ximagesrc performance.

[Stirling Westrup]

I'm currently prototyping a new video source to add to my application.
I've been asked to implement an X session as a source. However, I'm
getting strangely inconsistent results from tests of ximagesrc.

When I first gave this a try last last November, just to see if it was
feasible, I used gst-launch-1.0 to make a test pipeline that read from
one X session and wrote to another. It was *really* sluggish in
performance, enough so that I reported to my boss that it looked
unlikely to work.

A few weeks later I had a free afternoon on my hand, and tried again,
and THIS time I had no problems and was even able to capture a playing
YouTube video and display it on another screen without any noticeable
lag or delays. Alas, I did not keep a record of what the pipeline I
fed to gst-launch actually looked like, because I can't reproduce this
result.

Right now I'm trying to get a working test pipeline so I know what to
implement, and I can't get decent performance. No idea what I am doing
different this time. My command line is:

gst-launch-1.0 ximagesrc display-name=":1" ! videoconvert !
"video/x-raw,framerate=(fraction)25/1,pixel-aspect-ratio=(fraction)1/2,format=(string)I420"
! xvimagesink display=":2"

No idea why this is so slow, when the same machine can decode a 4K
video and display it on four monitors simultaneously without problem.

Anyway, does anyone have any suggestions as to what I could try to get
this working faster?

--
Stirling Westrup
Programmer, Entrepreneur.
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