[Spice-devel] [PATCH] make celt to be optional

[Alexander Larsson]

On Tue, 2012-06-12 at 16:33 +0200, Christophe Fergeau wrote:
> On Tue, Jun 12, 2012 at 09:59:39AM -0400, Marc-André Lureau wrote:
> > 
> > 
> > ----- Mensaje original -----
> > > On Tue, Jun 12, 2012 at 09:11:24AM -0400, Marc-André Lureau wrote:
> > > > As long as the bitstream is not frozen, we can't use opus, or we
> > > > will
> > > > have the same problems as with celt today.
> > >
> > > As I understand it, while the bitstream is not officially frozen yet,
> > > it's
> > > very unlikely to change before the real freeze (unless big last
> > > minute
> > > issues are fine), so an Opus mode (marked as "no compat guarantees,
> > > use at
> > > your own risk, ...") will probably not cause significant
> > > compatibilities issues.
> > 
> > That's just guesses. It's not about library API, but about bitstream.
> > There is no guarantee.
> 
> A guess supported by the slides at http://www.opus-codec.org/presentations/
> , by various mailing posts from opus developers, ...
> 
> > Sticking to celt051 is still a safer alternative.
> 
> Not suggesting dropping celt051 support upstream...
> 
> > Otherwise, how would you identify almost-frozen bitstream to frozen bitstream?
> > You would have to identify by library version (erk!)
> > and be compatible with the old and new bitstram (which might be complicated
> > depending on library design), or be incompatible with the intermediate version,
> > situation which we better avoid!
> 
> We would make no guarantee with interoperability between binaries using
> different opus versions until the format is officially frozen. I agree
> there's a bit of uncertainty in this move, but I think that at this point
> it's a reasonable assumption that things will work, even with different
> opus versions.

It seems like Opus is at a stage where we want to at least start adding
support for it so we can switch to it by default as early as possible.
Its not like this is a new idea, the plan was always to jump to a stable
bitstream format when one appeared.

However, that is imho a different issue than the celt051 support. A new
release of spice client and server supporting opus does not magically
make old servers and client disappear, so it would still be the case
that e.g. debian spice client would get lame audio performance if
connecting to say a RHEV spice client, or if some old client connects to
a server running on debian. In time, it would perhaps make sense to drop
celt051 support, but its seems pretty bad to release a client binary
that doesn't do audio well with all currently existing deployed servers.