[vlc-devel] Support for Windows on Arm

[Martin Storsjö]

On Fri, 9 Sep 2022, Steve Lhomme wrote:

> Hi,
>
> On 2022-09-09 10:22, Pierrick Bouvier wrote:
>> Hello,
>> 
>> I'm contacting you to talk about VLC support for Windows on Arm (arm64).
>> 
>> At Linaro, the project https://www.linaro.org/windows-on-arm/ is working 
>> to enable open source projects for this platform.
>> VLC being widely used is on our radar.
>> 
>> It seems like an experimental build of vlc 4.0 was made in 2018, and is 
>> available from VLC Windows download page ("Windows ARM 64" variant).
>> 
>> We would like to help creating up to date versions, to add same level of 
>> support than win32/win64 variants. Is there something blocking today 
>> (machine, support in vlc 3.0 branch)? How could we help?
>
> VLC 4.0 should build out of the box for Windows ARM. It should build 
> like the other Windows targets except adding `-a aarch64` to build.sh. 
> It should work with the LLVM Dockers we use (or any llvm-mingw build).

> Not sure there's mingw-w64 for ARM available.

I have no idea what you mean by this sentence - llvm-mingw uses mingw-w64?

> There may be some contribs that don't build properly, for example Qt may 
> refuse to build or not understand what's going on.

What on earth are you talking about here?

I build VLC 4.0/git for aarch64 locally (for testing llvm-mingw) nightly 
every 4 days (building for other archs inbetween), and it generally builds 
flawlessly, including Qt.

Building Qt for VLC 4.0 is a bit tricky though, due to the dependence on 
the binary shader compiler for ANGLE - it runs fine when cross compiling 
from x86_64 linux (and with newer upstream updated fxc2 repo, it also 
cross builds fine from aarch64 linux!), but I haven't tested building it 
natively on aarch64 windows (as msys2 doesn't exist in native form, but I 
presume the emulated version works fine - but building VLC for windows in 
msys2 is messy anyway).

// Martin