[FFmpeg-devel] [PATCH] hwcontext_vulkan: fix exporting multi-plane DRM modifiers

[Russell Greene]

Now realizing that there's not really a way to just query all
modifiers, you'd actually need to query all formats for their
modifiers...

Options as I see it are:
1. in init(), create a table of all (vk_format, modifier) pairs and
the `VkDrmFormatModifierPropertiesEXT` information about the pair for
fast lookup during the map code
2. the patch i've already suggested
3. don't support drivers with more than X modifiers per format
4. have a slow path for driver with more than that X modifiers per format

Or maybe some other options I'm not seeing?

> ...that's exactly what I posted.
> Set array to non-NULL, set nb to the array size you're giving it, and
> you'll get UP TO nb, no more, even if the driver has more.

Right, but what if the modifier you need info on is after nb?

On Sat, May 3, 2025 at 10:11 AM Russell Greene <russellgreene8 at gmail.com> wrote:
>
> > > If we're OK with a practical "we don't support drivers with more than
> > > X modifiers because we doubt it'll ever exist" then that's a valid
> > > answer as well.
> > If that's your concern, just fetch all info for all modifiers in the
> > init function.
>
> Works for me. I'm new to ffmpeg devel, I assume I should write a v2
> and send it to this list?
>
> Also, apologies for my mailing list sins (top posting, failing to
> reply to the correct message)
>
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