Perfect Interpolation

Help, Support & Bugs
1

Hi…

I’m trying to render my first DECENT song (and I would like to share it with you)…

I have problems when using the “arguru’s sinc” interpolation. I tried it in high and low priority, but when it reaches 14%, it stops and goes on very very very slowly. When renedering is finished and I listen to the wav, many instruments are cut, or detuned…
The cubic interpolation works fine so I could use it, but first of all I would like to know why I encountered this kind of problem…

Btw, if won’t be able to fix this problem, I’ll use the other… :) :)

2

sounds like some misterious bug… can the song be sent to someone for testing or is it based on VSTi samplers?

If you can send it, I could check if it does the same on my PC (never had such kind of problems), or you could send it to taktik for a slower but deeper inspection.

In general, Arguru’s is not so hugely better that you can’t live without.

By the way, good to hear about a song by you :drummer:

3

Wow!!

You answered in 10 minutes… THIS is a very efficient service…

I used Kontakt

It happens everytime I render in high priority (with both interpolation types). If using low priority, I encounter problems on with aruguru’s…

It starts normally and then it begins getting slow (3-4 seconds per row, maybe it’s normal I don’t know, but it takes one hour!!)

The CPU percentage on top right corner of Renoise window is always at 100%

I’ll try to render other songs and I’ll let you know

I

4

the huge amount of time requested is normal, expecially at high resolutions (32bit, 96khz).

what’s not normal is the result of the rendering.

let us know then

5

I noticed another thing:

everytime i render it, the wrong things change…

Maybe the first time instruments are detuned, the second are cut, the third are low of volume…

Btw, it seems to happen only with one song… I want to render other songs with Kontak’s instrumentst…

6

seems what was occurring to me the first times I was using softsamplers:
the rendering function starts from the first pattern, but if you didn’t set the sampler settings at the beginning of the song, and then you’ve modified it during the song, that parameters are not reset.

example:
let’s say I just start to make a song with Kontakt at its maximum volume.

then, on pattern 10, I lower the volume to 50%.

Now I render the song.

If I don’t put a “set kontakt volume to 100%” command on the first pattern, Kontakt data will be rendered at 50% volume.

Sorry if it sounds silly, but it is the only thing I can think of :unsure:

7

yes, what bantai said is correct, render with the same samplerate that your soundcard has, or most VST(i)'s will break.
Most of them cant work with 96Khz anyway and will give you very strange results then. So use 44,1 or maybe 48. You might also want to try 16bit instead of 32bit, might also be a reason for strange things.

Also, I dont know why you would want 96khz 32bit, you gotta keep in mind that its better to render at the exact settings you want to use later, because every resampling and bit-conversion does degrade the quality of the WAV-File. So if you want to burn to CD, render to 44,1/16 right from the start.
(the only thing which might be useful is to use 32bit rendering when you will master the song later in some other software, which means that you might change the volume of some tracks very much.)

8

Ok, I’ve been awake all night long(!!!) to test all the possible combinations.

First of all: this happens only with songs using Kontakt but problems are on other non-Kontakt intruments too.

I can’t use high priority at all

I have:

  • good results with cubic interpolation - 16 bit - 44100
  • same results, but one instrument with completly different settings in the ringmodulator plugin, with arguru’s interpolation - 16 bit - 48000
  • COMPLETE CHAOS in all the other combinations

Ok, I’ll use the 16 bit - 48000 - arguru’s, but I would like AT LEAST to know what’s the matter here…

9

I guess we have several problems here :

  • As already wrote above : Not all VSTs support variable samplerate settings, so it might happen that they sound totally different or wrong pitched when rendering in a different samplerate than the samplerate you composed your song. This is a bug of those VST, VSTs and there is nothing that we (the renoise staff) can do to solve this.

  • VSTi`s that read samples directly from disc might produce random errors when rendering with high priority. Either try rendering in “low priority” of try to disable the direct to disk playing in the VST plug that uses it.
    Kontakt for example has such an option because this is a well know problem that happens with every host while rendering.

And remember : the Interpolation algorithm (cubic or sync) is anyway used only for samples. VST`s are not affected by it and will sound totally equal in both modes.

As a workaround you could render first only all tracks that contain VST`s or play VST instruments, and then afterwards render only sampletracks in the high interpolation mode. Then mix both files them down in a sampleeditor.

For most stuff its really ok (you need superears or need to do frequency analysis to see the difference) if you simply render your song in the samplerate you normally play the song back and use low priority cubic interpolation mode.
Use 32 bit foat as bitdepth if you want to do furhter processing with other applications, else 16 bit.
Remember that a CD has a resolution of 44.1 kHz 16 bit, so you gain nothing if you render in a higher resolution now, but have to sample it down to the CD quality later.

10

That is of course true, but resampling afterwards (i.e. 48kHz → 44.1kHz) will degrade the quality quite a bit whereas bit conversion (32 → 16 bit) will not degrade the quality noticably compared to rendering in 16 bit from the start.