Title: [143094] trunk/Source/WebCore
- Revision
- 143094
- Author
- crog...@google.com
- Date
- 2013-02-15 19:47:19 -0800 (Fri, 15 Feb 2013)
Log Message
Enhance AudioBus copyFrom() and sumFrom() to be able to handle discrete and speakers up and down-mixing
https://bugs.webkit.org/show_bug.cgi?id=109983
Reviewed by Kenneth Russell.
The Web Audio spec has a more detailed explanation for how channels are to be up and down-mixed:
https://dvcs.w3.org/hg/audio/raw-file/tip/webaudio/specification.html#UpMix
This patch adds the initial support for handling ChannelInterpretation, although no
new JS API is yet implemented.
No new tests since no new APIs have yet been exposed.
* platform/audio/AudioBus.cpp:
(WebCore::AudioBus::copyFrom):
(WebCore):
(WebCore::AudioBus::sumFrom):
(WebCore::AudioBus::speakersCopyFrom):
(WebCore::AudioBus::speakersSumFrom):
(WebCore::AudioBus::discreteCopyFrom):
(WebCore::AudioBus::discreteSumFrom):
* platform/audio/AudioBus.h:
(AudioBus):
Modified Paths
Diff
Modified: trunk/Source/WebCore/ChangeLog (143093 => 143094)
--- trunk/Source/WebCore/ChangeLog 2013-02-16 03:26:06 UTC (rev 143093)
+++ trunk/Source/WebCore/ChangeLog 2013-02-16 03:47:19 UTC (rev 143094)
@@ -1,3 +1,29 @@
+2013-02-15 Chris Rogers <crog...@google.com>
+
+ Enhance AudioBus copyFrom() and sumFrom() to be able to handle discrete and speakers up and down-mixing
+ https://bugs.webkit.org/show_bug.cgi?id=109983
+
+ Reviewed by Kenneth Russell.
+
+ The Web Audio spec has a more detailed explanation for how channels are to be up and down-mixed:
+ https://dvcs.w3.org/hg/audio/raw-file/tip/webaudio/specification.html#UpMix
+
+ This patch adds the initial support for handling ChannelInterpretation, although no
+ new JS API is yet implemented.
+
+ No new tests since no new APIs have yet been exposed.
+
+ * platform/audio/AudioBus.cpp:
+ (WebCore::AudioBus::copyFrom):
+ (WebCore):
+ (WebCore::AudioBus::sumFrom):
+ (WebCore::AudioBus::speakersCopyFrom):
+ (WebCore::AudioBus::speakersSumFrom):
+ (WebCore::AudioBus::discreteCopyFrom):
+ (WebCore::AudioBus::discreteSumFrom):
+ * platform/audio/AudioBus.h:
+ (AudioBus):
+
2013-02-15 Tony Chang <t...@chromium.org>
Padding and border changes doesn't trigger relayout of children
Modified: trunk/Source/WebCore/platform/audio/AudioBus.cpp (143093 => 143094)
--- trunk/Source/WebCore/platform/audio/AudioBus.cpp 2013-02-16 03:26:06 UTC (rev 143093)
+++ trunk/Source/WebCore/platform/audio/AudioBus.cpp 2013-02-16 03:47:19 UTC (rev 143094)
@@ -210,10 +210,7 @@
channel(i)->scale(scale);
}
-// Just copies the samples from the source bus to this one.
-// This is just a simple copy if the number of channels match, otherwise a mixup or mixdown is done.
-// For now, we just support mixup from mono -> stereo and mixdown from stereo -> mono.
-void AudioBus::copyFrom(const AudioBus& sourceBus)
+void AudioBus::copyFrom(const AudioBus& sourceBus, ChannelInterpretation channelInterpretation)
{
if (&sourceBus == this)
return;
@@ -224,7 +221,54 @@
if (numberOfDestinationChannels == numberOfSourceChannels) {
for (unsigned i = 0; i < numberOfSourceChannels; ++i)
channel(i)->copyFrom(sourceBus.channel(i));
- } else if (numberOfDestinationChannels == 2 && numberOfSourceChannels == 1) {
+ } else {
+ switch (channelInterpretation) {
+ case Speakers:
+ speakersCopyFrom(sourceBus);
+ break;
+ case Discrete:
+ discreteCopyFrom(sourceBus);
+ break;
+ default:
+ ASSERT_NOT_REACHED();
+ }
+ }
+}
+
+void AudioBus::sumFrom(const AudioBus& sourceBus, ChannelInterpretation channelInterpretation)
+{
+ if (&sourceBus == this)
+ return;
+
+ unsigned numberOfSourceChannels = sourceBus.numberOfChannels();
+ unsigned numberOfDestinationChannels = numberOfChannels();
+
+ if (numberOfDestinationChannels == numberOfSourceChannels) {
+ for (unsigned i = 0; i < numberOfSourceChannels; ++i)
+ channel(i)->sumFrom(sourceBus.channel(i));
+ } else {
+ switch (channelInterpretation) {
+ case Speakers:
+ speakersSumFrom(sourceBus);
+ break;
+ case Discrete:
+ discreteSumFrom(sourceBus);
+ break;
+ default:
+ ASSERT_NOT_REACHED();
+ }
+ }
+}
+
+void AudioBus::speakersCopyFrom(const AudioBus& sourceBus)
+{
+ // FIXME: Implement down mixing 5.1 to stereo.
+ // https://bugs.webkit.org/show_bug.cgi?id=79192
+
+ unsigned numberOfSourceChannels = sourceBus.numberOfChannels();
+ unsigned numberOfDestinationChannels = numberOfChannels();
+
+ if (numberOfDestinationChannels == 2 && numberOfSourceChannels == 1) {
// Handle mono -> stereo case (for now simply copy mono channel into both left and right)
// FIXME: Really we should apply an equal-power scaling factor here, since we're effectively panning center...
const AudioChannel* sourceChannel = sourceBus.channel(0);
@@ -253,37 +297,22 @@
// Handle 5.1 -> mono case, copy center channel into mono.
// FIXME: We should have a better algorithm for this down mixing.
channel(0)->copyFrom(sourceBus.channel(2));
- } else if (numberOfDestinationChannels < numberOfSourceChannels) {
- // Default down mixing handling, just match the source channels with the first available destination channels.
- // 5.1 -> stereo case covered here.
- // FIXME: We should have a better algorithm for down mixing 5.1 to stereo.
- // https://bugs.webkit.org/show_bug.cgi?id=79192
- for (unsigned i = 0; i < numberOfDestinationChannels; ++i)
- channel(i)->copyFrom(sourceBus.channel(i));
- } else if (numberOfDestinationChannels > numberOfSourceChannels) {
- // Default up mixing handling, just match the destination channels with the first available source channels.
- // Stereo -> 5.1 case covered here.
- for (unsigned i = 0; i < numberOfSourceChannels; ++i)
- channel(i)->copyFrom(sourceBus.channel(i));
- for (unsigned i = numberOfSourceChannels; i < numberOfDestinationChannels; ++i)
- channel(i)->zero();
} else {
- // Case not handled
- ASSERT_NOT_REACHED();
+ // Fallback for unknown combinations.
+ discreteCopyFrom(sourceBus);
}
}
-void AudioBus::sumFrom(const AudioBus &sourceBus)
+void AudioBus::speakersSumFrom(const AudioBus& sourceBus)
{
+ // FIXME: Implement down mixing 5.1 to stereo.
+ // https://bugs.webkit.org/show_bug.cgi?id=79192
+
unsigned numberOfSourceChannels = sourceBus.numberOfChannels();
unsigned numberOfDestinationChannels = numberOfChannels();
- if (numberOfDestinationChannels == numberOfSourceChannels) {
- for (unsigned i = 0; i < numberOfChannels(); ++i)
- channel(i)->sumFrom(sourceBus.channel(i));
- } else if (numberOfDestinationChannels == 2 && numberOfSourceChannels == 1) {
- // Handle mono -> stereo case (for now simply sum mono channel into both left and right)
- // FIXME: Really we should apply an equal-power scaling factor here, since we're effectively panning center...
+ if (numberOfDestinationChannels == 2 && numberOfSourceChannels == 1) {
+ // Handle mono -> stereo case (summing mono channel into both left and right).
const AudioChannel* sourceChannel = sourceBus.channel(0);
channel(0)->sumFrom(sourceChannel);
channel(1)->sumFrom(sourceChannel);
@@ -305,21 +334,43 @@
// Handle 5.1 -> mono case, sum center channel into mono.
// FIXME: We should have a better algorithm for this down mixing.
channel(0)->sumFrom(sourceBus.channel(2));
- } else if (numberOfDestinationChannels < numberOfSourceChannels) {
- // Default down mixing, just summing the first available destination channels.
- // 5.1 -> stereo case covered here.
- // FIXME: We should have a better algorithm for down mixing 5.1 to stereo.
- // https://bugs.webkit.org/show_bug.cgi?id=79192
+ } else {
+ // Fallback for unknown combinations.
+ discreteSumFrom(sourceBus);
+ }
+}
+
+void AudioBus::discreteCopyFrom(const AudioBus& sourceBus)
+{
+ unsigned numberOfSourceChannels = sourceBus.numberOfChannels();
+ unsigned numberOfDestinationChannels = numberOfChannels();
+
+ if (numberOfDestinationChannels < numberOfSourceChannels) {
+ // Down-mix by copying channels and dropping the remaining.
+ for (unsigned i = 0; i < numberOfDestinationChannels; ++i)
+ channel(i)->copyFrom(sourceBus.channel(i));
+ } else if (numberOfDestinationChannels > numberOfSourceChannels) {
+ // Up-mix by copying as many channels as we have, then zeroing remaining channels.
+ for (unsigned i = 0; i < numberOfSourceChannels; ++i)
+ channel(i)->copyFrom(sourceBus.channel(i));
+ for (unsigned i = numberOfSourceChannels; i < numberOfDestinationChannels; ++i)
+ channel(i)->zero();
+ }
+}
+
+void AudioBus::discreteSumFrom(const AudioBus& sourceBus)
+{
+ unsigned numberOfSourceChannels = sourceBus.numberOfChannels();
+ unsigned numberOfDestinationChannels = numberOfChannels();
+
+ if (numberOfDestinationChannels < numberOfSourceChannels) {
+ // Down-mix by summing channels and dropping the remaining.
for (unsigned i = 0; i < numberOfDestinationChannels; ++i)
channel(i)->sumFrom(sourceBus.channel(i));
} else if (numberOfDestinationChannels > numberOfSourceChannels) {
- // Default up mixing, just summing the first available source channels.
- // stereo -> 5.1 case covered here.
+ // Up-mix by summing as many channels as we have.
for (unsigned i = 0; i < numberOfSourceChannels; ++i)
channel(i)->sumFrom(sourceBus.channel(i));
- } else {
- // Case not handled
- ASSERT_NOT_REACHED();
}
}
Modified: trunk/Source/WebCore/platform/audio/AudioBus.h (143093 => 143094)
--- trunk/Source/WebCore/platform/audio/AudioBus.h 2013-02-16 03:26:06 UTC (rev 143093)
+++ trunk/Source/WebCore/platform/audio/AudioBus.h 2013-02-16 03:47:19 UTC (rev 143094)
@@ -57,6 +57,11 @@
// Can define non-standard layouts here
};
+ enum ChannelInterpretation {
+ Speakers,
+ Discrete,
+ };
+
// allocate indicates whether or not to initially have the AudioChannels created with managed storage.
// Normal usage is to pass true here, in which case the AudioChannels will memory-manage their own storage.
// If allocate is false then setChannelMemory() has to be called later on for each channel before the AudioBus is useable...
@@ -115,12 +120,13 @@
void reset() { m_isFirstTime = true; } // for de-zippering
- // Assuming sourceBus has the same topology, copies sample data from each channel of sourceBus to our corresponding channel.
- void copyFrom(const AudioBus &sourceBus);
+ // Copies the samples from the source bus to this one.
+ // This is just a simple per-channel copy if the number of channels match, otherwise an up-mix or down-mix is done.
+ void copyFrom(const AudioBus& sourceBus, ChannelInterpretation = Speakers);
- // Sums the sourceBus into our bus with unity gain.
- // Our own internal gain m_busGain is ignored.
- void sumFrom(const AudioBus &sourceBus);
+ // Sums the samples from the source bus to this one.
+ // This is just a simple per-channel summing if the number of channels match, otherwise an up-mix or down-mix is done.
+ void sumFrom(const AudioBus& sourceBus, ChannelInterpretation = Speakers);
// Copy each channel from sourceBus into our corresponding channel.
// We scale by targetGain (and our own internal gain m_busGain), performing "de-zippering" to smoothly change from *lastMixGain to (targetGain*m_busGain).
@@ -142,6 +148,11 @@
protected:
AudioBus() { };
+ void speakersCopyFrom(const AudioBus&);
+ void discreteCopyFrom(const AudioBus&);
+ void speakersSumFrom(const AudioBus&);
+ void discreteSumFrom(const AudioBus&);
+
size_t m_length;
Vector<OwnPtr<AudioChannel> > m_channels;
int m_layout;
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