[Spice-devel] [PATCH spice-gtk 0/2] Allow to change the preferred compression on the fly

[Pavel Grunt]

Hi,

On Wed, 2015-11-11 at 09:48 +0100, Victor Toso wrote:
> Hi,
> 
> On Tue, Nov 10, 2015 at 05:44:05PM +0100, Pavel Grunt wrote:
> > Hi,
> > 
> > this series adds new public function for changing the preferred image
> > compression.
> > The new function is used in spicy under Option -> Preferred Image
> > compression
> > 
> > Pavel Grunt (2):
> >   channel-display: Add spice_display_change_preferred_compression
> >   spicy: Add support for changing compression
> > 
> >  doc/reference/spice-gtk-sections.txt |  1 +
> >  src/channel-display.c                | 41 +++++++++++++++++++----
> >  src/channel-display.h                |  1 +
> >  src/map-file                         |  1 +
> >  src/spice-glib-sym-file              |  1 +
> >  src/spicy.c                          | 63
> > ++++++++++++++++++++++++++++++++++++
> >  6 files changed, 101 insertions(+), 7 deletions(-)
> 
> Both patches looks good and I personally liked them. We already have the
> message so having an public API seems good idea, at least for testing
> tool like spicy.
> 
> Locally, while playing video, processing with quic is much higher then
> lz.. I thought it would be oppositve, funny :)
> 
> This could be used by client's to better usage of its resources. It
> would be good to have some debug messages about what compressions is
> being used because as this is 'preferred' it does not mean that it would
> switch the compression to it, right?

It is basically like running qemu with image-compression=X, but it is per
display channel. The preferred compression is not always used, e.g. if you
choose glz, you can receive images in glz, lz or without compression,
see red_compress_image() in server/red_worker.c [1]. Also there is a bug about
not working lz4 image compression [2]  - a client requests lz4 but the server
does not support it.

Thanks,
Pavel

[1] http://cgit.freedesktop.org/spice/spice/tree/server/red_worker.c#n4677
[2] https://bugs.freedesktop.org/show_bug.cgi?id=92821

> 
> So, ack by me.
>   Victor Toso