Chris@49: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@0: 
Chris@0: /*
Chris@52:     Sonic Visualiser
Chris@52:     An audio file viewer and annotation editor.
Chris@52:     Centre for Digital Music, Queen Mary, University of London.
Chris@52:     This file copyright 2006 Chris Cannam.
Chris@0:     
Chris@52:     This program is free software; you can redistribute it and/or
Chris@52:     modify it under the terms of the GNU General Public License as
Chris@52:     published by the Free Software Foundation; either version 2 of the
Chris@52:     License, or (at your option) any later version.  See the file
Chris@52:     COPYING included with this distribution for more information.
Chris@0: */
Chris@0: 
Chris@0: #ifndef _AUDIO_PLAY_SOURCE_H_
Chris@0: #define _AUDIO_PLAY_SOURCE_H_
Chris@0: 
Chris@1040: #include "BaseTypes.h"
Chris@1040: 
Chris@389: struct Auditionable {
Chris@389:     virtual ~Auditionable() { }
Chris@389: };
Chris@389: 
Chris@0: /**
Chris@0:  * Simple interface for audio playback.  This should be all that the
Chris@0:  * ViewManager needs to know about to synchronise with playback by
Chris@0:  * sample frame, but it doesn't provide enough to determine what is
Chris@0:  * actually being played or how.  See the audioio directory for a
Chris@0:  * concrete subclass.
Chris@0:  */
Chris@0: 
Chris@0: class AudioPlaySource
Chris@0: {
Chris@0: public:
Chris@27:     virtual ~AudioPlaySource() { }
Chris@27: 
Chris@0:     /**
Chris@0:      * Start playing from the given frame.  If playback is already
Chris@0:      * under way, reseek to the given frame and continue.
Chris@0:      */
Chris@1040:     virtual void play(sv_frame_t startFrame) = 0;
Chris@0: 
Chris@0:     /**
Chris@0:      * Stop playback.
Chris@0:      */
Chris@0:     virtual void stop() = 0;
Chris@0: 
Chris@0:     /**
Chris@0:      * Return whether playback is currently supposed to be happening.
Chris@0:      */
Chris@0:     virtual bool isPlaying() const = 0;
Chris@0: 
Chris@0:     /**
Chris@0:      * Return the frame number that is currently expected to be coming
Chris@0:      * out of the speakers.  (i.e. compensating for playback latency.)
Chris@0:      */
Chris@1040:     virtual sv_frame_t getCurrentPlayingFrame() = 0;
Chris@0: 
Chris@0:     /**
Chris@0:      * Return the current (or thereabouts) output levels in the range
Chris@0:      * 0.0 -> 1.0, for metering purposes.
Chris@0:      */
Chris@0:     virtual bool getOutputLevels(float &left, float &right) = 0;
Chris@40: 
Chris@40:     /**
Chris@249:      * Return the sample rate of the source material -- any material
Chris@249:      * that wants to play at a different rate will sound wrong.
Chris@249:      */
Chris@1040:     virtual sv_samplerate_t getSourceSampleRate() const = 0;
Chris@249: 
Chris@249:     /**
Chris@1321:      * Return the sample rate set by the target audio device (or 0 if
Chris@1321:      * the target hasn't told us yet).  If the source and target
Chris@1321:      * sample rates differ, resampling will occur.
Chris@1321:      *
Chris@1321:      * Note that we don't actually do any processing at the device
Chris@1321:      * sample rate. All processing happens at the source sample rate,
Chris@1321:      * and then a resampler is applied if necessary at the interface
Chris@1321:      * between application and driver layer.
Chris@40:      */
Chris@1321:     virtual sv_samplerate_t getDeviceSampleRate() const = 0;
Chris@389: 
Chris@389:     /**
Chris@389:      * Get the block size of the target audio device.  This may be an
Chris@389:      * estimate or upper bound, if the target has a variable block
Chris@389:      * size; the source should behave itself even if this value turns
Chris@389:      * out to be inaccurate.
Chris@389:      */
Chris@928:     virtual int getTargetBlockSize() const = 0;
Chris@389: 
Chris@389:     /**
Chris@389:      * Get the number of channels of audio that will be provided
Chris@389:      * to the play target.  This may be more than the source channel
Chris@389:      * count: for example, a mono source will provide 2 channels
Chris@389:      * after pan.
Chris@389:      */
Chris@928:     virtual int getTargetChannelCount() const = 0;
Chris@389: 
Chris@389:     /**
Chris@389:      * Set a plugin or other subclass of Auditionable as an
Chris@389:      * auditioning effect.
Chris@389:      */
Chris@389:     virtual void setAuditioningEffect(Auditionable *) = 0;
Chris@389: 
Chris@0: };
Chris@0: 
Chris@0: #endif