[Bug 796499] Changing the returned data from the buffer so that it can be modified and read without copying

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=796499

Sebastian Dröge (slomo) <***@coaxion.net> changed:

What |Removed |Added
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CC| |***@coaxion.net

--- Comment #4 from Sebastian Dröge (slomo) <***@coaxion.net> ---
Would it be possible to a) make sure that the buffer can't go out of scope (and
get destroyed) while there's a map, and b) to unmap the mapinfo if it was not
unmapped explicitly once it goes out of scope?

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=796499

Daniel Klamt <***@pengutronix.de> changed:

What |Removed |Added
----------------------------------------------------------------------------
CC| |***@pengutronix.de

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=796499

--- Comment #2 from Daniel Klamt <***@pengutronix.de> ---
Created attachment 372555
--> https://bugzilla.gnome.org/attachment.cgi?id=372555&action=edit
A gst-python element that uses the patch

gst-launch-1.0 videotestsrc ! videoconvert ! numpye ! videoconvert !
xvimagesink

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=796499

--- Comment #1 from Daniel Klamt <***@pengutronix.de> ---
Created attachment 372554
--> https://bugzilla.gnome.org/attachment.cgi?id=372554&action=edit
The Patch

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=796499

Tim-Philipp Müller <***@zen.co.uk> changed:

What |Removed |Added
----------------------------------------------------------------------------
Summary|Changing the returned data |Changing the returned data
|from the buffer so that it |from the buffer so that it
|can be modified an read |can be modified and read
|without copying |without copying

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=796499

Tim-Philipp Müller <***@zen.co.uk> changed:

What |Removed |Added
----------------------------------------------------------------------------
CC| |***@zen.co.uk
See Also| |https://bugzilla.gnome.org/
| |show_bug.cgi?id=678663
Severity|normal |enhancement

--- Comment #3 from Tim-Philipp Müller <***@zen.co.uk> ---
I'm guessing this is for version 1.14.1 not 1.4.1?

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=796499

Daniel Klamt <***@pengutronix.de> changed:

What |Removed |Added
----------------------------------------------------------------------------
Version|1.4.1 |1.14.1

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=796499

--- Comment #5 from Daniel Klamt <***@pengutronix.de> ---
As far as my understanding of python goes both a and b are handled
automatically by the python garbage collector.

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=796499

--- Comment #6 from Daniel Klamt <***@pengutronix.de> ---
The issue is that the Gst.MapInfo returned by Gst.Buffer.map would have a
bytes() object as .data member, not a memoryview().
And the original pointer would get lost when the GstMemoryInfo c structure was
recreated from the python object to be passed to gst_buffer_unmap.
https://paste.debian.net/1049985/

This would be a dirty fix
https://pastebin.com/NmUw1F3A

["GStreamer" (GNOME Bugzilla)]

https://bugzilla.gnome.org/show_bug.cgi?id=796499

GStreamer system administrator <***@gstreamer.net> changed:

What |Removed |Added
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Status|NEW |RESOLVED
Resolution|--- |OBSOLETE

--- Comment #7 from GStreamer system administrator <***@gstreamer.net> ---
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