diff options
author | Steve Block <steveblock@google.com> | 2011-05-06 11:45:16 +0100 |
---|---|---|
committer | Steve Block <steveblock@google.com> | 2011-05-12 13:44:10 +0100 |
commit | cad810f21b803229eb11403f9209855525a25d57 (patch) | |
tree | 29a6fd0279be608e0fe9ffe9841f722f0f4e4269 /Source/WebCore/platform/audio/AudioBus.h | |
parent | 121b0cf4517156d0ac5111caf9830c51b69bae8f (diff) | |
download | external_webkit-cad810f21b803229eb11403f9209855525a25d57.zip external_webkit-cad810f21b803229eb11403f9209855525a25d57.tar.gz external_webkit-cad810f21b803229eb11403f9209855525a25d57.tar.bz2 |
Merge WebKit at r75315: Initial merge by git.
Change-Id: I570314b346ce101c935ed22a626b48c2af266b84
Diffstat (limited to 'Source/WebCore/platform/audio/AudioBus.h')
-rw-r--r-- | Source/WebCore/platform/audio/AudioBus.h | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/Source/WebCore/platform/audio/AudioBus.h b/Source/WebCore/platform/audio/AudioBus.h new file mode 100644 index 0000000..4318b81 --- /dev/null +++ b/Source/WebCore/platform/audio/AudioBus.h @@ -0,0 +1,141 @@ +/* + * 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. + * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of + * its contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY APPLE 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 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 AudioBus_h +#define AudioBus_h + +#include "AudioChannel.h" +#include <wtf/Noncopyable.h> +#include <wtf/PassOwnPtr.h> +#include <wtf/Vector.h> + +namespace WebCore { + +// An AudioBus represents a collection of one or more AudioChannels. +// The data layout is "planar" as opposed to "interleaved". +// An AudioBus with one channel is mono, an AudioBus with two channels is stereo, etc. +class AudioBus : public Noncopyable { +public: + enum { + ChannelLeft = 0, + ChannelRight = 1, + ChannelCenter = 2, // center and mono are the same + ChannelMono = 2, + ChannelLFE = 3, + ChannelSurroundLeft = 4, + ChannelSurroundRight = 5, + }; + + enum { + LayoutCanonical = 0 + // Can define non-standard layouts here + }; + + // 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... + AudioBus(unsigned numberOfChannels, size_t length, bool allocate = true); + + // Tells the given channel to use an externally allocated buffer. + void setChannelMemory(unsigned channelIndex, float* storage, size_t length); + + // Channels + unsigned numberOfChannels() const { return m_channels.size(); } + + AudioChannel* channel(unsigned channel) { return m_channels[channel].get(); } + const AudioChannel* channel(unsigned channel) const { return const_cast<AudioBus*>(this)->m_channels[channel].get(); } + AudioChannel* channelByType(unsigned type); + + // Number of sample-frames + size_t length() const { return m_length; } + + // Sample-rate : 0.0 if unknown or "don't care" + double sampleRate() const { return m_sampleRate; } + void setSampleRate(double sampleRate) { m_sampleRate = sampleRate; } + + // Zeroes all channels. + void zero(); + + // Returns true if the channel count and frame-size match. + bool topologyMatches(const AudioBus &sourceBus) const; + + // Creates a new buffer from a range in the source buffer. + // 0 may be returned if the range does not fit in the sourceBuffer + static PassOwnPtr<AudioBus> createBufferFromRange(AudioBus* sourceBuffer, unsigned startFrame, unsigned endFrame); + + // Scales all samples by the same amount. + void scale(double scale); + + // Master gain for this bus - used with sumWithGainFrom() below + void setGain(double gain) { m_busGain = gain; } + double gain() { return m_busGain; } + + 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); + + // Sums the sourceBus into our bus with unity gain. + // Our own internal gain m_busGain is ignored. + void sumFrom(const AudioBus &sourceBus); + + // Copy or sum 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). + // The caller is responsible for setting up lastMixGain to point to storage which is unique for every "stream" which will be summed to this bus. + // This represents the dezippering memory. + void copyWithGainFrom(const AudioBus &sourceBus, double* lastMixGain, double targetGain); + void sumWithGainFrom(const AudioBus &sourceBus, double* lastMixGain, double targetGain); + + // Returns maximum absolute value across all channels (useful for normalization). + float maxAbsValue() const; + + // Makes maximum absolute value == 1.0 (if possible). + void normalize(); + + static PassOwnPtr<AudioBus> loadPlatformResource(const char* name, double sampleRate); + +protected: + AudioBus() { }; + + void processWithGainFrom(const AudioBus &sourceBus, double* lastMixGain, double targetGain, bool sumToBus); + void processWithGainFromMonoStereo(const AudioBus &sourceBus, double* lastMixGain, double targetGain, bool sumToBus); + + size_t m_length; + + Vector<OwnPtr<AudioChannel> > m_channels; + + int m_layout; + + double m_busGain; + bool m_isFirstTime; + double m_sampleRate; // 0.0 if unknown or N/A +}; + +} // WebCore + +#endif // AudioBus_h |