[LAU] [LAA] Qtractor 0.1.3 (frugal damsel) released!

[Rui Nuno Capela]

Mark Knecht wrote:
> On Sun, May 4, 2008 at 10:23 AM, Rui Nuno Capela <rncbc at rncbc.org> wrote:
>> Mark Knecht wrote:
> <SNIP>
>>>>  ok. we already have the "Root note", "Beats", "Meter" and "Tempo"
>> fields in
>>>> sight, which is a fair start imo.
>>>>
>>> Well, sndfile-info writes the word 'tempo' but I'm not completely
>>> comfortable that we know where the tempo values are. Both of the
>>> examples I provided say 120BPM. Unfortunately neither loop library is
>>> actually recorded at that tempo!
>>>
>>>
>>  that is *bad* news :( so the meta-data we get from libsndfile is bogus?
>>
>>  i guess we're back to square one (or is it zero?:).
>>
> 
> No, I really don't thin kit's quite that bad. In fact I thought it
> worked better than it did so maybe part of the problem is just lack of
> attention over the last few years and some bug creeping in here or
> there. Some of what's there is right, I think.
> 
> I really believe that just finding a couple of folks who have an
> interest and digging in will probably figure it out pretty quickly.
> 
> <SNIP>
>>  we'll have to resort that audio files must be integral in length to ever
>> get some kind of loop auto-fitting ...
>>
> 
> Well, independent of what the tempo is in a session, if I know an
> 8-bar pre-recorded loop is 120000 samples long (available from the
> loop's meta-data) and I know my session requires 140,000 samples to
> meet whatever the tempo is set to for 8 bars, then the resampling can
> be done on the fly.
> 
> To be clear, Acid Pro does NOT resample on the fly with extremely high
> quality. The quality is good but if I change a 68 BMP loop to 160 BPM
> I am absolutely going to hear artifacts all over the place. My
> experience is, however, that this gives 'character' to my work. It
> sounds real, funky, fun. Most of the time what I hear when I listen to
> a single resampled loop by itself is completely covered up when the
> song is done. If it's not then and only then would I bother with
> external, high quality resampling. 99.99% of the time it's just not an
> issue for me.
> 

but qtractor *does* time-stretching (what you call resample) on-the-fly!

you have two options here, being a trade-off between quality and cpu 
intensiveness:

1) soundtouch based, wsola-like algorithm - very fast but artifact 
prone--maybe with similar results as acid on-the-fly mode, you tell me

2) rubberband - good quality but resource intensive; might not be 
appropriate for heavy loaded sessions and/or older cpu's

just to let you know. qtractor does *not* touch any of your audio sample 
files, nor it creates any unless you're recording or exporting 
one--almost everything is or can be done on-the-fly ;)

byee
-- 
rncbc aka Rui Nuno Capela
rncbc at rncbc.org