[LAD] interesting blog post about syncing blender and ardour

Paul Davis paul at linuxaudiosystems.com
Fri Sep 25 16:06:38 UTC 2009

On Fri, Sep 25, 2009 at 11:19 AM, Fons Adriaensen <fons at kokkinizita.net> wrote:

> Interesting ?
> * How can this option be modified ?


    <Option name="timecode-source-is-synced" value="yes"/>

> * If varyspeed slaving is enabled,
>  - How many channels can be resampled ?
>    On my 2G P4 libsamplerate has trouble with
>    just 5 channels in real time.

in 2.X, the resampling is done with very poor quality linear
interpolation, so ardour can resample a pretty large number of tracks.
in 3.X, there are some choices about what type of interpolation to
use. the underlying assumption here is that if the user wants ardour
to varispeed (and note that the same code is used for
scrubbing/shuttling too), then they do not care *much* about quality.
this is not "sample rate conversion" in the traditional sense - its
"resample so that we can stay in sync".

>  - Will Ardour resample signals being recorderd
>    as well ?

ardour will not varispeed when recording. its possible that the
barrier to this happening has been broken - if so, it needs to be

> Note that the latter is essential.

essential perhaps. tremendously complex, certainly. as i've been
hearing said way too often at the linux plumbers conference that i'm
attending, "patches welcome" :)

If a signal is recorded
> with some speed error, and then played back with the same
> speed error the result should be the original signal. Since
> it will be resampled on playback it has to be resampled on
> record as well, in the opposite direction.

sure. however, i have no great interest in implementing this because
from my perspective, the "errors" that occur when the timecode source
is not sample clock synced are generally *not* repeatable, and thus
attempting to support this would actually not accomplish the goal. i
can see it being useful if you were programmatically controlling the
timecode source, but that's another use case entirely, and i have
about 23 kajillion things to work on before that would bubble to the
top of my own priority list.


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