support aarch64 architecture

[xunfeng1980]

Expected behaviour

Support aarch64 architecture

Actual behaviour

Don't support aarch64/arm64 architecture

• operating system
  Linux arm-builder 4.14.105-19-beta3 Linux wheels #1 SMP Wed May 8 11:19:15 CST 2019 aarch64 aarch64 aarch64 GNU/Linux
• architecture
  aarch64
• opencv-python version
  4.x

[skvark]

ARM support is tracked here: #13

Currently there is no plans to provide aarch64/arm64 packages due to the Python packaging ecosystem's incomplete support for those architectures.

[AshokBhat]

Python now supports manylinux2014 standard, which makes it possible to provide AArch64 wheels. For example, the latest version of NumPy now provides the AArch64 wheel (https://pypi.org/project/numpy/1.19.0/#files). Is there anything specific that you need anything beyond manylinux2014 support?

[Red-Eyed]

@AshokBhat wow, it's really cool, didn't know about that.
I think that it needs to configure cross compilation toolchains (compilers).
AFAIK, currently, there is only docker container that uses default CentOS toolchain (which is x86 or amd64)

[AshokBhat]

@Red-Eyed There are docker images available for AArch64 (aarch64 image: quay.io/pypa/manylinux2014_aarch64) in addition to x86_64 to build manylinux2014 images. https://github.com/pypa/manylinux has the details. Are you looking to build the images on an x86_64 host?

[skvark]

Docker images are not enough. ARM based hardware is needed to build ARM wheels (another option is cross compiling, which is something I would not like to implement... also auditwheel works only on ARM HW: pypa/auditwheel#244 (comment)). The only CI system which has currently ARM support is https://www.shippable.com/ (and Travis has probably some solution in alpha, don't know if released yet) so it's a major effort to start supplying ARM wheels for opencv-python and further increases my workload. Please continue discussing about this in the issue which is reserved for ARM based wheels: #13