diff --git a/Cargo.lock b/Cargo.lock
index 04d8328..ae820e8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4,12 +4,30 @@
 name = "adaptivegrain-rs"
 version = "0.2.2"
 dependencies = [
+ "criterion",
  "failure",
  "lazy_static",
  "vapoursynth",
  "vapoursynth-sys",
 ]
 
+[[package]]
+name = "atty"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
+dependencies = [
+ "hermit-abi",
+ "libc",
+ "winapi",
+]
+
+[[package]]
+name = "autocfg"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8aac770f1885fd7e387acedd76065302551364496e46b3dd00860b2f8359b9d"
+
 [[package]]
 name = "backtrace"
 version = "0.3.46"
@@ -38,6 +56,39 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 
+[[package]]
+name = "bstr"
+version = "0.2.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "31accafdb70df7871592c058eca3985b71104e15ac32f64706022c58867da931"
+dependencies = [
+ "lazy_static",
+ "memchr",
+ "regex-automata",
+ "serde",
+]
+
+[[package]]
+name = "bumpalo"
+version = "3.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5356f1d23ee24a1f785a56d1d1a5f0fd5b0f6a0c0fb2412ce11da71649ab78f6"
+
+[[package]]
+name = "byteorder"
+version = "1.3.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08c48aae112d48ed9f069b33538ea9e3e90aa263cfa3d1c24309612b1f7472de"
+
+[[package]]
+name = "cast"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b9434b9a5aa1450faa3f9cb14ea0e8c53bb5d2b3c1bfd1ab4fc03e9f33fbfb0"
+dependencies = [
+ "rustc_version",
+]
+
 [[package]]
 name = "cc"
 version = "1.0.50"
@@ -50,6 +101,127 @@ version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 
+[[package]]
+name = "clap"
+version = "2.33.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bdfa80d47f954d53a35a64987ca1422f495b8d6483c0fe9f7117b36c2a792129"
+dependencies = [
+ "bitflags",
+ "textwrap",
+ "unicode-width",
+]
+
+[[package]]
+name = "criterion"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "63f696897c88b57f4ffe3c69d8e1a0613c7d0e6c4833363c8560fbde9c47b966"
+dependencies = [
+ "atty",
+ "cast",
+ "clap",
+ "criterion-plot",
+ "csv",
+ "itertools",
+ "lazy_static",
+ "num-traits",
+ "oorandom",
+ "plotters",
+ "rayon",
+ "regex",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "tinytemplate",
+ "walkdir",
+]
+
+[[package]]
+name = "criterion-plot"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddeaf7989f00f2e1d871a26a110f3ed713632feac17f65f03ca938c542618b60"
+dependencies = [
+ "cast",
+ "itertools",
+]
+
+[[package]]
+name = "crossbeam-deque"
+version = "0.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9f02af974daeee82218205558e51ec8768b48cf524bd01d550abe5573a608285"
+dependencies = [
+ "crossbeam-epoch",
+ "crossbeam-utils",
+ "maybe-uninit",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "058ed274caafc1f60c4997b5fc07bf7dc7cca454af7c6e81edffe5f33f70dace"
+dependencies = [
+ "autocfg",
+ "cfg-if",
+ "crossbeam-utils",
+ "lazy_static",
+ "maybe-uninit",
+ "memoffset",
+ "scopeguard",
+]
+
+[[package]]
+name = "crossbeam-queue"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c695eeca1e7173472a32221542ae469b3e9aac3a4fc81f7696bcad82029493db"
+dependencies = [
+ "cfg-if",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.7.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c3c7c73a2d1e9fc0886a08b93e98eb643461230d5f1925e4036204d5f2e261a8"
+dependencies = [
+ "autocfg",
+ "cfg-if",
+ "lazy_static",
+]
+
+[[package]]
+name = "csv"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "00affe7f6ab566df61b4be3ce8cf16bc2576bca0963ceb0955e45d514bf9a279"
+dependencies = [
+ "bstr",
+ "csv-core",
+ "itoa",
+ "ryu",
+ "serde",
+]
+
+[[package]]
+name = "csv-core"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2b2466559f260f48ad25fe6317b3c8dac77b5bdb5763ac7d9d6103530663bc90"
+dependencies = [
+ "memchr",
+]
+
+[[package]]
+name = "either"
+version = "1.5.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bb1f6b1ce1c140482ea30ddd3335fc0024ac7ee112895426e0a629a6c20adfe3"
+
 [[package]]
 name = "failure"
 version = "0.1.7"
@@ -72,6 +244,39 @@ dependencies = [
  "synstructure",
 ]
 
+[[package]]
+name = "hermit-abi"
+version = "0.1.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "91780f809e750b0a89f5544be56617ff6b1227ee485bcb06ebe10cdf89bd3b71"
+dependencies = [
+ "libc",
+]
+
+[[package]]
+name = "itertools"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "284f18f85651fe11e8a991b2adb42cb078325c996ed026d994719efcfca1d54b"
+dependencies = [
+ "either",
+]
+
+[[package]]
+name = "itoa"
+version = "0.4.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b8b7a7c0c47db5545ed3fef7468ee7bb5b74691498139e4b3f6a20685dc6dd8e"
+
+[[package]]
+name = "js-sys"
+version = "0.3.39"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fa5a448de267e7358beaf4a5d849518fe9a0c13fce7afd44b06e68550e5562a7"
+dependencies = [
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -84,6 +289,73 @@ version = "0.2.68"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dea0c0405123bba743ee3f91f49b1c7cfb684eef0da0a50110f758ccf24cdff0"
 
+[[package]]
+name = "log"
+version = "0.4.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "14b6052be84e6b71ab17edffc2eeabf5c2c3ae1fdb464aae35ac50c67a44e1f7"
+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
+name = "maybe-uninit"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "60302e4db3a61da70c0cb7991976248362f30319e88850c487b9b95bbf059e00"
+
+[[package]]
+name = "memchr"
+version = "2.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3728d817d99e5ac407411fa471ff9800a778d88a24685968b36824eaf4bee400"
+
+[[package]]
+name = "memoffset"
+version = "0.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b4fc2c02a7e374099d4ee95a193111f72d2110197fe200272371758f6c3643d8"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
+name = "num-traits"
+version = "0.2.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c62be47e61d1842b9170f0fdeec8eba98e60e90e5446449a0545e5152acd7096"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
+name = "num_cpus"
+version = "1.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05499f3756671c15885fee9034446956fff3f243d6077b91e5767df161f766b3"
+dependencies = [
+ "hermit-abi",
+ "libc",
+]
+
+[[package]]
+name = "oorandom"
+version = "11.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94af325bc33c7f60191be4e2c984d48aaa21e2854f473b85398344b60c9b6358"
+
+[[package]]
+name = "plotters"
+version = "0.2.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f9b1d9ca091d370ea3a78d5619145d1b59426ab0c9eedbad2514a4cee08bf389"
+dependencies = [
+ "js-sys",
+ "num-traits",
+ "wasm-bindgen",
+ "web-sys",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.10"
@@ -102,12 +374,133 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rayon"
+version = "1.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "db6ce3297f9c85e16621bb8cca38a06779ffc31bb8184e1be4bed2be4678a098"
+dependencies = [
+ "crossbeam-deque",
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08a89b46efaf957e52b18062fb2f4660f8b8a4dde1807ca002690868ef2c85a9"
+dependencies = [
+ "crossbeam-deque",
+ "crossbeam-queue",
+ "crossbeam-utils",
+ "lazy_static",
+ "num_cpus",
+]
+
+[[package]]
+name = "regex"
+version = "1.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a6020f034922e3194c711b82a627453881bc4682166cabb07134a10c26ba7692"
+dependencies = [
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae1ded71d66a4a97f5e961fd0cb25a5f366a42a41570d16a763a69c092c26ae4"
+dependencies = [
+ "byteorder",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.6.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7fe5bd57d1d7414c6b5ed48563a2c855d995ff777729dcd91c369ec7fea395ae"
+
 [[package]]
 name = "rustc-demangle"
 version = "0.1.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4c691c0e608126e00913e33f0ccf3727d5fc84573623b8d65b2df340b5201783"
 
+[[package]]
+name = "rustc_version"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
+dependencies = [
+ "semver",
+]
+
+[[package]]
+name = "ryu"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed3d612bc64430efeb3f7ee6ef26d590dce0c43249217bddc62112540c7941e1"
+
+[[package]]
+name = "same-file"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "93fc1dc3aaa9bfed95e02e6eadabb4baf7e3078b0bd1b4d7b6b0b68378900502"
+dependencies = [
+ "winapi-util",
+]
+
+[[package]]
+name = "scopeguard"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
+
+[[package]]
+name = "semver"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
+dependencies = [
+ "semver-parser",
+]
+
+[[package]]
+name = "semver-parser"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
+
+[[package]]
+name = "serde"
+version = "1.0.110"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "99e7b308464d16b56eba9964e4972a3eee817760ab60d88c3f86e1fecb08204c"
+
+[[package]]
+name = "serde_derive"
+version = "1.0.110"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "818fbf6bfa9a42d3bfcaca148547aa00c7b915bec71d1757aa2d44ca68771984"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "serde_json"
+version = "1.0.53"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "993948e75b189211a9b31a7528f950c6adc21f9720b6438ff80a7fa2f864cea2"
+dependencies = [
+ "itoa",
+ "ryu",
+ "serde",
+]
+
 [[package]]
 name = "syn"
 version = "1.0.17"
@@ -131,6 +524,31 @@ dependencies = [
  "unicode-xid",
 ]
 
+[[package]]
+name = "textwrap"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d326610f408c7a4eb6f51c37c330e496b08506c9457c9d34287ecc38809fb060"
+dependencies = [
+ "unicode-width",
+]
+
+[[package]]
+name = "tinytemplate"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "45e4bc5ac99433e0dcb8b9f309dd271a165ae37dde129b9e0ce1bfdd8bfe4891"
+dependencies = [
+ "serde",
+ "serde_json",
+]
+
+[[package]]
+name = "unicode-width"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "caaa9d531767d1ff2150b9332433f32a24622147e5ebb1f26409d5da67afd479"
+
 [[package]]
 name = "unicode-xid"
 version = "0.2.0"
@@ -158,3 +576,109 @@ checksum = "c5ad7879f2893d1574b128d26e65aedf38c3c01ac3af1c7d09cc6bc4c5148b87"
 dependencies = [
  "cfg-if",
 ]
+
+[[package]]
+name = "walkdir"
+version = "2.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "777182bc735b6424e1a57516d35ed72cb8019d85c8c9bf536dccb3445c1a2f7d"
+dependencies = [
+ "same-file",
+ "winapi",
+ "winapi-util",
+]
+
+[[package]]
+name = "wasm-bindgen"
+version = "0.2.62"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e3c7d40d09cdbf0f4895ae58cf57d92e1e57a9dd8ed2e8390514b54a47cc5551"
+dependencies = [
+ "cfg-if",
+ "wasm-bindgen-macro",
+]
+
+[[package]]
+name = "wasm-bindgen-backend"
+version = "0.2.62"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c3972e137ebf830900db522d6c8fd74d1900dcfc733462e9a12e942b00b4ac94"
+dependencies = [
+ "bumpalo",
+ "lazy_static",
+ "log",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-macro"
+version = "0.2.62"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2cd85aa2c579e8892442954685f0d801f9129de24fa2136b2c6a539c76b65776"
+dependencies = [
+ "quote",
+ "wasm-bindgen-macro-support",
+]
+
+[[package]]
+name = "wasm-bindgen-macro-support"
+version = "0.2.62"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8eb197bd3a47553334907ffd2f16507b4f4f01bbec3ac921a7719e0decdfe72a"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+ "wasm-bindgen-backend",
+ "wasm-bindgen-shared",
+]
+
+[[package]]
+name = "wasm-bindgen-shared"
+version = "0.2.62"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a91c2916119c17a8e316507afaaa2dd94b47646048014bbdf6bef098c1bb58ad"
+
+[[package]]
+name = "web-sys"
+version = "0.3.39"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8bc359e5dd3b46cb9687a051d50a2fdd228e4ba7cf6fcf861a5365c3d671a642"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
+[[package]]
+name = "winapi"
+version = "0.3.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8093091eeb260906a183e6ae1abdba2ef5ef2257a21801128899c3fc699229c6"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-util"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
+dependencies = [
+ "winapi",
+]
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
diff --git a/Cargo.toml b/Cargo.toml
index 3257aad..1a37bb3 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,5 +11,11 @@ vapoursynth = "0.3.0"
 vapoursynth-sys = "0.3.0"
 
 [lib]
-crate-type = ["cdylib"]
+crate-type = ["cdylib", "rlib"]
 
+[dev-dependencies]
+criterion = "0.3"
+
+[[bench]]
+name = "mask"
+harness = false
diff --git a/benches/mask.rs b/benches/mask.rs
new file mode 100644
index 0000000..96f648d
--- /dev/null
+++ b/benches/mask.rs
@@ -0,0 +1,18 @@
+use adaptivegrain_rs::mask::*;
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+
+fn mask_value(c: &mut Criterion) {
+    black_box(FLOAT_RANGE.iter().count());
+    let ls = black_box(10.0);
+    let y = black_box(0.412323);
+    c.bench_function("mask value y=0.412", |b| {
+        b.iter(|| {
+            FLOAT_RANGE.iter().for_each(|&x| {
+                black_box(get_mask_value(black_box(x), y, ls));
+            });
+        })
+    });
+}
+
+criterion_group!(mask, mask_value);
+criterion_main!(mask);
diff --git a/src/lib.rs b/src/lib.rs
index 2854a04..d565328 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -5,7 +5,7 @@ extern crate lazy_static;
 #[macro_use]
 extern crate vapoursynth;
 
-mod mask;
+pub mod mask;
 
 use self::mask::Mask;
 use failure::Error;
diff --git a/src/mask.rs b/src/mask.rs
index 2b8f2a0..64fa395 100644
--- a/src/mask.rs
+++ b/src/mask.rs
@@ -17,7 +17,7 @@ lazy_static! {
 }
 
 #[inline]
-fn get_mask_value(x: f32, y: f32, luma_scaling: f32) -> f32 {
+pub fn get_mask_value(x: f32, y: f32, luma_scaling: f32) -> f32 {
     f32::powf(
         1.0 - (x
             * (x.mul_add(