[FFmpeg-devel] [PATCH v2 1/3] libavutil/imgutils: add utility to get plane sizes

Brian Kim bkkim at google.com
Tue Jul 21 00:32:20 EEST 2020


Just wanted to check if there was any consensus on what we wanted to do
with these changes. Are we holding off until a future module wide change?

On Wed, Jul 15, 2020 at 8:09 AM James Almer <jamrial at gmail.com> wrote:

> On 7/15/2020 4:06 AM, Nicolas George wrote:
> > Michael Niedermayer (12020-07-14):
> >> Let me phrase my suggestion in a more high level sense
> >>
> >> Currently the functions use int for lots of cases where they should not
> >> ultimately we want the functions to use more correct types for linesize
> >> sizes and so on.
> >>
> >> We need to add these function(s) because we fix a bug.
> >> Can we take a step toward more correct types while doing this in a
> >> way that makes sense ?
> >>
> >> if so that should be done.
> >>
> >> If not (as in its more mess than if its done later in some other way)
> >> then we should not try to do this now
> >>
> >> The idea is just to take a step towards how these functions/API should
> look
> >> ideally. Its not to make some inconvenient mess
> >
> > I strongly agree.
> >
> > If we use ints now, then the next time the same question comes this
> > function will be one more argument for using ints again. And the next
> > time, and the next time, all this making that much work for when we
> > cannot wait any longer to make the change, instead of that much less.
>
> I don't share the sentiment, since as i said an entire new set of
> functions will have to be added for a module-wide type switch. The way
> this function is designed here will not increase or reduce any future
> work in any way whatsoever. It's meant to be a solution today for a
> problem in the current state of the imgutils module.
>
> For all we know, by the time ints start being a real issue or the need
> to replace the current functions arise, the new set of functions might
> have to be designed in a way this one wont be reusable. For example,
> will AVPixelFormat have been replaced by then with an alternative that
> removes the need to have 20 entries to cover all bitdepths, chroma
> variants, endianness, and plane presence/order, for what's ultimately a
> single format?
>
> Sure, at first glance using the proper types here will seem like making
> a step forward, but we may instead be getting ahead of ourselves for no
> real gain. av_image_check_size() is truly future proof, as is
> av_image_check_sar(), but most others aren't, and that includes this one
> regardless of the data type we choose.
>
> >
> > Consistency is not a end in itself, it is a means to an end. And it is
> > one of the weakest arguments. If there are no other reason for doing
> things
> > one way or another, then sure, by all means let us choose the way that
> > looks the same at the rest of the code. But if there is a reason, if one
> > way is more efficient, or more convenient, or more future proof, or more
> > compatible, etc., then we choose this way, and too bad for consistency.
> >
> > Regards,
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