Normalize CSAMPLE (float) to 1.0

[Daniel Schürmann]

I think from historical reasons our CSAMPLES are normalized to SHORT_MAX.

This requires two unnecessary sample multiplications when copying to portaudio and when receiving from SoundSource.
(after applying Bug #1156569 "Change Soundsource API to reading float samples")

We may also incompatible when using external effect in future.

This fix sound quite easy, but I am afraid when we try to fix this, we will suffer some side effects.

Does one know what we have take into account for a fix?
Is it worth to do the work?

[RJ Skerry-Ryan (rryan)]

I've wanted to do this for a long while. That division by SHRT_MAX when
pushing samples to PA is something we could eliminate early on in the
reader threads. All the analysers take samples between -1.0 and 1.0 already
(and the AQ normalizes the samples after reading). Nothing off the top of
my head in the engine would go badly wrong if we normalize either. The VU
meters and clipping will need updating since they rely on samples being in
[-SHRT_MAX, SHRT_MAX]. I think rubberband and soundtouch are not specific
about the range of samples they receive. The EQs are the only question I
have but we could just test them. It's true this could cause problems in
the future for effects but [-1,1] normalized samples are pretty standard.

On Tue, Jul 23, 2013 at 5:31 AM, Daniel Schürmann <
<email address hidden>> wrote:

> Public bug reported:
>
> I think from historical reasons our CSAMPLES are normalized to
> SHORT_MAX.
>
> This requires two unnecessary sample multiplications when copying to
> portaudio and when receiving from SoundSource.
> (after applying Bug #1156569 "Change Soundsource API to reading float
> samples")
>
> We may also incompatible when using external effect in future.
>
> This fix sound quite easy, but I am afraid when we try to fix this, we
> will suffer some side effects.
>
> Does one know what we have take into account for a fix?
> Is it worth to do the work?
>
> ** Affects: mixxx
> Importance: Undecided
> Status: New
>
> --
> You received this bug notification because you are a member of Mixxx
> Development Team, which is subscribed to Mixxx.
> https://bugs.launchpad.net/bugs/1204039
>
> Title:
> Normalize CSAMPLE (float) to 1.0
>
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>

[RJ Skerry-Ryan (rryan)]

This changes the engine and doesn't touch the SoundSources:
https://github.com/mixxxdj/mixxx/pull/126

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/7112