diff --git a/.github/workflows/ci-android-emulator-tests.yml b/.github/workflows/ci-android-emulator-tests.yml
index 99593716bb..dbfec722f3 100644
--- a/.github/workflows/ci-android-emulator-tests.yml
+++ b/.github/workflows/ci-android-emulator-tests.yml
@@ -45,12 +45,6 @@ jobs:
         run: pip install meson
       - name: Setup nasm
         uses: ilammy/setup-nasm@13cbeb366c45c4379d3478cdcbadd8295feb5028 # v1.5.1
-      - name: Build dav1d with the Android NDK
-        working-directory: ext
-        run: bash dav1d_android.sh ${{ steps.setup-ndk.outputs.ndk-path }}
-      - name: Build libyuv with the Android NDK
-        working-directory: ext
-        run: bash libyuv_android.sh ${{ steps.setup-ndk.outputs.ndk-path }}
       - name: Setup JDK
         uses: actions/setup-java@387ac29b308b003ca37ba93a6cab5eb57c8f5f93 # v4.0.0
         with:
diff --git a/.github/workflows/ci-android-jni.yml b/.github/workflows/ci-android-jni.yml
index 19d2105ae4..f6b7cf420b 100644
--- a/.github/workflows/ci-android-jni.yml
+++ b/.github/workflows/ci-android-jni.yml
@@ -39,12 +39,6 @@ jobs:
         run: pip install meson
       - name: Setup nasm
         uses: ilammy/setup-nasm@13cbeb366c45c4379d3478cdcbadd8295feb5028 # v1.5.1
-      - name: Build dav1d with the Android NDK
-        working-directory: ext
-        run: bash dav1d_android.sh ${{ steps.setup-ndk.outputs.ndk-path }}
-      - name: Build libyuv with the Android NDK
-        working-directory: ext
-        run: bash libyuv_android.sh ${{ steps.setup-ndk.outputs.ndk-path }}
       - name: Setup JDK
         uses: actions/setup-java@387ac29b308b003ca37ba93a6cab5eb57c8f5f93 # v4.0.0
         with:
diff --git a/.github/workflows/ci-disable-gtest.yml b/.github/workflows/ci-disable-gtest.yml
index 95963f4eea..c8c12a16b8 100644
--- a/.github/workflows/ci-disable-gtest.yml
+++ b/.github/workflows/ci-disable-gtest.yml
@@ -41,12 +41,12 @@ jobs:
         toolchain: stable
         override: true
 
-    - name: Cache external dependencies
-      id: cache-ext
-      uses: actions/cache@13aacd865c20de90d75de3b17ebe84f7a17d57d2 # v4.0.0
-      with:
-        path: ext
-        key: ${{ runner.os }}-disable-gtest-${{ hashFiles('ext/*.cmd', 'ext/svt.sh') }}
+    - name: Install cargo-c
+      env:
+        LINK: https://github.com/lu-zero/cargo-c/releases/latest/download
+        CARGO_C_FILE: cargo-c-x86_64-unknown-linux-musl.tar.gz
+      run: |
+        curl -L $LINK/$CARGO_C_FILE | tar xz -C ~/.cargo/bin
     - name: Setup cmake
       uses: jwlawson/actions-setup-cmake@d06b37b47cfd043ec794ffa3e40e0b6b5858a7ec # v1.14.2
       with:
@@ -59,30 +59,6 @@ jobs:
         version: 2.15.05
     - uses: seanmiddleditch/gha-setup-ninja@8b297075da4cd2a5f1fd21fe011b499edf06e9d2 # v4
     - run: pip install meson
-    - name: Build aom
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e aom.cmd
-    - name: Build dav1d
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e dav1d.cmd
-    - name: Build rav1e
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e rav1e.cmd
-    - name: Build SVT-AV1
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e svt.cmd
-    - name: Build libyuv
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e libyuv.cmd
-    - name: Build libsharpyuv
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e libsharpyuv.cmd
 
     - name: Prepare libavif (cmake)
       run: >
@@ -96,6 +72,15 @@ jobs:
         -DAVIF_BUILD_EXAMPLES=ON -DAVIF_BUILD_APPS=ON
         -DAVIF_BUILD_TESTS=ON -DAVIF_ENABLE_GTEST=OFF
         -DAVIF_ENABLE_WERROR=ON
+    - name: Cache cargo registry
+      uses: actions/cache@88522ab9f39a2ea568f7027eddc7d8d8bc9d59c8 # v3.3.1
+      continue-on-error: true
+      with:
+        path: ~/.cargo/registry/cache
+        key: cargo-registry-${{ runner.os }}-${{ hashFiles('ext/rav1e/Cargo.lock') }}-disable-gtest
+        restore-keys: |
+          cargo-registry-${{ runner.os }}-${{ hashFiles('ext/rav1e/Cargo.lock') }}-
+          cargo-registry-${{ runner.os }}-
     - name: Build libavif (ninja)
       working-directory: ./build
       run: ninja
diff --git a/.github/workflows/ci-linux-golden-tests.yml b/.github/workflows/ci-linux-golden-tests.yml
index 48a6fa5247..e946b16a27 100644
--- a/.github/workflows/ci-linux-golden-tests.yml
+++ b/.github/workflows/ci-linux-golden-tests.yml
@@ -38,7 +38,8 @@ jobs:
       uses: actions/cache@13aacd865c20de90d75de3b17ebe84f7a17d57d2 # v4.0.0
       with:
         path: ext
-        key: ${{ runner.os }}-golden-tests-${{ hashFiles('ext/aom.cmd', 'ext/libyuv.cmd', 'ext/libxml2.cmd', 'ext/mp4box.sh') }}
+        key: ${{ runner.os }}-golden-tests-${{ hashFiles('ext/mp4box.sh') }}
+
     - name: Setup cmake
       uses: jwlawson/actions-setup-cmake@d06b37b47cfd043ec794ffa3e40e0b6b5858a7ec
       with:
@@ -50,18 +51,6 @@ jobs:
       with:
         version: 2.15.05
     - uses: seanmiddleditch/gha-setup-ninja@8b297075da4cd2a5f1fd21fe011b499edf06e9d2 # v4
-    - name: Build aom
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e aom.cmd
-    - name: Build libyuv
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e libyuv.cmd
-    - name: Build libxml2
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e libxml2.cmd
     - name: Build mp4box
       if: steps.cache-ext.outputs.cache-hit != 'true'
       working-directory: ./ext
diff --git a/.github/workflows/ci-mingw.yml b/.github/workflows/ci-mingw.yml
index aae454ab03..922baf647f 100644
--- a/.github/workflows/ci-mingw.yml
+++ b/.github/workflows/ci-mingw.yml
@@ -46,22 +46,8 @@ jobs:
           libyuv:p
           ninja:p
           zlib:p
-    - name: Cache external dependencies
-      id: cache-ext
-      uses: actions/cache@13aacd865c20de90d75de3b17ebe84f7a17d57d2 # v4.0.0
-      with:
-        path: ext
-        key: ${{ matrix.sys }}-mingw-${{ hashFiles('ext/*.cmd') }}
     - name: Print cmake version
       run: cmake --version
-    - name: Build libsharpyuv
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: ./libsharpyuv.cmd
-    - name: Build GoogleTest
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: ./googletest.cmd
 
     - name: Prepare libavif (cmake)
       run: >
diff --git a/.github/workflows/ci-unix-shared-installed.yml b/.github/workflows/ci-unix-shared-installed.yml
index 13052aa4f4..9786770544 100644
--- a/.github/workflows/ci-unix-shared-installed.yml
+++ b/.github/workflows/ci-unix-shared-installed.yml
@@ -33,13 +33,6 @@ jobs:
       # TODO(yguyon): Install libyuv (not available with brew).
       if: runner.os == 'macOS'
       run: echo "CMAKE_AVIF_FLAGS=\"-DAVIF_LIBYUV=OFF\""  >> $GITHUB_ENV
-
-    - name: Cache external dependencies
-      id: cache-ext
-      uses: actions/cache@13aacd865c20de90d75de3b17ebe84f7a17d57d2 # v4.0.0
-      with:
-        path: ext
-        key: ${{ runner.os }}-shared-installed-${{ hashFiles('ext/*.cmd') }}
     - name: Setup cmake
       uses: jwlawson/actions-setup-cmake@d06b37b47cfd043ec794ffa3e40e0b6b5858a7ec # v1.14.2
       with:
@@ -62,11 +55,6 @@ jobs:
       # `sudo apt-get install googletest libgtest-dev` leads to the following:
       #   "libgtest.a(gtest-all.cc.o): undefined reference to `std::__throw_bad_array_new_length()'"
       # so build it locally instead.
-    - name: Build GoogleTest
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e googletest.cmd
-
     - name: Prepare libavif (cmake)
       run: >
         mkdir build && cd build
diff --git a/.github/workflows/ci-unix-shared-local.yml b/.github/workflows/ci-unix-shared-local.yml
index 079b67e0e9..59e9b86abc 100644
--- a/.github/workflows/ci-unix-shared-local.yml
+++ b/.github/workflows/ci-unix-shared-local.yml
@@ -37,13 +37,6 @@ jobs:
     - uses: actions/setup-python@0a5c61591373683505ea898e09a3ea4f39ef2b9c # v5.0.0
       with:
         python-version: '3.x'
-
-    - name: Cache external dependencies
-      id: cache-ext
-      uses: actions/cache@13aacd865c20de90d75de3b17ebe84f7a17d57d2 # v4.0.0
-      with:
-        path: ext
-        key: ${{ runner.os }}-shared-local-${{ hashFiles('ext/*.cmd') }}
     - name: Setup cmake
       uses: jwlawson/actions-setup-cmake@d06b37b47cfd043ec794ffa3e40e0b6b5858a7ec # v1.14.2
       with:
@@ -58,26 +51,6 @@ jobs:
     - run: pip install meson
     - name: Print ImageMagick version
       run: convert --version
-    - name: Build aom
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e aom.cmd
-    - name: Build dav1d
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e dav1d.cmd
-    - name: Build libyuv
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e libyuv.cmd
-    - name: Build libsharpyuv
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e libsharpyuv.cmd
-    - name: Build GoogleTest
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e googletest.cmd
 
     - name: Prepare libavif (cmake)
       run: >
diff --git a/.github/workflows/ci-unix-static-av2.yml b/.github/workflows/ci-unix-static-av2.yml
index 4fe842672f..d33fbc5fd7 100644
--- a/.github/workflows/ci-unix-static-av2.yml
+++ b/.github/workflows/ci-unix-static-av2.yml
@@ -34,13 +34,13 @@ jobs:
         profile: minimal
         toolchain: stable
         override: true
+    - name: Install cargo-c
+      env:
+        LINK: https://github.com/lu-zero/cargo-c/releases/latest/download
+        CARGO_C_FILE: cargo-c-x86_64-unknown-linux-musl.tar.gz
+      run: |
+        curl -L $LINK/$CARGO_C_FILE | tar xz -C ~/.cargo/bin
 
-    - name: Cache external dependencies
-      id: cache-ext
-      uses: actions/cache@13aacd865c20de90d75de3b17ebe84f7a17d57d2 # v4.0.0
-      with:
-        path: ext
-        key: ${{ runner.os }}-static-av2-${{ hashFiles('ext/*.cmd', 'ext/svt.sh') }}
     - name: Setup cmake
       uses: jwlawson/actions-setup-cmake@d06b37b47cfd043ec794ffa3e40e0b6b5858a7ec # v1.14.2
       with:
@@ -53,35 +53,6 @@ jobs:
         version: 2.15.05
     - uses: seanmiddleditch/gha-setup-ninja@8b297075da4cd2a5f1fd21fe011b499edf06e9d2 # v4
     - run: pip install meson
-    - name: Build avm
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e avm.cmd
-    - name: Build dav1d
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e dav1d.cmd
-    - name: Build rav1e
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e rav1e.cmd
-    - name: Build SVT-AV1
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e svt.cmd
-    - name: Build libyuv
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e libyuv.cmd
-    - name: Build libsharpyuv
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e libsharpyuv.cmd
-    - name: Build GoogleTest
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      # Note: "apt install googletest" is sometimes insufficient for find_package(GTest) so build in ext/ instead.
-      run: bash -e googletest.cmd
 
     - name: Prepare libavif (cmake)
       run: >
@@ -98,6 +69,15 @@ jobs:
         -DAVIF_BUILD_EXAMPLES=ON -DAVIF_BUILD_APPS=ON
         -DAVIF_BUILD_TESTS=ON -DAVIF_ENABLE_GTEST=ON -DAVIF_LOCAL_GTEST=ON
         -DAVIF_ENABLE_WERROR=ON
+    - name: Cache cargo registry
+      uses: actions/cache@88522ab9f39a2ea568f7027eddc7d8d8bc9d59c8 # v3.3.1
+      continue-on-error: true
+      with:
+        path: ~/.cargo/registry/cache
+        key: cargo-registry-${{ runner.os }}-${{ hashFiles('ext/rav1e/Cargo.lock') }}-unix-static-av2
+        restore-keys: |
+          cargo-registry-${{ runner.os }}-${{ hashFiles('ext/rav1e/Cargo.lock') }}-
+          cargo-registry-${{ runner.os }}-
     - name: Build libavif (ninja)
       working-directory: ./build
       run: ninja
diff --git a/.github/workflows/ci-unix-static.yml b/.github/workflows/ci-unix-static.yml
index 8840751213..12e0c91de9 100644
--- a/.github/workflows/ci-unix-static.yml
+++ b/.github/workflows/ci-unix-static.yml
@@ -35,18 +35,28 @@ jobs:
         profile: minimal
         toolchain: stable
         override: true
+    - name: Install cargo-c (linux)
+      if: matrix.os == 'ubuntu-latest'
+      env:
+        LINK: https://github.com/lu-zero/cargo-c/releases/latest/download
+        CARGO_C_FILE: cargo-c-x86_64-unknown-linux-musl.tar.gz
+      run: |
+        curl -L $LINK/$CARGO_C_FILE | tar xz -C ~/.cargo/bin
+    - name: Install cargo-c (mac)
+      if: matrix.os == 'macos-latest'
+      env:
+        LINK: https://github.com/lu-zero/cargo-c/releases/latest/download
+        CARGO_C_FILE: cargo-c-macos.zip
+      run: |
+        curl -sLo $CARGO_C_FILE $LINK/$CARGO_C_FILE
+        unzip -o $CARGO_C_FILE -d ~/.cargo/bin
+        rm $CARGO_C_FILE
 
-    - name: Cache external dependencies
-      id: cache-ext
-      uses: actions/cache@13aacd865c20de90d75de3b17ebe84f7a17d57d2 # v4.0.0
-      with:
-        path: ext
-        key: ${{ runner.os }}-${{ matrix.build-type }}-${{ hashFiles('ext/*.cmd', 'ext/svt.sh') }}
     - name: Setup cmake
       uses: jwlawson/actions-setup-cmake@d06b37b47cfd043ec794ffa3e40e0b6b5858a7ec # v1.14.2
       with:
-        # CMake version 3.17 is required to build libwebp (which libsharpyuv is part of) on macOS.
-        cmake-version: '3.17.x'
+        # CMake version 3.18 is required to build libxml2
+        cmake-version: '3.18.x'
     - name: Print cmake version
       run: cmake --version
     - uses: ilammy/setup-nasm@13cbeb366c45c4379d3478cdcbadd8295feb5028 # v1.5.1
@@ -56,44 +66,6 @@ jobs:
     - run: pip install meson
     - name: Print ImageMagick version
       run: convert --version
-    - name: Build aom
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e aom.cmd
-    - name: Build dav1d
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e dav1d.cmd
-    - name: Build rav1e
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e rav1e.cmd
-    - name: Build SVT-AV1
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e svt.cmd
-    - name: Build libgav1
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e libgav1.cmd
-    - name: Build libyuv
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e libyuv.cmd
-    - name: Build libsharpyuv
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e libsharpyuv.cmd
-    - name: Build libargparse
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: bash -e libargparse.cmd
-    - name: Build GoogleTest
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      # Note: "apt install googletest" is sometimes insufficient for find_package(GTest) so build in ext/ instead.
-      run: bash -e googletest.cmd
-
     - name: Prepare libavif (cmake)
       run: >
         mkdir build && cd build
@@ -104,12 +76,22 @@ jobs:
         -DAVIF_CODEC_RAV1E=LOCAL -DAVIF_CODEC_SVT=LOCAL
         -DAVIF_CODEC_LIBGAV1=LOCAL -DAVIF_LIBYUV=LOCAL
         -DAVIF_LIBSHARPYUV=LOCAL
+        -DAVIF_LOCAL_LIBARGPARSE=ON
         -DAVIF_BUILD_EXAMPLES=ON -DAVIF_BUILD_APPS=ON
         -DAVIF_BUILD_TESTS=ON -DAVIF_ENABLE_GTEST=ON -DAVIF_LOCAL_GTEST=ON
         -DAVIF_ENABLE_EXPERIMENTAL_YCGCO_R=ON
         -DAVIF_ENABLE_EXPERIMENTAL_GAIN_MAP=ON
         -DAVIF_ENABLE_EXPERIMENTAL_AVIR=ON
         -DAVIF_ENABLE_WERROR=ON
+    - name: Cache cargo registry
+      uses: actions/cache@88522ab9f39a2ea568f7027eddc7d8d8bc9d59c8 # v3.3.1
+      continue-on-error: true
+      with:
+        path: ~/.cargo/registry/cache
+        key: cargo-registry-${{ runner.os }}-${{ hashFiles('ext/rav1e/Cargo.lock') }}-unix-static
+        restore-keys: |
+          cargo-registry-${{ runner.os }}-${{ hashFiles('ext/rav1e/Cargo.lock') }}-
+          cargo-registry-${{ runner.os }}-
     - name: Build libavif (ninja)
       working-directory: ./build
       run: ninja
diff --git a/.github/workflows/ci-windows.yml b/.github/workflows/ci-windows.yml
index 91a71b81d9..31a4853dcb 100644
--- a/.github/workflows/ci-windows.yml
+++ b/.github/workflows/ci-windows.yml
@@ -48,7 +48,13 @@ jobs:
       uses: actions/cache@13aacd865c20de90d75de3b17ebe84f7a17d57d2 # v4.0.0
       with:
         path: ext
-        key: ${{ runner.os }}-${{ hashFiles('ext/*.cmd') }}-alldeps
+        key: ${{ runner.os }}-${{ hashFiles('ext/aom.cmd', 'ext/libyuv.cmd') }}-alldeps
+    - name: Install cargo-c
+      run: |
+        $LINK = "https://github.com/lu-zero/cargo-c/releases/latest/download"
+        $CARGO_C_FILE = "cargo-c-windows-msvc"
+        curl -LO "$LINK/$CARGO_C_FILE.zip"
+        7z e -y "$CARGO_C_FILE.zip" -o"${env:USERPROFILE}\.cargo\bin"
     - name: Print cmake version
       run: cmake --version
     - uses: ilammy/setup-nasm@13cbeb366c45c4379d3478cdcbadd8295feb5028 # v1.5.1
@@ -68,22 +74,6 @@ jobs:
       env:
         CC: clang-cl
         CXX: clang-cl
-    - name: Build dav1d
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: ./dav1d.cmd
-    - name: Build rav1e
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: ./rav1e.cmd
-    - name: Build SVT-AV1
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: ./svt.cmd
-    - name: Build libgav1
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: ./libgav1.cmd
     - name: Build libyuv
       if: steps.cache-ext.outputs.cache-hit != 'true'
       working-directory: ./ext
@@ -93,22 +83,6 @@ jobs:
       env:
         CC: clang-cl
         CXX: clang-cl
-    - name: Build libjpeg
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: ./libjpeg.cmd
-    - name: Build libsharpyuv
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: ./libsharpyuv.cmd
-    - name: Build zlib and libpng
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: ./zlibpng.cmd
-    - name: Build GoogleTest
-      if: steps.cache-ext.outputs.cache-hit != 'true'
-      working-directory: ./ext
-      run: ./googletest.cmd
 
     - name: Prepare libavif (cmake)
       run: >
@@ -126,6 +100,14 @@ jobs:
         -DAVIF_ENABLE_EXPERIMENTAL_YCGCO_R=ON
         -DAVIF_ENABLE_EXPERIMENTAL_GAIN_MAP=ON
         -DAVIF_ENABLE_EXPERIMENTAL_AVIR=ON -DAVIF_ENABLE_WERROR=ON
+    - name: Cache cargo registry
+      uses: actions/cache@88522ab9f39a2ea568f7027eddc7d8d8bc9d59c8 # v3.3.1
+      continue-on-error: true
+      with:
+        path: ~/.cargo/registry/cache
+        key: cargo-registry-${{ runner.os }}-${{ hashFiles('ext/rav1e/Cargo.lock') }}-
+        restore-keys: |
+          cargo-registry-${{ runner.os }}-
     - name: Build libavif (ninja)
       working-directory: ./build
       run: ninja
@@ -138,16 +120,16 @@ jobs:
         /DWIN32 /D_WINDOWS /MD /O2 /Ob2
         -I.\apps\shared -I.\include -I.\third_party\iccjpeg
         -external:W0
-        -external:I.\ext\libpng
-        -external:I.\ext\libjpeg-turbo
-        -external:I.\ext\libjpeg-turbo\build.libavif
-        -external:I.\ext\zlib
-        -external:I.\build\ext\libpng
-        -external:I.\build\ext\zlib
+        -external:I.\build\_deps\libpng-src
+        -external:I.\build\libjpeg\src\libjpeg
+        -external:I.\build\libjpeg\src\libjpeg-build
+        -external:I.\build\_deps\zlib-src
+        -external:I.\build\_deps\libpng
+        -external:I.\build\_deps\zlib
         /link
-        ext\libjpeg-turbo\build.libavif\jpeg-static.lib
-        build\ext\libpng\libpng16_static.lib
-        build\ext\zlib\zlibstatic.lib
+        build\libjpeg\src\libjpeg-build\jpeg-static.lib
+        build\_deps\libpng\libpng16_static.lib
+        build\_deps\zlib\zlibstatic.lib
         build\avif.lib
         ws2_32.lib ntdll.lib userenv.lib bcrypt.lib advapi32.lib
         /out:avifenc.exe
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 30644e8a6b..8214ab18de 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,12 +8,23 @@ if(POLICY CMP0092)
     cmake_policy(SET CMP0092 NEW)
 endif()
 
+# Prevent warnings in CMake>=3.24 for ExternalProject_Add()
+# see https://cmake.org/cmake/help/latest/policy/CMP0135.html
+if(POLICY CMP0135)
+    cmake_policy(SET CMP0135 NEW) # valid for DOWNLOAD_EXTRACT_TIMESTAMP option in CMake 3.24 and later
+endif()
+
 # The root directory of the avif source
 set(AVIF_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}")
 
 # Specify search path for CMake modules to be loaded by include() and find_package()
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules")
 
+include(ExternalProject)
+include(FetchContent)
+include(FindPkgConfig)
+include(AvifExternalProjectUtils)
+
 project(libavif LANGUAGES C VERSION 1.0.4)
 
 # Set C99 as the default
@@ -106,6 +117,9 @@ option(AVIF_LOCAL_FUZZTEST
        "Build the Google FuzzTest framework by providing your own copy of the repo in ext/fuzztest (see Local Builds in README)"
        OFF
 )
+option(AVIF_LOCAL_LIBARGPARSE "Build libargparse locally as part of the CMake build process. Required to build avifgainmap util"
+       OFF
+)
 
 option(
     AVIF_ENABLE_COMPLIANCE_WARDEN
@@ -450,10 +464,13 @@ if(AVIF_CODEC_RAV1E_ENABLED)
     target_sources(avif_obj PRIVATE src/codec_rav1e.c)
 
     # Unfortunately, rav1e requires a few more libraries
-    if(WIN32)
-        target_link_libraries(rav1e::rav1e INTERFACE ntdll.lib userenv.lib ws2_32.lib bcrypt.lib)
-    elseif(UNIX AND NOT APPLE)
-        target_link_libraries(rav1e::rav1e INTERFACE ${CMAKE_DL_LIBS}) # for backtrace
+    # first check that RAV1E_LIBRARIES hasn't been populated by the LocalRav1e module
+    if(NOT RAV1E_LIBRARIES)
+        if(WIN32)
+            target_link_libraries(rav1e::rav1e INTERFACE ntdll.lib userenv.lib ws2_32.lib bcrypt.lib)
+        elseif(UNIX AND NOT APPLE)
+            target_link_libraries(rav1e::rav1e INTERFACE ${CMAKE_DL_LIBS}) # for backtrace
+        endif()
     endif()
 
     avif_target_link_library(rav1e::rav1e)
@@ -716,8 +733,8 @@ if(AVIF_BUILD_APPS)
         )
     endif()
     if(AVIF_ENABLE_EXPERIMENTAL_GAIN_MAP)
-        include(LocalLibargparse)
-        if(TARGET libargparse)
+        if(AVIF_LOCAL_LIBARGPARSE)
+            include(LocalLibargparse)
             set(AVIF_ENABLE_AVIFGAINMAPUTIL TRUE)
 
             set(AVIFGAINMAPUTIL_SRCS
@@ -743,6 +760,8 @@ if(AVIF_BUILD_APPS)
             target_include_directories(avifgainmaputil PRIVATE apps/avifgainmaputil/)
             target_link_libraries(avifgainmaputil libargparse avif_apps)
             # Don't add avifgainmaputil to installed apps for now.
+        else()
+            message(WARNING "AVIF_LOCAL_LIBARGPARSE is not enabled, not building avifgainmaputil")
         endif()
     endif()
 endif()
diff --git a/appveyor.yml b/appveyor.yml
index 1d1c6b6285..714e30009e 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -23,8 +23,6 @@ install:
  - dav1d.cmd
  - libjpeg.cmd
  - zlibpng.cmd
- - set "CC=clang-cl" && set "CXX=clang-cl"
- - libyuv.cmd
  - set "CC=" && set "CXX="
  - cd ..
  # Configure with CMake
diff --git a/cmake/Meson/crossfile-apple.meson.in b/cmake/Meson/crossfile-apple.meson.in
new file mode 100644
index 0000000000..800d35b684
--- /dev/null
+++ b/cmake/Meson/crossfile-apple.meson.in
@@ -0,0 +1,16 @@
+[binaries]
+c = ['clang']
+cpp = ['clang++']
+ar = ['ar']
+strip = ['strip']
+pkg-config = ['pkg-config']
+
+[host_machine]
+system = '@cross_system_name@'
+cpu_family = '@cross_system_processor@'
+cpu = '@cross_system_processor@'
+endian = '@cross_system_endian@'
+
+[built-in options]
+c_args = ['-arch', '@CMAKE_SYSTEM_PROCESSOR@', '-isysroot', '@CMAKE_OSX_SYSROOT@', '@cross_osx_deployment_target@' @cross_additional_cflags@]
+c_link_args = ['-arch', '@CMAKE_SYSTEM_PROCESSOR@', '-isysroot', '@CMAKE_OSX_SYSROOT@', '@cross_osx_deployment_target@' @cross_additional_cflags@]
diff --git a/cmake/Modules/AvifExternalProjectUtils.cmake b/cmake/Modules/AvifExternalProjectUtils.cmake
new file mode 100644
index 0000000000..8d19e53b48
--- /dev/null
+++ b/cmake/Modules/AvifExternalProjectUtils.cmake
@@ -0,0 +1,13 @@
+macro(avif_fetchcontent_populate_cmake name)
+    if(NOT ${name}_POPULATED)
+        FetchContent_Populate(${name})
+
+        # Force static build
+        set(BUILD_SHARED_LIBS_ORIG ${BUILD_SHARED_LIBS})
+        set(BUILD_SHARED_LIBS OFF CACHE INTERNAL "")
+
+        add_subdirectory(${${name}_SOURCE_DIR} ${${name}_BINARY_DIR} EXCLUDE_FROM_ALL)
+
+        set(BUILD_SHARED_LIBS ${BUILD_SHARED_LIBS_ORIG} CACHE BOOL "" FORCE)
+    endif()
+endmacro()
diff --git a/cmake/Modules/LocalAom.cmake b/cmake/Modules/LocalAom.cmake
index 6d67775b60..4a40b10412 100644
--- a/cmake/Modules/LocalAom.cmake
+++ b/cmake/Modules/LocalAom.cmake
@@ -1,8 +1,150 @@
-set(LIB_FILENAME "${AVIF_SOURCE_DIR}/ext/aom/build.libavif/${CMAKE_STATIC_LIBRARY_PREFIX}aom${CMAKE_STATIC_LIBRARY_SUFFIX}")
-if(NOT EXISTS "${LIB_FILENAME}")
-    message(FATAL_ERROR "libavif: ${LIB_FILENAME} is missing, bailing out")
+set(AVIF_LOCAL_AOM_GIT_TAG v3.8.1)
+set(AVIF_LOCAL_AVM_GIT_TAG research-v6.0.0)
+
+if(AVIF_CODEC_AVM)
+    # Building the avm repository generates files such as "libaom.a" because it is a fork of aom,
+    # so its build can be treated the same as aom
+    set(AOM_PACKAGE_NAME avm)
+    set(AOM_MESSAGE_PREFIX "libavif(AVIF_CODEC_AVM=LOCAL)")
+else()
+    set(AOM_PACKAGE_NAME aom)
+    set(AOM_MESSAGE_PREFIX "libavif(AVIF_CODEC_AOM=LOCAL)")
 endif()
 
-add_library(aom STATIC IMPORTED GLOBAL)
-set_target_properties(aom PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}" AVIF_LOCAL ON)
-target_include_directories(aom INTERFACE "${AVIF_SOURCE_DIR}/ext/aom")
+set(AOM_EXT_SOURCE_DIR "${AVIF_SOURCE_DIR}/ext/${AOM_PACKAGE_NAME}")
+set(LIB_FILENAME "${AVIF_SOURCE_DIR}/ext/aom/build.libavif/${CMAKE_STATIC_LIBRARY_PREFIX}aom${CMAKE_STATIC_LIBRARY_SUFFIX}")
+
+if(EXISTS "${LIB_FILENAME}")
+    message(STATUS "${AOM_MESSAGE_PREFIX}: compiled library found at ${LIB_FILENAME}")
+    add_library(aom STATIC IMPORTED GLOBAL)
+    set_target_properties(aom PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}" AVIF_LOCAL ON)
+    target_include_directories(aom INTERFACE "${AOM_EXT_SOURCE_DIR}")
+    if(AVIF_CODEC_AVM)
+        # ext/avm/aom/aom_encoder.h includes config/aom_config.h which is generated by the local build of avm.
+        target_include_directories(aom INTERFACE "${AOM_EXT_SOURCE_DIR}/build.libavif")
+    endif()
+else()
+    message(STATUS "${AOM_MESSAGE_PREFIX}: compiled library not found at ${LIB_FILENAME}, using FetchContent")
+    if(EXISTS "${AOM_EXT_SOURCE_DIR}")
+        message(STATUS "${AOM_MESSAGE_PREFIX}: ext/${AOM_PACKAGE_NAME} found; using as FetchContent SOURCE_DIR")
+        set(FETCHCONTENT_SOURCE_DIR_AOM "${AOM_EXT_SOURCE_DIR}")
+        message(CHECK_START "${AOM_MESSAGE_PREFIX}: configuring ${AOM_PACKAGE_NAME}")
+    else()
+        message(CHECK_START "${AOM_MESSAGE_PREFIX}: fetching and configuring ${AOM_PACKAGE_NAME}")
+    endif()
+
+    # aom sets its compile options by setting variables like CMAKE_C_FLAGS_RELEASE using
+    # CACHE FORCE, which effectively adds those flags to all targets. We stash and restore
+    # the original values and call avif_set_aom_compile_options to instead set the flags on all aom
+    # targets
+    function(avif_set_aom_compile_options target config)
+        string(REPLACE " " ";" AOM_C_FLAGS_LIST "${CMAKE_C_FLAGS_${config}}")
+        string(REPLACE " " ";" AOM_CXX_FLAGS_LIST "${CMAKE_CXX_FLAGS_${config}}")
+        foreach(flag ${AOM_C_FLAGS_LIST})
+            target_compile_options(${target} PRIVATE $<$<COMPILE_LANGUAGE:C>:${flag}>)
+        endforeach()
+        foreach(flag ${AOM_CXX_FLAGS_LIST})
+            target_compile_options(${target} PRIVATE $<$<COMPILE_LANGUAGE:CXX>:${flag}>)
+        endforeach()
+
+        get_target_property(sources ${target} SOURCES)
+        foreach(src ${sources})
+            if(src MATCHES "TARGET_OBJECTS:")
+                string(REGEX REPLACE "\\$<TARGET_OBJECTS:(.*)>" "\\1" source_target ${src})
+                avif_set_aom_compile_options(${source_target} ${config})
+            endif()
+        endforeach()
+    endfunction()
+
+    set(AOM_BINARY_DIR "${FETCHCONTENT_BASE_DIR}/${AOM_PACKAGE_NAME}-build")
+
+    if(ANDROID_ABI)
+        set(AOM_BINARY_DIR "${AOM_BINARY_DIR}/${ANDROID_ABI}")
+    endif()
+
+    if(AVIF_CODEC_AVM)
+        FetchContent_Declare(
+            libaom
+            GIT_REPOSITORY "https://gitlab.com/AOMediaCodec/avm.git"
+            BINARY_DIR "${AOM_BINARY_DIR}"
+            GIT_TAG ${AVIF_LOCAL_AVM_GIT_TAG}
+            GIT_PROGRESS ON
+            GIT_SHALLOW ON
+            UPDATE_COMMAND ""
+        )
+    else()
+        FetchContent_Declare(
+            libaom URL "https://aomedia.googlesource.com/aom/+archive/${AVIF_LOCAL_AOM_GIT_TAG}.tar.gz" BINARY_DIR
+                       "${AOM_BINARY_DIR}" UPDATE_COMMAND ""
+        )
+    endif()
+
+    set(CONFIG_PIC 1 CACHE INTERNAL "")
+    if(libyuv_FOUND)
+        set(CONFIG_LIBYUV 0 CACHE INTERNAL "")
+    else()
+        set(CONFIG_LIBYUV 1 CACHE INTERNAL "")
+    endif()
+    set(CONFIG_WEBM_IO 0 CACHE INTERNAL "")
+    set(ENABLE_DOCS 0 CACHE INTERNAL "")
+    set(ENABLE_EXAMPLES 0 CACHE INTERNAL "")
+    set(ENABLE_TESTDATA 0 CACHE INTERNAL "")
+    set(ENABLE_TESTS 0 CACHE INTERNAL "")
+    set(ENABLE_TOOLS 0 CACHE INTERNAL "")
+    if(NOT CMAKE_HOST_SYSTEM_PROCESSOR STREQUAL CMAKE_SYSTEM_PROCESSOR)
+        set(CONFIG_RUNTIME_CPU_DETECT 0 CACHE INTERNAL "")
+    endif()
+    if(CMAKE_OSX_ARCHITECTURES STREQUAL "arm64")
+        set(AOM_TARGET_CPU "arm64")
+    endif()
+
+    if(NOT libaom_POPULATED)
+        # Guard against the project setting cmake variables that would affect the parent build
+        # See comment above for avif_set_aom_compile_options
+        foreach(_config_setting CMAKE_C_FLAGS CMAKE_CXX_FLAGS CMAKE_EXE_LINKER_FLAGS)
+            foreach(_config_type DEBUG RELEASE MINSIZEREL RELWITHDEBINFO)
+                set(${_config_setting}_${_config_type}_ORIG ${${_config_setting}_${_config_type}})
+            endforeach()
+        endforeach()
+
+        avif_fetchcontent_populate_cmake(libaom)
+
+        set(_aom_config RELEASE)
+        if(CMAKE_BUILD_TYPE)
+            string(TOUPPER ${CMAKE_BUILD_TYPE} _aom_config)
+        endif()
+        list(LENGTH CMAKE_CONFIGURATION_TYPES num_configs)
+        if(${num_configs} GREATER 0)
+            list(GET CMAKE_CONFIGURATION_TYPES 0 _aom_config_type)
+            string(TOUPPER ${_aom_config_type} _aom_config)
+        endif()
+        avif_set_aom_compile_options(aom ${_aom_config})
+
+        foreach(_config_setting CMAKE_C_FLAGS CMAKE_CXX_FLAGS CMAKE_EXE_LINKER_FLAGS)
+            foreach(_config_type DEBUG RELEASE MINSIZEREL RELWITHDEBINFO)
+                set(${_config_setting}_${_config_type} ${${_config_setting}_${_config_type}_ORIG} CACHE STRING "" FORCE)
+                unset(${_config_setting}_${_config_type}_ORIG)
+            endforeach()
+        endforeach()
+        unset(_config_type)
+        unset(_config_setting)
+    endif()
+
+    # If we have libyuv, we disable CONFIG_LIBYUV so that aom does not include the libyuv
+    # sources from its third-party vendor library. But we still want AOM to have libyuv, only
+    # linked against this project's target. Here we update the value in aom_config.h and add libyuv
+    # to AOM's link libraries
+    if(libyuv_FOUND)
+        file(READ ${AOM_BINARY_DIR}/config/aom_config.h AOM_CONFIG_H)
+        if("${AOM_CONFIG_H}" MATCHES "CONFIG_LIBYUV 0")
+            string(REPLACE "CONFIG_LIBYUV 0" "CONFIG_LIBYUV 1" AOM_CONFIG_H "${AOM_CONFIG_H}")
+            file(WRITE ${AOM_BINARY_DIR}/config/aom_config.h "${AOM_CONFIG_H}")
+        endif()
+        target_link_libraries(aom PRIVATE $<TARGET_FILE:yuv::yuv>)
+    endif()
+
+    set_property(TARGET aom PROPERTY AVIF_LOCAL ON)
+    target_include_directories(aom INTERFACE "${libaom_SOURCE_DIR}" ${AOM_BINARY_DIR})
+
+    message(CHECK_PASS "complete")
+endif()
diff --git a/cmake/Modules/LocalAvm.cmake b/cmake/Modules/LocalAvm.cmake
index a61d58bf75..f641d7ffaa 100644
--- a/cmake/Modules/LocalAvm.cmake
+++ b/cmake/Modules/LocalAvm.cmake
@@ -1,11 +1 @@
-# Building the avm repository generates files such as "libaom.a" because it is a fork of aom.
-set(LIB_FILENAME "${AVIF_SOURCE_DIR}/ext/avm/build.libavif/${CMAKE_STATIC_LIBRARY_PREFIX}aom${CMAKE_STATIC_LIBRARY_SUFFIX}")
-if(NOT EXISTS "${LIB_FILENAME}")
-    message(FATAL_ERROR "libavif: ${LIB_FILENAME} (from avm) is missing, bailing out")
-endif()
-
-add_library(aom STATIC IMPORTED GLOBAL)
-set_target_properties(aom PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}" AVIF_LOCAL ON)
-target_include_directories(aom INTERFACE "${AVIF_SOURCE_DIR}/ext/avm")
-# ext/avm/aom/aom_encoder.h includes config/aom_config.h which is generated by the local build of avm.
-target_include_directories(aom INTERFACE "${AVIF_SOURCE_DIR}/ext/avm/build.libavif")
+include(LocalAom)
diff --git a/cmake/Modules/LocalDav1d.cmake b/cmake/Modules/LocalDav1d.cmake
index 56bbeed966..d516568682 100644
--- a/cmake/Modules/LocalDav1d.cmake
+++ b/cmake/Modules/LocalDav1d.cmake
@@ -1,25 +1,132 @@
+set(AVIF_LOCAL_DAV1D_TAG "1.4.0")
+
+function(avif_build_local_dav1d)
+    set(download_step_args)
+    if(EXISTS "${AVIF_SOURCE_DIR}/ext/dav1d")
+        message(STATUS "libavif(AVIF_CODEC_DAV1D=LOCAL): ext/dav1d found, using as SOURCE_DIR")
+        set(source_dir "${AVIF_SOURCE_DIR}/ext/dav1d")
+    else()
+        message(STATUS "libavif(AVIF_CODEC_DAV1D=LOCAL): ext/dav1d not found, fetching")
+        set(source_dir "${FETCHCONTENT_BASE_DIR}/dav1d-src")
+        list(APPEND download_step_args GIT_REPOSITORY https://code.videolan.org/videolan/dav1d.git GIT_TAG
+             ${AVIF_LOCAL_DAV1D_TAG} GIT_SHALLOW ON
+        )
+    endif()
+
+    find_program(NINJA_EXECUTABLE NAMES ninja ninja-build REQUIRED)
+    find_program(MESON_EXECUTABLE meson REQUIRED)
+
+    set(PATH $ENV{PATH})
+    if(WIN32)
+        string(REPLACE ";" "\$<SEMICOLON>" PATH "${PATH}")
+    endif()
+    if(ANDROID_TOOLCHAIN_ROOT)
+        set(PATH "${ANDROID_TOOLCHAIN_ROOT}/bin$<IF:$<BOOL:${WIN32}>,$<SEMICOLON>,:>${PATH}")
+    endif()
+
+    if(ANDROID)
+        list(APPEND CMAKE_PROGRAM_PATH "${ANDROID_TOOLCHAIN_ROOT}/bin")
+
+        if(CMAKE_SYSTEM_PROCESSOR STREQUAL "armv7-a")
+            set(android_arch "arm")
+        elseif(CMAKE_SYSTEM_PROCESSOR STREQUAL "aarch64")
+            set(android_arch "aarch64")
+        elseif(CMAKE_SYSTEM_PROCESSOR STREQUAL "x86_64")
+            set(android_arch "x86_64")
+        else()
+            set(android_arch "x86")
+        endif()
+
+        set(CROSS_FILE "${source_dir}/package/crossfiles/${android_arch}-android.meson")
+    elseif(APPLE)
+        # If we are cross compiling generate the corresponding file to use with meson
+        if(NOT CMAKE_SYSTEM_PROCESSOR STREQUAL CMAKE_HOST_SYSTEM_PROCESSOR)
+            string(TOLOWER "${CMAKE_SYSTEM_NAME}" cross_system_name)
+            if(CMAKE_C_BYTE_ORDER STREQUAL "BIG_ENDIAN")
+                set(cross_system_endian "big")
+            else()
+                set(cross_system_endian "little")
+            endif()
+            if(CMAKE_SYSTEM_PROCESSOR STREQUAL "arm64")
+                set(cross_system_processor "aarch64")
+            else()
+                set(cross_system_processor "${CMAKE_SYSTEM_PROCESSOR}")
+            endif()
+            if(CMAKE_OSX_DEPLOYMENT_TARGET)
+                set(cross_osx_deployment_target "-mmacosx-version-min=${CMAKE_OSX_DEPLOYMENT_TARGET}")
+            endif()
+
+            set(CROSS_FILE "${PROJECT_BINARY_DIR}/crossfile-apple.meson")
+            configure_file("cmake/Meson/crossfile-apple.meson.in" "${CROSS_FILE}")
+        endif()
+    endif()
+
+    if(CROSS_FILE)
+        set(EXTRA_ARGS "--cross-file=${CROSS_FILE}")
+    endif()
+
+    set(build_dir "${FETCHCONTENT_BASE_DIR}/dav1d-build")
+    set(install_dir "${FETCHCONTENT_BASE_DIR}/dav1d-install")
+
+    if(ANDROID_ABI)
+        set(build_dir "${build_dir}/${ANDROID_ABI}")
+        set(install_dir "${install_dir}/${ANDROID_ABI}")
+    endif()
+    file(MAKE_DIRECTORY ${install_dir}/include)
+
+    ExternalProject_Add(
+        dav1d
+        ${download_step_args}
+        DOWNLOAD_DIR "${source_dir}"
+        LOG_DIR "${build_dir}"
+        STAMP_DIR "${build_dir}"
+        TMP_DIR "${build_dir}"
+        SOURCE_DIR "${source_dir}"
+        BINARY_DIR "${build_dir}"
+        INSTALL_DIR "${install_dir}"
+        LIST_SEPARATOR |
+        UPDATE_COMMAND ""
+        CONFIGURE_COMMAND
+            ${CMAKE_COMMAND} -E env "PATH=${PATH}" ${MESON_EXECUTABLE} setup --buildtype=release --default-library=static
+            --prefix=<INSTALL_DIR> --libdir=lib -Denable_asm=true -Denable_tools=false -Denable_examples=false
+            -Denable_tests=false ${EXTRA_ARGS} <SOURCE_DIR>
+        BUILD_COMMAND ${CMAKE_COMMAND} -E env "PATH=${PATH}" ${NINJA_EXECUTABLE} -C <BINARY_DIR>
+        INSTALL_COMMAND ${CMAKE_COMMAND} -E env "PATH=${PATH}" ${NINJA_EXECUTABLE} -C <BINARY_DIR> install
+        BUILD_BYPRODUCTS <INSTALL_DIR>/lib/libdav1d.a
+    )
+
+    add_library(dav1d::dav1d STATIC IMPORTED)
+    set_target_properties(dav1d::dav1d PROPERTIES IMPORTED_LOCATION ${install_dir}/lib/libdav1d.a AVIF_LOCAL ON)
+    target_include_directories(dav1d::dav1d INTERFACE "${install_dir}/include")
+    target_link_directories(dav1d::dav1d INTERFACE ${install_dir}/lib)
+    add_dependencies(dav1d::dav1d dav1d)
+endfunction()
+
 set(AVIF_DAV1D_BUILD_DIR "${AVIF_SOURCE_DIR}/ext/dav1d/build")
 # If ${ANDROID_ABI} is set, look for the library under that subdirectory.
 if(DEFINED ANDROID_ABI)
     set(AVIF_DAV1D_BUILD_DIR "${AVIF_DAV1D_BUILD_DIR}/${ANDROID_ABI}")
 endif()
 set(LIB_FILENAME "${AVIF_DAV1D_BUILD_DIR}/src/libdav1d${CMAKE_STATIC_LIBRARY_SUFFIX}")
-if(NOT EXISTS "${LIB_FILENAME}")
-    if("${CMAKE_STATIC_LIBRARY_SUFFIX}" STREQUAL ".a")
-        message(FATAL_ERROR "libavif: ${LIB_FILENAME} is missing, bailing out")
-    else()
-        # On windows, meson will produce a libdav1d.a instead of the expected libdav1d.dll/.lib.
-        # See https://github.com/mesonbuild/meson/issues/8153.
-        set(LIB_FILENAME "${AVIF_SOURCE_DIR}/ext/dav1d/build/src/libdav1d.a")
-        if(NOT EXISTS "${LIB_FILENAME}")
-            message(FATAL_ERROR "libavif: ${LIB_FILENAME} (or libdav1d${CMAKE_STATIC_LIBRARY_SUFFIX}) is missing, bailing out")
-        endif()
-    endif()
+if(NOT EXISTS "${LIB_FILENAME}" AND NOT "${CMAKE_STATIC_LIBRARY_SUFFIX}" STREQUAL ".a")
+    # On windows, meson will produce a libdav1d.a instead of the expected libdav1d.dll/.lib.
+    # See https://github.com/mesonbuild/meson/issues/8153.
+    set(LIB_FILENAME "${AVIF_DAV1D_BUILD_DIR}/src/libdav1d.a")
 endif()
+if(EXISTS "${LIB_FILENAME}")
+    message(STATUS "libavif(AVIF_CODEC_DAV1D=LOCAL): compiled library found at ${LIB_FILENAME}")
+    add_library(dav1d::dav1d STATIC IMPORTED)
+    set_target_properties(dav1d::dav1d PROPERTIES IMPORTED_LOCATION ${LIB_FILENAME} AVIF_LOCAL ON)
+    target_include_directories(
+        dav1d::dav1d INTERFACE "${AVIF_DAV1D_BUILD_DIR}" "${AVIF_DAV1D_BUILD_DIR}/include"
+                               "${AVIF_DAV1D_BUILD_DIR}/include/dav1d" "${AVIF_SOURCE_DIR}/ext/dav1d/include"
+    )
+else()
+    message(STATUS "libavif(AVIF_CODEC_DAV1D=LOCAL): compiled library not found at ${LIB_FILENAME}; using ExternalProject")
 
-add_library(dav1d::dav1d STATIC IMPORTED)
-set_target_properties(dav1d::dav1d PROPERTIES IMPORTED_LOCATION ${LIB_FILENAME} AVIF_LOCAL ON)
-target_include_directories(
-    dav1d::dav1d INTERFACE "${AVIF_DAV1D_BUILD_DIR}" "${AVIF_DAV1D_BUILD_DIR}/include" "${AVIF_DAV1D_BUILD_DIR}/include/dav1d"
-                           "${AVIF_SOURCE_DIR}/ext/dav1d/include"
-)
+    avif_build_local_dav1d()
+endif()
+
+if(EXISTS "${AVIF_SOURCE_DIR}/ext/dav1d")
+    set_target_properties(dav1d::dav1d PROPERTIES FOLDER "ext/dav1d")
+endif()
diff --git a/cmake/Modules/LocalGoogletest.cmake b/cmake/Modules/LocalGoogletest.cmake
index c26f2db392..4c17c72d5c 100644
--- a/cmake/Modules/LocalGoogletest.cmake
+++ b/cmake/Modules/LocalGoogletest.cmake
@@ -1,3 +1,6 @@
+set(AVIF_LOCAL_GTEST_GIT_TAG v1.14.0)
+
+set(GTest_FOUND ON CACHE BOOL "")
 set(GTEST_INCLUDE_DIRS ${AVIF_SOURCE_DIR}/ext/googletest/googletest/include)
 set(GTEST_LIB_FILENAME
     ${AVIF_SOURCE_DIR}/ext/googletest/build/lib/${CMAKE_STATIC_LIBRARY_PREFIX}gtest${CMAKE_STATIC_LIBRARY_SUFFIX}
@@ -5,24 +8,45 @@ set(GTEST_LIB_FILENAME
 set(GTEST_MAIN_LIB_FILENAME
     ${AVIF_SOURCE_DIR}/ext/googletest/build/lib/${CMAKE_STATIC_LIBRARY_PREFIX}gtest_main${CMAKE_STATIC_LIBRARY_SUFFIX}
 )
-if(NOT EXISTS ${GTEST_INCLUDE_DIRS}/gtest/gtest.h)
-    message(FATAL_ERROR "googletest(AVIF_LOCAL_GTEST): ${GTEST_INCLUDE_DIRS}/gtest/gtest.h is missing, bailing out")
-elseif(NOT EXISTS ${GTEST_LIB_FILENAME})
-    message(FATAL_ERROR "googletest(AVIF_LOCAL_GTEST): ${GTEST_LIB_FILENAME} is missing, bailing out")
-elseif(NOT EXISTS ${GTEST_MAIN_LIB_FILENAME})
-    message(FATAL_ERROR "googletest(AVIF_LOCAL_GTEST): ${GTEST_MAIN_LIB_FILENAME} is missing, bailing out")
+if(EXISTS ${GTEST_INCLUDE_DIRS}/gtest/gtest.h AND EXISTS ${GTEST_LIB_FILENAME} AND EXISTS ${GTEST_MAIN_LIB_FILENAME})
+    message(STATUS "libavif(AVIF_LOCAL_GTEST): compiled library found in ext/googletest")
+
+    add_library(GTest::gtest STATIC IMPORTED)
+    set_target_properties(GTest::gtest PROPERTIES IMPORTED_LOCATION "${GTEST_LIB_FILENAME}" AVIF_LOCAL ON)
+
+    if(TARGET Threads::Threads)
+        target_link_libraries(GTest::gtest INTERFACE Threads::Threads)
+    endif()
+    target_include_directories(GTest::gtest INTERFACE "${GTEST_INCLUDE_DIRS}")
+
+    add_library(GTest::gtest_main STATIC IMPORTED)
+    target_link_libraries(GTest::gtest_main INTERFACE GTest::gtest)
+    set_target_properties(GTest::gtest_main PROPERTIES IMPORTED_LOCATION "${GTEST_MAIN_LIB_FILENAME}" AVIF_LOCAL ON)
 else()
-    message(STATUS "Found local ext/googletest")
-endif()
+    message(STATUS "libavif(AVIF_LOCAL_GTEST): compiled library not found in ext/googletest; using FetchContent")
+    if(EXISTS "${AVIF_SOURCE_DIR}/ext/googletest")
+        message(STATUS "libavif(AVIF_LOCAL_GTEST): ext/googletest found; using as FetchContent SOURCE_DIR")
+        set(FETCHCONTENT_SOURCE_DIR_GOOGLETEST "${AVIF_SOURCE_DIR}/ext/googletest")
+        message(CHECK_START "libavif(AVIF_LOCAL_GTEST): configuring googletest")
+    else()
+        message(CHECK_START "libavif(AVIF_LOCAL_GTEST): fetching and configuring googletest")
+    endif()
 
-add_library(GTest::gtest STATIC IMPORTED)
-set_target_properties(GTest::gtest PROPERTIES IMPORTED_LOCATION "${GTEST_LIB_FILENAME}" AVIF_LOCAL ON)
+    FetchContent_Declare(
+        googletest
+        GIT_REPOSITORY https://github.com/google/googletest.git
+        GIT_TAG ${AVIF_LOCAL_GTEST_GIT_TAG}
+        GIT_SHALLOW ON
+    )
+    set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+    set(BUILD_GMOCK ON CACHE BOOL "" FORCE)
 
-if(TARGET Threads::Threads)
-    target_link_libraries(GTest::gtest INTERFACE Threads::Threads)
-endif()
-target_include_directories(GTest::gtest INTERFACE "${GTEST_INCLUDE_DIRS}")
+    avif_fetchcontent_populate_cmake(googletest)
+
+    set_target_properties(gtest gtest_main PROPERTIES AVIF_LOCAL ON)
 
-add_library(GTest::gtest_main STATIC IMPORTED)
-target_link_libraries(GTest::gtest_main INTERFACE GTest::gtest)
-set_target_properties(GTest::gtest_main PROPERTIES IMPORTED_LOCATION "${GTEST_MAIN_LIB_FILENAME}" AVIF_LOCAL ON)
+    add_library(GTest::gtest ALIAS gtest)
+    add_library(GTest::gtest_main ALIAS gtest_main)
+
+    message(CHECK_PASS "complete")
+endif()
diff --git a/cmake/Modules/LocalJpeg.cmake b/cmake/Modules/LocalJpeg.cmake
index b91b0740e5..818337205b 100644
--- a/cmake/Modules/LocalJpeg.cmake
+++ b/cmake/Modules/LocalJpeg.cmake
@@ -1,16 +1,53 @@
+set(AVIF_LOCAL_JPEG_TAG "3.0.2")
+
+add_library(JPEG::JPEG STATIC IMPORTED GLOBAL)
+
 set(LIB_DIR "${AVIF_SOURCE_DIR}/ext/libjpeg-turbo/build.libavif")
 if(MSVC)
     set(LIB_FILENAME "${LIB_DIR}/${CMAKE_STATIC_LIBRARY_PREFIX}jpeg-static${CMAKE_STATIC_LIBRARY_SUFFIX}")
 else()
     set(LIB_FILENAME "${LIB_DIR}/${CMAKE_STATIC_LIBRARY_PREFIX}jpeg${CMAKE_STATIC_LIBRARY_SUFFIX}")
 endif()
-if(NOT EXISTS "${LIB_FILENAME}")
-    message(FATAL_ERROR "libavif: ${LIB_FILENAME} is missing, bailing out")
+if(EXISTS "${LIB_FILENAME}")
+    message(STATUS "libavif(AVIF_LOCAL_JPEG): ${LIB_FILENAME} found, using for local JPEG")
+    set(JPEG_INCLUDE_DIR "${AVIF_SOURCE_DIR}/ext/libjpeg-turbo")
+else()
+    message(STATUS "libavif(AVIF_LOCAL_JPEG): ${LIB_FILENAME} not found, fetching")
+    set(LIB_DIR "${CMAKE_CURRENT_BINARY_DIR}/libjpeg/src/libjpeg-build")
+    if(MSVC)
+        set(LIB_FILENAME "${LIB_DIR}/${CMAKE_STATIC_LIBRARY_PREFIX}jpeg-static${CMAKE_STATIC_LIBRARY_SUFFIX}")
+    else()
+        set(LIB_FILENAME "${LIB_DIR}/${CMAKE_STATIC_LIBRARY_PREFIX}jpeg${CMAKE_STATIC_LIBRARY_SUFFIX}")
+    endif()
+
+    set(JPEG_INSTALL_DIR "${prefix}/libjpeg-install")
+
+    ExternalProject_Add(
+        libjpeg
+        PREFIX ${CMAKE_CURRENT_BINARY_DIR}/libjpeg
+        GIT_REPOSITORY "https://github.com/libjpeg-turbo/libjpeg-turbo.git"
+        GIT_TAG "${AVIF_LOCAL_JPEG_TAG}"
+        LIST_SEPARATOR |
+        BUILD_COMMAND ${CMAKE_COMMAND} --build <BINARY_DIR> --config $<CONFIG> --target jpeg-static
+        CMAKE_ARGS -DCMAKE_C_COMPILER=${CMAKE_C_COMPILER}
+                   -DCMAKE_BUILD_TYPE=${CMAKE_BUILD_TYPE}
+                   -DCMAKE_C_FLAGS=${CMAKE_C_FLAGS}
+                   -DCMAKE_C_FLAGS_DEBUG=${CMAKE_C_FLAGS_DEBUG}
+                   -DCMAKE_C_FLAGS_RELEASE=${CMAKE_C_FLAGS_RELEASE}
+                   -DCMAKE_C_FLAGS_MINSIZEREL=${CMAKE_C_FLAGS_MINSIZEREL}
+                   -DCMAKE_C_FLAGS_RELWITHDEBINFO=${CMAKE_C_FLAGS_RELWITHDEBINFO}
+                   -DENABLE_SHARED=OFF
+                   -DENABLE_STATIC=ON
+                   -DCMAKE_BUILD_TYPE=Release
+                   -DWITH_TURBOJPEG=OFF
+        BUILD_BYPRODUCTS "${LIB_FILENAME}"
+        INSTALL_COMMAND ""
+    )
+    add_dependencies(JPEG::JPEG libjpeg)
+    set(JPEG_INCLUDE_DIR ${CMAKE_CURRENT_BINARY_DIR}/libjpeg/src/libjpeg)
 endif()
 
-add_library(JPEG::JPEG STATIC IMPORTED GLOBAL)
 set_target_properties(JPEG::JPEG PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}" AVIF_LOCAL ON)
-set(JPEG_INCLUDE_DIR "${AVIF_SOURCE_DIR}/ext/libjpeg-turbo")
 target_include_directories(JPEG::JPEG INTERFACE "${JPEG_INCLUDE_DIR}")
 
 # Also add the build directory path because it contains jconfig.h,
diff --git a/cmake/Modules/LocalLibXml2.cmake b/cmake/Modules/LocalLibXml2.cmake
index 598a0bd55e..97f9eee510 100644
--- a/cmake/Modules/LocalLibXml2.cmake
+++ b/cmake/Modules/LocalLibXml2.cmake
@@ -1,9 +1,46 @@
+set(AVIF_LOCAL_LIBXML_GIT_TAG "v2.11.5")
+
 set(LIB_FILENAME "${AVIF_SOURCE_DIR}/ext/libxml2/install.libavif/lib/${AVIF_LIBRARY_PREFIX}xml2${CMAKE_STATIC_LIBRARY_SUFFIX}")
-if(NOT EXISTS "${LIB_FILENAME}")
-    message(FATAL_ERROR "libavif: ${LIB_FILENAME} is missing, bailing out")
-endif()
+if(EXISTS "${LIB_FILENAME}")
+    message(STATUS "libavif(AVIF_LOCAL_LIBXML2): compiled library found at ${LIB_FILENAME}")
+    add_library(LibXml2 STATIC IMPORTED GLOBAL)
+    set_target_properties(LibXml2 PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}" AVIF_LOCAL ON)
+    target_include_directories(LibXml2 INTERFACE "${AVIF_SOURCE_DIR}/ext/libxml2/install.libavif/include/libxml2")
+    add_library(LibXml2::LibXml2 ALIAS LibXml2)
+else()
+    message(STATUS "libavif(AVIF_LOCAL_LIBXML2): compiled library not found at ${LIB_FILENAME}; using FetchContent")
+    if(EXISTS "${AVIF_SOURCE_DIR}/ext/libxml2")
+        message(STATUS "libavif(AVIF_LOCAL_LIBXML2): ext/libxml2 found; using as FetchContent SOURCE_DIR")
+        set(FETCHCONTENT_SOURCE_DIR_LIBXML2 "${AVIF_SOURCE_DIR}/ext/libxml2")
+        message(CHECK_START "libavif(AVIF_LOCAL_LIBXML2): configuring libxml2")
+    else()
+        message(CHECK_START "libavif(AVIF_LOCAL_LIBXML2): fetching and configuring libxml2")
+    endif()
+
+    set(LIBXML2_WITH_PYTHON OFF CACHE INTERNAL "-")
+    set(LIBXML2_WITH_ZLIB OFF CACHE INTERNAL "-")
+    set(LIBXML2_WITH_LZMA OFF CACHE INTERNAL "-")
+    set(LIBXML2_WITH_ICONV OFF CACHE INTERNAL "-")
+    set(LIBXML2_WITH_TESTS OFF CACHE INTERNAL "-")
+    set(LIBXML2_WITH_PROGRAMS OFF CACHE INTERNAL "-")
+
+    set(LIBXML2_BINARY_DIR "${FETCHCONTENT_BASE_DIR}/libxml2-build")
+    if(ANDROID_ABI)
+        set(LIBXML2_BINARY_DIR "${LIBXML2_BINARY_DIR}/${ANDROID_ABI}")
+    endif()
 
-add_library(LibXml2 STATIC IMPORTED GLOBAL)
-set_target_properties(LibXml2 PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}" AVIF_LOCAL ON)
-target_include_directories(LibXml2 INTERFACE "${AVIF_SOURCE_DIR}/ext/libxml2/install.libavif/include/libxml2")
-add_library(LibXml2::LibXml2 ALIAS LibXml2)
+    FetchContent_Declare(
+        libxml2
+        GIT_REPOSITORY "https://gitlab.gnome.org/GNOME/libxml2.git"
+        BINARY_DIR "${LIBXML2_BINARY_DIR}"
+        GIT_TAG "${AVIF_LOCAL_LIBXML_GIT_TAG}"
+        GIT_SHALLOW ON
+        UPDATE_COMMAND ""
+    )
+
+    avif_fetchcontent_populate_cmake(libxml2)
+
+    set_property(TARGET LibXml2 PROPERTY AVIF_LOCAL ON)
+
+    message(CHECK_PASS "complete")
+endif()
diff --git a/cmake/Modules/LocalLibargparse.cmake b/cmake/Modules/LocalLibargparse.cmake
index 012aafe85d..870b272c50 100644
--- a/cmake/Modules/LocalLibargparse.cmake
+++ b/cmake/Modules/LocalLibargparse.cmake
@@ -1,10 +1,35 @@
+set(AVIF_LOCAL_LIBARGPARSE_GIT_TAG ee74d1b53bd680748af14e737378de57e2a0a954)
+
 set(LIBARGPARSE_FILENAME
     "${AVIF_SOURCE_DIR}/ext/libargparse/build/${CMAKE_STATIC_LIBRARY_PREFIX}argparse${CMAKE_STATIC_LIBRARY_SUFFIX}"
 )
+
 if(EXISTS "${LIBARGPARSE_FILENAME}")
+    message(STATUS "libavif(AVIF_LOCAL_LIBARGPARSE): compiled library found at ${LIBARGPARSE_FILENAME}")
     add_library(libargparse STATIC IMPORTED GLOBAL)
     set_target_properties(libargparse PROPERTIES IMPORTED_LOCATION "${LIBARGPARSE_FILENAME}" AVIF_LOCAL ON)
     target_include_directories(libargparse INTERFACE "${AVIF_SOURCE_DIR}/ext/libargparse/src")
 else()
-    message(WARNING "${LIBARGPARSE_FILENAME} is missing, not building avifgainmaputil, please run ext/libargparse.cmd")
+    message(STATUS "libavif(AVIF_LOCAL_LIBARGPARSE): compiled library not found at ${LIBARGPARSE_FILENAME}; using FetchContent")
+    if(EXISTS "${AVIF_SOURCE_DIR}/ext/libargparse")
+        message(STATUS "libavif(AVIF_LOCAL_LIBARGPARSE): ext/libargparse found; using as FetchContent SOURCE_DIR")
+        set(FETCHCONTENT_SOURCE_DIR_LIBARGPARSE "${AVIF_SOURCE_DIR}/ext/libargparse")
+        message(CHECK_START "libavif(AVIF_LOCAL_LIBARGPARSE): configuring libargparse")
+    else()
+        message(CHECK_START "libavif(AVIF_LOCAL_LIBARGPARSE): fetching and configuring libargparse")
+    endif()
+
+    FetchContent_Declare(
+        libargparse
+        GIT_REPOSITORY "https://github.com/kmurray/libargparse.git"
+        GIT_TAG ${AVIF_LOCAL_LIBARGPARSE_GIT_TAG}
+        UPDATE_COMMAND ""
+    )
+    avif_fetchcontent_populate_cmake(libargparse)
+
+    message(CHECK_PASS "complete")
+endif()
+
+if(EXISTS "${AVIF_SOURCE_DIR}/ext/libargparse")
+    set_target_properties(libargparse PROPERTIES FOLDER "ext/libargparse")
 endif()
diff --git a/cmake/Modules/LocalLibgav1.cmake b/cmake/Modules/LocalLibgav1.cmake
index c383497ec7..d5f9f7264e 100644
--- a/cmake/Modules/LocalLibgav1.cmake
+++ b/cmake/Modules/LocalLibgav1.cmake
@@ -1,14 +1,54 @@
+set(AVIF_LOCAL_LIBGAV1_GIT_TAG "v0.19.0")
+
 set(AVIF_LIBGAV1_BUILD_DIR "${AVIF_SOURCE_DIR}/ext/libgav1/build")
 # If ${ANDROID_ABI} is set, look for the library under that subdirectory.
 if(DEFINED ANDROID_ABI)
     set(AVIF_LIBGAV1_BUILD_DIR "${AVIF_LIBGAV1_BUILD_DIR}/${ANDROID_ABI}")
 endif()
 set(LIB_FILENAME "${AVIF_LIBGAV1_BUILD_DIR}/libgav1${CMAKE_STATIC_LIBRARY_SUFFIX}")
-if(NOT EXISTS "${LIB_FILENAME}")
-    message(FATAL_ERROR "libavif: ${LIB_FILENAME} is missing, bailing out")
+
+if(EXISTS "${LIB_FILENAME}")
+    message(STATUS "libavif(AVIF_CODEC_LIBGAV1=LOCAL): compiled library found at ${LIB_FILENAME}")
+    add_library(libgav1_static STATIC IMPORTED GLOBAL)
+    set_target_properties(libgav1_static PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}")
+    target_include_directories(libgav1_static INTERFACE "${AVIF_SOURCE_DIR}/ext/libgav1/src")
+else()
+    message(STATUS "libavif(AVIF_CODEC_LIBGAV1=LOCAL): compiled library not found at ${LIB_FILENAME}; using FetchContent")
+
+    if(EXISTS "${AVIF_SOURCE_DIR}/ext/libgav1")
+        message(STATUS "libavif(AVIF_CODEC_LIBGAV1=LOCAL): ext/libgav1 found; using as FetchContent SOURCE_DIR")
+        set(FETCHCONTENT_SOURCE_DIR_LIBGAV1 "${AVIF_SOURCE_DIR}/ext/libgav1")
+        message(CHECK_START "libavif(AVIF_CODEC_LIBGAV1=LOCAL): configuring libgav1")
+    else()
+        message(CHECK_START "libavif(AVIF_CODEC_LIBGAV1=LOCAL): fetching and configuring libgav1")
+    endif()
+
+    set(LIBGAV1_BINARY_DIR "${FETCHCONTENT_BASE_DIR}/libgav1-build")
+    if(ANDROID_ABI)
+        set(LIBGAV1_BINARY_DIR "${LIBGAV1_BINARY_DIR}/${ANDROID_ABI}")
+    endif()
+
+    set(LIBGAV1_THREADPOOL_USE_STD_MUTEX 1 CACHE INTERNAL "")
+    set(LIBGAV1_ENABLE_EXAMPLES OFF CACHE INTERNAL "")
+    set(LIBGAV1_ENABLE_TESTS OFF CACHE INTERNAL "")
+    set(LIBGAV1_MAX_BITDEPTH 12 CACHE INTERNAL "")
+
+    FetchContent_Declare(
+        libgav1
+        GIT_REPOSITORY "https://chromium.googlesource.com/codecs/libgav1"
+        BINARY_DIR "${LIBGAV1_BINARY_DIR}"
+        GIT_TAG "${AVIF_LOCAL_LIBGAV1_GIT_TAG}"
+        GIT_SHALLOW ON
+        UPDATE_COMMAND ""
+    )
+
+    avif_fetchcontent_populate_cmake(libgav1)
+    message(CHECK_PASS "complete")
 endif()
 
-add_library(libgav1_static STATIC IMPORTED GLOBAL)
-set_target_properties(libgav1_static PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}" AVIF_LOCAL ON)
-target_include_directories(libgav1_static INTERFACE "${AVIF_SOURCE_DIR}/ext/libgav1/src")
+set_property(TARGET libgav1_static PROPERTY AVIF_LOCAL ON)
 add_library(libgav1::libgav1 ALIAS libgav1_static)
+
+if(EXISTS "${AVIF_SOURCE_DIR}/ext/libgav1")
+    set_property(TARGET libgav1_static PROPERTY FOLDER "ext/libgav1")
+endif()
diff --git a/cmake/Modules/LocalLibsharpyuv.cmake b/cmake/Modules/LocalLibsharpyuv.cmake
index 73aacac275..468f6be6e3 100644
--- a/cmake/Modules/LocalLibsharpyuv.cmake
+++ b/cmake/Modules/LocalLibsharpyuv.cmake
@@ -1,10 +1,62 @@
+set(AVIF_LOCAL_LIBSHARPYUV_GIT_TAG v1.3.2)
+
 set(LIB_FILENAME "${CMAKE_CURRENT_SOURCE_DIR}/ext/libwebp/build/libsharpyuv${CMAKE_STATIC_LIBRARY_SUFFIX}")
-if(NOT EXISTS "${LIB_FILENAME}")
-    message(FATAL_ERROR "libavif(AVIF_LIBSHARPYUV=LOCAL): ${LIB_FILENAME} is missing, bailing out")
-endif()
+if(EXISTS "${LIB_FILENAME}")
+    message(STATUS "libavif(AVIF_LIBSHARPYUV=LOCAL): compiled library found at ${LIB_FILENAME}")
+    add_library(sharpyuv::sharpyuv STATIC IMPORTED GLOBAL)
+    set_target_properties(sharpyuv::sharpyuv PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}" AVIF_LOCAL ON)
+    target_include_directories(sharpyuv::sharpyuv INTERFACE "${AVIF_SOURCE_DIR}/ext/libwebp")
+
+    set(libsharpyuv_FOUND ON)
+else()
+    message(STATUS "libavif(AVIF_LIBSHARPYUV=LOCAL): compiled library not found at ${LIB_FILENAME}; using FetchContent")
+
+    if(EXISTS "${AVIF_SOURCE_DIR}/ext/libwebp")
+        message(STATUS "libavif(AVIF_LIBSHARPYUV=LOCAL): ext/libwebp found; using as FetchContent SOURCE_DIR")
+        set(FETCHCONTENT_SOURCE_DIR_LIBWEBP "${AVIF_SOURCE_DIR}/ext/libwebp")
+        message(CHECK_START "libavif(AVIF_LIBSHARPYUV=LOCAL): configuring libwebp")
+    else()
+        message(CHECK_START "libavif(AVIF_LIBSHARPYUV=LOCAL): fetching and configuring libwebp")
+    endif()
+
+    set(WEBP_BUILD_ANIM_UTILS OFF CACHE BOOL "")
+    set(WEBP_BUILD_CWEBP OFF CACHE BOOL "")
+    set(WEBP_BUILD_DWEBP OFF CACHE BOOL "")
+    set(WEBP_BUILD_GIF2WEBP OFF CACHE BOOL "")
+    set(WEBP_BUILD_IMG2WEBP OFF CACHE BOOL "")
+    set(WEBP_BUILD_VWEBP OFF CACHE BOOL "")
+    set(WEBP_BUILD_WEBPINFO OFF CACHE BOOL "")
+    set(WEBP_BUILD_LIBWEBPMUX OFF CACHE BOOL "")
+    set(WEBP_BUILD_WEBPMUX OFF CACHE BOOL "")
+    set(WEBP_BUILD_EXTRAS OFF CACHE BOOL "")
+
+    set(LIBSHARPYUV_BINARY_DIR "${FETCHCONTENT_BASE_DIR}/libwebp")
+    if(ANDROID_ABI)
+        set(LIBSHARPYUV_BINARY_DIR "${LIBSHARPYUV_BINARY_DIR}/${ANDROID_ABI}")
+    endif()
 
-add_library(sharpyuv::sharpyuv STATIC IMPORTED GLOBAL)
-set_target_properties(sharpyuv::sharpyuv PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}" AVIF_LOCAL ON)
-target_include_directories(sharpyuv::sharpyuv INTERFACE "${AVIF_SOURCE_DIR}/ext/libwebp")
+    FetchContent_Declare(
+        libwebp
+        GIT_REPOSITORY "https://chromium.googlesource.com/webm/libwebp"
+        BINARY_DIR "${LIBSHARPYUV_BINARY_DIR}"
+        GIT_TAG "${AVIF_LOCAL_LIBSHARPYUV_GIT_TAG}"
+        GIT_SHALLOW ON
+        UPDATE_COMMAND ""
+    )
 
-set(libsharpyuv_FOUND ON)
+    avif_fetchcontent_populate_cmake(libwebp)
+
+    set_property(TARGET sharpyuv PROPERTY POSITION_INDEPENDENT_CODE ON)
+    set_property(TARGET sharpyuv PROPERTY AVIF_LOCAL ON)
+
+    target_include_directories(
+        sharpyuv INTERFACE $<BUILD_INTERFACE:${libwebp_SOURCE_DIR}> $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDE_DIR}>
+    )
+
+    add_library(sharpyuv::sharpyuv ALIAS sharpyuv)
+    message(CHECK_PASS "complete")
+endif()
+
+if(EXISTS "${AVIF_SOURCE_DIR}/ext/libwebp")
+    set_property(TARGET sharpyuv PROPERTY FOLDER "ext/libwebp")
+endif()
diff --git a/cmake/Modules/LocalLibyuv.cmake b/cmake/Modules/LocalLibyuv.cmake
index 5ef11c7d02..829fb33558 100644
--- a/cmake/Modules/LocalLibyuv.cmake
+++ b/cmake/Modules/LocalLibyuv.cmake
@@ -1,22 +1,58 @@
-set(AVIF_LIBYUV_BUILD_DIR "${AVIF_SOURCE_DIR}/ext/libyuv/build")
+set(AVIF_LOCAL_LIBYUV_TAG "a6a2ec654b1be1166b376476a7555c89eca0c275")
 
+set(AVIF_LIBYUV_BUILD_DIR "${AVIF_SOURCE_DIR}/ext/libyuv/build")
 # If ${ANDROID_ABI} is set, look for the library under that subdirectory.
 if(DEFINED ANDROID_ABI)
     set(AVIF_LIBYUV_BUILD_DIR "${AVIF_LIBYUV_BUILD_DIR}/${ANDROID_ABI}")
 endif()
 set(LIB_FILENAME "${AVIF_LIBYUV_BUILD_DIR}/${AVIF_LIBRARY_PREFIX}yuv${CMAKE_STATIC_LIBRARY_SUFFIX}")
 
-if(NOT EXISTS "${LIB_FILENAME}")
-    message(FATAL_ERROR "libavif(AVIF_LIBYUV=LOCAL): ${LIB_FILENAME} is missing, bailing out")
-endif()
+if(EXISTS "${LIB_FILENAME}")
+    message(STATUS "libavif(AVIF_LIBYUV=LOCAL): compiled library found at ${LIB_FILENAME}")
+    set(LIBYUV_INCLUDE_DIR "${AVIF_SOURCE_DIR}/ext/libyuv/include")
+
+    add_library(yuv::yuv STATIC IMPORTED GLOBAL)
+    set_target_properties(yuv::yuv PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}" AVIF_LOCAL ON)
+    target_include_directories(yuv::yuv INTERFACE "${LIBYUV_INCLUDE_DIR}")
+    set_target_properties(yuv::yuv PROPERTIES FOLDER "ext/libyuv")
+else()
+    message(STATUS "libavif(AVIF_LIBYUV=LOCAL): compiled library not found at ${LIB_FILENAME}; using FetchContent")
+    if(EXISTS "${AVIF_SOURCE_DIR}/ext/libyuv")
+        message(STATUS "libavif(AVIF_LIBYUV=LOCAL): ext/libyuv found; using as FetchContent SOURCE_DIR")
+        set(FETCHCONTENT_SOURCE_DIR_LIBYUV "${AVIF_SOURCE_DIR}/ext/libyuv")
+        message(CHECK_START "libavif(AVIF_LIBYUV=LOCAL): configuring libyuv")
+    else()
+        message(CHECK_START "libavif(AVIF_LIBYUV=LOCAL): fetching and configuring libyuv")
+    endif()
+
+    set(LIBYUV_BINARY_DIR "${FETCHCONTENT_BASE_DIR}/libyuv-build")
+    if(ANDROID_ABI)
+        set(LIBYUV_BINARY_DIR "${LIBYUV_BINARY_DIR}/${ANDROID_ABI}")
+    endif()
+    FetchContent_Declare(
+        libyuv
+        GIT_REPOSITORY "https://chromium.googlesource.com/libyuv/libyuv"
+        BINARY_DIR "${LIBYUV_BINARY_DIR}"
+        GIT_TAG "${AVIF_LOCAL_LIBYUV_TAG}"
+        UPDATE_COMMAND ""
+    )
 
-message(STATUS "libavif: local libyuv found; libyuv-based fast paths enabled.")
+    avif_fetchcontent_populate_cmake(libyuv)
 
-set(LIBYUV_INCLUDE_DIR "${AVIF_SOURCE_DIR}/ext/libyuv/include")
+    set_target_properties(yuv PROPERTIES AVIF_LOCAL ON POSITION_INDEPENDENT_CODE ON)
 
-add_library(yuv::yuv STATIC IMPORTED GLOBAL)
-set_target_properties(yuv::yuv PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}" AVIF_LOCAL ON)
-target_include_directories(yuv::yuv INTERFACE "${LIBYUV_INCLUDE_DIR}")
+    add_library(yuv::yuv ALIAS yuv)
+
+    set(LIBYUV_INCLUDE_DIR "${libyuv_SOURCE_DIR}/include")
+
+    target_include_directories(yuv INTERFACE ${LIBYUV_INCLUDE_DIR})
+
+    if(EXISTS "${AVIF_SOURCE_DIR}/ext/libyuv")
+        set_target_properties(yuv PROPERTIES FOLDER "ext/libyuv")
+    endif()
+
+    message(CHECK_PASS "complete")
+endif()
 
 set(libyuv_FOUND ON)
 
diff --git a/cmake/Modules/LocalRav1e.cmake b/cmake/Modules/LocalRav1e.cmake
index 642934d926..97dbea8a89 100644
--- a/cmake/Modules/LocalRav1e.cmake
+++ b/cmake/Modules/LocalRav1e.cmake
@@ -1,8 +1,113 @@
-set(LIB_FILENAME "${AVIF_SOURCE_DIR}/ext/rav1e/build.libavif/usr/lib/${AVIF_LIBRARY_PREFIX}rav1e${CMAKE_STATIC_LIBRARY_SUFFIX}")
-if(NOT EXISTS "${LIB_FILENAME}")
-    message(FATAL_ERROR "libavif: compiled rav1e library is missing (in ext/rav1e/build.libavif/usr/lib), bailing out")
-endif()
+set(AVIF_LOCAL_RAV1E_GIT_TAG v0.7.0)
+set(AVIF_LOCAL_CORROSION_GIT_TAG v0.4.4)
+set(AVIF_LOCAL_CARGOC_GIT_TAG v0.9.27)
+
+set(RAV1E_LIB_FILENAME
+    "${AVIF_SOURCE_DIR}/ext/rav1e/build.libavif/usr/lib/${AVIF_LIBRARY_PREFIX}rav1e${CMAKE_STATIC_LIBRARY_SUFFIX}"
+)
+
+if(EXISTS "${RAV1E_LIB_FILENAME}")
+    message(STATUS "libavif(AVIF_CODEC_RAV1E=LOCAL): compiled rav1e library found at ${RAV1E_LIB_FILENAME}")
+    add_library(rav1e::rav1e STATIC IMPORTED)
+    set_target_properties(rav1e::rav1e PROPERTIES IMPORTED_LOCATION "${RAV1E_LIB_FILENAME}" IMPORTED_SONAME rav1e AVIF_LOCAL ON)
+    target_include_directories(rav1e::rav1e INTERFACE "${AVIF_SOURCE_DIR}/ext/rav1e/build.libavif/usr/include/rav1e")
+else()
+    message(
+        STATUS "libavif(AVIF_CODEC_RAV1E=LOCAL): compiled rav1e library not found at ${RAV1E_LIB_FILENAME}; using FetchContent"
+    )
+    if(EXISTS "${AVIF_SOURCE_DIR}/ext/rav1e")
+        message(STATUS "libavif(AVIF_CODEC_RAV1E=LOCAL): ext/rav1e found; using as FetchContent SOURCE_DIR")
+        set(FETCHCONTENT_SOURCE_DIR_RAV1E "${AVIF_SOURCE_DIR}/ext/rav1e")
+        message(CHECK_START "libavif(AVIF_CODEC_RAV1E=LOCAL): configuring rav1e")
+    else()
+        message(CHECK_START "libavif(AVIF_CODEC_RAV1E=LOCAL): fetching and configuring rav1e")
+    endif()
+
+    find_program(CARGO_CINSTALL cargo-cinstall HINTS "$ENV{HOME}/.cargo/bin")
+
+    if(CARGO_CINSTALL)
+        add_executable(cargo-cinstall IMPORTED GLOBAL)
+        set_property(TARGET cargo-cinstall PROPERTY IMPORTED_LOCATION ${CARGO_CINSTALL})
+    endif()
+
+    FetchContent_Declare(
+        Corrosion
+        GIT_REPOSITORY https://github.com/corrosion-rs/corrosion.git
+        GIT_TAG ${AVIF_LOCAL_CORROSION_GIT_TAG}
+        GIT_SHALLOW ON
+    )
+
+    if(APPLE)
+        if(CMAKE_OSX_ARCHITECTURES STREQUAL "arm64" OR CMAKE_SYSTEM_PROCESSOR STREQUAL "arm64")
+            set(Rust_CARGO_TARGET "aarch64-apple-darwin")
+        endif()
+    endif()
+
+    FetchContent_MakeAvailable(Corrosion)
+
+    if(NOT TARGET cargo-cinstall)
+        FetchContent_Declare(
+            cargoc
+            GIT_REPOSITORY https://github.com/lu-zero/cargo-c.git
+            GIT_TAG "${AVIF_LOCAL_CARGOC_GIT_TAG}"
+            GIT_SHALLOW ON
+        )
+        FetchContent_MakeAvailable(cargoc)
 
-add_library(rav1e::rav1e STATIC IMPORTED)
-set_target_properties(rav1e::rav1e PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}" IMPORTED_SONAME rav1e AVIF_LOCAL ON)
-target_include_directories(rav1e::rav1e INTERFACE "${AVIF_SOURCE_DIR}/ext/rav1e/build.libavif/usr/include/rav1e")
+        corrosion_import_crate(
+            MANIFEST_PATH ${cargoc_SOURCE_DIR}/Cargo.toml PROFILE release IMPORTED_CRATES MYVAR_IMPORTED_CRATES FEATURES
+            vendored-openssl
+        )
+
+        set(CARGO_CINSTALL $<TARGET_FILE:cargo-cinstall>)
+    endif()
+
+    FetchContent_Declare(
+        rav1e
+        GIT_REPOSITORY https://github.com/xiph/rav1e.git
+        GIT_TAG "${AVIF_LOCAL_RAV1E_GIT_TAG}"
+        GIT_SHALLOW ON
+    )
+    FetchContent_MakeAvailable(rav1e)
+
+    set(RAV1E_LIB_FILENAME
+        ${CMAKE_CURRENT_BINARY_DIR}/ext/rav1e/usr/lib/${CMAKE_STATIC_LIBRARY_PREFIX}rav1e${CMAKE_STATIC_LIBRARY_SUFFIX}
+    )
+    set(RAV1E_ENVVARS)
+    if(CMAKE_C_IMPLICIT_LINK_DIRECTORIES MATCHES "alpine-linux-musl")
+        list(APPEND RAV1E_ENVVARS "RUSTFLAGS=-C link-args=-Wl,-z,stack-size=2097152 -C target-feature=-crt-static")
+    endif()
+    if(CMAKE_HOST_SYSTEM_NAME STREQUAL "Darwin" AND CMAKE_OSX_SYSROOT)
+        list(APPEND RAV1E_ENVVARS "SDKROOT=${CMAKE_OSX_SYSROOT}")
+    endif()
+    if(CMAKE_HOST_SYSTEM_NAME STREQUAL "Darwin" AND CMAKE_OSX_DEPLOYMENT_TARGET)
+        list(APPEND RAV1E_ENVVARS "MACOSX_DEPLOYMENT_TARGET=${CMAKE_OSX_DEPLOYMENT_TARGET}")
+    endif()
+
+    add_custom_target(
+        rav1e
+        COMMAND ${CMAKE_COMMAND} -E env ${RAV1E_ENVVARS} ${CARGO_CINSTALL} cinstall -v --release --library-type=staticlib
+                --prefix=/usr --target ${Rust_CARGO_TARGET_CACHED} --destdir ${CMAKE_CURRENT_BINARY_DIR}/ext/rav1e
+        DEPENDS cargo-cinstall
+        BYPRODUCTS ${RAV1E_LIB_FILENAME}
+        USES_TERMINAL
+        WORKING_DIRECTORY ${rav1e_SOURCE_DIR}
+    )
+    set(RAV1E_INCLUDE_DIR "${CMAKE_CURRENT_BINARY_DIR}/ext/rav1e/usr/include/rav1e")
+    file(MAKE_DIRECTORY ${RAV1E_INCLUDE_DIR})
+    set(RAV1E_FOUND ON)
+
+    set(RAV1E_LIBRARIES ${Rust_CARGO_TARGET_LINK_NATIVE_LIBS})
+    if(WIN32)
+        # Remove msvcrt from RAV1E_LIBRARIES since it's linked by default
+        list(REMOVE_ITEM RAV1E_LIBRARIES "msvcrt.lib" "-lmsvcrt")
+    endif()
+
+    add_library(rav1e::rav1e STATIC IMPORTED)
+    add_dependencies(rav1e::rav1e rav1e)
+    target_link_libraries(rav1e::rav1e INTERFACE "${RAV1E_LIBRARIES}")
+    set_target_properties(rav1e::rav1e PROPERTIES IMPORTED_LOCATION "${RAV1E_LIB_FILENAME}" AVIF_LOCAL ON FOLDER "ext/rav1e")
+    target_include_directories(rav1e::rav1e INTERFACE "${RAV1E_INCLUDE_DIR}")
+
+    message(CHECK_PASS "complete")
+endif()
diff --git a/cmake/Modules/LocalSvt.cmake b/cmake/Modules/LocalSvt.cmake
index 1edc3a68d4..c41534cfda 100644
--- a/cmake/Modules/LocalSvt.cmake
+++ b/cmake/Modules/LocalSvt.cmake
@@ -1,8 +1,95 @@
+set(AVIF_LOCAL_SVT_GIT_TAG "v1.7.0")
+
 set(LIB_FILENAME "${AVIF_SOURCE_DIR}/ext/SVT-AV1/Bin/Release/${AVIF_LIBRARY_PREFIX}SvtAv1Enc${CMAKE_STATIC_LIBRARY_SUFFIX}")
-if(NOT EXISTS "${LIB_FILENAME}")
-    message(FATAL_ERROR "libavif: compiled svt library is missing (in ext/SVT-AV1/Bin/Release), bailing out")
+
+if(EXISTS "${LIB_FILENAME}")
+    message(STATUS "libavif(AVIF_CODEC_SVT=LOCAL): compiled library found at ${LIB_FILENAME}")
+    add_library(SvtAv1Enc STATIC IMPORTED GLOBAL)
+    set_target_properties(SvtAv1Enc PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}" AVIF_LOCAL ON)
+    target_include_directories(SvtAv1Enc INTERFACE "${AVIF_SOURCE_DIR}/ext/SVT-AV1/include")
+else()
+    message(STATUS "libavif(AVIF_CODEC_SVT=LOCAL): compiled library not found at ${LIB_FILENAME}; using FetchContent")
+    if(EXISTS "${AVIF_SOURCE_DIR}/ext/SVT-AV1")
+        message(STATUS "libavif(AVIF_CODEC_SVT=LOCAL): ext/SVT-AV1 found; using as FetchContent SOURCE_DIR")
+        set(FETCHCONTENT_SOURCE_DIR_SVT "${AVIF_SOURCE_DIR}/ext/SVT-AV1")
+        message(CHECK_START "libavif(AVIF_CODEC_SVT=LOCAL): configuring SVT-AV1")
+    else()
+        message(CHECK_START "libavif(AVIF_CODEC_SVT=LOCAL): fetching and configuring SVT-AV1")
+    endif()
+
+    set(SVT_BINARY_DIR "${FETCHCONTENT_BASE_DIR}/svt-build")
+    if(ANDROID_ABI)
+        set(SVT_BINARY_DIR "${SVT_BINARY_DIR}/${ANDROID_ABI}")
+    endif()
+
+    # Workaround https://gitlab.kitware.com/cmake/cmake/-/issues/25042 by enabling ASM before ASM_NASM
+    if(NOT CMAKE_ASM_COMPILER)
+        include(CheckLanguage)
+        check_language(ASM)
+        if(CMAKE_ASM_COMPILER)
+            enable_language(ASM)
+        endif()
+    endif()
+    if(NOT CMAKE_ASM_NASM_COMPILER)
+        include(CheckLanguage)
+        check_language(ASM_NASM)
+        if(CMAKE_ASM_NASM_COMPILER)
+            enable_language(ASM_NASM)
+        endif()
+    endif()
+
+    FetchContent_Declare(
+        svt
+        GIT_REPOSITORY "https://gitlab.com/AOMediaCodec/SVT-AV1.git"
+        BINARY_DIR "${SVT_BINARY_DIR}"
+        GIT_TAG "${AVIF_LOCAL_SVT_GIT_TAG}"
+        UPDATE_COMMAND ""
+        GIT_SHALLOW ON
+    )
+
+    set(BUILD_DEC OFF CACHE BOOL "")
+    set(BUILD_APPS OFF CACHE BOOL "")
+    set(NATIVE OFF CACHE BOOL "")
+
+    set(CMAKE_BUILD_TYPE_ORIG ${CMAKE_BUILD_TYPE})
+    set(CMAKE_BUILD_TYPE Release CACHE INTERNAL "")
+
+    set(CMAKE_OUTPUT_DIRECTORY_ORIG "${CMAKE_OUTPUT_DIRECTORY}")
+    set(CMAKE_OUTPUT_DIRECTORY "${SVT_BINARY_DIR}" CACHE INTERNAL "")
+
+    avif_fetchcontent_populate_cmake(svt)
+
+    set(CMAKE_BUILD_TYPE ${CMAKE_BUILD_TYPE_ORIG} CACHE STRING "" FORCE)
+    set(CMAKE_OUTPUT_DIRECTORY ${CMAKE_OUTPUT_DIRECTORY_ORIG} CACHE STRING "" FORCE)
+
+    set(SVT_INCLUDE_DIR ${SVT_BINARY_DIR}/include)
+    file(MAKE_DIRECTORY ${SVT_INCLUDE_DIR}/svt-av1)
+
+    file(GLOB _svt_header_files ${svt_SOURCE_DIR}/Source/API/*.h)
+
+    set(_svt_header_byproducts)
+
+    foreach(_svt_header_file ${_svt_header_files})
+        get_filename_component(_svt_header_name "${_svt_header_file}" NAME)
+        set(_svt_header_output ${SVT_INCLUDE_DIR}/svt-av1/${_svt_header_name})
+        add_custom_command(
+            OUTPUT ${_svt_header_output}
+            COMMAND ${CMAKE_COMMAND} -E copy_if_different ${_svt_header_file} ${_svt_header_output}
+            DEPENDS ${_svt_header_file}
+            VERBATIM
+        )
+        list(APPEND _svt_header_byproducts ${_svt_header_output})
+    endforeach()
+
+    add_custom_target(_svt_install_headers DEPENDS ${_svt_header_byproducts})
+    add_dependencies(SvtAv1Enc _svt_install_headers)
+    set_target_properties(SvtAv1Enc PROPERTIES AVIF_LOCAL ON)
+
+    target_include_directories(SvtAv1Enc INTERFACE ${SVT_INCLUDE_DIR})
+
+    message(CHECK_PASS "complete")
 endif()
 
-add_library(SvtAv1Enc STATIC IMPORTED GLOBAL)
-set_target_properties(SvtAv1Enc PROPERTIES IMPORTED_LOCATION "${LIB_FILENAME}" AVIF_LOCAL ON)
-target_include_directories(SvtAv1Enc INTERFACE "${AVIF_SOURCE_DIR}/ext/SVT-AV1/include")
+if(EXISTS "${AVIF_SOURCE_DIR}/ext/SVT-AV1")
+    set_target_properties(SvtAv1Enc PROPERTIES FOLDER "ext/SVT-AV1")
+endif()
diff --git a/cmake/Modules/LocalZlibpng.cmake b/cmake/Modules/LocalZlibpng.cmake
index 4e7b39f3c2..cc7076faec 100644
--- a/cmake/Modules/LocalZlibpng.cmake
+++ b/cmake/Modules/LocalZlibpng.cmake
@@ -1,21 +1,46 @@
-# ---------------------------------------------------------------------------------------
-# This insanity is for people embedding libavif or making fully static or Windows builds.
-# Any proper unix environment should ignore these entire following blocks.
+set(AVIF_LOCAL_ZLIB_GIT_TAG v1.3)
+set(AVIF_LOCAL_LIBPNG_GIT_TAG v1.6.40)
+
+if(EXISTS "${AVIF_SOURCE_DIR}/ext/zlib")
+    message(STATUS "libavif(AVIF_ZLIBPNG=LOCAL): ext/zlib found; using as FetchContent SOURCE_DIR")
+    set(FETCHCONTENT_SOURCE_DIR_ZLIB "${AVIF_SOURCE_DIR}/ext/zlib")
+    message(CHECK_START "libavif(AVIF_ZLIBPNG=LOCAL): configuring zlib")
+else()
+    message(CHECK_START "libavif(AVIF_ZLIBPNG=LOCAL): fetching and configuring zlib")
+endif()
+
+set(ZLIB_SOURCE_DIR "${FETCHCONTENT_BASE_DIR}/zlib-src")
+set(ZLIB_BINARY_DIR "${FETCHCONTENT_BASE_DIR}/zlib")
+if(ANDROID_ABI)
+    set(ZLIB_BINARY_DIR "${ZLIB_BINARY_DIR}/${ANDROID_ABI}")
+endif()
+
+FetchContent_Declare(
+    zlib
+    GIT_REPOSITORY "https://github.com/madler/zlib.git"
+    SOURCE_DIR "${ZLIB_SOURCE_DIR}" BINARY_DIR "${ZLIB_BINARY_DIR}"
+    GIT_TAG "${AVIF_LOCAL_ZLIB_GIT_TAG}"
+    GIT_SHALLOW ON
+    UPDATE_COMMAND ""
+)
+
 # Put the value of ZLIB_INCLUDE_DIR in the cache. This works around cmake behavior that has been updated by
 # cmake policy CMP0102 in cmake 3.17. Remove the CACHE workaround when we require cmake 3.17 or later. See
 # https://gitlab.kitware.com/cmake/cmake/-/issues/21343.
-set(ZLIB_INCLUDE_DIR "${AVIF_SOURCE_DIR}/ext/zlib" CACHE PATH "zlib include dir")
+set(ZLIB_INCLUDE_DIR "${ZLIB_SOURCE_DIR}" CACHE PATH "zlib include dir")
 # This include_directories() call must be before add_subdirectory(ext/zlib) to work around the
 # zlib/CMakeLists.txt bug fixed by https://github.com/madler/zlib/pull/818.
 include_directories(SYSTEM $<BUILD_INTERFACE:${ZLIB_INCLUDE_DIR}>)
 
-add_subdirectory(ext/zlib EXCLUDE_FROM_ALL)
+if(NOT zlib_POPULATED)
+    avif_fetchcontent_populate_cmake(zlib)
 
-# Re-enable example and example64 targets, as these are used by tests
-if(AVIF_BUILD_TESTS)
-    set_property(TARGET example PROPERTY EXCLUDE_FROM_ALL FALSE)
-    if(TARGET example64)
-        set_property(TARGET example64 PROPERTY EXCLUDE_FROM_ALL FALSE)
+    # Re-enable example and example64 targets, as these are used by tests
+    if(AVIF_BUILD_TESTS)
+        set_property(TARGET example PROPERTY EXCLUDE_FROM_ALL FALSE)
+        if(TARGET example64)
+            set_property(TARGET example64 PROPERTY EXCLUDE_FROM_ALL FALSE)
+        endif()
     endif()
 endif()
 
@@ -25,24 +50,50 @@ target_include_directories(zlibstatic INTERFACE $<BUILD_INTERFACE:${ZLIB_INCLUDE
 # include directories for add_subdirectory(ext/libpng). Because we set PNG_BUILD_ZLIB,
 # libpng/CMakeLists.txt won't call find_package(ZLIB REQUIRED) and will see an empty
 # ${ZLIB_INCLUDE_DIRS}.
-include_directories($<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/ext/zlib>)
+include_directories("${zlib_BINARY_DIR}")
 set(CMAKE_DEBUG_POSTFIX "")
 
 add_library(ZLIB::ZLIB ALIAS zlibstatic)
 
+message(CHECK_PASS "complete")
+
+if(EXISTS "${AVIF_SOURCE_DIR}/ext/libpng")
+    message(STATUS "libavif(AVIF_ZLIBPNG=LOCAL): ext/libpng found; using as FetchContent SOURCE_DIR")
+    set(FETCHCONTENT_SOURCE_DIR_LIBPNG "${AVIF_SOURCE_DIR}/ext/libpng")
+    message(CHECK_START "libavif(AVIF_ZLIBPNG=LOCAL): configuring libpng")
+else()
+    message(CHECK_START "libavif(AVIF_ZLIBPNG=LOCAL): fetching and configuring libpng")
+endif()
+
 # This is the only way I could avoid libpng going crazy if it found awk.exe, seems benign otherwise
 set(PREV_ANDROID ${ANDROID})
 set(ANDROID TRUE)
-set(PNG_BUILD_ZLIB "${AVIF_SOURCE_DIR}/ext/zlib" CACHE STRING "" FORCE)
+set(PNG_BUILD_ZLIB "${zlib_SOURCE_DIR}" CACHE STRING "" FORCE)
 set(PNG_SHARED OFF CACHE BOOL "")
 set(PNG_TESTS OFF CACHE BOOL "")
 set(PNG_EXECUTABLES OFF CACHE BOOL "")
 
-add_subdirectory("${AVIF_SOURCE_DIR}/ext/libpng" EXCLUDE_FROM_ALL)
+set(LIBPNG_BINARY_DIR "${FETCHCONTENT_BASE_DIR}/libpng")
+if(ANDROID_ABI)
+    set(LIBPNG_BINARY_DIR "${LIBPNG_BINARY_DIR}/${ANDROID_ABI}")
+endif()
+
+FetchContent_Declare(
+    libpng
+    GIT_REPOSITORY "https://github.com/glennrp/libpng.git"
+    BINARY_DIR "${LIBPNG_BINARY_DIR}"
+    GIT_TAG "${AVIF_LOCAL_LIBPNG_GIT_TAG}"
+    GIT_SHALLOW ON
+    UPDATE_COMMAND ""
+)
+
+avif_fetchcontent_populate_cmake(libpng)
 
-set(PNG_PNG_INCLUDE_DIR "${AVIF_SOURCE_DIR}/ext/libpng")
-include_directories($<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/ext/libpng>)
+set(PNG_PNG_INCLUDE_DIR "${libpng_SOURCE_DIR}")
+include_directories("${libpng_BINARY_DIR}")
 set(ANDROID ${PREV_ANDROID})
 
 set_target_properties(png_static zlibstatic PROPERTIES AVIF_LOCAL ON)
 add_library(PNG::PNG ALIAS png_static)
+
+message(CHECK_PASS "complete")