GES 1.12 -- Multiple encodings to multiple files

Wed Jul 4 00:04:03 UTC 2018

Because the only way I know to connect to "query-position" is to follow the
example I found in ges-pipeline.c

chain->query_position_id =
    g_signal_connect (ges_track_get_composition (track), "query-position",
    G_CALLBACK (_query_position_cb), self);

which led me to write the following:

//  It is necessary to connect the "query-position" signal to each track
g_signal_connect(
    videoTrack->priv->composition,                      //
(GESTrack*)->priv->compositoin
    "query-position",
    G_CALLBACK(CompositionJob::cbQueryPosition),        // my callback
method
    m_gstPipeline);                                     // GstPipeline*

So basically I had to pull in the definition of _GESTrackPrivate to make
that work.

If there is a better way to do it then please let me know.  (I am not
usually a glib programmer so perhaps there is something I don't know about.)

On Tue, Jul 3, 2018 at 4:37 PM, Thibault Saunier <tsaunier at gnome.org> wrote:

> Why do you think you need to access the composition?
> On Tue, Jul 3, 2018 at 7:22 PM David Ing <ding at panopto.com> wrote:
> >
> > Thanks Thibault.
> >
> > Unfortunetly I would need a method which is not exposed through the
> headers:  ges_track_get_composition  ... I will need to pull in code from
> the *.c files to implement the method on my end ... a dirty deed indeed.
> >
> >
> > On Mon, Jul 2, 2018 at 10:05 AM, Thibault Saunier <tsaunier at gnome.org>
> wrote:
> >>
> >> Hello David,
> >>
> >> There should be no problem using a GstPipeline as long as you make
> >> sure to connect to the query-position signal of each track, I do not
> >> think there is any other quirk but I might be misremembering :-)
> >>
> >> With the GESPipeline API I do not see a clean way to do what you want
> >> so I believe your best bet is to just use a GstPipeline.
> >>
> >> Regards,
> >>
> >> Thibault
> >> On Mon, Jul 2, 2018 at 12:41 PM David Ing <ding at panopto.com> wrote:
> >> >
> >> > I sent the original message on this thread Friday evening (US Pacific
> Time) ... chances are that most people never saw it, so I'm trying again:
> >> >
> >> > On a prior email thread, it was suggested that GESTimeline and
> GstPipeline are not 100% compatible with each other:
> https://lists.freedesktop.org/archives/gstreamer-devel/2018-
> March/067349.html
> >> >
> >> > >     The GES timeline can indeed be used in a regular gstreamer
> pipeline, but there
> >> > >     are some undocumented quirks, amongst them the "query-position"
> signal emitted
> >> > >     by the NLEComposition wrapped by the GESTrack object, this is
> why using GESPipeline
> >> > >     is the recommended approach.
> >> >
> >> >
> >> > I am now in the position of being forced to use the GstPipeline with
> the GESTimeline (for reasons described in the first message of this
> thread).  I wonder if anybody can shed some light on the problems that I
> might see, and provide a hint about how I might overcome them.  I am
> working in C / C++ so I have a lot of options, but I would benefit from a
> little guidance.
> >> >
> >> >
> >> > On Fri, Jun 29, 2018 at 4:24 PM, David Ing <ding at panopto.com> wrote:
> >> >>
> >> >> To partially answer my own question:  I think I need to use a
> GstPipeline rather than a GESPipeline (so I can have full control over the
> GstElements which do the encoding and writing to files).
> >> >>
> >> >> On another email thread, it was suggested that GESTimeline and
> GstPipeline are not 100% compatible with each other:
> https://lists.freedesktop.org/archives/gstreamer-devel/2018-
> March/067349.html
> >> >>
> >> >> >     The GES timeline can indeed be used in a regular gstreamer
> pipeline, but there
> >> >> >     are some undocumented quirks, amongst them the
> "query-position" signal emitted
> >> >> >     by the NLEComposition wrapped by the GESTrack object, this is
> why using GESPipeline
> >> >> >     is the recommended approach.
> >> >>
> >> >>
> >> >> If I use GESTimeline with GstPipeline, what kinds of trouble can I
> expect?
> >> >>
> >> >> On Fri, Jun 29, 2018 at 1:32 PM, David Ing <ding at panopto.com> wrote:
> >> >>>
> >> >>> I am using GES 1.12 and I am trying to build a single GESPipeline
> with a somewhat complicated set of outputs.  I am coding in C++ (using
> gstreamer headers and libs).
> >> >>>
> >> >>> Consider a representative example:
> >> >>>
> >> >>> I have built a GESTimeline which sits inside a GESPipeline.
> >> >>>
> >> >>> I want to generate multiple encodings.
> >> >>>
> >> >>> Low quality video AVC (h.264)
> >> >>> Mid quality video AVC (h.264)
> >> >>> High quality video AVC (h.264)
> >> >>> High quality audio AAC
> >> >>>
> >> >>> I want to shunt these encodings into multiple containers.
> >> >>>
> >> >>> HLS folder (all encodings)
> >> >>> MP4 high quality (encodings 3 & 4)
> >> >>> MP4 mid quality (encodings 2 & 4)
> >> >>>
> >> >>> Presumably, the most efficient approach (computationally) is to use
> a single pipeline for all of this.  Computational efficiency is of
> paramount importance to me.
> >> >>>
> >> >>> My question is:  What approach should I take?
> >> >>>
> >> >>> One approach is to manually construct the GstElements I need for
> encoding and muxing, and connect them together in the appropriate way
> within the GESPipeline (I guess they would source directly from the sinks
> on the GESTimeline).  Is that the correct approach?  Or is there another
> approach that will work better?
> >> >>>
> >> >>> Guidance is appreciated.
> >> >>
> >> >>
> >> >
> >> > _______________________________________________
> >> > gstreamer-devel mailing list
> >> > gstreamer-devel at lists.freedesktop.org
> >> > https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
> >> _______________________________________________
> >> gstreamer-devel mailing list
> >> gstreamer-devel at lists.freedesktop.org
> >> https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
> >
> >
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> > https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
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