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Bug 763457 - gstparse: element properties are contained in a GstPipeline instead of a GstBin
gstparse: element properties are contained in a GstPipeline instead of a GstBin
Product: GStreamer
Classification: Platform
Component: gstreamer (core)
git master
Other Linux
: Normal normal
: 1.9.1
Assigned To: GStreamer Maintainers
GStreamer Maintainers
Depends on:
Reported: 2016-03-10 12:03 UTC by Carlos Rafael Giani
Modified: 2016-03-24 12:52 UTC
See Also:
GNOME target: ---
GNOME version: ---

patch which adds a new parse flag for using bins instead of pipelines (3.75 KB, patch)
2016-03-11 08:30 UTC, Carlos Rafael Giani
committed Details | Review

Description Carlos Rafael Giani 2016-03-10 12:03:35 UTC
When running this pipeline:

  gst-launch-1.0 playbin uri=<URI> video-sink="identity ! autovideosink"

The "identity ! autovideosink" should be contained within a GstBin, which is then the videosink. But instead, they are contained within a GstPipeline. The result is a GstPipeline containing another GstPipeline. Worse, the sub-pipeline has a pad.

This can probably lead to undefined behavior. Example:

  gst-launch-1.0 playbin uri=<URI> video-sink="decodebin ! autovideosink"

This never reaches the PLAYING state.

It would make sense to contain the elements in a GstBin instead.
Comment 1 Sebastian Dröge (slomo) 2016-03-11 07:34:32 UTC
It uses gst_parse_bin_from_description() already, which uses gst_parse_launch_full() internally.

And that one calls
>  bin = GST_BIN (gst_element_factory_make ("pipeline", NULL));

So the solution would be to pass through the information that we want a bin, not a pipeline. Maybe by adding a new value to GstParseFlags for backwards compatibility (someone might expect gst_parse_bin_from_description() to return a GstPipeline).
Comment 2 Sebastian Dröge (slomo) 2016-03-11 07:34:53 UTC
Do you want to write a patch?
Comment 3 Carlos Rafael Giani 2016-03-11 07:35:58 UTC
Yeah okay I'll try. I should have something soon for 1.8.
Comment 4 Carlos Rafael Giani 2016-03-11 08:30:03 UTC
Created attachment 323686 [details] [review]
patch which adds a new parse flag for using bins instead of pipelines

Here. Adds the flag and also makes the internal parser code use this flag for element property values so we no longer have pipelines inside pipelines.
Comment 5 Sebastian Dröge (slomo) 2016-03-24 12:52:30 UTC
commit eca5bafe818d9c05b6a856b1a6eb78807a260010
Author: Carlos Rafael Giani <>
Date:   Fri Mar 11 09:23:04 2016 +0100

    parse-launch: Add flag for placing elements in a bin instead of a pipeline
    By default, gst_parse_launch_full() creates a GstPipeline if there's more
    than one toplevel element. Add a flag to let it use a GstBin instead.
    Also fix the parser to let it use this flag for GST_TYPE_ELEMENT property
    values, to avoid having GstPipelines inside other GstPipelines.