1222405 - Build band limited tables lazily in PeriodicWave

Status: RESOLVED FIXED

(Core :: Web Audio, defect, P2)

Description

[Dan Minor [:dminor]]

In Bug 1171436, :karlt suggested building the band limited tables for PeriodicWave lazily:

The tricky part is that, when createBandLimitedTables() is called, we don't know what the fundamental frequency will be, and so we don't know which partials will be above Nyquist.

Part of the full optimization solution would be to create the tables lazily, when required, at which point the fundamental is known, but I'm guessing that might be quite a redesign.

Comment 1

[Dan Minor [:dminor]]

Attachment: MozReview Request: Bug 1222405 - (part 1) Store PeriodicWave components for later use r=padenot

Bug 1222405 - (part 1) Store PeriodicWave components for later use r?padenot

We need to store the components used to create the PeriodicWave for later use
if we want to be able to build the band limited tables lazily.

Comment 2

[Dan Minor [:dminor]]

Attachment: MozReview Request: Bug 1222405 - (part 2) Build band limited tables after fundamental frequency is known r=padenot

Bug 1222405 - (part 2) Build band limited tables after fundamental frequency is known r?padenot

If we build the band limited tables after the fundamental frequency is known,
we can exclude partials that are above the nyquist frequency for the sampling
frequency being used.

We rebuild the band limited tables each time we see a request for data for a
lower fundamental frequency so we have the required partials.

Comment 3

[Dan Minor [:dminor]]

Attachment: MozReview Request: Bug 1222405 - (part 3) Build band limited tables lazily r=padenot

Bug 1222405 - (part 3) Build band limited tables lazily r?padenot

This builds the band limited tables for each range index individually as
required.

Comment 4

[Paul Adenot (:padenot)]

Comment on attachment 8688945 [details]
MozReview Request: Bug 1222405 - (part 1) Store PeriodicWave components for later use r=padenot

https://reviewboard.mozilla.org/r/25465/#review23479

::: dom/media/webaudio/blink/PeriodicWave.h:107
(Diff revision 1)
>      // Creates tables based on numberOfComponents Fourier coefficients.

This comment needs to be updated.

Comment 5

[Paul Adenot (:padenot)]

Comment on attachment 8688946 [details]
MozReview Request: Bug 1222405 - (part 2) Build band limited tables after fundamental frequency is known r=padenot

https://reviewboard.mozilla.org/r/25467/#review23597

Comment 6

[Paul Adenot (:padenot)]

Comment on attachment 8688947 [details]
MozReview Request: Bug 1222405 - (part 3) Build band limited tables lazily r=padenot

https://reviewboard.mozilla.org/r/25469/#review23599

Comment 7

[Dan Minor [:dminor]]

Comment on attachment 8688945 [details]
MozReview Request: Bug 1222405 - (part 1) Store PeriodicWave components for later use r=padenot

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/25465/diff/1-2/

Comment 8

[Dan Minor [:dminor]]

Comment on attachment 8688946 [details]
MozReview Request: Bug 1222405 - (part 2) Build band limited tables after fundamental frequency is known r=padenot

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/25467/diff/1-2/

Comment 9

[Dan Minor [:dminor]]

Comment on attachment 8688947 [details]
MozReview Request: Bug 1222405 - (part 3) Build band limited tables lazily r=padenot

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/25469/diff/1-2/

Comment 10

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/c8382566ebac
https://hg.mozilla.org/integration/mozilla-inbound/rev/7f2f19c2aca1
https://hg.mozilla.org/integration/mozilla-inbound/rev/3785489fa210

Comment 11

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

https://hg.mozilla.org/mozilla-central/rev/c8382566ebac
https://hg.mozilla.org/mozilla-central/rev/7f2f19c2aca1
https://hg.mozilla.org/mozilla-central/rev/3785489fa210