cannam@64: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */ cannam@64: cannam@64: /* cannam@64: Vamp cannam@64: cannam@64: An API for audio analysis and feature extraction plugins. cannam@64: cannam@64: Centre for Digital Music, Queen Mary, University of London. cannam@64: Copyright 2006 Chris Cannam. cannam@64: cannam@64: Permission is hereby granted, free of charge, to any person cannam@64: obtaining a copy of this software and associated documentation cannam@64: files (the "Software"), to deal in the Software without cannam@64: restriction, including without limitation the rights to use, copy, cannam@64: modify, merge, publish, distribute, sublicense, and/or sell copies cannam@64: of the Software, and to permit persons to whom the Software is cannam@64: furnished to do so, subject to the following conditions: cannam@64: cannam@64: The above copyright notice and this permission notice shall be cannam@64: included in all copies or substantial portions of the Software. cannam@64: cannam@64: THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, cannam@64: EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF cannam@64: MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND cannam@64: NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR cannam@64: ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF cannam@64: CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION cannam@64: WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. cannam@64: cannam@64: Except as contained in this notice, the names of the Centre for cannam@64: Digital Music; Queen Mary, University of London; and Chris Cannam cannam@64: shall not be used in advertising or otherwise to promote the sale, cannam@64: use or other dealings in this Software without prior written cannam@64: authorization. cannam@64: */ cannam@64: cannam@64: #ifndef _VAMP_PLUGIN_CHANNEL_ADAPTER_H_ cannam@64: #define _VAMP_PLUGIN_CHANNEL_ADAPTER_H_ cannam@64: cannam@64: #include "PluginWrapper.h" cannam@64: cannam@64: namespace Vamp { cannam@64: cannam@64: namespace HostExt { cannam@64: cannam@64: /** cannam@64: * PluginChannelAdapter is a Vamp plugin adapter that implements a cannam@64: * policy for management of plugins that expect a different number of cannam@64: * input channels from the number actually available in the source cannam@64: * audio data. cannam@64: * cannam@64: * A host using PluginChannelAdapter may ignore the getMinChannelCount cannam@64: * and getMaxChannelCount reported by the plugin, and still expect the cannam@64: * plugin to run. cannam@64: * cannam@64: * PluginChannelAdapter implements the following policy: cannam@64: * cannam@64: * -- If the plugin supports the provided number of channels directly, cannam@64: * PluginChannelAdapter will just run the plugin as normal. cannam@64: * cannam@64: * -- If the plugin only supports exactly one channel but more than cannam@64: * one channel is provided, PluginChannelAdapter will use the mean of cannam@64: * the channels. This ensures that the resulting values remain within cannam@64: * the same magnitude range as expected for mono data. cannam@64: * cannam@64: * -- If the plugin requires more than one channel but exactly one is cannam@64: * provided, the provided channel will be duplicated across all the cannam@64: * plugin input channels. cannam@64: * cannam@64: * If none of the above apply: cannam@64: * cannam@64: * -- If the plugin requires more channels than are provided, the cannam@64: * minimum acceptable number of channels will be produced by adding cannam@64: * empty (zero valued) channels to those provided. cannam@64: * cannam@64: * -- If the plugin requires fewer channels than are provided, the cannam@64: * maximum acceptable number of channels will be produced by cannam@64: * discarding the excess channels. cannam@64: * cannam@64: * Hosts requiring a different channel policy from the above will need cannam@64: * to implement it themselves, instead of using PluginChannelAdapter. cannam@64: * cannam@64: * Note that PluginChannelAdapter does not override the minimum and cannam@64: * maximum channel counts returned by the wrapped plugin. The host cannam@64: * will need to be aware that it is using a PluginChannelAdapter, and cannam@64: * be prepared to ignore these counts as necessary. (This contrasts cannam@64: * with the approach used in PluginInputDomainAdapter, which aims to cannam@64: * make the host completely unaware of which underlying input domain cannam@64: * is in fact in use.) cannam@64: * cannam@64: * (The rationale for this is that a host may wish to use the cannam@64: * PluginChannelAdapter but still discriminate in some way on the cannam@64: * basis of the number of channels actually supported. For example, a cannam@64: * simple stereo audio host may prefer to reject plugins that require cannam@64: * more than two channels on the grounds that doesn't actually cannam@64: * understand what they are for, rather than allow the channel adapter cannam@64: * to make a potentially meaningless channel conversion for them.) cannam@64: * cannam@64: * In every respect other than its management of channels, the cannam@64: * PluginChannelAdapter behaves identically to the plugin that it cannam@64: * wraps. The wrapped plugin will be deleted when the wrapper is cannam@64: * deleted. cannam@64: */ cannam@64: cannam@64: class PluginChannelAdapter : public PluginWrapper cannam@64: { cannam@64: public: cannam@64: PluginChannelAdapter(Plugin *plugin); // I take ownership of plugin cannam@64: virtual ~PluginChannelAdapter(); cannam@64: cannam@64: bool initialise(size_t channels, size_t stepSize, size_t blockSize); cannam@64: cannam@64: FeatureSet process(const float *const *inputBuffers, RealTime timestamp); cannam@64: cannam@64: protected: cannam@70: class Impl; cannam@70: Impl *m_impl; cannam@64: }; cannam@64: cannam@64: } cannam@64: cannam@64: } cannam@64: cannam@64: #endif