diff --git a/.github/workflows/emscripten.yml b/.github/workflows/emscripten.yml
index 7c7d3fb536..07131585b6 100644
--- a/.github/workflows/emscripten.yml
+++ b/.github/workflows/emscripten.yml
@@ -9,7 +9,7 @@ on:
 jobs:
   emscripten:
     env:
-      EMSCRIPTEN_VERSION: 1.37.26
+      EMSCRIPTEN_VERSION: 3.1.43
     runs-on: ubuntu-20.04
     steps:
     - uses: actions/checkout@v3
diff --git a/build-emscripten.sh b/build-emscripten.sh
index 0992c02046..d94604b834 100755
--- a/build-emscripten.sh
+++ b/build-emscripten.sh
@@ -2,52 +2,116 @@
 set -e
 DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
-CORES=$(nproc --all)
+CORES="${CORES:-`nproc --all`}"
+ENABLE_LIBDE265="${ENABLE_LIBDE265:-1}"
+LIBDE265_VERSION="${LIBDE265_VERSION:-1.0.12}"
+ENABLE_AOM="${ENABLE_AOM:-0}"
+AOM_VERSION="${AOM_VERSION:-3.6.1}"
+STANDALONE="${STANDALONE:-0}"
+DEBUG="${DEBUG:-0}"
+USE_WASM="${USE_WASM:-1}"
+
 echo "Build using ${CORES} CPU cores"
 
-LIBDE265_VERSION=1.0.8
-[ -s "libde265-${LIBDE265_VERSION}.tar.gz" ] || curl \
-    -L \
-    -o libde265-${LIBDE265_VERSION}.tar.gz \
-    https://github.com/strukturag/libde265/releases/download/v${LIBDE265_VERSION}/libde265-${LIBDE265_VERSION}.tar.gz
-if [ ! -s "libde265-${LIBDE265_VERSION}/libde265/.libs/libde265.so" ]; then
-    tar xf libde265-${LIBDE265_VERSION}.tar.gz
-    cd libde265-${LIBDE265_VERSION}
-    [ -x configure ] || ./autogen.sh
-    emconfigure ./configure --disable-sse --disable-dec265 --disable-sherlock265
-    emmake make -j${CORES}
-    cd ..
+LIBRARY_LINKER_FLAGS=""
+LIBRARY_INCLUDE_FLAGS=""
+
+CONFIGURE_ARGS_LIBDE265=""
+if [ "$ENABLE_LIBDE265" = "1" ]; then
+    [ -s "libde265-${LIBDE265_VERSION}.tar.gz" ] || curl \
+        -L \
+        -o libde265-${LIBDE265_VERSION}.tar.gz \
+        https://github.com/strukturag/libde265/releases/download/v${LIBDE265_VERSION}/libde265-${LIBDE265_VERSION}.tar.gz
+    if [ ! -s "libde265-${LIBDE265_VERSION}/libde265/.libs/libde265.so" ]; then
+        tar xf libde265-${LIBDE265_VERSION}.tar.gz
+        cd libde265-${LIBDE265_VERSION}
+        [ -x configure ] || ./autogen.sh
+        emconfigure ./configure --disable-sse --disable-dec265 --disable-sherlock265
+        emmake make -j${CORES}
+        cd ..
+    fi
+    CONFIGURE_ARGS_LIBDE265="-DLIBDE265_INCLUDE_DIR=${DIR}/libde265-${LIBDE265_VERSION} -DLIBDE265_LIBRARY=-L${DIR}/libde265-${LIBDE265_VERSION}/libde265/.libs"
+    LIBRARY_LINKER_FLAGS="$LIBRARY_LINKER_FLAGS -lde265"
+    LIBRARY_INCLUDE_FLAGS="$LIBRARY_INCLUDE_FLAGS -L${DIR}/libde265-${LIBDE265_VERSION}/libde265/.libs"
+fi
+
+CONFIGURE_ARGS_AOM=""
+if [ "$ENABLE_AOM" = "1" ]; then
+    [ -s "aom-${AOM_VERSION}.tar.gz" ] || curl \
+        -L \
+        -o aom-${AOM_VERSION}.tar.gz \
+        "https://aomedia.googlesource.com/aom/+archive/v${AOM_VERSION}.tar.gz"
+    if [ ! -s "aom-${AOM_VERSION}/libaom.a" ]; then
+        mkdir -p aom-${AOM_VERSION}/aom-source
+        tar xf aom-${AOM_VERSION}.tar.gz -C aom-${AOM_VERSION}/aom-source
+        cd aom-${AOM_VERSION}
+
+        emcmake cmake aom-source \
+            -DENABLE_CCACHE=1 \
+            -DAOM_TARGET_CPU=generic \
+            -DENABLE_DOCS=0 \
+            -DENABLE_TESTS=0 \
+            -DENABLE_EXAMPLES=0 \
+            -DENABLE_TESTDATA=0 \
+            -DENABLE_TOOLS=0 \
+            -DCONFIG_MULTITHREAD=0 \
+            -DCONFIG_RUNTIME_CPU_DETECT=0 \
+            -DBUILD_SHARED_LIBS=1 \
+            -DCMAKE_BUILD_TYPE=Release
+
+        emmake make -j${CORES}
+
+        cd ..
+    fi
+
+    CONFIGURE_ARGS_AOM="-DAOM_INCLUDE_DIR=${DIR}/aom-${AOM_VERSION}/aom-source -DAOM_LIBRARY=-L${DIR}/aom-${AOM_VERSION}"
+    LIBRARY_LINKER_FLAGS="$LIBRARY_LINKER_FLAGS -laom"
+    LIBRARY_INCLUDE_FLAGS="$LIBRARY_INCLUDE_FLAGS -L${DIR}/aom-${AOM_VERSION}"
 fi
 
-CONFIGURE_ARGS="-DENABLE_MULTITHREADING_SUPPORT=OFF -DWITH_GDK_PIXBUF=OFF -DWITH_EXAMPLES=OFF -DBUILD_SHARED_LIBS=ON"
-#export PKG_CONFIG_PATH="${DIR}/libde265-${LIBDE265_VERSION}"
+EXTRA_EXE_LINKER_FLAGS="-lembind"
+EXTRA_COMPILER_FLAGS=""
+if [ "$STANDALONE" = "1" ]; then
+    EXTRA_EXE_LINKER_FLAGS=""
+    EXTRA_COMPILER_FLAGS="-D__EMSCRIPTEN_STANDALONE_WASM__=1"
+fi
 
+CONFIGURE_ARGS="-DENABLE_MULTITHREADING_SUPPORT=OFF -DWITH_GDK_PIXBUF=OFF -DWITH_EXAMPLES=OFF -DBUILD_SHARED_LIBS=ON -DENABLE_PLUGIN_LOADING=OFF"
 emcmake cmake $CONFIGURE_ARGS \
-    -DLIBDE265_INCLUDE_DIR="${DIR}/libde265-${LIBDE265_VERSION}" \
-    -DLIBDE265_LIBRARY="-L${DIR}/libde265-${LIBDE265_VERSION}/libde265/.libs"
+    -DCMAKE_C_FLAGS="${EXTRA_COMPILER_FLAGS}" \
+    -DCMAKE_CXX_FLAGS="${EXTRA_COMPILER_FLAGS}" \
+    -DCMAKE_EXE_LINKER_FLAGS="${LIBRARY_LINKER_FLAGS} ${EXTRA_EXE_LINKER_FLAGS}" \
+    $CONFIGURE_ARGS_LIBDE265 \
+    $CONFIGURE_ARGS_AOM
+
 emmake make -j${CORES}
 
-export TOTAL_MEMORY=16777216
+LIBHEIFA="libheif/libheif.a"
+EXPORTED_FUNCTIONS=$($EMSDK/upstream/bin/llvm-nm $LIBHEIFA --format=just-symbols | grep "^heif_\|^de265_\|^aom_" | grep "[^:]$" | sed 's/^/_/' | paste -sd "," -)
 
 echo "Running Emscripten..."
-emcc libheif/libheif.so \
-     --bind \
-     --closure 0 \
-    -s NO_EXIT_RUNTIME=1 \
-    -s TOTAL_MEMORY=${TOTAL_MEMORY} \
+
+BUILD_FLAGS="-lembind -o libheif.js --pre-js pre.js --post-js post.js -sWASM=$USE_WASM"
+RELEASE_BUILD_FLAGS="-O3"
+
+if [ "$STANDALONE" = "1" ]; then
+    echo "Building in standalone (non-web) build mode"
+    BUILD_FLAGS="$BUILD_FLAGS -s STANDALONE_WASM=1 -s WASM=1 -o libheif.wasm --no-entry"
+fi
+
+if [ "$DEBUG" = "1" ]; then
+    echo "Building in debug mode"
+    RELEASE_BUILD_FLAGS="--profile -g"
+fi
+
+emcc "$LIBHEIFA" \
+    -s EXPORTED_FUNCTIONS="$EXPORTED_FUNCTIONS,_free,_malloc,_memcpy" \
     -s ALLOW_MEMORY_GROWTH=1 \
-    -s ASSERTIONS=0 \
-    -s INVOKE_RUN=0 \
-    -s DOUBLE_MODE=0 \
-    -s PRECISE_F32=0 \
-    -s DISABLE_EXCEPTION_CATCHING=1 \
-    -s USE_CLOSURE_COMPILER=0 \
-    -s LEGACY_VM_SUPPORT=1 \
+    -s ERROR_ON_UNDEFINED_SYMBOLS=0 \
+    -s LLD_REPORT_UNDEFINED \
     --memory-init-file 0 \
-    -O3 \
     -std=c++11 \
-    -L${DIR}/libde265-${LIBDE265_VERSION}/libde265/.libs \
-    -lde265 \
-    --pre-js pre.js \
-    --post-js post.js \
-    -o libheif.js
+    $LIBRARY_INCLUDE_FLAGS \
+    $LIBRARY_LINKER_FLAGS \
+    $BUILD_FLAGS \
+    $RELEASE_BUILD_FLAGS
diff --git a/libheif/heif.cc b/libheif/heif.cc
index 954c6c9a15..30f3b0401d 100644
--- a/libheif/heif.cc
+++ b/libheif/heif.cc
@@ -33,7 +33,7 @@
 #include <set>
 #include <limits>
 
-#if defined(__EMSCRIPTEN__)
+#if defined(__EMSCRIPTEN__) && !defined(__EMSCRIPTEN_STANDALONE_WASM__)
 #include "heif_emscripten.h"
 #endif
 
diff --git a/libheif/heif_emscripten.h b/libheif/heif_emscripten.h
index 23e4262153..42b7417205 100644
--- a/libheif/heif_emscripten.h
+++ b/libheif/heif_emscripten.h
@@ -112,7 +112,7 @@ static emscripten::val heif_js_decode_image(struct heif_image_handle* handle,
   result.set("width", width);
   int height = heif_image_get_height(image, heif_channel_Y);
   result.set("height", height);
-  std::string data;
+  std::basic_string<unsigned char> data;
   result.set("chroma", heif_image_get_chroma_format(image));
   result.set("colorspace", heif_image_get_colorspace(image));
   switch (heif_image_get_colorspace(image)) {
@@ -127,7 +127,7 @@ static emscripten::val heif_js_decode_image(struct heif_image_handle* handle,
       const uint8_t* plane_v = heif_image_get_plane_readonly(image,
                                                              heif_channel_Cr, &stride_v);
       data.resize((width * height) + (2 * round_odd(width) * round_odd(height)));
-      char* dest = const_cast<char*>(data.data());
+      unsigned char* dest = const_cast<unsigned char*>(data.data());
       strided_copy(dest, plane_y, width, height, stride_y);
       strided_copy(dest + (width * height), plane_u,
                    round_odd(width), round_odd(height), stride_u);
@@ -142,7 +142,7 @@ static emscripten::val heif_js_decode_image(struct heif_image_handle* handle,
       const uint8_t* plane_rgb = heif_image_get_plane_readonly(image,
                                                                heif_channel_interleaved, &stride_rgb);
       data.resize(width * height * 3);
-      char* dest = const_cast<char*>(data.data());
+      unsigned char* dest = const_cast<unsigned char*>(data.data());
       strided_copy(dest, plane_rgb, width * 3, height, stride_rgb);
     }
       break;
@@ -153,7 +153,7 @@ static emscripten::val heif_js_decode_image(struct heif_image_handle* handle,
       const uint8_t* plane_grey = heif_image_get_plane_readonly(image,
                                                                 heif_channel_Y, &stride_grey);
       data.resize(width * height);
-      char* dest = const_cast<char*>(data.data());
+      unsigned char* dest = const_cast<unsigned char*>(data.data());
       strided_copy(dest, plane_grey, width, height, stride_grey);
     }
       break;
diff --git a/post.js b/post.js
index 3c0e70fec8..fd733a5841 100644
--- a/post.js
+++ b/post.js
@@ -175,40 +175,6 @@ var libheif = {
     }
 };
 
-var key;
-
-// Expose enum values.
-var enums = {
-    "heif_error_code": true,
-    "heif_suberror_code": true,
-    "heif_compression_format": true,
-    "heif_chroma": true,
-    "heif_colorspace": true,
-    "heif_channel": true
-};
-var e;
-for (e in enums) {
-    if (!enums.hasOwnProperty(e)) {
-        continue;
-    }
-    for (key in Module[e]) {
-        if (!Module[e].hasOwnProperty(key) ||
-            key === "values") {
-            continue;
-        }
-
-        libheif[key] = Module[e][key];
-    }
-}
-
-// Expose internal C API.
-for (key in Module) {
-    if (enums.hasOwnProperty(key) || key.indexOf("heif_") !== 0) {
-        continue;
-    }
-    libheif[key] = Module[key];
-}
-
 // don't pollute the global namespace
 delete this['Module'];
 
diff --git a/pre.js b/pre.js
index 25e608e583..3978ad958f 100644
--- a/pre.js
+++ b/pre.js
@@ -29,5 +29,47 @@ var Module = {
         console.error(text);
     },
     canvas: {},
-    noInitialRun: true
+    noInitialRun: true,
+    onRuntimeInitialized: function() {
+        // Expose enum values.
+        var enums = {
+            "heif_error_code": true,
+            "heif_suberror_code": true,
+            "heif_compression_format": true,
+            "heif_chroma": true,
+            "heif_colorspace": true,
+            "heif_channel": true
+        };
+        var e;
+        for (e in enums) {
+            if (!enums.hasOwnProperty(e)) {
+                continue;
+            }
+
+            for (key in this[e]) {
+                if (!this[e].hasOwnProperty(key) ||
+                    key === "values") {
+                    continue;
+                }
+
+                libheif[key] = this[e][key];
+            }
+        }
+
+        // Expose internal C API.
+        for (key in this) {
+            if (enums.hasOwnProperty(key.slice(1)) || key.indexOf("_heif_") !== 0) {
+                continue;
+            }
+            libheif[key.slice(1)] = this[key];
+        }
+
+        // Expose embind API.
+        for (key in Module) {
+            if (enums.hasOwnProperty(key) || key.indexOf("heif_") !== 0) {
+                continue;
+            }
+            libheif[key] = Module[key];
+        }
+    }
 };
diff --git a/scripts/install-emscripten.sh b/scripts/install-emscripten.sh
index d3b638e624..066c77f463 100755
--- a/scripts/install-emscripten.sh
+++ b/scripts/install-emscripten.sh
@@ -11,7 +11,6 @@ fi
 
 LIBSTDC_BASE=http://de.archive.ubuntu.com/ubuntu/pool/main/g/gcc-5
 EMSDK_DOWNLOAD=https://github.com/emscripten-core/emsdk.git
-EMSDK_VERSION=3.1.29
 
 CODENAME=$(/usr/bin/lsb_release --codename --short)
 if [ "$CODENAME" = "trusty" ] && [ ! -e "/usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21" ]; then
@@ -33,13 +32,13 @@ if [ ! -d emsdk ]; then
 fi
 
 cd emsdk
-echo "Updating SDK base to ${EMSDK_VERSION} ..."
+echo "Updating SDK base to ${VERSION} ..."
 git checkout main
 git pull --verbose
-git checkout ${EMSDK_VERSION}
+git checkout ${VERSION}
 
-echo "Installing SDK version ${VERSION} ..."
-./emsdk install sdk-fastcomp-${VERSION}-64bit
+echo "Installing SDK version latest ..."
+./emsdk install ${VERSION}
 
-echo "Activating SDK version ${VERSION} ..."
-./emsdk activate sdk-fastcomp-${VERSION}-64bit
+echo "Activating SDK version latest ..."
+./emsdk activate ${VERSION}