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Efficient Compression Tool

Efficient Compression Tool (or ECT) is a C++ file optimizer.
It supports PNG, JPEG, GZIP and ZIP files.

Performance (v0.9.2)

All tests were run on macOS 12.5 using an Intel i7-7700HQ and clang.
File: enwik8, 100,000,000 bytes, compressed into gzip format

Compressor File Size Time
ECT -1 36,493,257 3.5s
gzip -9 36,475,811 5.8s
zopfli -i1 35,102,371 1m 30.2s
ECT -2 35,019,440 14.8s
zopfli -i5 34,983,757 2m 12.0s
ECT -3 35,014,543 16.2s
zopfli -i15 34,966,078 3m 59.9s
ECT -4 34,963,581 19.8s
zopfli -i30 34,961,453 6m 30.6s
ECT -5 34,942,796 25.1s
ECT -6 34,943,943 41.9s
ECT -7 34,942,348 59.7s
ECT -8 34,941,125 2m 25.6s
ECT -9 34,937,781 3m 17.9s


To build ECT, you need to recursively clone it, just downloading isn’t enough, i. e. git clone --recursive
You may also need to install nasm if it is not available already.

Command line

ECT is built with cmake

mkdir build
cd build
cmake ../src

In addition, you can add the following arguments to the cmake call to turn various features on and off:

  • -DECT_MULTITHREADING=OFF: Turn off multithreading support

With Xcode

You can use cmake to generate an Xcode project. Just add -G Xcode to the end of the cmake command:

mkdir build
cd build
cmake ../src -G Xcode

You will run into a slight issue in that Xcode doesn't know how to compile some of the asm files within mozjpeg. To fix this, locate your copy of nasm (/usr/local/bin/nasm in the example) navigate to the Build Rules of the simd target, and add a custom rule to process source files matching *.asm with the following script:

/usr/local/bin/nasm "-I${PROJECT_DIR}/mozjpeg" -DMACHO -D__x86_64__ "-I${PROJECT_DIR}/mozjpeg/simd/nasm/" "-I${PROJECT_DIR}/mozjpeg/simd/x86_64/" -f macho64 -o "${BUILT_PRODUCTS_DIR}/x86_64/${INPUT_FILE_BASE}.o" "${INPUT_FILE_PATH}"

and set $(BUILT_PRODUCTS_DIR)/x86_64/${INPUT_FILE_BASE}.o as the output files.

If you are using Xcode for development and do not need maximum speed, you can also disable the asm files by adding -DWITH_SIMD=OFF to the cmake.