Video backend selection

[Andreas Schleth]

Hi,

you know, that I greatly appreciate your work in KPA, but in the case of
video playback I do not fully understand why the internal video viewer
exists in the first place. Is it unthinkable to dump the internal viewer
and instead repurpose the "open with external program" dialog (wrap it
internally, with a config option and optionally a detection module) and
just call VLC, mplayer or whatever video player is installed. There is
probably no system around without any video player. If you need to
install one of the backends anyway, the GUI would be there too. I think
along similar lines as why we have no image manipulation options in KPA:
there are programs around that do a great job at this - Gimp, Darktable,
you name it. (Except for the old promise: "Kimdaba does not touch your
files").

As Jesper pointed out in another post: it is a lot of work to
re-implement all gui features of a full blown video player. The keyword
is "re-". I just had another look and found a lot of new(? or new found)
features integrated in the RMB menu. Still, while the features present
in the integrated viewer right now are quite a lot better than a while
ago, they are still far from perfect, so why bother...? The effort spent
on the video viewer seems to me a lot like re-inventing the wheel. So,
why not slim down the code base at this point?

I may simply not understand why KPA really needs an integrated video
player (this might well be *my* problem). Loading time? Process
overhead? ...?  I only use the external program option (and am happy for
having it!) for viewing video anyway and only look at the internal
player for testing. OK: the tags and categories are only shown with the
internal version and the option to choose a customized thumbnail is a
unique feature ... but still ... If you have a few 1000 videos in the
database, you probably are just as content with being able to select one
of the autogenerated videothumbnails.
I still miss the option to select or switch audio channels and the many
other features I learned to love in VLC and I understand, that this
would be a lot of implementation effort - and other people might have
other pain points (subtitles anyone?).
A compromise might be to include the existing internal viewer in the
choices for a default video player in the settings dialog.

As for the original UX question:

The first time I tested it, I clicked the one time dialog away too
quickly (nobody reads, understands and remembers dialogs if not forced
to :-) and then found the option to choose the backend in the viewer
settings. However, when switching backends (at one time I had all 3
options available) I never found any difference in the behaviour of the
player. Did I not look closely enough? So, why bother. If it plays it
plays. (To be honest, I was quite disappointed at that time as in my
naivety I expected to find a VLC backend with all the bells and whistles
of VLC - never mind!)
Only if it doesn't play (or, beware, crashes), the user needs to find an
option to remedy the situation. And then, the backends may all use the
same deficient libavcodec. So, the problem might not be fixable inside
KPA at all. I had situations when a certain video would only play in
Mplayer and nothing else. This could only be fixed by carefully
reinstalling the proper codec libraries. Therefore, some documentation
for troubleshooting would go a long way.

Therefore, my vote goes to "autodetect" with the option to choose in the
settings dialog.

Best regards, Andreas


Am 04.01.22 um 19:38 schrieb Jesper K. Pedersen:
> I don't feel strong either way.
>
> The dialog is a one time dialog that shows up as you upgrade KDV, and
> given the trouble that all three plugins have I think the user should
> know what he chooses otherwise he will just end up wondering why the
> preview doesn't work all of a sudden (if you switch from QtAV to one
> of the other backends behind his back).
>
> But again, I don't feel strong about it. Maybe at least inform him
> that you are switching backend when doing so, and offer him the config
> dialog
>
> Cheers
> Jesper.
>
> On 1/4/22 00:53, Johannes Zarl-Zierl wrote:
>> Hi!
>>
>> I'm not yet totally pleased with the way the user is prompted to
>> choose a
>> video player backend.
>>
>> So instead of prompting right away I thought that maybe just choosing a
>> sensible default would be a nicer user experience (currently the first
>> available of VLC > QtAV > Phonon).
>>
>> Since there have been reports with some players crashing outside of
>> KPHotoAlbums control, I've also added a crash detection: if KPA
>> terminated
>> during video playback, it automatically selects a different video
>> player next
>> time. As a last resort, the selection dialog is shown.
>>
>> I've not yet commited the change to master, but I would like some
>> feedback
>> regarding the UX. What do you think?
>>
>> The feature is currently in branch work/jzarl/crash-sentinel
>>
>> https://invent.kde.org/graphics/kphotoalbum/-/commit/
>> 78cfa242b9972792eee4661466508beed66b37aa
>>
>> Cheers,
>>    Johannes
>>
>>