diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index d0a5d10064..01dfd230d3 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        rust: ["1.61.0", stable, beta, nightly]
+        rust: ["1.64.0", stable, beta, nightly]
         features: [gif, jpeg, png, tiff, ico, pnm, tga, webp, bmp, hdr, dxt, dds, farbfeld, openexr, jpeg_rayon, webp-encoder, '']
     steps:
     - uses: actions/checkout@v2
diff --git a/Cargo.toml b/Cargo.toml
index 8fe4622cae..dd4e9d0a2e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,7 +5,7 @@ edition = "2018"
 resolver = "2"
 
 # note: when changed, also update test runner in `.github/workflows/rust.yml`
-rust-version = "1.61.0"
+rust-version = "1.64.0"
 
 license = "MIT"
 description = "Imaging library written in Rust. Provides basic filters and decoders for the most common image formats."
diff --git a/src/codecs/jpeg/encoder.rs b/src/codecs/jpeg/encoder.rs
index 82c582fb57..9dc5bb2c09 100644
--- a/src/codecs/jpeg/encoder.rs
+++ b/src/codecs/jpeg/encoder.rs
@@ -763,7 +763,7 @@ fn build_quantization_segment(m: &mut Vec<u8>, precision: u8, identifier: u8, qt
 fn encode_coefficient(coefficient: i32) -> (u8, u16) {
     // since this is inlined, in the main AC case the compiler figures out that coefficient cannot be zero, so BSR on x86 doesn't need a branch
     if let Some(nz) = NonZeroI32::new(coefficient) {
-        let leading_zeros = nz.abs().leading_zeros() as u8;
+        let leading_zeros = nz.unsigned_abs().leading_zeros() as u8;
 
         // first shift right signed by 31 to make everything 1 if negative,
         // then shift right unsigned to make the leading bits 0