<adfeno>Perhaps off-topic: Speaking of mlt, I find it confusing that I can't do a trick similar to `ffmpeg ... -filter:a "atempo=tempo=1.25, asetrate=r=40k" ...' using mlt.
<adfeno>it seems to either: (a) make the audio too slow; (b) the voice/audio sounding stronger than I want, and not allowing finner control/tune; (c) having "pop"/strange sounds together with the original track; (d) or just segfaults when changing rate using sox.rate.
<adfeno>This of course is an issue with mlt itself, not Guix, nor Guix's mlt package.
<adfeno>ofosos[m]: I wonder if Qt is really needed in mlt, I mean, most Qt stuff take hours to build at least in Intel Core i5-2410M CPU @ 2.30GHz, i686 with 4 GiB RAM and `guix package' set with `-c 1'. And Qt stuff as far as I know must be kept without substitutes due to this issue.
<adfeno>Should'n't Kdenlive's mlt be separated from non-Kdenlive mlt?
<ng0>for a software with just a Qt frontend and nothing else separation makes no sense
<adfeno>ng0: Oh, we have substitutes for Qt stuff? That's awesome :D
<ng0>the things that are not substitutable are small in numbers I think.. grep for "substitutable" in the source
<adfeno>strangely enough I always ended up building the "qt*" stuff for each package that depend on these, for some strange reason. And I only do upgrades or installs after a fresh `guix pull'
<ofosos[m]>Btw, I have the following problem: after successfully building a package, how to I rebuild or challenge it to check for reproducibility? All options I tried end up not rebuilding the package :(
<ofosos[m]>Neat, I'm getting better at this. First try and package does build :)