[Spice-devel] Video playback problem (videos play upside down from Linux guests)

[Leonardo E. Reiter]

In reference to Gerd Hoffman's response here:
http://lists.freedesktop.org/archives/spice-devel/2010-September/001258.html

we have spent a fair amount of time analyzing the behaviors and would
appreciate some hints...

We can reproduce this easily using SPICE 0.6.3 server and client, linked to
freedesktop.org's git QEMU version from the same vintage.  It always fails
when using Flash player inside Firefox, inside a VM running RHEL 6 for
example.  The video flips up and down randomly almost immediately after
playback starts.

We can only see this behavior if we connect to the VM from a Windows
computer.  If we connect from a Linux computer with the SPICE client, it
never flips.

We have investigated the code to understand at least what the SPICE server
and client do with the top_down flag, but we cannot figure out where this
flag originates yet.  If it originates from the guest, there must be some
other bit that is being translated because we cannot find a reference to it
from the win32 QXL driver for example.  Our guess is that rendering
bottom/up video is simply not supported on most Linux X servers, which
explains why this never fails with the Linux client.  It also seems to
explain why the Linux flash player does not have the same bug when run
natively (not in a KVM session).  This is just a theory.

Gerd, do you have any more insight into this?  No doubt the Flash player
plugin is probably doing the wrong thing, but some hint as to how this flag
makes its way from the QXL driver all the way to the client would be greatly
appreciated. We are thinking of experimenting with an override in case the
application misbehaves.

Thanks very much in advance,

Leo Reiter
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