android currently uses jpeg because BitmapFactory cannot handle the raw pixel data sent by xpra.
We should add a
--encoding=[jpeg|png|raw] option passed to the server via capabilities to allow us to encode pixel data as png.
As far as I can tell, this is the easiest way of getting non-lossy pixel data on android clients.
The client sends its desired encoding to the server together with the list of supported encodings, the server can then decide which one to use based on the intersection with what it supports with this list.
The server will default to just rgb24 and png for older clients so things work as before if nothing is specified, one can also specify
--encoding on the server, this will be used as default encoding value should the client not specify which encoding it wants to use.
this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/27