Dynamic Oversampling up to 128x or more

[A Former User]

@Christoph-Hart When will it be ready?
Is it possible for you to add this dynamic os node as soon as possible please? :folded_hands:

[Christoph Hart]

The dynamic oversampler has arrived (container::oversampler).

[orange]

@Christoph-Hart said in Dynamic Oversampling up to 128x or more:

The dynamic oversampler has arrived (container::oversampler).

Wow! Thank you!

[A Former User]

@Christoph-Hart said in Dynamic Oversampling up to 128x or more:

The dynamic oversampler has arrived (container::oversampler).

Trying to compile the current commit, getting these errors:

No template named 'parameter_node_base'; did you mean 'pimpl::parameter_node_base'?

'hi_zstd/hi_zstd_3.mm' file not found

[d.healey]

@Steve-Mohican It seems the code is missing a few pimpls :)

[Christoph Hart]

@d-healey Should be fine now. The other error is a glitch, make sure you do a clean rebuild.

[A Former User]

@Steve-Mohican It seems the code is missing a few pimpls :)

@d-healey I guessed that too but I just wanted to be sure :)

@d-healey Should be fine now. The other error is a glitch, make sure you do a clean rebuild.

@Christoph-Hart Thanks.

I think no_mod_normalisation(getStaticId()) (212th line) also needs pimpl:: prefix too?

How can we use this node? There is no option for the oversampling rate selection.

[Christoph Hart]

@Steve-Mohican Click on the parameter icon of the oversample node.

[A Former User]

@Christoph-Hart I can't see the options for higher than 16x oversampling rate. When the parameter range is increased, the node doesn't seem to work more than 16x. Can you add more rates please (yes the ram can blow up for some DSP codes but it will be fine for some cheap DSP codes) which is also requested in this topic?

One more thing about the latency. While the oversampling rate changes, will the delay compensation adjusted dynamically?

[Christoph Hart]

@harris-rosendahl There‘s not delay compensation going on, you need to do this manually.

You can enable 32x oversampling by changing the source code but that‘s the highest that the JUCE oversampler can do.

[A Former User]

@Christoph-Hart

You can enable 32x oversampling by changing the source code but that‘s the highest that the JUCE oversampler can do.

Thank you for the info. Can you add 32x rate too please? It would be good at least we have 32x without being have to change the source code.

[Christoph Hart]

@harris-rosendahl I just took a look and the JUCE oversampler actually only supports 16x:

https://github.com/juce-framework/JUCE/blob/2f980209cc4091a4490bb1bafc5d530f16834e58/modules/juce_dsp/processors/juce_Oversampling.cpp#L547

The exponent need to be smaller than 5, so 2^4=16x is all you can get here.

[fastermaster]

Hi guys, interesting subject. OS for higher than 16x can really be interesting for heavy saturation processors, i'm guessing 32 and 64x would completely remove any aliasing there is even in heavy situations.

Is there a way to overcome this Juce limitation?

[Frankbeat]

@fastermaster 64x oversampling? I'm trying hard to hear a difference between 2x and 4x from what I saw in videos on that subject. Can it really be worth to force a processor to run a audio thread on 64*44100(or more) samples? Unfortunately I can't test this myself with my old machine but I highly doubt there's a good reason for oversample with such a high rate. No offense, just being curious…

[ustk]

@Frankbeat @fastermaster In fact one of the most important things in oversampling is the quality of the stop band filter.
a 16x OS with a good rejection has nothing to be ashamed of when compared to a 64x with a lesser rejection quality.
Unfortunately, the Juce filter doesn't appear to be that good, so I can understand the limitation to 16x might be problematic in some situations (though I haven't checked against another one)

[Christoph Hart]

@ustk there are multiple filter options available in the JUCE sampler and I just picked one without giving it too much thought, so if you find parameters that sound better I'm happy to add those as options.

[fastermaster]

thanks guys, I'm working on a distortion emulation, so avoiding aliasing is a must, I want to offer the option of 4x 8x and 16x. I'll just need to figure what's the best filter to use in this case.

Did someone experimented with the filters? The reaper And aliasing seem to be quite good, I wonder what they're using.

[pluginboi]

I've been playing around with the filterHalfBandFIREquiripple in my hise projects and its really nice. You have to compensate for a but more latency compared to the current oversampling filter but this one is linear phase.

[ustk]

@pluginboi That is good to know
My knowledge of the topic stops there. But from what I know about filters, linear phase isn't better than conventional filters, they are just different tools. Since they cause pre-ringing as a result of phase compensation, they are generally bad on fast transient material because of the smoothing they create.

I think having a filter selector in the oversample node would be great for selecting the one that better suits the needs.

[Dan Korneff]

@ustk said in Dynamic Oversampling up to 128x or more:

I think having a filter selector in the oversample node would be great for selecting the one that better suits the needs.

@Christoph-Hart Do you think adding a selectable oversampling type could be implemented? I'm getting a lot of requests for this and figured I'd hit you before I attempt to hack something together.