[FFmpeg-devel] [PATCH v3 2/2] libavformat/vapoursynth: Update to API version 4, load library at runtime

[Ramiro Polla]

On Tue, Jul 30, 2024 at 4:12 PM Ramiro Polla <ramiro.polla at gmail.com> wrote:
> On Mon, Jul 29, 2024 at 5:56 AM Stefan Oltmanns via ffmpeg-devel
> <ffmpeg-devel at ffmpeg.org> wrote:
> > Am 28.07.24 um 15:15 schrieb Ramiro Polla:
> > > I think calling win32_dlopen() with a full path will be problematic for
> > > systems without KB2533623. win32_dlopen() might need to be fixed in a
> > > separate patch.
> >
> > Yes, win32_dlopen would need to check if a full path is already given
> > and if yes skip all the stuff to determine it's own and system32 path,
> > but instead just use the given parameter directly. To check if it's a
> > full path it should be enough to check if it either starts with "\??\"
> > (NT-style path) or if the second character is ":" (win32 style path).
> >
> > But is this really is needed for an operating system that reached
> > support end over 4 years ago and does not have a security patch applied
> > released over 13 years ago?
> > I don't know what ffmpeg's exact policy is in this case, just asking.
>
> Makes sense. I sent a patchset to clean this, but I haven't been able
> to test on a real Windows system.

I finally managed to test the patches on a real Windows system.

They both look good to me, I'll apply them in a couple of days if
there are no other comments.

It would be helpful to write a page in the trac wiki with a basic
howto and common pitfalls. I had problems installing python and
vapoursynth for my user only, and then for all users on the Windows
machine. I had to uninstall everything, remove some registry keys, and
try again using administrator to install to all users. I also had to
manually install Microsoft Visual C++ Redistributable. There was no
good error message telling me what was going wrong. When I added an
av_log() with FormatMessage() after LoadLibraryW() failed, the error
message was also unhelpful.

Ramiro