Re: [ecasound] lossless conversion broken?

From: Kai Vehmanen <kvehmanen@email-addr-hidden>
Date: Sun Dec 12 2010 - 20:04:23 EET


On Fri, 5 Nov 2010, Dan Muresan wrote:

> I'm curious, what are the consistency requirements for a minor vs.
> major release? I've just realized that there is no custom Ecasound

basicly the versioning policy is documented in the beginning of NEWS:

About the version numbers... "vX.Y[.Z[.R]][+extraT]" :

   X = major version - incremented after major redesigns
   Y = minor version - incremented when new features are added
   Z = micro version - incremented if major.minor version is not
                        modified (optional)
   R = revision - urgent fixes to planned releases (optional)

   extraT - 'beta', 'pre' and 'rc' releases (optional)

So a fairly loose set of criteria. In practise, change in X.Y is a signal
that users should pay more attention when upgrading (check what new
features are available, do a basic smoke test with old features they use
the most). I think this conversion change is X.Y material, as it has an
impact (albeit very small) to all use-cases.

> file format (i.e. floats never get stored in any files). What would be
> affected by changes in the conversion formulas?

Basicly there can be single-bit differences in outputs (both fixed and
float), given same input objects for 2.7.2 and 2.8.0. Only chainsetups
with all-float inputs _and_ outputs are not impacted (so e.g. pure JACK
input and JACK output chainsetup is not affected). Still, I don't think
the changes are something that could cause degraded real-life audio
quality, but it's still a change.

Possible distortion due to combination of asymmetric conversions and
processing applied to the float samples, is something more concrete, but
here the possible damage, if any, has already been done, and can no longer
be reversed. So also from this perspective, upgrade to 2.8.0 is a

So essentially setting the version to 2.8.0 is a signal to users to check
ecasound is matching their expectations and quality-criteria in this area.

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Received on Sun Dec 12 20:15:09 2010

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