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author | Ben Murdoch <benm@google.com> | 2010-10-22 13:02:20 +0100 |
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committer | Ben Murdoch <benm@google.com> | 2010-10-26 15:21:41 +0100 |
commit | a94275402997c11dd2e778633dacf4b7e630a35d (patch) | |
tree | e66f56c67e3b01f22c9c23cd932271ee9ac558ed /WebCore/platform/audio/AudioUtilities.cpp | |
parent | 09e26c78506587b3f5d930d7bc72a23287ffbec0 (diff) | |
download | external_webkit-a94275402997c11dd2e778633dacf4b7e630a35d.zip external_webkit-a94275402997c11dd2e778633dacf4b7e630a35d.tar.gz external_webkit-a94275402997c11dd2e778633dacf4b7e630a35d.tar.bz2 |
Merge WebKit at r70209: Initial merge by Git
Change-Id: Id23a68efa36e9d1126bcce0b137872db00892c8e
Diffstat (limited to 'WebCore/platform/audio/AudioUtilities.cpp')
-rw-r--r-- | WebCore/platform/audio/AudioUtilities.cpp | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/WebCore/platform/audio/AudioUtilities.cpp b/WebCore/platform/audio/AudioUtilities.cpp new file mode 100644 index 0000000..32f4335 --- /dev/null +++ b/WebCore/platform/audio/AudioUtilities.cpp @@ -0,0 +1,58 @@ +/* + * 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" + +#include "AudioUtilities.h" + +#include <math.h> + +namespace WebCore { + +namespace AudioUtilities { + +double decibelsToLinear(double decibels) +{ + return pow(10.0, 0.05 * decibels); +} + +double linearToDecibels(double linear) +{ + // It's not possible to calculate decibels for a zero linear value since it would be -Inf. + // -1000.0 dB represents a very tiny linear value in case we ever reach this case. + ASSERT(linear); + if (!linear) + return -1000.0; + + return 20.0 * log10(linear); +} + +double discreteTimeConstantForSampleRate(double timeConstant, double sampleRate) +{ + return 1.0 - pow(1.0 / M_E, 1.0 / (sampleRate * timeConstant)); +} + +} // AudioUtilites + +} // WebCore |