[vlc-devel] [PATCH v3 09/14] libvlc: allow selecting the video hardware acceleration

[Alexandre Janniaux]

Hi,

On Fri, Feb 14, 2020 at 07:58:32AM +0100, Steve Lhomme wrote:
> On 2020-02-13 18:56, Rémi Denis-Courmont wrote:
> > Le torstaina 13. helmikuuta 2020, 17.44.50 EET Steve Lhomme a écrit :
> > > The values in the enum reflect the currently available decoder devices.
> > > ---
> > >   include/vlc/libvlc_media_player.h | 53 +++++++++++++++++++++++++++++++
> > >   lib/libvlc.sym                    |  1 +
> > >   lib/media_player.c                | 22 +++++++++++++
> > >   3 files changed, 76 insertions(+)
> > >
> > > diff --git a/include/vlc/libvlc_media_player.h
> > > b/include/vlc/libvlc_media_player.h index 5e0255a10ac..ad19c383a0c 100644
> > > --- a/include/vlc/libvlc_media_player.h
> > > +++ b/include/vlc/libvlc_media_player.h
> > > @@ -503,6 +503,59 @@ void libvlc_video_set_format_callbacks(
> > > libvlc_media_player_t *mp, libvlc_video_cleanup_cb cleanup );
> > >
> > >
> > > +/**
> > > + * Enumeration of the Video hardware processing acceleration to be used.
> > > + * can be passed to @a libvlc_video_set_video_acceleration
> > > + */
> > > +typedef enum libvlc_video_acceleration_t {
> >
> > No way.
> >
> > Plugins come and go. They can be added externally, or with new versions, they
> > can be removed, and of course, they depend on the platform and build options.
> > They cannot be described with an enum.
>
> The documentation says there's no guarantee it will be respected. Most
> people will never need to touch this. Those who do that's because they have
> a reason to do it.

People having a reason to do this might use the options as well
or provide additional API through another libvlccore wrapper.

Using this feature could be nice but it could probably provide
a list of accepted identifiers (strings or richer opaque structure)
instead of relying on an enum. It will provide a clearer API and
more stable over time, but I wonder what cost it implies on the
user in term of complexity, like making application work with
HW acceleration on a platform but silently disable it on another.

I also don't think that this feature really makes a lot of sense
as a libVLC user because it's too low level for the majority of
cases, but I'm not really sure what simpler concept could be
exposed instead.

What use case do you have that is not solved by the automatic
probing ?

Regards,
--
Alexandre Janniaux
Videolabs