --features binary
+cargo build --release --no-default-features --features binary,threading
 
 # Build with additional features
 cargo build --release --features ffmpeg  # FFmpeg input support

src/analyze/inter.rs

@@ -6,7 +6,9 @@ use std::{
 use aligned::{A64, Aligned};
 use arrayvec::ArrayVec;
 use num_rational::Rational32;
-use rayon::iter::{IntoParallelIterator, ParallelIterator};
+use rayon::iter::IntoParallelIterator;
+#[cfg(feature = "threading")]
+use rayon::iter::ParallelIterator;
 use v_frame::{
     chroma::ChromaSubsampling,
     frame::Frame,