Those are the elements he cares about and we should expose their APIs
as is, event if they are not classified as effects. For example if
the user want to use a capsfilter as effect, he should be able to set
its caps.
Otherwise the changes won't be reflected in the NLE backend.
This makes speed changes working inside ges-launch-1.0
ges-launch-1.0 +clip /path/to/file i=10 d=5 +effect videorate set-rate 5.0
https://bugzilla.gnome.org/show_bug.cgi?id=794699
Before this patch, NLE and GES did not support NleOperations (respectively
GESEffects) that changed the speed/tempo/rate at which the source plays. For
example, the 'pitch' element can make audio play faster or slower. In GES 1.5.90
and before, an NleOperation containing the pitch element to change the rate (or
tempo) would cause a pipeline state change to PAUSED after that stack; that has
been fixed in 1.5.91 (see #755012 [0]). But even then, in 1.5.91 and later,
NleComposition would send segment events to its NleSources assuming that one
source second is equal to one pipeline second. The resulting early EOS event
(in the case of a source rate higher than 1.0) would cause it to switch stacks
too early, causing confusion in the timeline and spectacularly messed up
output.
This patch fixes that by searching for rate-changing elements in
GESTrackElements such as GESEffects. If such rate-changing elements are found,
their final effect on the playing rate is stored in the corresponding NleObject
as the 'media duration factor', named like this because the 'media duration',
or source duration, of an NleObject can be computed by multiplying the duration
with the media duration factor of that object and its parents (this is called
the 'recursive media duration factor'). For example, a 4-second NleSource with
an NleOperation with a media duration factor of 2.0 will have an 8-second media
duration, which means that for playing 4 seconds in the pipeline, the seek
event sent to it must span 8 seconds of media. (So, the 'duration' of an
NleObject or GES object always refers to its duration in the timeline, not the
media duration.)
To summarize:
* Rate-changing elements are registered in the GESEffectClass (pitch::tempo and
pitch::rate are registered by default);
* GESTimelineElement is responsible for detecting rate-changing elements and
computing the media_duration_factor;
* GESTrackElement is responsible for storing the media_duration_factor in
NleObject;
* NleComposition is responsible for the recursive_media_duration_factor;
* The latter property finally fixes media time computations in NleObject.
NLE and GES tests are included.
[0] https://bugzilla.gnome.org/show_bug.cgi?id=755012
Differential Revision: https://phabricator.freedesktop.org/D276
Making it possible to create the nleobject right at the creation
of the element.
Reviewed-by: Thibault Saunier <thibault.saunier@collabora.com>
Differential Revision: https://phabricator.freedesktop.org/D738
g-ir-scanner includes section docs as class/interface docs if the section name is equal to the lowercase type name.
Since all the documentation is in section blocks, rename them to match the type names.
https://bugzilla.gnome.org/show_bug.cgi?id=727776
