AnalyserNode should downmix channels to mono.

AnalyserNode should downmix channels to mono.

In an AnalyserNode, the input data should be downmixed to mono
according to the down mixing rules before returning the time or
frequency data.  Chrome currently just sums all of the channels together.

See issue https://github.com/WebAudio/web-audio-api/issues/719 that clarifies how downmixing is done.

BUG=564939
TEST=realtimeanalyser-downmix.html

Committed: https://crrev.com/e73947aa166aa79759d3d54e703b07f91a1bc8e3
Cr-Commit-Position: refs/heads/master@{#382376}

[Raymond Toy, 2016-03-16 21:18:17]

rtoy@chromium.org changed reviewers:
+ hongchan@chromium.org

[Raymond Toy, 2016-03-16 21:18:18]

PTAL

[hongchan, 2016-03-16 21:51:42]

lgtm

https://codereview.chromium.org/1803233002/diff/60001/third_party/WebKit/Layo...
File third_party/WebKit/LayoutTests/webaudio/realtimeanalyser-downmix.html
(right):

https://codereview.chromium.org/1803233002/diff/60001/third_party/WebKit/Layo...
third_party/WebKit/LayoutTests/webaudio/realtimeanalyser-downmix.html:84: // Run
analyser as an automatic pull node. Do NOT connect to the destination.
Why running as an automatic pull mode does matter?

https://codereview.chromium.org/1803233002/diff/60001/third_party/WebKit/Layo...
File third_party/WebKit/LayoutTests/webaudio/resources/audio-testing.js (left):

https://codereview.chromium.org/1803233002/diff/60001/third_party/WebKit/Layo...
third_party/WebKit/LayoutTests/webaudio/resources/audio-testing.js:266: 
nit: I put 2 spaces intentionally here, but doesn't really matter.

[Raymond Toy, 2016-03-16 21:58:23]

https://codereview.chromium.org/1803233002/diff/60001/third_party/WebKit/Layo...
File third_party/WebKit/LayoutTests/webaudio/realtimeanalyser-downmix.html
(right):

https://codereview.chromium.org/1803233002/diff/60001/third_party/WebKit/Layo...
third_party/WebKit/LayoutTests/webaudio/realtimeanalyser-downmix.html:84: // Run
analyser as an automatic pull node. Do NOT connect to the destination.
On 2016/03/16 21:51:42, hoch wrote:
> Why running as an automatic pull mode does matter?

Because the source is also connected to the destination and since the analyser
is a pass through (I think), the destination doesn't have what I want.

I'm using the destination downmixing to create the reference for the downmixed
signal that the analyser should also be doing.

Shall I expand on this comment?

https://codereview.chromium.org/1803233002/diff/60001/third_party/WebKit/Layo...
File third_party/WebKit/LayoutTests/webaudio/resources/audio-testing.js (left):

https://codereview.chromium.org/1803233002/diff/60001/third_party/WebKit/Layo...
third_party/WebKit/LayoutTests/webaudio/resources/audio-testing.js:266: 
On 2016/03/16 21:51:42, hoch wrote:
> nit: I put 2 spaces intentionally here, but doesn't really matter.

I didn't mean to change this file. (I originally had my own downmixing function
here, but don't need it anymore.)

[Raymond Toy, 2016-03-18 17:33:04]

https://codereview.chromium.org/1803233002/diff/60001/third_party/WebKit/Layo...
File third_party/WebKit/LayoutTests/webaudio/realtimeanalyser-downmix.html
(right):

https://codereview.chromium.org/1803233002/diff/60001/third_party/WebKit/Layo...
third_party/WebKit/LayoutTests/webaudio/realtimeanalyser-downmix.html:84: // Run
analyser as an automatic pull node. Do NOT connect to the destination.
On 2016/03/16 21:58:23, Raymond Toy wrote:
> On 2016/03/16 21:51:42, hoch wrote:
> > Why running as an automatic pull mode does matter?
> 
> Because the source is also connected to the destination and since the analyser
> is a pass through (I think), the destination doesn't have what I want.
> 
> I'm using the destination downmixing to create the reference for the downmixed
> signal that the analyser should also be doing.
> 
> Shall I expand on this comment?

More comments added.

https://codereview.chromium.org/1803233002/diff/60001/third_party/WebKit/Layo...
File third_party/WebKit/LayoutTests/webaudio/resources/audio-testing.js (left):

https://codereview.chromium.org/1803233002/diff/60001/third_party/WebKit/Layo...
third_party/WebKit/LayoutTests/webaudio/resources/audio-testing.js:266: 
On 2016/03/16 21:58:23, Raymond Toy wrote:
> On 2016/03/16 21:51:42, hoch wrote:
> > nit: I put 2 spaces intentionally here, but doesn't really matter.
> 
> I didn't mean to change this file. (I originally had my own downmixing
function
> here, but don't need it anymore.)

Done.

[Raymond Toy, 2016-03-18 17:39:34]

Description was changed from

==========
AnalyserNode should downmix channels to mono.

In an AnalyserNode, the input data should be downmixed to mono
according to the down mixing rules before returning the time or
frequency data.

BUG=564939
TEST=realtimeanalyser-downmix.html
==========

to

==========
AnalyserNode should downmix channels to mono.

In an AnalyserNode, the input data should be downmixed to mono
according to the down mixing rules before returning the time or
frequency data.  Chrome currently just sums all of the channels together.

See issue https://github.com/WebAudio/web-audio-api/issues/719 that clarifies
how downmixing is done.

BUG=564939
TEST=realtimeanalyser-downmix.html
==========

[Raymond Toy, 2016-03-21 18:12:59]

The CQ bit was checked by rtoy@chromium.org

[Raymond Toy, 2016-03-21 18:12:59]

The patchset sent to the CQ was uploaded after l-g-t-m from
hongchan@chromium.org
Link to the patchset: https://codereview.chromium.org/1803233002/#ps80001
(title: " ")

[commit-bot: I haz the power, 2016-03-21 18:13:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1803233002/80001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1803233002/80001

[commit-bot: I haz the power, 2016-03-21 20:40:55]

Description was changed from

==========
AnalyserNode should downmix channels to mono.

In an AnalyserNode, the input data should be downmixed to mono
according to the down mixing rules before returning the time or
frequency data.  Chrome currently just sums all of the channels together.

See issue https://github.com/WebAudio/web-audio-api/issues/719 that clarifies
how downmixing is done.

BUG=564939
TEST=realtimeanalyser-downmix.html
==========

to

==========
AnalyserNode should downmix channels to mono.

In an AnalyserNode, the input data should be downmixed to mono
according to the down mixing rules before returning the time or
frequency data.  Chrome currently just sums all of the channels together.

See issue https://github.com/WebAudio/web-audio-api/issues/719 that clarifies
how downmixing is done.

BUG=564939
TEST=realtimeanalyser-downmix.html
==========

[commit-bot: I haz the power, 2016-03-21 20:40:56]

Committed patchset #5 (id:80001)

[commit-bot: I haz the power, 2016-03-21 20:42:14]

Description was changed from

==========
AnalyserNode should downmix channels to mono.

In an AnalyserNode, the input data should be downmixed to mono
according to the down mixing rules before returning the time or
frequency data.  Chrome currently just sums all of the channels together.

See issue https://github.com/WebAudio/web-audio-api/issues/719 that clarifies
how downmixing is done.

BUG=564939
TEST=realtimeanalyser-downmix.html
==========

to

==========
AnalyserNode should downmix channels to mono.

In an AnalyserNode, the input data should be downmixed to mono
according to the down mixing rules before returning the time or
frequency data.  Chrome currently just sums all of the channels together.

See issue https://github.com/WebAudio/web-audio-api/issues/719 that clarifies
how downmixing is done.

BUG=564939
TEST=realtimeanalyser-downmix.html

Committed: https://crrev.com/e73947aa166aa79759d3d54e703b07f91a1bc8e3
Cr-Commit-Position: refs/heads/master@{#382376}
==========

[commit-bot: I haz the power, 2016-03-21 20:42:15]

Patchset 5 (id:??) landed as
https://crrev.com/e73947aa166aa79759d3d54e703b07f91a1bc8e3
Cr-Commit-Position: refs/heads/master@{#382376}