21 changed files with 611 additions and 750 deletions
--- a/.dockerignore
+++ b/.dockerignore
@ -1,7 +1,4 @@
+scripts
+.github
 .editorconfig
-.gitignore
-/.git/
-/.github/
-/.pre-commit-hooks.yaml
-/scripts/
-/target/
+.pre-commit-hooks.yaml
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@ -3,12 +3,7 @@ name: deploy
 on:
  push:
    tags:
-      - v*.*.*
-
-concurrency:
-  # If we ever end up with two concurrent jobs for releasing the same tag, the former should be cancelled
-  group: release-${{ github.ref }}
-  cancel-in-progress: true
+      - "v*.*.*"

 permissions:
  actions: read
@ -59,15 +54,15 @@ jobs:

      - name: Get the Oxipng version
        id: oxipngMeta
-        run: >
-          echo "version=$(cargo metadata --format-version 1 --no-deps |
-          jq -r '.packages[] | select(.name == "oxipng").version')" >> "$GITHUB_OUTPUT"
+        run:
+          echo "version=$(cargo metadata --format-version 1 --no-deps | jq -r '.packages[] | select(.name == "oxipng").version')"
+          >> "$GITHUB_OUTPUT"

      - name: Retrieve ${{ matrix.target }} binary
-        uses: dawidd6/action-download-artifact@v21
+        uses: dawidd6/action-download-artifact@v11
        with:
          workflow: oxipng.yml
-          commit: ${{ github.sha }}
+          commit: ${{ env.GITHUB_SHA }}
          name: Oxipng binary (${{ matrix.target }})
          path: target

@ -128,7 +123,7 @@ jobs:
        run: tail -n +3 CHANGELOG.md | sed -e '/^$/,$d' > RELEASE_NOTES.txt

      - name: Create release
-        uses: softprops/action-gh-release@v3
+        uses: softprops/action-gh-release@v2
        with:
          name: v${{ steps.oxipngMeta.outputs.version }}
          body_path: RELEASE_NOTES.txt
--- a/.github/workflows/docker.yml
+++ b/.github/workflows/docker.yml
@ -2,9 +2,9 @@ name: docker
 on:
  push:
    branches:
-      - master
+      - 'master'
    tags:
-      - v*.*.*
+      - 'v*.*.*'
  pull_request:
    types:
      - opened
@ -17,44 +17,76 @@ on:
        type: boolean
        default: true

-concurrency:
-  # If we ever end up with two concurrent Docker build jobs for the same commit
-  # and same versioning context, the former should be cancelled
-  group: docker-${{ github.sha }}-${{ github.ref_type }}-${{ github.head_ref }}
-  cancel-in-progress: true
+env:
+  REGISTRY: ghcr.io
+  # ghcr.io/OWNER/REPO
+  IMAGE_NAME: ${{ github.repository }}

 jobs:
  build:
-    uses: docker/github-builder/.github/workflows/build.yml@v1
+    runs-on: ubuntu-latest
    permissions:
      contents: read
      packages: write
      id-token: write
      attestations: write
-    with:
-      output: image
-      platforms: linux/amd64,linux/arm64
-      push: ${{ github.event_name != 'pull_request' }}
-      cache: ${{ github.event_name != 'workflow_dispatch' || inputs.use_cache }}
-      # We don't sign the image because ghcr.io doesn't support OCI Referrers API yet, and the fallback relies on pushing new tags on each build
-      # https://github.com/docker/github-builder/issues/109#issuecomment-3885082486
-      # https://github.com/opencontainers/distribution-spec/blob/v1.1.0/spec.md#backwards-compatibility
-      sign: false
-      sbom: true
-      meta-images: ghcr.io/${{ github.repository }}
-      meta-tags: |
-        type=ref,event=branch
-        type=ref,event=pr
-        type=semver,pattern={{raw}}
-      set-meta-annotations: true
-      set-meta-labels: true
-      labels: |
-        org.opencontainers.image.title=Oxipng
-      annotations: |
-        org.opencontainers.image.title=Oxipng

-    secrets:
-      registry-auths: |
-        - registry: ghcr.io
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v3
+
+      # Workaround: https://github.com/docker/build-push-action/issues/461
+      - name: Setup Docker buildx
+        uses: docker/setup-buildx-action@v3
+
+      # Login against a Docker registry except on PR
+      # https://github.com/docker/login-action
+      - name: Log into registry ${{ env.REGISTRY }}
+        if: github.event_name != 'pull_request'
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
          username: ${{ github.actor }}
          password: ${{ secrets.GITHUB_TOKEN }}
+
+      # Extract metadata (tags, labels) for Docker
+      # For some reason the title have to be set manually
+      # https://github.com/docker/metadata-action
+      - name: Extract Docker metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          labels: |
+            org.opencontainers.image.title=Oxipng
+          annotations: |
+            org.opencontainers.image.title=Oxipng
+
+      # Build and push Docker image with Buildx (don't push on PR)
+      # Cache isn't used for tags and on workflow_dispatch if specified
+      # https://github.com/docker/build-push-action
+      - name: Build and push Docker image
+        id: build-and-push
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          no-cache: ${{ (github.event_name == 'workflow_dispatch' && !inputs.use_cache) || startsWith(github.ref, 'refs/tags/') }}
+
+      # Attest the build provenance
+      # TODO: enable push to registry when referrers API will be supported by ghcr.io
+      - name: Attest Build Provenance
+        if: github.event_name != 'pull_request'
+        uses: actions/attest-build-provenance@v3
+        with:
+          subject-name: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          subject-digest: ${{ steps.build-and-push.outputs.digest }}
+          push-to-registry: false
--- a/.github/workflows/oxipng.yml
+++ b/.github/workflows/oxipng.yml
@ -8,11 +8,6 @@ on:
      - synchronize
  workflow_dispatch:

-concurrency:
-  # If we ever end up with two concurrent CI jobs for the same commit, the former should be cancelled
-  group: ci-${{ github.sha }}
-  cancel-in-progress: true
-
 jobs:
  ci:
    name: CI
@ -60,6 +55,7 @@ jobs:

    env:
      CARGO_BUILD_TARGET: ${{ matrix.target }}
+      RUSTFLAGS: '-Zlocation-detail=none'

    steps:
      - name: Checkout source
@ -78,7 +74,7 @@ jobs:
        with:
          toolchain: nightly
          target: ${{ env.CARGO_BUILD_TARGET }}
-          components: clippy, rustfmt, rust-src
+          components: clippy, rustfmt
          cache-bin: false
          cache-shared-key: cache

@ -129,12 +125,10 @@ jobs:
        run: cargo doc --release --no-deps

      - name: Build CLI binary
-        run: cargo build --release -Zbuild-std
-        env:
-          RUSTFLAGS: "-Zlocation-detail=none -Zunstable-options -Cpanic=immediate-abort"
+        run: cargo build --release

      - name: Upload CLI binary as artifact
-        uses: actions/upload-artifact@v7
+        uses: actions/upload-artifact@v5
        with:
          name: Oxipng binary (${{ matrix.target }})
          path: |
--- a/.gitignore
+++ b/.gitignore
@ -1,6 +1,6 @@
-.DS_Store
+target
 *.bk
+.DS_Store
 *.out.png
-/.idea/
-/node_modules/
-/target/
+/.idea
+/node_modules
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -1,21 +1,7 @@
-## Version 10.1.1
-
- [Performance] Improve Bigrams performance, giving notably faster results at lower levels.
- [Improvement] Change `--np` flag to also prevent conversion to indexed from other color types.
- [Improvement] Improve support for recompressing ICC profiles with high compression ratios.
- [Misc] Add warning when `--ziwi` exceeds `--zi`.
- [Build] Further reduce size of binaries.
-
-## Version 10.1.0
-
- [Feature] Add `--json` option for machine-readable output.
- [Improvement] New default output with file counter and summary. (Use an extra `-v` flag to get the same output as before.)
- [Bugfix] Fix fast mode sometimes giving suboptimal results for small, indexed images.
-
 ## Version 10.0.0

 - [Breaking] CLI: Change short zopfli flag from `-Z` to `-z`.
- [Breaking] CLI: Change `--pretend`/`-P` to `--dry-run`/`-d`.
+- [Breaking] CLI: Change `--pretend`/`-P` to `--dry-run`/`-D`.
 - [Breaking] CLI: Change `--interlace` options from `1`/`0` to `on`/`off`.
 - [Breaking] API: Change `Options.interlace: Option<Interlacing>` to `Options.interlace: Option<bool>`.
 - [Breaking] API: Change `Options.filter: IndexSet<RowFilter>` to `Options.filters: IndexSet<FilterStrategy>`.
--- a/Cargo.lock
+++ b/Cargo.lock
@ -10,9 +10,9 @@ checksum = "320119579fcad9c21884f5c4861d16174d0e06250625266f50fe6898340abefa"

 [[package]]
 name = "anstream"
-version = "1.0.0"
+version = "0.6.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "824a212faf96e9acacdbd09febd34438f8f711fb84e09a8916013cd7815ca28d"
+checksum = "3ae563653d1938f79b1ab1b5e668c87c76a9930414574a6583a7b7e11a8e6192"
 dependencies = [
 "anstyle",
 "anstyle-parse",
@ -25,37 +25,37 @@ dependencies = [

 [[package]]
 name = "anstyle"
-version = "1.0.14"
+version = "1.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "940b3a0ca603d1eade50a4846a2afffd5ef57a9feac2c0e2ec2e14f9ead76000"
+checksum = "862ed96ca487e809f1c8e5a8447f6ee2cf102f846893800b20cebdf541fc6bbd"

 [[package]]
 name = "anstyle-parse"
-version = "1.0.0"
+version = "0.2.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "52ce7f38b242319f7cabaa6813055467063ecdc9d355bbb4ce0c68908cd8130e"
+checksum = "4e7644824f0aa2c7b9384579234ef10eb7efb6a0deb83f9630a49594dd9c15c2"
 dependencies = [
 "utf8parse",
 ]

 [[package]]
 name = "anstyle-query"
-version = "1.1.5"
+version = "1.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "40c48f72fd53cd289104fc64099abca73db4166ad86ea0b4341abe65af83dadc"
+checksum = "9e231f6134f61b71076a3eab506c379d4f36122f2af15a9ff04415ea4c3339e2"
 dependencies = [
- "windows-sys",
+ "windows-sys 0.60.2",
 ]

 [[package]]
 name = "anstyle-wincon"
-version = "3.0.11"
+version = "3.0.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "291e6a250ff86cd4a820112fb8898808a366d8f9f58ce16d1f538353ad55747d"
+checksum = "3e0633414522a32ffaac8ac6cc8f748e090c5717661fddeea04219e2344f5f2a"
 dependencies = [
 "anstyle",
 "once_cell_polyfill",
- "windows-sys",
+ "windows-sys 0.60.2",
 ]

 [[package]]
@ -66,9 +66,9 @@ checksum = "c08606f8c3cbf4ce6ec8e28fb0014a2c086708fe954eaa885384a6165172e7e8"

 [[package]]
 name = "bitflags"
-version = "2.11.1"
+version = "2.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c4512299f36f043ab09a583e57bceb5a5aab7a73db1805848e8fef3c9e8c78b3"
+checksum = "2261d10cca569e4643e526d8dc2e62e433cc8aba21ab764233731f8d369bf394"

 [[package]]
 name = "bitvec"
@ -84,15 +84,15 @@ dependencies = [

 [[package]]
 name = "bumpalo"
-version = "3.20.2"
+version = "3.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5d20789868f4b01b2f2caec9f5c4e0213b41e3e5702a50157d699ae31ced2fcb"
+checksum = "46c5e41b57b8bba42a04676d81cb89e9ee8e859a1a66f80a5a72e1cb76b34d43"

 [[package]]
 name = "bytemuck"
-version = "1.25.0"
+version = "1.23.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c8efb64bd706a16a1bdde310ae86b351e4d21550d98d056f22f8a7f7a2183fec"
+checksum = "3995eaeebcdf32f91f980d360f78732ddc061097ab4e39991ae7a6ace9194677"

 [[package]]
 name = "byteorder-lite"
@ -102,9 +102,9 @@ checksum = "8f1fe948ff07f4bd06c30984e69f5b4899c516a3ef74f34df92a2df2ab535495"

 [[package]]
 name = "cc"
-version = "1.2.60"
+version = "1.2.38"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "43c5703da9466b66a946814e1adf53ea2c90f10063b86290cc9eb67ce3478a20"
+checksum = "80f41ae168f955c12fb8960b057d70d0ca153fb83182b57d86380443527be7e9"
 dependencies = [
 "find-msvc-tools",
 "shlex",
@ -112,24 +112,24 @@ dependencies = [

 [[package]]
 name = "cfg-if"
-version = "1.0.4"
+version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
+checksum = "2fd1289c04a9ea8cb22300a459a72a385d7c73d3259e2ed7dcb2af674838cfa9"

 [[package]]
 name = "clap"
-version = "4.6.1"
+version = "4.5.53"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1ddb117e43bbf7dacf0a4190fef4d345b9bad68dfc649cb349e7d17d28428e51"
+checksum = "c9e340e012a1bf4935f5282ed1436d1489548e8f72308207ea5df0e23d2d03f8"
 dependencies = [
 "clap_builder",
 ]

 [[package]]
 name = "clap_builder"
-version = "4.6.0"
+version = "4.5.53"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "714a53001bf66416adb0e2ef5ac857140e7dc3a0c48fb28b2f10762fc4b5069f"
+checksum = "d76b5d13eaa18c901fd2f7fca939fefe3a0727a953561fefdf3b2922b8569d00"
 dependencies = [
 "anstream",
 "anstyle",
@ -140,15 +140,15 @@ dependencies = [

 [[package]]
 name = "clap_lex"
-version = "1.1.0"
+version = "0.7.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c8d4a3bb8b1e0c1050499d1815f5ab16d04f0959b233085fb31653fbfc9d98f9"
+checksum = "b94f61472cee1439c0b966b47e3aca9ae07e45d070759512cd390ea2bebc6675"

 [[package]]
 name = "colorchoice"
-version = "1.0.5"
+version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1d07550c9036bf2ae0c684c4297d503f838287c83c53686d05370d0e139ae570"
+checksum = "b05b61dc5112cbb17e4b6cd61790d9845d13888356391624cbe7e41efeac1e75"

 [[package]]
 name = "crc32fast"
@ -159,6 +159,15 @@ dependencies = [
 "cfg-if",
 ]

+[[package]]
+name = "crossbeam-channel"
+version = "0.5.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "82b8f8f868b36967f9606790d1903570de9ceaf870a7bf9fbbd3016d636a2cb2"
+dependencies = [
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "crossbeam-deque"
 version = "0.8.6"
@ -192,18 +201,18 @@ checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"

 [[package]]
 name = "env_filter"
-version = "1.0.1"
+version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "32e90c2accc4b07a8456ea0debdc2e7587bdd890680d71173a15d4ae604f6eef"
+checksum = "186e05a59d4c50738528153b83b0b0194d3a29507dfec16eccd4b342903397d0"
 dependencies = [
 "log",
 ]

 [[package]]
 name = "env_logger"
-version = "0.11.10"
+version = "0.11.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0621c04f2196ac3f488dd583365b9c09be011a4ab8b9f37248ffcc8f6198b56a"
+checksum = "13c863f0904021b108aa8b2f55046443e6b1ebde8fd4a15c399893aae4fa069f"
 dependencies = [
 "anstream",
 "anstyle",
@ -224,7 +233,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "39cab71617ae0d63f51a36d69f866391735b51691dbda63cf6f96d042b63efeb"
 dependencies = [
 "libc",
- "windows-sys",
+ "windows-sys 0.61.0",
 ]

 [[package]]
@ -237,16 +246,28 @@ dependencies = [
 ]

 [[package]]
-name = "find-msvc-tools"
-version = "0.1.9"
+name = "filetime"
+version = "0.2.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5baebc0774151f905a1a2cc41989300b1e6fbb29aff0ceffa1064fdd3088d582"
+checksum = "bc0505cd1b6fa6580283f6bdf70a73fcf4aba1184038c90902b92b3dd0df63ed"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "libredox",
+ "windows-sys 0.60.2",
+]
+
+[[package]]
+name = "find-msvc-tools"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ced73b1dacfc750a6db6c0a0c3a3853c8b41997e2e2c563dc90804ae6867959"

 [[package]]
 name = "flate2"
-version = "1.1.9"
+version = "1.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "843fba2746e448b37e26a819579957415c8cef339bf08564fe8b7ddbd959573c"
+checksum = "4a3d7db9596fecd151c5f638c0ee5d5bd487b6e0ea232e5dc96d5250f6f94b1d"
 dependencies = [
 "crc32fast",
 "miniz_oxide",
@ -266,9 +287,9 @@ checksum = "0cc23270f6e1808e30a928bdc84dea0b9b4136a8bc82338574f23baf47bbd280"

 [[package]]
 name = "hashbrown"
-version = "0.17.0"
+version = "0.16.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4f467dd6dccf739c208452f8014c75c18bb8301b050ad1cfb27153803edb0f51"
+checksum = "841d1cc9bed7f9236f321df977030373f4a4163ae1a7dbfe1a51a2c1a51d9100"

 [[package]]
 name = "image"
@ -285,9 +306,9 @@ dependencies = [

 [[package]]
 name = "indexmap"
-version = "2.14.0"
+version = "2.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d466e9454f08e4a911e14806c24e16fba1b4c121d1ea474396f396069cf949d9"
+checksum = "0ad4bb2b565bca0645f4d68c5c9af97fba094e9791da685bf83cb5f3ce74acf2"
 dependencies = [
 "equivalent",
 "hashbrown",
@ -296,27 +317,21 @@ dependencies = [

 [[package]]
 name = "is_terminal_polyfill"
-version = "1.70.2"
+version = "1.70.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a6cb138bb79a146c1bd460005623e142ef0181e3d0219cb493e02f7d08a35695"
-
-[[package]]
-name = "itoa"
-version = "1.0.18"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8f42a60cbdf9a97f5d2305f08a87dc4e09308d1276d28c869c684d7777685682"
+checksum = "7943c866cc5cd64cbc25b2e01621d07fa8eb2a1a23160ee81ce38704e97b8ecf"

 [[package]]
 name = "libc"
-version = "0.2.185"
+version = "0.2.175"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "52ff2c0fe9bc6cb6b14a0592c2ff4fa9ceb83eea9db979b0487cd054946a2b8f"
+checksum = "6a82ae493e598baaea5209805c49bbf2ea7de956d50d7da0da1164f9c6d28543"

 [[package]]
 name = "libdeflate-sys"
-version = "1.25.2"
+version = "1.25.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "72753e0008ea87963d2f0770042d0df7abe51fafbb8dcaf618ac440f2f1fec0a"
+checksum = "23bd6304ebf75390d8a99b88bdf2a266f62647838140cb64af8e6702f6e3fddc"
 dependencies = [
 "cc",
 "pkg-config",
@ -324,30 +339,35 @@ dependencies = [

 [[package]]
 name = "libdeflater"
-version = "1.25.2"
+version = "1.25.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d1ee41cf6fb1bb6030dfb59ffb7bc01ab26aade44142084c87f0fc7a1658fe71"
+checksum = "d5d4880e6d634d3d029d65fa016038e788cc728a17b782684726fb34ee140caf"
 dependencies = [
 "libdeflate-sys",
 ]

 [[package]]
-name = "linux-raw-sys"
-version = "0.12.1"
+name = "libredox"
+version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "32a66949e030da00e8c7d4434b251670a91556f4144941d37452769c25d58a53"
+checksum = "416f7e718bdb06000964960ffa43b4335ad4012ae8b99060261aa4a8088d5ccb"
+dependencies = [
+ "bitflags",
+ "libc",
+ "redox_syscall",
+]
+
+[[package]]
+name = "linux-raw-sys"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "df1d3c3b53da64cf5760482273a98e575c651a67eec7f77df96b5b642de8f039"

 [[package]]
 name = "log"
-version = "0.4.30"
+version = "0.4.28"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "616ec5685824bcc94416c6d4a7a446eea774a31efd7062c8480ba6fd06d7a6e5"
-
-[[package]]
-name = "memchr"
-version = "2.8.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f8ca58f447f06ed17d5fc4043ce1b10dd205e060fb3ce5b979b8ed8e59ff3f79"
+checksum = "34080505efa8e45a4b816c349525ebe327ceaa8559756f0356cba97ef3bf7432"

 [[package]]
 name = "miniz_oxide"
@ -361,9 +381,9 @@ dependencies = [

 [[package]]
 name = "moxcms"
-version = "0.7.11"
+version = "0.7.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ac9557c559cd6fc9867e122e20d2cbefc9ca29d80d027a8e39310920ed2f0a97"
+checksum = "ddd32fa8935aeadb8a8a6b6b351e40225570a37c43de67690383d87ef170cd08"
 dependencies = [
 "num-traits",
 "pxfm",
@ -380,17 +400,19 @@ dependencies = [

 [[package]]
 name = "once_cell_polyfill"
-version = "1.70.2"
+version = "1.70.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "384b8ab6d37215f3c5301a95a4accb5d64aa607f1fcb26a11b5303878451b4fe"
+checksum = "a4895175b425cb1f87721b59f0f286c2092bd4af812243672510e1ac53e2e0ad"

 [[package]]
 name = "oxipng"
-version = "10.1.1"
+version = "10.0.0"
 dependencies = [
 "bitvec",
 "clap",
+ "crossbeam-channel",
 "env_logger",
+ "filetime",
 "glob",
 "image",
 "indexmap",
@ -400,7 +422,6 @@ dependencies = [
 "rayon",
 "rgb",
 "rustc-hash",
- "serde_json",
 "zopfli",
 ]

@ -412,15 +433,15 @@ checksum = "487f2ccd1e17ce8c1bfab3a65c89525af41cfad4c8659021a1e9a2aacd73b89b"

 [[package]]
 name = "pkg-config"
-version = "0.3.33"
+version = "0.3.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "19f132c84eca552bf34cab8ec81f1c1dcc229b811638f9d283dceabe58c5569e"
+checksum = "7edddbd0b52d732b21ad9a5fab5c704c14cd949e5e9a1ec5929a24fded1b904c"

 [[package]]
 name = "png"
-version = "0.18.1"
+version = "0.18.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "60769b8b31b2a9f263dae2776c37b1b28ae246943cf719eb6946a1db05128a61"
+checksum = "97baced388464909d42d89643fe4361939af9b7ce7a31ee32a168f832a70f2a0"
 dependencies = [
 "bitflags",
 "crc32fast",
@ -429,28 +450,13 @@ dependencies = [
 "miniz_oxide",
 ]

-[[package]]
-name = "proc-macro2"
-version = "1.0.106"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8fd00f0bb2e90d81d1044c2b32617f68fcb9fa3bb7640c23e9c748e53fb30934"
-dependencies = [
- "unicode-ident",
-]
-
 [[package]]
 name = "pxfm"
-version = "0.1.29"
+version = "0.1.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e0c5ccf5294c6ccd63a74f1565028353830a9c2f5eb0c682c355c471726a6e3f"
-
-[[package]]
-name = "quote"
-version = "1.0.45"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "41f2619966050689382d2b44f664f4bc593e129785a36d6ee376ddf37259b924"
+checksum = "83f9b339b02259ada5c0f4a389b7fb472f933aa17ce176fd2ad98f28bb401fde"
 dependencies = [
- "proc-macro2",
+ "num-traits",
 ]

 [[package]]
@ -461,9 +467,9 @@ checksum = "dc33ff2d4973d518d823d61aa239014831e521c75da58e3df4840d3f47749d09"

 [[package]]
 name = "rayon"
-version = "1.12.0"
+version = "1.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fb39b166781f92d482534ef4b4b1b2568f42613b53e5b6c160e24cfbfa30926d"
+checksum = "368f01d005bf8fd9b1206fb6fa653e6c4a81ceb1466406b81792d87c5677a58f"
 dependencies = [
 "either",
 "rayon-core",
@ -480,73 +486,40 @@ dependencies = [
 ]

 [[package]]
-name = "rgb"
-version = "0.8.53"
+name = "redox_syscall"
+version = "0.5.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "47b34b781b31e5d73e9fbc8689c70551fd1ade9a19e3e28cfec8580a79290cc4"
+checksum = "5407465600fb0548f1442edf71dd20683c6ed326200ace4b1ef0763521bb3b77"
+dependencies = [
+ "bitflags",
+]
+
+[[package]]
+name = "rgb"
+version = "0.8.52"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0c6a884d2998352bb4daf0183589aec883f16a6da1f4dde84d8e2e9a5409a1ce"
 dependencies = [
 "bytemuck",
 ]

 [[package]]
 name = "rustc-hash"
-version = "2.1.2"
+version = "2.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "94300abf3f1ae2e2b8ffb7b58043de3d399c73fa6f4b73826402a5c457614dbe"
+checksum = "357703d41365b4b27c590e3ed91eabb1b663f07c4c084095e60cbed4362dff0d"

 [[package]]
 name = "rustix"
-version = "1.1.4"
+version = "1.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b6fe4565b9518b83ef4f91bb47ce29620ca828bd32cb7e408f0062e9930ba190"
+checksum = "cd15f8a2c5551a84d56efdc1cd049089e409ac19a3072d5037a17fd70719ff3e"
 dependencies = [
 "bitflags",
 "errno",
 "libc",
 "linux-raw-sys",
- "windows-sys",
-]
-
-[[package]]
-name = "serde"
-version = "1.0.228"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9a8e94ea7f378bd32cbbd37198a4a91436180c5bb472411e48b5ec2e2124ae9e"
-dependencies = [
- "serde_core",
-]
-
-[[package]]
-name = "serde_core"
-version = "1.0.228"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "41d385c7d4ca58e59fc732af25c3983b67ac852c1a25000afe1175de458b67ad"
-dependencies = [
- "serde_derive",
-]
-
-[[package]]
-name = "serde_derive"
-version = "1.0.228"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d540f220d3187173da220f885ab66608367b6574e925011a9353e4badda91d79"
-dependencies = [
- "proc-macro2",
- "quote",
- "syn",
-]
-
-[[package]]
-name = "serde_json"
-version = "1.0.150"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e8014e44b4736ed0538adeecded0fce2a272f22dc9578a7eb6b2d9993c74cfb9"
-dependencies = [
- "itoa",
- "memchr",
- "serde",
- "serde_core",
- "zmij",
+ "windows-sys 0.61.0",
 ]

 [[package]]
@ -557,9 +530,9 @@ checksum = "0fda2ff0d084019ba4d7c6f371c95d8fd75ce3524c3cb8fb653a3023f6323e64"

 [[package]]
 name = "simd-adler32"
-version = "0.3.9"
+version = "0.3.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "703d5c7ef118737c72f1af64ad2f6f8c5e1921f818cdcb97b8fe6fc69bf66214"
+checksum = "d66dc143e6b11c1eddc06d5c423cfc97062865baf299914ab64caa38182078fe"

 [[package]]
 name = "strsim"
@ -567,17 +540,6 @@ version = "0.11.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"

-[[package]]
-name = "syn"
-version = "2.0.117"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e665b8803e7b1d2a727f4023456bbbbe74da67099c585258af0ad9c5013b9b99"
-dependencies = [
- "proc-macro2",
- "quote",
- "unicode-ident",
-]
-
 [[package]]
 name = "tap"
 version = "1.0.1"
@ -586,20 +548,14 @@ checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"

 [[package]]
 name = "terminal_size"
-version = "0.4.4"
+version = "0.4.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "230a1b821ccbd75b185820a1f1ff7b14d21da1e442e22c0863ea5f08771a8874"
+checksum = "60b8cb979cb11c32ce1603f8137b22262a9d131aaa5c37b5678025f22b8becd0"
 dependencies = [
 "rustix",
- "windows-sys",
+ "windows-sys 0.60.2",
 ]

-[[package]]
-name = "unicode-ident"
-version = "1.0.24"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e6e4313cd5fcd3dad5cafa179702e2b244f760991f45397d14d4ebf38247da75"
-
 [[package]]
 name = "utf8parse"
 version = "0.2.2"
@ -608,19 +564,99 @@ checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"

 [[package]]
 name = "windows-link"
-version = "0.2.1"
+version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
+checksum = "5e6ad25900d524eaabdbbb96d20b4311e1e7ae1699af4fb28c17ae66c80d798a"
+
+[[package]]
+name = "windows-link"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "45e46c0661abb7180e7b9c281db115305d49ca1709ab8242adf09666d2173c65"

 [[package]]
 name = "windows-sys"
-version = "0.61.2"
+version = "0.60.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
+checksum = "f2f500e4d28234f72040990ec9d39e3a6b950f9f22d3dba18416c35882612bcb"
 dependencies = [
- "windows-link",
+ "windows-targets",
 ]

+[[package]]
+name = "windows-sys"
+version = "0.61.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e201184e40b2ede64bc2ea34968b28e33622acdbbf37104f0e4a33f7abe657aa"
+dependencies = [
+ "windows-link 0.2.0",
+]
+
+[[package]]
+name = "windows-targets"
+version = "0.53.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d5fe6031c4041849d7c496a8ded650796e7b6ecc19df1a431c1a363342e5dc91"
+dependencies = [
+ "windows-link 0.1.3",
+ "windows_aarch64_gnullvm",
+ "windows_aarch64_msvc",
+ "windows_i686_gnu",
+ "windows_i686_gnullvm",
+ "windows_i686_msvc",
+ "windows_x86_64_gnu",
+ "windows_x86_64_gnullvm",
+ "windows_x86_64_msvc",
+]
+
+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "86b8d5f90ddd19cb4a147a5fa63ca848db3df085e25fee3cc10b39b6eebae764"
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c7651a1f62a11b8cbd5e0d42526e55f2c99886c77e007179efff86c2b137e66c"
+
+[[package]]
+name = "windows_i686_gnu"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c1dc67659d35f387f5f6c479dc4e28f1d4bb90ddd1a5d3da2e5d97b42d6272c3"
+
+[[package]]
+name = "windows_i686_gnullvm"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9ce6ccbdedbf6d6354471319e781c0dfef054c81fbc7cf83f338a4296c0cae11"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "581fee95406bb13382d2f65cd4a908ca7b1e4c2f1917f143ba16efe98a589b5d"
+
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2e55b5ac9ea33f2fc1716d1742db15574fd6fc8dadc51caab1c16a3d3b4190ba"
+
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0a6e035dd0599267ce1ee132e51c27dd29437f63325753051e71dd9e42406c57"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.53.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "271414315aff87387382ec3d271b52d7ae78726f5d44ac98b4f4030c91880486"
+
 [[package]]
 name = "wyz"
 version = "0.5.1"
@ -630,12 +666,6 @@ dependencies = [
 "tap",
 ]

-[[package]]
-name = "zmij"
-version = "1.0.21"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b8848ee67ecc8aedbaf3e4122217aff892639231befc6a1b58d29fff4c2cabaa"
-
 [[package]]
 name = "zopfli"
 version = "0.8.3"
--- a/Cargo.toml
+++ b/Cargo.toml
@ -20,7 +20,7 @@ homepage = "https://github.com/oxipng/oxipng"
 license = "MIT"
 name = "oxipng"
 repository = "https://github.com/oxipng/oxipng"
-version = "10.1.1"
+version = "10.0.0"
 rust-version = "1.85.1"

 [badges]
@ -38,32 +38,59 @@ name = "zopfli"
 required-features = ["zopfli"]

 [dependencies]
-bitvec = "1.0.1"
-clap = { version = "4.6.0", optional = true, features = ["wrap_help"] }
-env_logger = { version = "0.11.10", optional = true, default-features = false, features = ["auto-color"] }
-image = { version = "0.25.9", optional = true, default-features = false, features = ["png"] }
-indexmap = "2.14.0"
-libdeflater = "1.25.2"
-log = "0.4.30"
-parse-size = { version = "1.1.0", optional = true }
-rayon = { version = "1.11.0", optional = true }
-rgb = "0.8.53"
-rustc-hash = "2.1.2"
 zopfli = { version = "0.8.3", optional = true, default-features = false, features = ["std", "zlib"] }
+rgb = "0.8.52"
+indexmap = "2.12.1"
+libdeflater = "1.25.0"
+log = "0.4.28"
+bitvec = "1.0.1"
+rustc-hash = "2.1.1"

-[target.'cfg(windows)'.dependencies]
-glob = { version = "0.3.3", optional = true }
+[dependencies.env_logger]
+optional = true
+default-features = false
+features = ["auto-color"]
+version = "0.11.8"

-[dev-dependencies]
-serde_json = "1.0.150"
+[dependencies.crossbeam-channel]
+optional = true
+version = "0.5.15"
+
+[dependencies.filetime]
+optional = true
+version = "0.2.26"
+
+[dependencies.rayon]
+optional = true
+version = "1.11.0"
+
+[dependencies.clap]
+optional = true
+version = "4.5.53"
+features = ["wrap_help"]
+
+[dependencies.parse-size]
+optional = true
+version = "1.1.0"
+
+[target.'cfg(windows)'.dependencies.glob]
+optional = true
+version = "0.3.3"
+
+[dependencies.image]
+optional = true
+default-features = false
+features = ["png"]
+version = "0.25.9"

 [features]
 binary = ["dep:clap", "dep:glob", "dep:env_logger", "dep:parse-size"]
-default = ["binary", "parallel", "zopfli"]
-parallel = ["dep:rayon", "indexmap/rayon"]
+default = ["binary", "parallel", "zopfli", "filetime"]
+parallel = ["dep:rayon", "indexmap/rayon", "dep:crossbeam-channel"]
 freestanding = ["libdeflater/freestanding"]
 sanity-checks = ["dep:image"]
 zopfli = ["dep:zopfli"]
+filetime = ["dep:filetime"]
 system-libdeflate = ["libdeflater/dynamic"]

 [lib]
--- a/MANUAL.txt
+++ b/MANUAL.txt
@ -1,4 +1,4 @@
-oxipng 10.1.0
+oxipng 10.0.0
 Losslessly improve compression of PNG files

 Usage: oxipng [OPTIONS] <files>...
@ -105,13 +105,10 @@ Options:
          losslessly.

  -v, --verbose...
-          Show per-file info (use multiple times for more detail)
+          Run in verbose mode (use twice to increase verbosity)

  -q, --quiet
-          Suppress all output messages
-
-  -j, --json
-          Print results as JSON
+          Run in quiet mode

  -f, --filters <list>
          Perform compression trials with each of the given filter types. You can specify a
--- a/README.md
+++ b/README.md
@ -8,7 +8,7 @@
 ## Overview

 Oxipng is a multithreaded lossless PNG/APNG compression optimizer. It can be used via a command-line
-interface or as a library in other Rust programs. It is fast and highly effective.
+interface or as a library in other Rust programs.

 ## Installing

@ -76,14 +76,7 @@ All options are case-sensitive.
 \* Note that oxipng is not a brute-force optimizer. This means that while higher optimization levels
 are almost always better or equal to lower levels, this is not guaranteed and it is possible in
 rare circumstances that a lower level may give a marginally smaller output. Similarly, using Zopfli
-compression (`-z`) is not guaranteed to always be better than default compression.
-
-## APNG support
-
-Oxipng currently only supports limited optimization of animated PNGs (APNGs). It can perform
-alpha-optimization, refiltering and recompression of all frames, but all transformations will be
-disabled. For best results, it is recommended to use another tool such as
-[apngopt](https://sourceforge.net/projects/apng/files/APNG_Optimizer/) before running Oxipng.
+compression (`-z`) is not guaranteed to always be better than without.

 ## Git integration via [pre-commit]

@ -138,13 +131,17 @@ and specifying the desired ones, for example:

 ## History

-Oxipng began in 2015 as a rewrite of the OptiPNG project. The core goal was to implement
-multithreading, which would have been very difficult to do within the existing C codebase of OptiPNG.
+Oxipng began as a complete rewrite of the OptiPNG project,
+which was assumed to be dead as no commit had been made to it since March 2014.
+(OptiPNG has since released a new version, after Oxipng was first released.)
+The name has been changed to avoid confusion and potential legal issues.
+
+The core goal of rewriting OptiPNG was to implement multithreading,
+which would be very difficult to do within the existing C codebase of OptiPNG.
 This also served as an opportunity to choose a more modern, safer language (Rust).

-However, Oxipng has evolved considerably since then. While some of the options remain similar to
-OptiPNG, the architecture and capabilities are now quite different. It is not a drop-in
-replacement - if you are migrating from OptiPNG, please check the [help](MANUAL.txt) before use.
+Note that, while similar, Oxipng is not a drop-in replacement for OptiPNG.
+If you are migrating from OptiPNG, please check the [help](MANUAL.txt) before using.

 ## Contributing

@ -154,11 +151,42 @@ to submit a fix with the bug report, it is preferred that you do so via pull req
 however you do not need to be a Rust developer to contribute.
 Other contributions (such as improving documentation or translations) are also welcome via GitHub.

-## Benchmarks
-
-An independent benchmark is linked here with permission by the author:\
-[oxipng and friends: A comparison of PNG optimization tools](https://op111.net/posts/2025/09/png-compression-oxipng-optipng-fileoptimizer-cwebp/)
-
 ## License

 Oxipng is open-source software, distributed under the MIT license.
+
+## Benchmarks
+
+Tested Oxipng 9.0.0 (commit `c16519b38b0519988db625913be919d4f0e42f5d`, compiled
+on `rustc 1.74.0-nightly (7b4d9e155 2023-09-28)`) against OptiPNG version 0.7.7,
+as packaged by Debian unstable, on a Linux 6.5.0-2-amd64 kernel, Intel Core
+i7-12700 CPU (8 performance cores, 4 efficiency cores, 20 threads), DDR5-5200
+RAM in dual channel configuration.
+
+```
+
+Benchmark 1: ./target/release/oxipng -P ./tests/files/rgb_16_should_be_grayscale_8.png
+  Time (mean ± σ):      59.6 ms ±   7.7 ms    [User: 77.4 ms, System: 3.6 ms]
+  Range (min … max):    53.3 ms …  89.9 ms    32 runs
+
+Benchmark 2: optipng -simulate ./tests/files/rgb_16_should_be_grayscale_8.png
+  Time (mean ± σ):     132.4 ms ±   0.8 ms    [User: 132.5 ms, System: 0.6 ms]
+  Range (min … max):   131.8 ms … 134.4 ms    22 runs
+
+Summary
+  ./target/release/oxipng -P ./tests/files/rgb_16_should_be_grayscale_8.png ran
+    2.22 ± 0.29 times faster than optipng -simulate ./tests/files/rgb_16_should_be_grayscale_8.png
+
+Benchmark 1: ./target/release/oxipng -o4 -P ./tests/files/rgb_16_should_be_grayscale_8.png
+  Time (mean ± σ):      88.7 ms ±   4.3 ms    [User: 270.3 ms, System: 11.0 ms]
+  Range (min … max):    86.8 ms … 109.4 ms    26 runs
+
+Benchmark 2: optipng -o 4 -simulate ./tests/files/rgb_16_should_be_grayscale_8.png
+  Time (mean ± σ):     444.9 ms ±   0.3 ms    [User: 444.8 ms, System: 0.7 ms]
+  Range (min … max):   444.4 ms … 445.6 ms    10 runs
+
+Summary
+  ./target/release/oxipng -o4 -P ./tests/files/rgb_16_should_be_grayscale_8.png ran
+    5.01 ± 0.25 times faster than optipng -o 4 -simulate ./tests/files/rgb_16_should_be_grayscale_8.png
+
+```
--- a/src/apng.rs
+++ b/src/apng.rs
@ -1,3 +1,5 @@
+use std::io::Write;
+
 use crate::{
    PngResult,
    error::PngError,
@ -50,14 +52,15 @@ impl Frame {
    #[must_use]
    pub fn fctl_data(&self, sequence_number: u32) -> Vec<u8> {
        let mut byte_data = Vec::with_capacity(26);
-        byte_data.extend_from_slice(&sequence_number.to_be_bytes());
-        byte_data.extend_from_slice(&self.width.to_be_bytes());
-        byte_data.extend_from_slice(&self.height.to_be_bytes());
-        byte_data.extend_from_slice(&self.x_offset.to_be_bytes());
-        byte_data.extend_from_slice(&self.y_offset.to_be_bytes());
-        byte_data.extend_from_slice(&self.delay_num.to_be_bytes());
-        byte_data.extend_from_slice(&self.delay_den.to_be_bytes());
-        byte_data.extend_from_slice(&[self.dispose_op, self.blend_op]);
+        byte_data.write_all(&sequence_number.to_be_bytes()).unwrap();
+        byte_data.write_all(&self.width.to_be_bytes()).unwrap();
+        byte_data.write_all(&self.height.to_be_bytes()).unwrap();
+        byte_data.write_all(&self.x_offset.to_be_bytes()).unwrap();
+        byte_data.write_all(&self.y_offset.to_be_bytes()).unwrap();
+        byte_data.write_all(&self.delay_num.to_be_bytes()).unwrap();
+        byte_data.write_all(&self.delay_den.to_be_bytes()).unwrap();
+        byte_data.push(self.dispose_op);
+        byte_data.push(self.blend_op);
        byte_data
    }

@ -65,8 +68,8 @@ impl Frame {
    #[must_use]
    pub fn fdat_data(&self, sequence_number: u32) -> Vec<u8> {
        let mut byte_data = Vec::with_capacity(4 + self.data.len());
-        byte_data.extend_from_slice(&sequence_number.to_be_bytes());
-        byte_data.extend_from_slice(&self.data);
+        byte_data.write_all(&sequence_number.to_be_bytes()).unwrap();
+        byte_data.write_all(&self.data).unwrap();
        byte_data
    }
 }
--- a/src/cli.rs
+++ b/src/cli.rs
@ -212,7 +212,7 @@ losslessly.")
        )
        .arg(
            Arg::new("verbose")
-                .help("Show per-file info (use multiple times for more detail)")
+                .help("Run in verbose mode (use twice to increase verbosity)")
                .short('v')
                .long("verbose")
                .action(ArgAction::Count)
@ -220,20 +220,12 @@ losslessly.")
        )
        .arg(
            Arg::new("quiet")
-                .help("Suppress all output messages")
+                .help("Run in quiet mode")
                .short('q')
                .long("quiet")
                .action(ArgAction::SetTrue)
                .conflicts_with("verbose"),
        )
-        .arg(
-            Arg::new("json")
-                .help("Print results as JSON")
-                .short('j')
-                .long("json")
-                .action(ArgAction::SetTrue)
-                .conflicts_with("stdout"),
-        )
        .arg(
            Arg::new("filters")
                .help("Filters to try (0-9; see '--help' for details)")
@ -298,8 +290,6 @@ The default value depends on the optimization level preset.")
        .arg(
            Arg::new("no-palette-reduction")
                .help("Do not change color palette")
-                .long_help("\
-Do not convert to indexed and do not modify an existing color palette.")
                .long("np")
                .action(ArgAction::SetTrue),
        )
--- a/src/evaluate.rs
+++ b/src/evaluate.rs
@ -8,12 +8,12 @@ use std::sync::{
    atomic::{AtomicUsize, Ordering::*},
 };

+#[cfg(feature = "parallel")]
+use crossbeam_channel::{Receiver, Sender, unbounded};
 use deflate::Deflater;
 use indexmap::IndexSet;
 use log::trace;
 use rayon::prelude::*;
-#[cfg(feature = "parallel")]
-use std::sync::mpsc::{Receiver, Sender, channel};

 #[cfg(not(feature = "parallel"))]
 use crate::rayon;
@ -73,7 +73,7 @@ impl Evaluator {
        final_round: bool,
    ) -> Self {
        #[cfg(feature = "parallel")]
-        let eval_channel = channel();
+        let eval_channel = unbounded();
        Self {
            deadline,
            filters,
@ -118,7 +118,7 @@ impl Evaluator {

    /// Check if the image is smaller than others
    pub fn try_image(&self, image: Arc<PngImage>) {
-        let description = image.ihdr.color_type.to_string();
+        let description = format!("{}", image.ihdr.color_type);
        self.try_image_with_description(image, &description);
    }

@ -154,19 +154,6 @@ impl Evaluator {
                let idat_data = deflater.deflate(&filtered, best_candidate_size.get());
                if let Ok(idat_data) = idat_data {
                    let estimated_output_size = image.estimated_output_size(&idat_data);
-                    trace!(
-                        "Eval: {}-bit {:23} {:8}   {} bytes",
-                        image.ihdr.bit_depth, description, filter, estimated_output_size
-                    );
-
-                    // Skip if it exceeds best known size. (This is important to ensure
-                    // the evaluator returns no result when all candidates are too large.)
-                    if let Some(max) = best_candidate_size.get() {
-                        if estimated_output_size > max {
-                            return;
-                        }
-                    }
-
                    // We only need to retain the IDAT data in the final round
                    let new = Candidate {
                        image: image.clone(),
@ -177,6 +164,10 @@ impl Evaluator {
                        nth,
                    };
                    best_candidate_size.set_min(estimated_output_size);
+                    trace!(
+                        "Eval: {}-bit {:23} {:8}   {} bytes",
+                        image.ihdr.bit_depth, description, filter, estimated_output_size
+                    );

                    #[cfg(feature = "parallel")]
                    {
--- a/src/headers.rs
+++ b/src/headers.rs
@ -263,11 +263,11 @@ pub fn extract_icc(iccp: &Chunk, max_size: Option<usize>) -> Option<Vec<u8>> {
    if compression_method != 0 {
        return None; // The profile is supposed to be compressed (method 0)
    }
-    // Libdeflate works with a fixed size buffer. Since the decompressed size is unknown we have to
-    // guess the required buffer size. We allow a fairly generous 10x factor with a minimum of 1000.
-    let mut out_size = (compressed_data.len() * 10).max(1000);
-    // For sanity, impose a default limit of 1MB.
-    out_size = out_size.min(max_size.unwrap_or(1_000_000));
+    // The decompressed size is unknown so we have to guess the required buffer size
+    let mut out_size = compressed_data.len() * 2 + 1000;
+    if let Some(max) = max_size {
+        out_size = out_size.min(max);
+    }
    match inflate(compressed_data, out_size) {
        Ok(icc) => Some(icc),
        Err(e) => {
--- a/src/lib.rs
+++ b/src/lib.rs
@ -7,9 +7,9 @@ extern crate rayon;
 mod rayon;

 use std::{
-    fs::File,
+    fs::{File, Metadata},
    io::{BufWriter, Read, Write, stdin, stdout},
-    path::PathBuf,
+    path::{Path, PathBuf},
    sync::{
        Arc,
        atomic::{AtomicBool, Ordering},
@ -64,7 +64,6 @@ pub mod internal_tests {
 }

 pub type PngResult<T> = Result<T, PngError>;
-pub type OptimizationResult = PngResult<(usize, usize)>;

 #[derive(Debug)]
 /// A raw image definition which can be used to create an optimized png
@ -87,7 +86,7 @@ impl RawImage {
        color_type: ColorType,
        bit_depth: BitDepth,
        data: Vec<u8>,
-    ) -> PngResult<Self> {
+    ) -> Result<Self, PngError> {
        // Validate bit depth
        let valid_depth = match color_type {
            ColorType::Grayscale { .. } => true,
@ -166,15 +165,40 @@ impl RawImage {
 /// Perform optimization on the input file using the options provided
 ///
 /// Returns the original and optimized file sizes
-pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> OptimizationResult {
+pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> PngResult<(usize, usize)> {
    // Read in the file and try to decode as PNG.
    info!("Processing: {input}");

    let deadline = Arc::new(Deadline::new(opts.timeout));

+    // grab metadata before even opening input file to preserve atime
+    let opt_metadata_preserved;
    let in_data = match *input {
-        InFile::Path(ref input_path) => PngData::read_file(input_path)?,
+        InFile::Path(ref input_path) => {
+            if matches!(
+                output,
+                OutFile::Path {
+                    preserve_attrs: true,
+                    ..
+                }
+            ) {
+                opt_metadata_preserved = input_path
+                    .metadata()
+                    .map_err(|err| {
+                        // Fail if metadata cannot be preserved
+                        PngError::new(&format!(
+                            "Unable to read metadata from input file {input_path:?}: {err}"
+                        ))
+                    })
+                    .map(Some)?;
+                trace!("preserving metadata: {opt_metadata_preserved:?}");
+            } else {
+                opt_metadata_preserved = None;
+            }
+            PngData::read_file(input_path)?
+        }
        InFile::StdIn => {
+            opt_metadata_preserved = None;
            let mut data = Vec::new();
            stdin()
                .read_to_end(&mut data)
@ -196,7 +220,7 @@ pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> Optimizatio
            (OutFile::Path { path, .. }, InFile::Path(input_path))
                if path.as_ref().is_none_or(|p| p == input_path) =>
            {
-                info!("Could not optimize further, no change written: {input}");
+                info!("{input}: Could not optimize further, no change written");
                return Ok((in_length, in_length));
            }
            _ => {
@ -228,34 +252,18 @@ pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> Optimizatio
            buffer
                .write_all(&optimized_output)
                .map_err(|e| PngError::WriteFailed("stdout".into(), e))?;
-            info!("{savings}: stdout");
        }
-        (
-            OutFile::Path {
-                path,
-                preserve_attrs,
-            },
-            _,
-        ) => {
-            let input_metadata = if *preserve_attrs {
-                input.path().and_then(|in_path| {
-                    let meta = in_path.metadata();
-                    if let Err(e) = &meta {
-                        warn!("Unable to read metadata from {in_path:?}: {e}");
-                    }
-                    meta.ok()
-                })
-            } else {
-                None
-            };
-
+        (OutFile::Path { path, .. }, _) => {
            let output_path = path
                .as_ref()
                .map_or_else(|| input.path().unwrap(), PathBuf::as_path);
            let out_file = File::create(output_path)
                .map_err(|err| PngError::WriteFailed(output_path.display().to_string(), err))?;
+            if let Some(metadata_input) = &opt_metadata_preserved {
+                copy_permissions(metadata_input, &out_file)?;
+            }

-            let mut buffer = BufWriter::new(&out_file);
+            let mut buffer = BufWriter::new(out_file);
            buffer
                .write_all(&optimized_output)
                // flush BufWriter so IO errors don't get swallowed silently on close() by drop!
@ -263,18 +271,8 @@ pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> Optimizatio
                .map_err(|e| PngError::WriteFailed(output_path.display().to_string(), e))?;
            // force drop and thereby closing of file handle before modifying any timestamp
            std::mem::drop(buffer);
-
-            if let Some(metadata_input) = &input_metadata {
-                let set_time = metadata_input
-                    .modified()
-                    .and_then(|m| out_file.set_modified(m));
-                if let Err(e) = set_time {
-                    warn!("Unable to set modification time on {output_path:?}: {e}");
-                }
-                let set_perm = out_file.set_permissions(metadata_input.permissions());
-                if let Err(e) = set_perm {
-                    warn!("Unable to set permissions on {output_path:?}: {e}");
-                }
+            if let Some(metadata_input) = &opt_metadata_preserved {
+                copy_times(metadata_input, output_path)?;
            }
            info!("{}: {}", savings, output_path.display());
        }
@ -644,3 +642,29 @@ fn recompress_frames(
 const fn is_fully_optimized(original_size: usize, optimized_size: usize, opts: &Options) -> bool {
    original_size <= optimized_size && !opts.force
 }
+
+fn copy_permissions(metadata_input: &Metadata, out_file: &File) -> PngResult<()> {
+    out_file
+        .set_permissions(metadata_input.permissions())
+        .map_err(|err_io| {
+            PngError::new(&format!(
+                "Unable to set permissions for output file: {err_io}"
+            ))
+        })
+}
+
+#[cfg(not(feature = "filetime"))]
+const fn copy_times(_: &Metadata, _: &Path) -> PngResult<()> {
+    Ok(())
+}
+
+#[cfg(feature = "filetime")]
+fn copy_times(input_path_meta: &Metadata, out_path: &Path) -> PngResult<()> {
+    let mtime = filetime::FileTime::from_last_modification_time(input_path_meta);
+    trace!("attempting to set file modification time: {mtime:?}");
+    filetime::set_file_mtime(out_path, mtime).map_err(|err_io| {
+        PngError::new(&format!(
+            "Unable to set file times on {out_path:?}: {err_io}"
+        ))
+    })
+}
--- a/src/main.rs
+++ b/src/main.rs
@ -6,10 +6,9 @@ use std::num::NonZeroU64;
 use std::{
    ffi::{OsStr, OsString},
    fs::DirBuilder,
-    io::{IsTerminal, Write, stdout},
+    io::Write,
    path::PathBuf,
    process::ExitCode,
-    sync::atomic::{AtomicUsize, Ordering::AcqRel},
    time::Duration,
 };

@ -19,9 +18,7 @@ use indexmap::IndexSet;
 use log::{Level, LevelFilter, error, warn};
 #[cfg(feature = "zopfli")]
 use oxipng::ZopfliOptions;
-use oxipng::{
-    Deflater, FilterStrategy, InFile, OptimizationResult, Options, OutFile, PngError, StripChunks,
-};
+use oxipng::{Deflater, FilterStrategy, InFile, Options, OutFile, PngError, StripChunks};
 use rayon::prelude::*;

 use crate::cli::DISPLAY_CHUNKS;
@ -38,7 +35,7 @@ fn main() -> ExitCode {
        .after_long_help("")
        .get_matches_from(std::env::args());

-    let (mut out_file, out_dir, opts) = match parse_opts_into_struct(&matches) {
+    let (out_file, out_dir, opts) = match parse_opts_into_struct(&matches) {
        Ok(x) => x,
        Err(x) => {
            error!("{x}");
@ -46,128 +43,51 @@ fn main() -> ExitCode {
        }
    };

-    // Determine input and output
-    let file_args = matches.get_many::<PathBuf>("files").unwrap().cloned();
-    #[cfg(windows)]
-    let inputs: Vec<_> = file_args.flat_map(apply_glob_pattern).collect();
-    #[cfg(not(windows))]
-    let inputs: Vec<_> = file_args.collect();
-    let using_stdin = inputs.len() == 1 && inputs[0].to_str() == Some("-");
-    if using_stdin && out_dir.is_some() {
-        error!("Cannot use --dir when reading from stdin.");
-        return ExitCode::FAILURE;
-    }
-    if using_stdin && matches!(out_file, OutFile::Path { path: None, .. }) {
-        out_file = OutFile::StdOut;
-    }
-    let using_stdout = matches!(out_file, OutFile::StdOut);
-    let json = matches.get_flag("json");
-    if using_stdout && json {
-        error!("Cannot use --json when writing to stdout.");
-        return ExitCode::FAILURE;
-    }
+    let files = collect_files(
+        #[cfg(windows)]
+        matches
+            .get_many::<PathBuf>("files")
+            .unwrap()
+            .cloned()
+            .flat_map(apply_glob_pattern)
+            .collect(),
+        #[cfg(not(windows))]
+        matches
+            .get_many::<PathBuf>("files")
+            .unwrap()
+            .cloned()
+            .collect(),
+        &out_dir,
+        &out_file,
+        matches.get_flag("recursive"),
+        true,
+    );

-    let files = if using_stdin {
-        vec![(InFile::StdIn, out_file)]
+    let parallel_files = matches.get_flag("parallel-files");
+    let summary = if parallel_files {
+        files
+            .into_par_iter()
+            .map(|(input, output)| process_file(&input, &output, &opts))
+            .min()
    } else {
-        collect_files(
-            inputs,
-            &out_dir,
-            &out_file,
-            matches.get_flag("recursive"),
-            true,
-        )
+        files
+            .into_iter()
+            .map(|(input, output)| process_file(&input, &output, &opts))
+            .min()
    };

-    let is_verbose = matches.get_count("verbose") > 0;
-    let print_summary = !matches.get_flag("quiet") && !using_stdout;
-    let print_progress = print_summary && !is_verbose && stdout().is_terminal();
-    let total_files = files.len();
-    let num_processed = AtomicUsize::new(0);
-    if print_progress {
-        print!("Files processed: 0/{}...", total_files);
-        stdout().flush().ok();
+    match summary.unwrap_or(OptimizationResult::Skipped) {
+        OptimizationResult::Ok => ExitCode::SUCCESS,
+        OptimizationResult::Failed => ExitCode::FAILURE,
+        OptimizationResult::Skipped => ExitCode::from(3),
    }
-    let process = |(input, output): &(InFile, OutFile)| {
-        let result = process_file(input, output, &opts);
-        if print_progress && matches!(result, OptimizationResult::Ok(_)) {
-            let value = num_processed.fetch_add(1, AcqRel) + 1;
-            print!("\rFiles processed: {}/{}...", value, total_files);
-            stdout().flush().ok();
-        }
-        result
-    };
-    let results: Vec<OptimizationResult> = if matches.get_flag("parallel-files") {
-        files.par_iter().map(process).collect()
-    } else {
-        files.iter().map(process).collect()
-    };
+}

-    // Collect stats
-    let mut num_succeeded = 0;
-    let mut num_not_optimized = 0;
-    let mut num_failed = 0;
-    let mut total_in: i64 = 0;
-    let mut total_out: i64 = 0;
-    for result in &results {
-        match result {
-            Ok((insize, outsize)) => {
-                num_succeeded += 1;
-                total_in += *insize as i64;
-                total_out += *outsize as i64;
-                if !opts.force && insize == outsize {
-                    num_not_optimized += 1;
-                }
-            }
-            Err(PngError::C2PAMetadataPreventsChanges | PngError::InflatedDataTooLong(_)) => {}
-            Err(_) => num_failed += 1,
-        }
-    }
-
-    // Print results
-    if json {
-        json_output(&files, &results);
-    } else if print_summary {
-        let in_bytes = format_bytes(total_in, true);
-        let out_bytes = format_bytes(total_out, true);
-        let saved = total_in - total_out;
-        let saved_bytes = format_bytes(saved, false);
-        let percent = if total_in > 0 {
-            saved as f64 / total_in as f64 * 100_f64
-        } else {
-            0_f64
-        };
-        if is_verbose {
-            println!("--------------------");
-        }
-        println!("\rFiles processed: {num_succeeded}/{total_files}   ");
-        println!("Input size: {}", in_bytes);
-        println!("Output size: {}", out_bytes);
-        println!("Total saved: {} ({:.2}%)", saved_bytes, percent);
-        if num_not_optimized == 1 {
-            println!("({num_not_optimized} file could not be optimized further)");
-        } else if num_not_optimized > 0 {
-            println!("({num_not_optimized} files could not be optimized further)");
-        }
-        if matches.get_flag("dry-run") {
-            println!("Dry run, no changes saved");
-        }
-    }
-
-    // For optimizing single files, this will return the correct exit code always.
-    // For recursive optimization, the correct choice is a bit subjective.
-    // We're choosing to return a 0 exit code if ANY file in the set
-    // runs correctly.
-    // The reason for this is that recursion may pick up files that are not
-    // PNG files, and return an error for them.
-    // We don't really want to return an error code for those files.
-    if num_succeeded > 0 {
-        ExitCode::SUCCESS
-    } else if num_failed > 0 {
-        ExitCode::FAILURE
-    } else {
-        ExitCode::from(3)
-    }
+#[derive(Eq, PartialEq, Ord, PartialOrd)]
+enum OptimizationResult {
+    Ok,
+    Failed,
+    Skipped,
 }

 fn collect_files(
@ -178,8 +98,10 @@ fn collect_files(
    top_level: bool, //explicitly specify files
 ) -> Vec<(InFile, OutFile)> {
    let mut in_out_pairs = Vec::new();
+    let allow_stdin = top_level && files.len() == 1;
    for input in files {
-        if input.is_dir() {
+        let using_stdin = allow_stdin && input.to_str() == Some("-");
+        if !using_stdin && input.is_dir() {
            if recursive {
                match input.read_dir() {
                    Ok(dir) => {
@ -196,15 +118,6 @@ fn collect_files(
            }
            continue;
        }
-
-        // Skip non png files if not given on top level
-        if !top_level && {
-            let extension = input.extension().map(OsStr::to_ascii_lowercase);
-            extension != Some(OsString::from("png")) && extension != Some(OsString::from("apng"))
-        } {
-            continue;
-        }
-
        let out_file =
            if let (Some(out_dir), &OutFile::Path { preserve_attrs, .. }) = (out_dir, out_file) {
                let path = Some(out_dir.join(input.file_name().unwrap()));
@ -215,7 +128,19 @@ fn collect_files(
            } else {
                (*out_file).clone()
            };
-        let in_file = InFile::Path(input);
+        let in_file = if using_stdin {
+            InFile::StdIn
+        } else {
+            // Skip non png files if not given on top level
+            if !top_level && {
+                let extension = input.extension().map(OsStr::to_ascii_lowercase);
+                extension != Some(OsString::from("png"))
+                    && extension != Some(OsString::from("apng"))
+            } {
+                continue;
+            }
+            InFile::Path(input)
+        };
        in_out_pairs.push((in_file, out_file));
    }
    in_out_pairs
@ -240,9 +165,8 @@ fn parse_opts_into_struct(
 ) -> Result<(OutFile, Option<PathBuf>, Options), String> {
    let log_level = match matches.get_count("verbose") {
        _ if matches.get_flag("quiet") => LevelFilter::Off,
-        0 => LevelFilter::Warn,
-        1 => LevelFilter::Info,
-        2 => LevelFilter::Debug,
+        0 => LevelFilter::Info,
+        1 => LevelFilter::Debug,
        _ => LevelFilter::Trace,
    };
    env_logger::builder()
@ -251,8 +175,7 @@ fn parse_opts_into_struct(
            match record.level() {
                Level::Error | Level::Warn => {
                    let style = buf.default_level_style(record.level());
-                    // Prepend carriage return to clear progress line
-                    writeln!(buf, "\r{style}{}{style:#}", record.args())
+                    writeln!(buf, "{style}{}{style:#}", record.args())
                }
                // Leave info, debug and trace unstyled
                _ => writeln!(buf, "{}", record.args()),
@ -430,16 +353,6 @@ fn parse_opts_into_struct(
        let iterations_without_improvement = *matches
            .get_one::<NonZeroU64>("iterations-without-improvement")
            .unwrap_or(&NonZeroU64::MAX);
-
-        if iterations_without_improvement > iteration_count
-            && iterations_without_improvement != NonZeroU64::MAX
-        {
-            warn!(
-                "--ziwi ({}) is higher than --zi ({}) and will never be reached.",
-                iterations_without_improvement, iteration_count
-            );
-        }
-
        opts.deflater = Deflater::Zopfli(ZopfliOptions {
            iteration_count,
            iterations_without_improvement,
@ -527,128 +440,26 @@ fn process_file(input: &InFile, output: &OutFile, opts: &Options) -> Optimizatio
    if let (Some(max_size), InFile::Path(path)) = (opts.max_decompressed_size, input) {
        if path.metadata().is_ok_and(|m| m.len() > max_size as u64) {
            warn!("{input}: Skipped: File exceeds the maximum size ({max_size} bytes)");
-            return Err(PngError::InflatedDataTooLong(max_size));
+            return OptimizationResult::Skipped;
        }
    }

-    let result = oxipng::optimize(input, output, opts);
-    match &result {
-        Ok(_) => {}
+    match oxipng::optimize(input, output, opts) {
+        // For optimizing single files, this will return the correct exit code always.
+        // For recursive optimization, the correct choice is a bit subjective.
+        // We're choosing to return a 0 exit code if ANY file in the set
+        // runs correctly.
+        // The reason for this is that recursion may pick up files that are not
+        // PNG files, and return an error for them.
+        // We don't really want to return an error code for those files.
+        Ok(_) => OptimizationResult::Ok,
        Err(e @ PngError::C2PAMetadataPreventsChanges | e @ PngError::InflatedDataTooLong(_)) => {
            warn!("{input}: Skipped: {e}");
+            OptimizationResult::Skipped
        }
        Err(e) => {
            error!("{input}: {e}");
+            OptimizationResult::Failed
        }
    }
-    result
-}
-
-/// Write optimization results as json.
-/// ```
-/// {
-///   "results": [
-///     {
-///       "input": string,
-///       "status": "success",
-///       "output": string|null,
-///       "insize": number,
-///       "outsize": number
-///     },
-///     {
-///       "input": string,
-///       "status": "error",
-///       "error": string
-///     }
-///   ]
-/// }
-/// ```
-fn json_output(files: &[(InFile, OutFile)], results: &[OptimizationResult]) {
-    print!(r#"{{"results":["#);
-    let mut first = true;
-    results
-        .iter()
-        .zip(files)
-        .for_each(|(result, (input, output))| {
-            if !first {
-                print!(",");
-            }
-            print!(r#"{{"input":"{}","#, json_escape(&input.to_string()));
-            match result {
-                Ok((insize, outsize)) => {
-                    let outpath = match output {
-                        OutFile::None => "null".to_owned(),
-                        OutFile::Path { path: None, .. } => {
-                            format!(r#""{}""#, json_escape(&input.to_string()))
-                        }
-                        OutFile::Path { path: Some(p), .. } => {
-                            format!(r#""{}""#, json_escape(&p.display().to_string()))
-                        }
-                        OutFile::StdOut => unreachable!(),
-                    };
-                    print!(
-                        r#""status":"success","output":{},"insize":{},"outsize":{}}}"#,
-                        outpath, insize, outsize
-                    );
-                }
-                Err(e) => {
-                    print!(
-                        r#""status":"error","error":"{}"}}"#,
-                        json_escape(&e.to_string())
-                    );
-                }
-            }
-            first = false;
-        });
-    print!("]}}");
-}
-
-fn json_escape(string: &str) -> String {
-    string
-        .replace("\\", "\\\\")
-        .replace("\"", "\\\"")
-        .replace("\n", "\\n")
-        .replace("\t", "\\t")
-        .replace("\r", "\\r")
-        .replace("\x08", "\\b")
-        .replace("\x0c", "\\f")
-}
-
-/// Format byte counts as IEC units to 3 significant figures.
-fn format_bytes(count: i64, include_raw: bool) -> String {
-    const K: i64 = 1 << 10;
-    const M: i64 = 1 << 20;
-    const G: i64 = 1 << 30;
-    fn format_3sf(value: f64) -> String {
-        match value.abs() {
-            ..9.995 => format!("{:.2}", value),
-            9.995..99.95 => format!("{:.1}", value),
-            _ => format!("{:.0}", value),
-        }
-    }
-    let formatted = match count.abs() {
-        ..K => format!("{} bytes", count),
-        K..M => format!("{} KiB", format_3sf(count as f64 / K as f64)),
-        M..G => format!("{} MiB", format_3sf(count as f64 / M as f64)),
-        _ => format!("{} GiB", format_3sf(count as f64 / G as f64)),
-    };
-    if include_raw && count.abs() >= K {
-        format!("{} ({} bytes)", formatted, count)
-    } else {
-        formatted
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::format_bytes;
-
-    #[test]
-    fn test_format_bytes() {
-        assert_eq!(format_bytes(1023, false), "1023 bytes");
-        assert_eq!(format_bytes(800_000, false), "781 KiB");
-        assert_eq!(format_bytes(12_500_000, false), "11.9 MiB");
-        assert_eq!(format_bytes(2_000_000_000, false), "1.86 GiB");
-        assert_eq!(format_bytes(-1024, false), "-1.00 KiB");
-    }
 }
--- a/src/png/mod.rs
+++ b/src/png/mod.rs
@ -1,11 +1,13 @@
-use std::{fs, path::Path, sync::Arc};
+use std::{fs, io::Write, path::Path, sync::Arc};

+use bitvec::bitarr;
 use libdeflater::{CompressionLvl, Compressor};
 use log::warn;
+use rgb::ComponentSlice;
 use rustc_hash::FxHashMap;

 use crate::{
-    Options, PngResult,
+    Options,
    apng::*,
    colors::{BitDepth, ColorType},
    deflate,
@ -43,18 +45,18 @@ pub struct PngData {
 impl PngData {
    /// Create a new `PngData` struct by opening a file
    #[inline]
-    pub fn new(filepath: &Path, opts: &Options) -> PngResult<Self> {
+    pub fn new(filepath: &Path, opts: &Options) -> Result<Self, PngError> {
        let byte_data = Self::read_file(filepath)?;

        Self::from_slice(&byte_data, opts)
    }

-    pub fn read_file(filepath: &Path) -> PngResult<Vec<u8>> {
+    pub fn read_file(filepath: &Path) -> Result<Vec<u8>, PngError> {
        fs::read(filepath).map_err(|e| PngError::ReadFailed(filepath.display().to_string(), e))
    }

    /// Create a new `PngData` struct by reading a slice
-    pub fn from_slice(byte_data: &[u8], opts: &Options) -> PngResult<Self> {
+    pub fn from_slice(byte_data: &[u8], opts: &Options) -> Result<Self, PngError> {
        let mut byte_offset: usize = 0;
        // Test that png header is valid
        let header = byte_data.get(0..8).ok_or(PngError::TruncatedData)?;
@ -163,15 +165,17 @@ impl PngData {
        let mut output = vec![0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A];
        // IHDR
        let mut ihdr_data = Vec::with_capacity(13);
-        ihdr_data.extend_from_slice(&self.raw.ihdr.width.to_be_bytes());
-        ihdr_data.extend_from_slice(&self.raw.ihdr.height.to_be_bytes());
-        ihdr_data.extend_from_slice(&[self.raw.ihdr.bit_depth as u8]);
-        ihdr_data.extend_from_slice(&[
-            self.raw.ihdr.color_type.png_header_code(),
-            0, // Compression -- deflate
-            0, // Filter method -- 5-way adaptive filtering
-            self.raw.ihdr.interlaced as u8,
-        ]);
+        ihdr_data.write_all(&self.raw.ihdr.width.to_be_bytes()).ok();
+        ihdr_data
+            .write_all(&self.raw.ihdr.height.to_be_bytes())
+            .ok();
+        ihdr_data.write_all(&[self.raw.ihdr.bit_depth as u8]).ok();
+        ihdr_data
+            .write_all(&[self.raw.ihdr.color_type.png_header_code()])
+            .ok();
+        ihdr_data.write_all(&[0]).ok(); // Compression -- deflate
+        ihdr_data.write_all(&[0]).ok(); // Filter method -- 5-way adaptive filtering
+        ihdr_data.write_all(&[self.raw.ihdr.interlaced as u8]).ok();
        write_png_block(b"IHDR", &ihdr_data, &mut output);
        // Ancillary chunks - split into those that come before IDAT and those that come after
        let mut aux_split = self.aux_chunks.split(|c| &c.name == b"IDAT");
@ -190,7 +194,7 @@ impl PngData {
            ColorType::Indexed { palette } => {
                let mut palette_data = Vec::with_capacity(palette.len() * 3);
                for px in palette {
-                    palette_data.extend_from_slice(px.rgb().as_ref());
+                    palette_data.extend_from_slice(px.rgb().as_slice());
                }
                write_png_block(b"PLTE", &palette_data, &mut output);
                if let Some(last_trns) = palette.iter().rposition(|px| px.a != 255) {
@ -246,7 +250,7 @@ impl PngData {
 }

 impl PngImage {
-    pub fn new(ihdr: IhdrData, compressed_data: &[u8]) -> PngResult<Self> {
+    pub fn new(ihdr: IhdrData, compressed_data: &[u8]) -> Result<Self, PngError> {
        let raw_data = deflate::inflate(compressed_data, ihdr.raw_data_size())?;

        // Reject files with incorrect width/height or truncated data
@ -330,7 +334,7 @@ impl PngImage {
    }

    /// Reverse all filters applied on the image, returning an unfiltered IDAT bytestream
-    fn unfilter_image(&self) -> PngResult<Vec<u8>> {
+    fn unfilter_image(&self) -> Result<Vec<u8>, PngError> {
        let mut unfiltered = Vec::with_capacity(self.data.len());
        let bpp = self.bytes_per_channel() * self.channels_per_pixel();
        let mut last_line: Vec<u8> = Vec::new();
@ -372,12 +376,6 @@ impl PngImage {
        let mut f_buf = Vec::new();
        // For heuristic strategies, keep track of the actual filter used for each line
        let mut filters_used = Vec::new();
-        // Pre-allocate buffers for the Bigrams strategy to avoid per-line allocations
-        let (mut bigram_seen, mut bigram_touched) = if matches!(strategy, FilterStrategy::Bigrams) {
-            (vec![false; 0x10000], Vec::<u16>::new())
-        } else {
-            (Vec::new(), Vec::new())
-        };
        for (i, line) in self.scan_lines(false).enumerate() {
            if prev_pass != line.pass || line.data.len() != prev_line.len() {
                prev_line = vec![0; line.data.len()];
@ -469,29 +467,18 @@ impl PngImage {
                        let mut best_size = usize::MAX;
                        for f in try_filters {
                            f.filter_line(bpp, &mut line_data, &prev_line, &mut f_buf, alpha_bytes);
-                            let mut count = 0;
+                            let mut set = bitarr![0; 0x10000];
                            for pair in f_buf.windows(2) {
                                let bigram = ((pair[0] as usize) << 8) | pair[1] as usize;
-                                if !bigram_seen[bigram] {
-                                    count += 1;
-                                    if count >= best_size {
-                                        break;
-                                    }
-                                    bigram_seen[bigram] = true;
-                                    bigram_touched.push(bigram as u16);
-                                }
+                                set.set(bigram, true);
                            }
-                            if count < best_size {
-                                best_size = count;
+                            let size = set.count_ones();
+                            if size < best_size {
+                                best_size = size;
                                std::mem::swap(&mut best_line, &mut f_buf);
                                best_line_raw.clone_from(&line_data);
                                best_filter = *f;
                            }
-                            // Clear only the entries that were touched
-                            for &idx in &bigram_touched {
-                                bigram_seen[idx as usize] = false;
-                            }
-                            bigram_touched.clear();
                        }
                    }
                    FilterStrategy::BigEnt => {
--- a/src/reduction/color.rs
+++ b/src/reduction/color.rs
@ -1,7 +1,7 @@
 use std::hash::{BuildHasherDefault, Hash};

 use indexmap::IndexSet;
-use rgb::{ComponentMap, FromSlice, RGB, RGBA, alt::Gray};
+use rgb::{ComponentMap, ComponentSlice, FromSlice, RGB, RGBA, alt::Gray};
 use rustc_hash::FxHasher;

 use crate::{
@ -193,7 +193,7 @@ pub fn indexed_to_channels(
    let mut data = Vec::with_capacity(out_size);
    for b in &png.data {
        let color = palette.get(*b as usize).unwrap_or(&black);
-        data.extend_from_slice(&color.as_ref()[ch_start..=ch_end]);
+        data.extend_from_slice(&color.as_slice()[ch_start..=ch_end]);
    }

    Some(PngImage {
--- a/src/reduction/mod.rs
+++ b/src/reduction/mod.rs
@ -118,7 +118,7 @@ pub(crate) fn perform_reductions(
    // Attempt to reduce to indexed
    // Keep the existing `png` var in case it is grayscale - we can test both for depth reduction later
    let mut indexed = None;
-    if opts.color_type_reduction && opts.palette_reduction && !deadline.passed() {
+    if opts.color_type_reduction && !deadline.passed() {
        if let Some(reduced) = reduced_to_indexed(&png, opts.grayscale_reduction) {
            // Make sure the palette gets sorted (but don't bother evaluating both results)
            let new = Arc::new(sorted_palette(&reduced).unwrap_or(reduced));
--- a/tests/files/json.png
+++ b/tests/files/json.png
--- a/tests/flags.rs
+++ b/tests/flags.rs
@ -1,12 +1,11 @@
-use indexmap::indexset;
-use oxipng::{internal_tests::*, *};
-use serde_json::Value;
 use std::{
    fs::remove_file,
    path::{Path, PathBuf},
-    process::Command,
 };

+use indexmap::indexset;
+use oxipng::{internal_tests::*, *};
+
 const GRAY: u8 = 0;
 const RGB: u8 = 2;
 const INDEXED: u8 = 3;
@ -96,9 +95,13 @@ fn test_it_converts(

 #[test]
 fn verbose_mode() {
-    use log::{Level, LevelFilter, Log, Metadata, Record, set_logger, set_max_level};
    use std::cell::RefCell;
-    use std::sync::mpsc::{Sender, channel};
+    #[cfg(not(feature = "parallel"))]
+    use std::sync::mpsc::{Sender, channel as unbounded};
+
+    #[cfg(feature = "parallel")]
+    use crossbeam_channel::{Sender, unbounded};
+    use log::{Level, LevelFilter, Log, Metadata, Record, set_logger, set_max_level};

    // Rust runs tests in parallel by default.
    // We want to make sure that we verify only logs from our test.
@ -138,7 +141,7 @@ fn verbose_mode() {
    let input = PathBuf::from("tests/files/verbose_mode.png");
    let (output, opts) = get_opts(&input);

-    let (sender, receiver) = channel();
+    let (sender, receiver) = unbounded();

    let thread_init = move || {
        // Initialise logs storage for all threads within our test.
@ -427,9 +430,12 @@ fn interlaced_0_to_1_other_filter_mode() {
 fn preserve_attrs() {
    let input = PathBuf::from("tests/files/preserve_attrs.png");

+    #[cfg(feature = "filetime")]
    let meta_input = input
        .metadata()
-        .expect("unable to get metadata for input file");
+        .expect("unable to get file metadata for output file");
+    #[cfg(feature = "filetime")]
+    let mtime_canon = filetime::FileTime::from_last_modification_time(&meta_input);

    let (mut output, opts) = get_opts(&input);
    if let OutFile::Path { preserve_attrs, .. } = &mut output {
@ -443,6 +449,17 @@ fn preserve_attrs() {
    let output = output.path().unwrap();
    assert!(output.exists());

+    #[cfg(feature = "filetime")]
+    let meta_output = output
+        .metadata()
+        .expect("unable to get file metadata for output file");
+    #[cfg(feature = "filetime")]
+    assert_eq!(
+        &mtime_canon,
+        &filetime::FileTime::from_last_modification_time(&meta_output),
+        "expected modification time to be identical to that of input",
+    );
+
    match PngData::new(output, &opts) {
        Ok(x) => x,
        Err(x) => {
@ -451,21 +468,9 @@ fn preserve_attrs() {
        }
    };

-    let meta_output = output
-        .metadata()
-        .expect("unable to get metadata for output file");
-    assert_eq!(
-        meta_input.modified().ok(),
-        meta_output.modified().ok(),
-        "expected modification time to be identical to that of input",
-    );
-    assert_eq!(
-        meta_input.permissions(),
-        meta_output.permissions(),
-        "expected permissions to be identical to that of input",
-    );
-
    remove_file(output).ok();
+
+    // TODO: Actually check permissions
 }

 #[test]
@ -659,39 +664,3 @@ fn zopfli_mode() {
        BitDepth::Eight,
    );
 }
-#[test]
-fn json_success() {
-    let path = "tests/files/json.png";
-    let output = Command::new(env!("CARGO_BIN_EXE_oxipng"))
-        .args(["--json", "--nx", "--nz", path])
-        .output()
-        .expect("Failed to run executable");
-    assert!(output.status.success());
-    let stdout = String::from_utf8_lossy(&output.stdout);
-    let data: Value = serde_json::from_str(&stdout).expect("Failed to parse JSON");
-    let result = &data["results"][0];
-    assert_eq!(result["input"], path);
-    assert_eq!(result["status"], "success");
-    assert_eq!(result["output"], path);
-    assert_eq!(result["insize"], result["outsize"]);
-}
-
-#[test]
-fn json_dry_run() {
-    let path = "tests/files/json.png";
-    let path2 = "tests/files/escape chars \\ \" \n \t \r \x08 \x0c.png";
-    let output = Command::new(env!("CARGO_BIN_EXE_oxipng"))
-        .args(["--json", "--dry-run", path, path2])
-        .output()
-        .expect("Failed to run executable");
-    assert!(output.status.success());
-    let stdout = String::from_utf8_lossy(&output.stdout);
-    let data: Value = serde_json::from_str(&stdout).expect("Failed to parse JSON");
-    let result = &data["results"][0];
-    assert_eq!(result["input"], path);
-    assert_eq!(result["status"], "success");
-    assert_eq!(result["output"], Value::Null);
-    let result2 = &data["results"][1];
-    assert_eq!(result2["input"], path2);
-    assert_eq!(result2["status"], "error");
-}