This is the proper way to export functions, regardless of our custom symbols
export file. This ensures the API definition in the headers match what happens
to the functions.
For users of libvlc with manual DLL loading (especially languages not
compatible with C that have to recode the access to the libvlc DLL) it is
important to know the ABI version of the DLL, in case of API/ABI changes the
wrapper need to be updated and know when the provided DLL package matches or
not. This is especially critical for VLC 4.0 which has not changed version in
4 years and yet the libvlc API keeps changing.
This is similar to the versions of libavcodec/libavformat/etc. When the API is
changed the version values should be updated as well, and hopefully documented
as well.
One should avoid loading the DLL of a mismatching libvlc major ABI version.
Since it's likely to not be usable in the end, it's better not to load it at
all.
This should also be backported to VLC 3.0.
My bad, libvlc_time_t is in ms. The timer API should use the sane unit
than libvlc_clock(), that is us in int64_t.
Also add missing vlc_tick_t <-> us conversion (no harm since 1 tick = 1
us for now).
Any LibVLC users could request a timer from the player. This Media Player
timer has its own event API since:
- It is only used to receive time update points:
- The timer is not locked by the player lock. Indeed the player lock can be
too "slow" (it can be recursive, it is used by the playlist, and is it held
when sending all events). So it's not a good idea to hold this lock for
every frame/sample updates.
- The minimum delay between each updates can be configured: it avoids to flood
the UI when playing a media file with very high fps or very low audio sample
size.
The libvlc_media_player_time_point struct is used by timer update
callbacks. This public struct hold all the informations to interpolate a
time at a given date. It can be done with the
libvlc_media_player_time_point_interpolate() helper. That way, it is
now possible to get the last player time without holding any locks.
There is only one type of timer (for now):
libvlc_media_player_watch_time(): update are sent only when a frame or a
sample is outputted. Users of this timer should take into account that
the delay between each updates is not regular and can be up to 1seconds
(depending of the input). In that case, they should use their own timer
(from their mainloop) and use
libvlc_media_player_time_point_interpolate() to get the last time.
As discussed on vlc-devel a few years back, it is desirable, if not
sometimes necessary, for media objects to be independent from any given
instance.
A typical reason would be to preparse media in one instance but play
them in another.
Thomas Guillem
Steve Lhomme
Marvin Scholz
Martin Finkel
Rémi Denis-Courmont