Time Streching

I need to time strech loops without pitch it…
renoise can’t do this i think ?
what tool do you use for time streching ?
:drummer:

:walkman:

I’ll ramble for a while…

There are so many different methods out there, all of which work better/worse with different types of sounds. One might be good on simple drum beats, another might be better for vocals, another might be better for melodic material with no beats, one might be really good with natural sounds instead of electronic sounds, or vice versa, etc, etc.

The problem is that the quality of the results are usually directly related to how much time and effort was put into developing the algorithm itself. It’s easy as hell to make a simple, granular style stretching algorithm - I’ve done it myself in my own VST. The results are almost identical to Renoise’s sample offset command (09xx) because it simply involves triggering little slices of the audio buffer in a way that creates a slowed down effect. In other words, “not that good”, unless you’re making oldskool jungle with a lot of stretched ragga vocals :P

To get something that doesn’t sound like stuttery crap (I honestly like the sound, but let’s be truthful, it has a very limited appeal) you suddenly have to get into some pretty serious and sophisticated programming, usually doing a lot of complex FFT-based processing, resynthesis, phase vocoding, etc. - all of which will introduce a pretty nasty latency by the way.

Then you have some other kind of “inbetween” methods such as the beat mode found in Ableton Live, which seems to be some combination of playing the attack portion of each drum hit in the sample, and then looping /stretching the tail portion of the drum sounds to create extra space between the hits when you slow it down. Conceptually this stretching method is not TOO complex but it’s definitely not that simple either. It would still involve some analysing of the waveform before you can stretch it, an accurate method to correctly detect the drum hits in the loop (a pretty complex topic in its own right), a method to decide the perfect loop points in the tail of the drum hits, etc.

Overall I don’t think we can really expect the Renoise crew (and by that I mean Taktik) to somehow come up with this stuff while developing and maintaining Renoise itself. There are people who have pretty much dedicated all of their time to developing time-stretching algorithms, and even then the results are not perfect. Like I said, each method works better on different types of sounds, so for perfect results you basically have to make a new algorithm for each type of sound… which, let’s face it, is very impractical.

There are a couple of nice open source algorithms out there like Paul’s Extreme Sound Stretch, as well as fairly detailed documentation/research found on sites like DSP Dimension, so maybe there’s something out there already which could be used in Renoise. The problem is that if one method is included in Renoise then inevitably some people will be unhappy with it, and then they will start demanding that a better method is created which works on their sounds, etc. It could be a tricky can of worms to open.

Anyway, I do agree with you for the most part, some extra options for this in Renoise would be lovely. I’m keeping this one in perspective though, because it’s a very difficult topic overall and in my opinion there are far more important things to focus on first before we get into this kinda stuff.

:)

Yeah there area many ways to do it, and many different programs/plugins to use. One method I’m using myself sometimes is just pitching up/down the drumloop to desired speed to fit the BPM, then I’ll add effects, shapers, Vocoders, EQ’s or whatever to remove the “pitced” effect. (Removing the feeling of the sample being played in different speeds). Work’s pretty fine for me unless there’s too much of time stretching.

If I have to stretch too much i prefer slicing up the loop in parts and recreate the beat using the bits and slices =) … making a small loop in the end of the slice/sample will take away the feeling of the sample stopping abruptly at the end and the slices blend together better.

It’s more work but doable, but you get a warm, fuzzy feeling of accomplishemt after doing some hard labor, slicing and looping all the parts =)

(I prefer to do it this way most of the time becouse you can easily create variations and fills using the slices)

:D good luck

Not sure about that, it doesn’t seem like people are bitching about the builtin filter/phaser/flanger etc…? Even something bad would rock so much!

For me mostly for the following reason: I occasionally and for fun sample something (1, 2, 4 bars) and put drums and melodies to it. But once I did that, it’s a PITA to change the tempo (since that changes the pitch of the sampled piece and it doesn’t fit the added melodies anymore), even more so when using VSTi’s because you can’t easily (and sometimes not at all) finetune them.

What I’m trying to get at is that it would be cool to play around with the tempo in Renoise with some basic timestretching… and when you decided on a speed you can still do the timestretching externally, using the algorithms of hardcore smoothness.

Plus, if the timestretch code got put in a .dll (and whatever the equivalent is on a mac) people would first come up with neat implementations (which would not be offically supported at all (beyond explaining the API etc.))… and then hopefully all sorts of stuff that have got nothing to do with timestretching? :D

As for a workaround: use a pitchshifter VST to cancel the effect of playing the sample/slower (unfortunately I don’t know of any decent free pitchshift VST… if anyone has suggestions please do share?).

thanks to all.
i found tow soft who make very good timestrech;
Beatcreator from ZeroX www.beatcreator.com and FlStudio from imageline www.flStudio.com
beatcreator is like a wav editor and FL is a workstation, i think still using Renoise for my music and do time strech with one of this soft…

beatcreator is little expensive, but interesting…
FlStudio can make many thing but very expensive in XXL version with lot of stuff…but you can strech and export in hi Wav quality in demo mode…

good day :yeah:

http://www.celemony.com/melodyne/

:blink:

ModPlugTracker have time strech in is wav editor !!!

www.modplug.com
:huh:

I don’t see it. Where is the stretch function?

Ok. Does it sound any good?

I will say very little. This plugin rocks!

http://www.koen.smartelectronix.com/KTGranulator/

++

It’s the shit. Scarily good on vocals.

Time strech in FL Studio is the best i’ve ever heard… :eek:

:drummer:

In fact it’s the same as in BeatCreator. Both licensed the algorithms from http://www.zplane.de/, AFAIK.

Try “Waves UltraPitch Shift” - the best I have tried. I have a demo only but could do what I want in realtime, record it and playback (: Also try “Waves SoundShifter”

But for freeware is the best [afaik] -> Phase Vocoder Plugin by Richard Bloor, “specMonkey” or Spectral Monkeyage v0.1 [I found it via the net].

You can also try Prosoniq.Timefactory.v2.02-Time StretchPitch Shift (:

Hope this helps…

Another fine stretch tool is ‘Paul’s Extreme Sound Stretch’:
http://hypermammut.sourceforge.net/paulstretch/

No. I answered straight away reading the original post. (Should also mean, I’m currently playing with this tool.) Anyway, kaneel, thanks for pointing me there, I’ll read it. ;)