Dynamically changing resolution of visualisations

[Yogesh Marwaha]

Hi,

I'm to add possibility of changing resolution of visualisation shown in my
application (using playbin2; sparklemedia.sourceforge.net). Here are some
points: -

(I still have not coded anything regarding subject yet, only gst-launch stuff)

* goom, for example, provides only one caps structure on its source pad, so
changing its width and height is sufficient; but libvisual_jakdaw provides
three caps structures on its source pad, which one should I use or should I
change width/height on all?

* which element decides on what resolution the visualisation is run, and how?
I suppose it to be visualisation element and some default values.

* is there any way I can force the visualisation to render on same resolution
as the current video output widget?

That's all for now. Please reply asap.

Regards,

Yogesh Marwaha
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[Yogesh Marwaha]

On Saturday 23 Jul 2011 20:14:17 Yogesh Marwaha wrote:
> Hi,
>
> I'm to add possibility of changing resolution of visualisation shown in my
> application (using playbin2; sparklemedia.sourceforge.net). Here are some
> points: -
I am now thinking of simplify things and allow there quality settings viz.
Low, High, and Best.
Low: Visualisations are rendered in a size 1/4 of the widget's size
High: Visualisations are rendered in a size 1/2 of the widget's size
Best: Visualisations are rendered in a size 1/1 of the widget's size
>
> (I still have not coded anything regarding subject yet, only gst-launch
> stuff)
>
> * goom, for example, provides only one caps structure on its source pad, so
> changing its width and height is sufficient; but libvisual_jakdaw provides
> three caps structures on its source pad, which one should I use or should I
> change width/height on all?
I'm thinking of following bin as visualisation: -
goom (or any other visualisation) ! ffmpegcolorspace ! capsfilter ! videoscale

I've the following working (preliminary) code (please notice the caps, advice
is needed on it): -
    GstElement *newVisualisationElement =
gst_element_factory_make(visualisation.toLocal8Bit(), "visualisation1");
    GstElement *newCapsfilterElement = gst_element_factory_make("capsfilter",
"visualisation2");
    GstCaps *caps = gst_caps_new_simple ("video/x-raw-yuv",
                                         "width", G_TYPE_INT, 640,
                                         "height", G_TYPE_INT, 480,
                                         NULL);
    g_object_set(G_OBJECT(newCapsfilterElement), "caps", caps, NULL);

    GstElement *newFfmpegcolorspaceElement =
gst_element_factory_make("ffmpegcolorspace", "visualisation3");
    GstElement *newVideoscaleElement = gst_element_factory_make("videoscale",
"visualisation4");
    if(newVisualisationElement){
        m_pVisualisationBin = gst_bin_new("visualisation-bin");

        gst_bin_add_many(GST_BIN(m_pVisualisationBin),
newVisualisationElement, newFfmpegcolorspaceElement, newCapsfilterElement,
newVideoscaleElement, NULL);
        gst_element_link_many(newVisualisationElement,
newFfmpegcolorspaceElement, newCapsfilterElement, newVideoscaleElement, NULL);
        gst_element_add_pad(m_pVisualisationBin, gst_ghost_pad_new("sink",
gst_element_get_static_pad(newVisualisationElement, "sink")));
        gst_element_add_pad(m_pVisualisationBin, gst_ghost_pad_new("src",
gst_element_get_static_pad(newVideoscaleElement, "src")));

        g_object_set(G_OBJECT(m_pPlayBin), "flags", PLAYBIN_FLAG_NO_VIS,
NULL);
        g_object_set(G_OBJECT(m_pPlayBin), "vis-plugin", m_pVisualisationBin,
NULL);
        g_object_set(G_OBJECT(m_pPlayBin), "flags", PLAYBIN_FLAG_VIS, NULL);
        mCurrentVisualisation = visualisation;
        return true;
    }

Code is tested with xvimagesink and ximagesink with similar behaviour.
>
> * which element decides on what resolution the visualisation is run, and
> how? I suppose it to be visualisation element and some default values.
?
>
> * is there any way I can force the visualisation to render on same
> resolution as the current video output widget?

?

Regards,

Yogesh Marwaha
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[hidden email]
http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel