diff --git a/flake.lock b/flake.lock
index ddecf2c..c0493d2 100644
--- a/flake.lock
+++ b/flake.lock
@@ -109,16 +109,16 @@
     "mnn-src": {
       "flake": false,
       "locked": {
-        "lastModified": 1749173738,
-        "narHash": "sha256-pNljvQ4xMZ4VmuxQyXt+boNBZD0+UZNpNLrWrj8Rtfw=",
+        "lastModified": 1753256753,
+        "narHash": "sha256-aTpwVZBkpQiwOVVXDfQIVEx9CswNiPbvNftw8KsoW+Q=",
         "owner": "alibaba",
         "repo": "MNN",
-        "rev": "ebdada82634300956e08bd4056ecfeb1e4f23b32",
+        "rev": "a739ea5870a4a45680f0e36ba9662ca39f2f4eec",
         "type": "github"
       },
       "original": {
         "owner": "alibaba",
-        "ref": "3.2.0",
+        "ref": "3.2.2",
         "repo": "MNN",
         "type": "github"
       }
diff --git a/flake.nix b/flake.nix
index ddd2e70..9aae400 100644
--- a/flake.nix
+++ b/flake.nix
@@ -22,7 +22,7 @@
       inputs.nixpkgs.follows = "nixpkgs";
     };
     mnn-src = {
-      url = "github:alibaba/MNN/3.2.0";
+      url = "github:alibaba/MNN/3.2.2";
       flake = false;
     };
   };
diff --git a/models/retinaface.mnn b/models/retinaface.mnn
index 45b7d85..7d702e2 100644
Binary files a/models/retinaface.mnn and b/models/retinaface.mnn differ
diff --git a/src/facedet/retinaface.rs b/src/facedet/retinaface.rs
index 20911b0..7ce7754 100644
--- a/src/facedet/retinaface.rs
+++ b/src/facedet/retinaface.rs
@@ -274,7 +274,7 @@ impl FaceDetection {
 
     pub fn detect_faces(
         &self,
-        image: ndarray::Array3<u8>,
+        image: ndarray::ArrayView3<u8>,
         config: FaceDetectionConfig,
     ) -> Result<FaceDetectionOutput> {
         let (height, width, _channels) = image.dim();
@@ -299,7 +299,8 @@ impl FaceDetection {
             .map(|((b, s), l)| (b, s, l))
             .multiunzip();
 
-        let keep_indices = nms(&boxes, &scores, config.threshold, config.nms_threshold);
+        let keep_indices =
+            nms(&boxes, &scores, config.threshold, config.nms_threshold).change_context(Error)?;
 
         let bboxes = boxes
             .into_iter()
@@ -327,7 +328,7 @@ impl FaceDetection {
         })
     }
 
-    pub fn run_models(&self, image: ndarray::Array3<u8>) -> Result<FaceDetectionModelOutput> {
+    pub fn run_models(&self, image: ndarray::ArrayView3<u8>) -> Result<FaceDetectionModelOutput> {
         #[rustfmt::skip]
         use ::tap::*;
         let output = self
diff --git a/src/faceembed/facenet.rs b/src/faceembed/facenet.rs
index 441a9c3..5dfe4dd 100644
--- a/src/faceembed/facenet.rs
+++ b/src/faceembed/facenet.rs
@@ -1,5 +1,5 @@
 use crate::errors::*;
-use ndarray::{Array1, ArrayView3};
+use ndarray::{Array1, Array2, ArrayView3, ArrayView4};
 use std::path::Path;
 
 #[derive(Debug)]
@@ -36,4 +36,8 @@ impl EmbeddingGenerator {
     pub fn embedding(&self, roi: ArrayView3<u8>) -> Result<Array1<u8>> {
         todo!()
     }
+
+    pub fn embeddings(&self, roi: ArrayView4<u8>) -> Result<Array2<u8>> {
+        todo!()
+    }
 }