chore(deps): bump the rust-dependencies group with 2 updates (#818 )

Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
ci: cherry-pick changes from PR #815
2026-05-27 17:18:56 +00:00 · 2026-05-08 23:37:53 +02:00 · 2026-05-08 20:25:30 +00:00 · 2026-04-22 20:29:48 +00:00 · 2026-04-20 02:48:32 +00:00 · 2026-04-15 18:49:43 +00:00
21 changed files with 748 additions and 609 deletions
--- a/.dockerignore
+++ b/.dockerignore
@ -1,4 +1,7 @@
-scripts
-.github
 .editorconfig
-.pre-commit-hooks.yaml
+.gitignore
+/.git/
+/.github/
+/.pre-commit-hooks.yaml
+/scripts/
+/target/
--- a/.github/workflows/deploy.yml
+++ b/.github/workflows/deploy.yml
@ -3,7 +3,12 @@ name: deploy
 on:
  push:
    tags:
-      - "v*.*.*"
+      - 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

 permissions:
  actions: read
@ -54,15 +59,15 @@ 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@v11
+        uses: dawidd6/action-download-artifact@v21
        with:
          workflow: oxipng.yml
-          commit: ${{ env.GITHUB_SHA }}
+          commit: ${{ github.sha }}
          name: Oxipng binary (${{ matrix.target }})
          path: target

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

      - name: Create release
-        uses: softprops/action-gh-release@v2
+        uses: softprops/action-gh-release@v3
        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
@ -17,76 +17,44 @@ on:
        type: boolean
        default: true

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

 jobs:
  build:
-    runs-on: ubuntu-latest
+    uses: docker/github-builder/.github/workflows/build.yml@v1
    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

-    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 }}
+    secrets:
+      registry-auths: |
+        - registry: ghcr.io
          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
@ -8,6 +8,11 @@ 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
@ -55,7 +60,6 @@ jobs:

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

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

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

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

      - name: Upload CLI binary as artifact
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v7
        with:
          name: Oxipng binary (${{ matrix.target }})
          path: |
--- a/.gitignore
+++ b/.gitignore
@ -1,6 +1,6 @@
-target
-*.bk
 .DS_Store
+*.bk
 *.out.png
-/.idea
-/node_modules
+/.idea/
+/node_modules/
+/target/
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -1,7 +1,21 @@
+## 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 = "0.6.20"
+version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3ae563653d1938f79b1ab1b5e668c87c76a9930414574a6583a7b7e11a8e6192"
+checksum = "824a212faf96e9acacdbd09febd34438f8f711fb84e09a8916013cd7815ca28d"
 dependencies = [
 "anstyle",
 "anstyle-parse",
@ -25,37 +25,37 @@ dependencies = [

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

 [[package]]
 name = "crc32fast"
@ -159,15 +159,6 @@ 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"
@ -201,18 +192,18 @@ checksum = "48c757948c5ede0e46177b7add2e67155f70e33c07fea8284df6576da70b3719"

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

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

 [[package]]
@ -245,29 +236,17 @@ dependencies = [
 "simd-adler32",
 ]

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

 [[package]]
 name = "png"
-version = "0.18.0"
+version = "0.18.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "97baced388464909d42d89643fe4361939af9b7ce7a31ee32a168f832a70f2a0"
+checksum = "60769b8b31b2a9f263dae2776c37b1b28ae246943cf719eb6946a1db05128a61"
 dependencies = [
 "bitflags",
 "crc32fast",
@ -451,12 +430,27 @@ dependencies = [
 ]

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

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

 [[package]]
 name = "rayon"
-version = "1.11.0"
+version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "368f01d005bf8fd9b1206fb6fa653e6c4a81ceb1466406b81792d87c5677a58f"
+checksum = "fb39b166781f92d482534ef4b4b1b2568f42613b53e5b6c160e24cfbfa30926d"
 dependencies = [
 "either",
 "rayon-core",
@ -485,41 +479,74 @@ dependencies = [
 "crossbeam-utils",
 ]

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

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

 [[package]]
 name = "rustix"
-version = "1.1.2"
+version = "1.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cd15f8a2c5551a84d56efdc1cd049089e409ac19a3072d5037a17fd70719ff3e"
+checksum = "b6fe4565b9518b83ef4f91bb47ce29620ca828bd32cb7e408f0062e9930ba190"
 dependencies = [
 "bitflags",
 "errno",
 "libc",
 "linux-raw-sys",
- "windows-sys 0.61.0",
+ "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",
 ]

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

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

 [[package]]
 name = "strsim"
@ -540,6 +567,17 @@ 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"
@ -548,14 +586,20 @@ checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"

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

+[[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"
@ -564,99 +608,19 @@ checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"

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

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

-[[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"
@ -666,6 +630,12 @@ 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 = "10.0.0"
+version = "10.1.1"
 rust-version = "1.85.1"

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

 [dependencies]
-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"
+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"] }

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

-[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"
+[dev-dependencies]
+serde_json = "1.0.150"

 [features]
 binary = ["dep:clap", "dep:glob", "dep:env_logger", "dep:parse-size"]
-default = ["binary", "parallel", "zopfli", "filetime"]
-parallel = ["dep:rayon", "indexmap/rayon", "dep:crossbeam-channel"]
+default = ["binary", "parallel", "zopfli"]
+parallel = ["dep:rayon", "indexmap/rayon"]
 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 10.0.0
+oxipng 10.1.0
 Losslessly improve compression of PNG files

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

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

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

  -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.
+interface or as a library in other Rust programs. It is fast and highly effective.

 ## Installing

@ -76,7 +76,14 @@ 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 without.
+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.

 ## Git integration via [pre-commit]

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

 ## History

-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.
+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.
 This also served as an opportunity to choose a more modern, safer language (Rust).

-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.
+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.

 ## Contributing

@ -151,42 +154,11 @@ 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
@ -1,5 +1,3 @@
-use std::io::Write;
-
 use crate::{
    PngResult,
    error::PngError,
@ -52,15 +50,14 @@ impl Frame {
    #[must_use]
    pub fn fctl_data(&self, sequence_number: u32) -> Vec<u8> {
        let mut byte_data = Vec::with_capacity(26);
-        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.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
    }

@ -68,8 +65,8 @@ 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.write_all(&sequence_number.to_be_bytes()).unwrap();
-        byte_data.write_all(&self.data).unwrap();
+        byte_data.extend_from_slice(&sequence_number.to_be_bytes());
+        byte_data.extend_from_slice(&self.data);
        byte_data
    }
 }
--- a/src/cli.rs
+++ b/src/cli.rs
@ -212,7 +212,7 @@ losslessly.")
        )
        .arg(
            Arg::new("verbose")
-                .help("Run in verbose mode (use twice to increase verbosity)")
+                .help("Show per-file info (use multiple times for more detail)")
                .short('v')
                .long("verbose")
                .action(ArgAction::Count)
@ -220,12 +220,20 @@ losslessly.")
        )
        .arg(
            Arg::new("quiet")
-                .help("Run in quiet mode")
+                .help("Suppress all output messages")
                .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)")
@ -290,6 +298,8 @@ 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 = unbounded();
+        let eval_channel = channel();
        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 = format!("{}", image.ihdr.color_type);
+        let description = image.ihdr.color_type.to_string();
        self.try_image_with_description(image, &description);
    }

@ -154,6 +154,19 @@ 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(),
@ -164,10 +177,6 @@ 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)
    }
-    // 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);
-    }
+    // 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));
    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, Metadata},
+    fs::File,
    io::{BufWriter, Read, Write, stdin, stdout},
-    path::{Path, PathBuf},
+    path::PathBuf,
    sync::{
        Arc,
        atomic::{AtomicBool, Ordering},
@ -64,6 +64,7 @@ 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
@ -86,7 +87,7 @@ impl RawImage {
        color_type: ColorType,
        bit_depth: BitDepth,
        data: Vec<u8>,
-    ) -> Result<Self, PngError> {
+    ) -> PngResult<Self> {
        // Validate bit depth
        let valid_depth = match color_type {
            ColorType::Grayscale { .. } => true,
@ -165,40 +166,15 @@ 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) -> PngResult<(usize, usize)> {
+pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> OptimizationResult {
    // 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) => {
-            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::Path(ref input_path) => PngData::read_file(input_path)?,
        InFile::StdIn => {
-            opt_metadata_preserved = None;
            let mut data = Vec::new();
            stdin()
                .read_to_end(&mut data)
@ -220,7 +196,7 @@ pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> PngResult<(
            (OutFile::Path { path, .. }, InFile::Path(input_path))
                if path.as_ref().is_none_or(|p| p == input_path) =>
            {
-                info!("{input}: Could not optimize further, no change written");
+                info!("Could not optimize further, no change written: {input}");
                return Ok((in_length, in_length));
            }
            _ => {
@ -252,18 +228,34 @@ pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> PngResult<(
            buffer
                .write_all(&optimized_output)
                .map_err(|e| PngError::WriteFailed("stdout".into(), e))?;
+            info!("{savings}: stdout");
        }
-        (OutFile::Path { path, .. }, _) => {
+        (
+            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
+            };
+
            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!
@ -271,8 +263,18 @@ pub fn optimize(input: &InFile, output: &OutFile, opts: &Options) -> PngResult<(
                .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) = &opt_metadata_preserved {
-                copy_times(metadata_input, output_path)?;
+
+            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}");
+                }
            }
            info!("{}: {}", savings, output_path.display());
        }
@ -642,29 +644,3 @@ 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
@ -6,9 +6,10 @@ use std::num::NonZeroU64;
 use std::{
    ffi::{OsStr, OsString},
    fs::DirBuilder,
-    io::Write,
+    io::{IsTerminal, Write, stdout},
    path::PathBuf,
    process::ExitCode,
+    sync::atomic::{AtomicUsize, Ordering::AcqRel},
    time::Duration,
 };

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

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

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

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

-    match summary.unwrap_or(OptimizationResult::Skipped) {
-        OptimizationResult::Ok => ExitCode::SUCCESS,
-        OptimizationResult::Failed => ExitCode::FAILURE,
-        OptimizationResult::Skipped => ExitCode::from(3),
+    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();
    }
-}
+    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()
+    };

-#[derive(Eq, PartialEq, Ord, PartialOrd)]
-enum OptimizationResult {
-    Ok,
-    Failed,
-    Skipped,
+    // 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)
+    }
 }

 fn collect_files(
@ -98,10 +178,8 @@ 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 {
-        let using_stdin = allow_stdin && input.to_str() == Some("-");
-        if !using_stdin && input.is_dir() {
+        if input.is_dir() {
            if recursive {
                match input.read_dir() {
                    Ok(dir) => {
@ -118,6 +196,15 @@ 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()));
@ -128,19 +215,7 @@ fn collect_files(
            } else {
                (*out_file).clone()
            };
-        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)
-        };
+        let in_file = InFile::Path(input);
        in_out_pairs.push((in_file, out_file));
    }
    in_out_pairs
@ -165,8 +240,9 @@ 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::Info,
-        1 => LevelFilter::Debug,
+        0 => LevelFilter::Warn,
+        1 => LevelFilter::Info,
+        2 => LevelFilter::Debug,
        _ => LevelFilter::Trace,
    };
    env_logger::builder()
@ -175,7 +251,8 @@ fn parse_opts_into_struct(
            match record.level() {
                Level::Error | Level::Warn => {
                    let style = buf.default_level_style(record.level());
-                    writeln!(buf, "{style}{}{style:#}", record.args())
+                    // Prepend carriage return to clear progress line
+                    writeln!(buf, "\r{style}{}{style:#}", record.args())
                }
                // Leave info, debug and trace unstyled
                _ => writeln!(buf, "{}", record.args()),
@ -353,6 +430,16 @@ 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,
@ -440,26 +527,128 @@ 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 OptimizationResult::Skipped;
+            return Err(PngError::InflatedDataTooLong(max_size));
        }
    }

-    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,
+    let result = oxipng::optimize(input, output, opts);
+    match &result {
+        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
@ -1,13 +1,11 @@
-use std::{fs, io::Write, path::Path, sync::Arc};
+use std::{fs, path::Path, sync::Arc};

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

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

        Self::from_slice(&byte_data, opts)
    }

-    pub fn read_file(filepath: &Path) -> Result<Vec<u8>, PngError> {
+    pub fn read_file(filepath: &Path) -> PngResult<Vec<u8>> {
        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) -> Result<Self, PngError> {
+    pub fn from_slice(byte_data: &[u8], opts: &Options) -> PngResult<Self> {
        let mut byte_offset: usize = 0;
        // Test that png header is valid
        let header = byte_data.get(0..8).ok_or(PngError::TruncatedData)?;
@ -165,17 +163,15 @@ 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.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();
+        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,
+        ]);
        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");
@ -194,7 +190,7 @@ 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_slice());
+                    palette_data.extend_from_slice(px.rgb().as_ref());
                }
                write_png_block(b"PLTE", &palette_data, &mut output);
                if let Some(last_trns) = palette.iter().rposition(|px| px.a != 255) {
@ -250,7 +246,7 @@ impl PngData {
 }

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

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

    /// Reverse all filters applied on the image, returning an unfiltered IDAT bytestream
-    fn unfilter_image(&self) -> Result<Vec<u8>, PngError> {
+    fn unfilter_image(&self) -> PngResult<Vec<u8>> {
        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();
@ -376,6 +372,12 @@ 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()];
@ -467,18 +469,29 @@ 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 set = bitarr![0; 0x10000];
+                            let mut count = 0;
                            for pair in f_buf.windows(2) {
                                let bigram = ((pair[0] as usize) << 8) | pair[1] as usize;
-                                set.set(bigram, true);
+                                if !bigram_seen[bigram] {
+                                    count += 1;
+                                    if count >= best_size {
+                                        break;
+                                    }
+                                    bigram_seen[bigram] = true;
+                                    bigram_touched.push(bigram as u16);
+                                }
                            }
-                            let size = set.count_ones();
-                            if size < best_size {
-                                best_size = size;
+                            if count < best_size {
+                                best_size = count;
                                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, ComponentSlice, FromSlice, RGB, RGBA, alt::Gray};
+use rgb::{ComponentMap, 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_slice()[ch_start..=ch_end]);
+        data.extend_from_slice(&color.as_ref()[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 && !deadline.passed() {
+    if opts.color_type_reduction && opts.palette_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
@ -1,11 +1,12 @@
+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;
@ -95,13 +96,9 @@ fn test_it_converts(

 #[test]
 fn verbose_mode() {
-    use std::cell::RefCell;
-    #[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};
+    use std::cell::RefCell;
+    use std::sync::mpsc::{Sender, channel};

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

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

    let thread_init = move || {
        // Initialise logs storage for all threads within our test.
@ -430,12 +427,9 @@ 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 file metadata for output file");
-    #[cfg(feature = "filetime")]
-    let mtime_canon = filetime::FileTime::from_last_modification_time(&meta_input);
+        .expect("unable to get metadata for input file");

    let (mut output, opts) = get_opts(&input);
    if let OutFile::Path { preserve_attrs, .. } = &mut output {
@ -449,17 +443,6 @@ 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) => {
@ -468,9 +451,21 @@ fn preserve_attrs() {
        }
    };

-    remove_file(output).ok();
+    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",
+    );

-    // TODO: Actually check permissions
+    remove_file(output).ok();
 }

 #[test]
@ -664,3 +659,39 @@ 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");
+}