[Fixed v2.0.0a3] .WAV Writer DC Offset issue

[Purrbox]

Hi there,

I am having an issue with the wav writer, the entire bottom half of the outputted waveform is missing, I tried a few other mods and setting it to mono but all have the same problem.

Thanks

[Purrbox]

Update:

I’ve just tried playing a song in Arkos Tracker and directly patching windows “speakers” into audacity audio input and recording what happens, the same issue is present. So it would appear it’s not the .WAV writer at fault but something else…

[Targhan]

Hi,

Well, this is “normal” to me. I simply consider the 0 to be the bottom of the generated volume. Is it a problem? It makes absolutely no difference whether the sound is “centered” or not, but please correct me if I’m wrong.

[XiA]

Well, for one thing you’re throwing out half the dynamic range of the audio.

https://en.wikipedia.org/wiki/DC_bias#Audio

[Targhan]

You’re right indeed. I’ll add that to my TODO list, but it is going to be on low-priority. Any good audio software can get rid of this, along with a bit of normalization.

[XiA]

As long as it’s on your ToDo-list, I’m happy! 🙂

[Targhan]

I’ve done a simple DC offset based on the average, it gives good results enough. Ready in the next version.

[XiA]

It’s not a DC offset issue. Zero is at the correct position. Adjusting it by adding/subtracting from the values of the waveform will make it a DC offset issue.

And adding a DC offset issue is likely to introduce audible artefacts.

[Targhan]

Well, yes and no. The zero is well located, but DC offset is considered null when the average of the sample is at 0. Which is not the case right now. If you try to normalize, nothing happens.

The DC offset correction I implemented for alpha 3 gives the same result as the OcenAudio software, so I consider is viable and useful.

[Author]

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