1106649 - Use band-limited wave tables for OscillatorNode

Status: RESOLVED FIXED

(Core :: Web Audio, defect)

Description

[Paul Adenot (:padenot)]

The BLIT code has some issues:
- DC offset, so we need to DC block, and that has impact on the timbre
- ugly waveforms at low frequencies

Now that we have PeriodicWave implemented, we can just use it for the basic waveforms as well.

Comment 1

[Paul Adenot (:padenot)]

Attachment: Use band-limited wave tables to implement basic waveforms. r=

I had to fix the triangle in Blink's code because the initial phase was wrong.

Comment 2

[Karl Tomlinson (:karlt)]

Comment on attachment 8530995 [details] [diff] [review]
Use band-limited wave tables to implement basic waveforms. r=

>           case OscillatorType::Sine:
>-            mPhase = 0.0;
>             break;

mPhase means something quite different when using mPeriodicWave, so it's
probably better to leave the 0.0 here until some kind conversion is performed.

>+            if (n & 1) {
>+              b = 2 * (2 / (n * piFloat) * 2 / (n * piFloat)) * ((((n - 1) >> 1) & 1) ? -1 : 1);

This can be simplified somewhat.
If (n&1), then ((n-1)>>1) == (n>>1).
((n>>1)&1) is true iff (n&2).

Comment 3

[Karl Tomlinson (:karlt)]

Is mSignalPeriod unused outside of UpdateParametersIfNeeded() now?
Can it be made a local variable or removed?

Comment 4

[Paul Adenot (:padenot)]

(In reply to Karl Tomlinson (back Dec 22 :karlt) from comment #3)
> Is mSignalPeriod unused outside of UpdateParametersIfNeeded() now?
> Can it be made a local variable or removed?

Yes.

Comment 5

[Paul Adenot (:padenot)]

Attachment: Use band-limited wave tables to implement basic waveforms. r=

Uploading last version (the triangle formula is not fixed yet).

Comment 6

[Paul Adenot (:padenot)]

Attachment: Use band-limited wave tables to implement basic waveforms. r=

Comment 7

[Paul Adenot (:padenot)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/3ae2161027a6

Comment 8

[Paul Adenot (:padenot)]

backed out for opt bustage:
https://hg.mozilla.org/integration/mozilla-inbound/rev/9d72b8315f65

Comment 9

[Paul Adenot (:padenot)]

relanded https://hg.mozilla.org/integration/mozilla-inbound/rev/a2b0a16b8898

Comment 10

[Ryan VanderMeulen [:RyanVM]]

Something in this push made test_periodicWave.html permafail. Backed out.
https://hg.mozilla.org/integration/mozilla-inbound/rev/72d7ae169b09

https://treeherder.mozilla.org/logviewer.html#?job_id=5080110&repo=mozilla-inbound

Comment 11

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/ffab1d2bd4ce