Red Hat Bugzilla – Bug 53676
Flashing remote video
Last modified: 2005-10-31 17:00:50 EST
Description of Problem:
Using more than one program such as xawtv at a time to display video
inputs can cause the windows to flash. The flashing appears to be an
alternating pattern of images from both video inputs. This occurs if:
- hardware scaling is used
- the video source is on a separate system from the display
The flashing stops if you...
- use hardware scaling on only 1 video window at a time OR
- use only 1 video window per display in a multi-head configuration
Version-Release number of selected component (if applicable):
Use two systems, one to capture the video and the other to display
the video. We have reproduced the symptom with both Matrox and Savage
multi-head display cards. Put more than one video card into the video
capture system (e.g., WinTV). Run at least two video display programs such
as xawtv (similar symptoms from motv) with the X display set to another
Steps to Reproduce:
1. Set up the two systems
2. xhost + on the display system
on the video capture system
3. export DISPLAY=display:0 (display == display system name)
4. xawtv -c /dev/video0 -remote &
5. xawtv -c /dev/video1 -remote &
When second window appears, both windows begin to flash. If you have
a multi-head card, moving one window to another display makes the
flashing stop. Even better, on a multi-head card, have one window
half on one display and half on the other - only one half will flash.
Because of this symptom - we do not believe it is a problem with xawtv,
but a problem with the X server (or X libraries) itself.
Both video windows work w/o any flashing.
By adding -noscale to the command line of EITHER program will prevent
the flashing. As noted above, video windows on separate multi-head
displays will not flash either.
Please report this bug upstream to XFree86 directly. You can do so by
submitting a bug report via email to firstname.lastname@example.org. They are much
better equipped and familiar with the code than am I to debug and fix