cannam@59: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
cannam@59: 
cannam@59: /*
cannam@59:     Vamp
cannam@59: 
cannam@59:     An API for audio analysis and feature extraction plugins.
cannam@59: 
cannam@59:     Centre for Digital Music, Queen Mary, University of London.
cannam@59:     Copyright 2006 Chris Cannam.
cannam@59:   
cannam@59:     Permission is hereby granted, free of charge, to any person
cannam@59:     obtaining a copy of this software and associated documentation
cannam@59:     files (the "Software"), to deal in the Software without
cannam@59:     restriction, including without limitation the rights to use, copy,
cannam@59:     modify, merge, publish, distribute, sublicense, and/or sell copies
cannam@59:     of the Software, and to permit persons to whom the Software is
cannam@59:     furnished to do so, subject to the following conditions:
cannam@59: 
cannam@59:     The above copyright notice and this permission notice shall be
cannam@59:     included in all copies or substantial portions of the Software.
cannam@59: 
cannam@59:     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
cannam@59:     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
cannam@59:     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
cannam@59:     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR
cannam@59:     ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
cannam@59:     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
cannam@59:     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
cannam@59: 
cannam@59:     Except as contained in this notice, the names of the Centre for
cannam@59:     Digital Music; Queen Mary, University of London; and Chris Cannam
cannam@59:     shall not be used in advertising or otherwise to promote the sale,
cannam@59:     use or other dealings in this Software without prior written
cannam@59:     authorization.
cannam@59: */
cannam@59: 
cannam@59: #ifndef _VAMP_PLUGIN_CHANNEL_ADAPTER_H_
cannam@59: #define _VAMP_PLUGIN_CHANNEL_ADAPTER_H_
cannam@59: 
cannam@59: #include "PluginWrapper.h"
cannam@59: 
cannam@59: namespace Vamp {
cannam@59: 
cannam@59: namespace HostExt {
cannam@59: 
cannam@59: /**
cannam@59:  * PluginChannelAdapter implements a policy for management of plugins
cannam@59:  * that expect a different number of input channels from the number
cannam@59:  * actually available in the source audio data.
cannam@59:  *
cannam@59:  * A host using PluginChannelAdapter may ignore the getMinChannelCount
cannam@59:  * and getMaxChannelCount reported by the plugin, and still expect the
cannam@59:  * plugin to run.
cannam@59:  *
cannam@59:  * PluginChannelAdapter implements the following policy:
cannam@59:  *
cannam@59:  * -- If the plugin supports the provided number of channels directly,
cannam@59:  * PluginChannelAdapter will just run the plugin as normal.
cannam@59:  *
cannam@59:  * -- If the plugin only supports exactly one channel but more than
cannam@59:  * one channel is provided, PluginChannelAdapter will use the mean of
cannam@59:  * the channels.  This ensures that the resulting values remain within
cannam@59:  * the same magnitude range as expected for mono data.
cannam@59:  *
cannam@59:  * -- If the plugin requires more than one channel but exactly one is
cannam@59:  * provided, the provided channel will be duplicated across all the
cannam@59:  * plugin input channels.
cannam@59:  *
cannam@59:  * If none of the above apply:
cannam@59:  * 
cannam@59:  * -- If the plugin requires more channels than are provided, the
cannam@59:  * minimum acceptable number of channels will be produced by adding
cannam@59:  * empty (zero valued) channels to those provided.
cannam@59:  *
cannam@59:  * -- If the plugin requires fewer channels than are provided, the
cannam@59:  * maximum acceptable number of channels will be produced by
cannam@59:  * discarding the excess channels.
cannam@59:  *
cannam@59:  * Hosts requiring a different channel policy from the above will need
cannam@59:  * to implement it themselves, instead of using PluginChannelAdapter.
cannam@59:  */
cannam@59: 
cannam@59: class PluginChannelAdapter : public PluginWrapper
cannam@59: {
cannam@59: public:
cannam@59:     PluginChannelAdapter(Plugin *plugin); // I take ownership of plugin
cannam@59:     virtual ~PluginChannelAdapter();
cannam@59: 
cannam@59:     bool initialise(size_t channels, size_t stepSize, size_t blockSize);
cannam@59: 
cannam@59:     FeatureSet process(const float *const *inputBuffers, RealTime timestamp);
cannam@59: 
cannam@59: protected:
cannam@59:     size_t m_blockSize;
cannam@59:     size_t m_inputChannels;
cannam@59:     size_t m_pluginChannels;
cannam@59:     float **m_buffer;
cannam@59:     const float **m_forwardPtrs;
cannam@59: };
cannam@59: 
cannam@59: }
cannam@59: 
cannam@59: }
cannam@59: 
cannam@59: #endif