ximagesrc: delay image reconstruction when using DAMAGE

Submitted by Stirling Westrup

Link to original bug (#693037)

Description

ximagesrc has a feature where it will use the X Damage feature to only send updates for changed parts of the screen, rather than entire screens. However, when using damage, performance as a whole degrades badly, rather than improving.

This pipeline can easily handle 25 frames-per-second of updates on my system:

gst-launch-1.0 ximagesrc display-name=:1 use-damage=false ! videoconvert ! 'video/x-raw,pixel-aspect-ratio=(fraction)1/1' ! videorate ! xvimagesink display=:2

However, if one removes the 'use-damage=false' clause to permit ximagesrc to 'optimize' buffers, then one quickly gets results like this:

$ gst-launch-1.0 ximagesrc display-name=:1 ! videoconvert ! 'video/x-raw,pixel-aspect-ratio=(fraction)1/1' ! videorate ! xvimagesink display=:2
Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
WARNING: from element /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0: A lot of buffers are being dropped.
Additional debug info:
gstbasesink.c(2675): gst_base_sink_is_too_late (): /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0:
There may be a timestamping problem, or this computer is too slow.
WARNING: from element /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0: A lot of buffers are being dropped.
Additional debug info:
gstbasesink.c(2675): gst_base_sink_is_too_late (): /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0:
There may be a timestamping problem, or this computer is too slow.
WARNING: from element /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0: A lot of buffers are being dropped.
Additional debug info:
gstbasesink.c(2675): gst_base_sink_is_too_late (): /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0:
There may be a timestamping problem, or this computer is too slow.
WARNING: from element /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0: A lot of buffers are being dropped.
Additional debug info:
gstbasesink.c(2675): gst_base_sink_is_too_late (): /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0:
There may be a timestamping problem, or this computer is too slow.
WARNING: from element /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0: A lot of buffers are being dropped.
Additional debug info:
gstbasesink.c(2675): gst_base_sink_is_too_late (): /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0:
There may be a timestamping problem, or this computer is too slow.
WARNING: from element /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0: A lot of buffers are being dropped.
Additional debug info:
gstbasesink.c(2675): gst_base_sink_is_too_late (): /GstPipeline:pipeline0/GstXvImageSink:xvimagesink0:
There may be a timestamping problem, or this computer is too slow.
^CCaught interrupt -- handling interrupt.