2010-10-05 Chris Rogers <crogers@google.com>
authorcrogers@google.com <crogers@google.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Tue, 5 Oct 2010 07:45:05 +0000 (07:45 +0000)
committercrogers@google.com <crogers@google.com@268f45cc-cd09-0410-ab3c-d52691b4dbfc>
Tue, 5 Oct 2010 07:45:05 +0000 (07:45 +0000)
        Reviewed by Kenneth Russell.

        Add EqualPowerPanner files
        https://bugs.webkit.org/show_bug.cgi?id=45077

        No new tests since audio API is not yet implemented.

        * platform/audio/EqualPowerPanner.cpp: Added.
        (WebCore::EqualPowerPanner::EqualPowerPanner):
        (WebCore::EqualPowerPanner::pan):
        * platform/audio/EqualPowerPanner.h: Added.
        (WebCore::EqualPowerPanner::reset):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@69089 268f45cc-cd09-0410-ab3c-d52691b4dbfc

WebCore/ChangeLog
WebCore/platform/audio/EqualPowerPanner.cpp [new file with mode: 0644]
WebCore/platform/audio/EqualPowerPanner.h [new file with mode: 0644]

index 38ebcde68e49f242b1b5e90c2a2ebf6ba90d8ae9..6073e300be836b8b1cd059ef6db0091ac30a0b87 100644 (file)
@@ -1,3 +1,18 @@
+2010-10-05  Chris Rogers  <crogers@google.com>
+
+        Reviewed by Kenneth Russell.
+
+        Add EqualPowerPanner files
+        https://bugs.webkit.org/show_bug.cgi?id=45077
+
+        No new tests since audio API is not yet implemented.
+
+        * platform/audio/EqualPowerPanner.cpp: Added.
+        (WebCore::EqualPowerPanner::EqualPowerPanner):
+        (WebCore::EqualPowerPanner::pan):
+        * platform/audio/EqualPowerPanner.h: Added.
+        (WebCore::EqualPowerPanner::reset):
+
 2010-10-05  Chris Rogers  <crogers@google.com>
 
         Reviewed by Kenneth Russell.
diff --git a/WebCore/platform/audio/EqualPowerPanner.cpp b/WebCore/platform/audio/EqualPowerPanner.cpp
new file mode 100644 (file)
index 0000000..2e4e10f
--- /dev/null
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2010, Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1.  Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#if ENABLE(WEB_AUDIO)
+
+#include "EqualPowerPanner.h"
+
+#include "AudioBus.h"
+#include "AudioUtilities.h"
+#include <math.h>
+
+// Use a 50ms smoothing / de-zippering time-constant.
+const double SmoothingTimeConstant = 0.050;
+namespace WebCore {
+
+EqualPowerPanner::EqualPowerPanner(double sampleRate)
+    : Panner(PanningModelEqualPower)
+    , m_isFirstRender(true)
+    , m_gainL(0.0)
+    , m_gainR(0.0)
+{
+    m_smoothingConstant = AudioUtilities::discreteTimeConstantForSampleRate(SmoothingTimeConstant, sampleRate);
+}
+
+void EqualPowerPanner::pan(double azimuth, double /*elevation*/, AudioBus* inputBus, AudioBus* outputBus, size_t framesToProcess)
+{
+    // FIXME: implement stereo sources
+    bool isInputSafe = inputBus && inputBus->numberOfChannels() == 1 && framesToProcess <= inputBus->length();
+    ASSERT(isInputSafe);
+    if (!isInputSafe)
+        return;
+
+    bool isOutputSafe = outputBus && outputBus->numberOfChannels() == 2 && framesToProcess <= outputBus->length();
+    ASSERT(isOutputSafe);
+    if (!isOutputSafe)
+        return;
+
+    AudioChannel* channel = inputBus->channel(0);
+    float* sourceP = channel->data();                               
+    float* destinationL = outputBus->channelByType(AudioBus::ChannelLeft)->data();
+    float* destinationR = outputBus->channelByType(AudioBus::ChannelRight)->data();
+
+    if (!sourceP || !destinationL || !destinationR)
+        return;
+
+    // Pan smoothly from left to right with azimuth going from -30 -> +30 degrees.
+    double desiredPanPosition;
+    if (azimuth > 30.0)
+        desiredPanPosition = 1.0;
+    else if (azimuth < -30.0)
+        desiredPanPosition = 0.0;
+    else
+        desiredPanPosition = (azimuth + 30.0) / 60.0;
+
+    double desiredGainL = 0.5 * cos(M_PI * desiredPanPosition) + 0.5;
+    double desiredGainR = sqrt(1.0 - desiredGainL*desiredGainL);
+
+    // Don't de-zipper on first render call.
+    if (m_isFirstRender) {
+        m_isFirstRender = false;
+        m_gainL = desiredGainL;
+        m_gainR = desiredGainR;
+    }
+
+    // Cache in local variables.
+    double gainL = m_gainL;
+    double gainR = m_gainR;
+
+    // Get local copy of smoothing constant.
+    const double SmoothingConstant = m_smoothingConstant;
+
+    int n = framesToProcess;
+
+    while (n--) {
+        float input = *sourceP++;
+        gainL += (desiredGainL - gainL) * SmoothingConstant;
+        gainR += (desiredGainR - gainR) * SmoothingConstant;
+        *destinationL++ = static_cast<float>(input * gainL);
+        *destinationR++ = static_cast<float>(input * gainR);
+    }
+
+    m_gainL = gainL;
+    m_gainR = gainR;
+}
+
+} // namespace WebCore
+
+#endif // ENABLE(WEB_AUDIO)
diff --git a/WebCore/platform/audio/EqualPowerPanner.h b/WebCore/platform/audio/EqualPowerPanner.h
new file mode 100644 (file)
index 0000000..f20617e
--- /dev/null
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2010, Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1.  Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef EqualPowerPanner_h
+#define EqualPowerPanner_h
+
+#include "Panner.h"
+
+namespace WebCore {
+
+// Common type of stereo panner as found in normal audio mixing equipment.
+
+class EqualPowerPanner : public Panner {
+public:
+    EqualPowerPanner(double sampleRate);
+
+    virtual void pan(double azimuth, double elevation, AudioBus* inputBus, AudioBus* outputBuf, size_t framesToProcess);
+
+    virtual void reset() { m_isFirstRender = true; }
+
+private:
+    // For smoothing / de-zippering
+    bool m_isFirstRender;
+    double m_smoothingConstant;
+    
+    double m_gainL;
+    double m_gainR;
+};
+
+} // namespace WebCore
+
+#endif // EqualPowerPanner_h