comparison base/AudioPlaySource.h @ 0:da6937383da8

initial import

+/* -*- c-basic-offset: 4 -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    A waveform viewer and audio annotation editor.
+    Chris Cannam, Queen Mary University of London, 2005
+    
+    This is experimental software.  Not for distribution.
+*/
+
+#ifndef _AUDIO_PLAY_SOURCE_H_
+#define _AUDIO_PLAY_SOURCE_H_
+
+/**
+ * Simple interface for audio playback.  This should be all that the
+ * ViewManager needs to know about to synchronise with playback by
+ * sample frame, but it doesn't provide enough to determine what is
+ * actually being played or how.  See the audioio directory for a
+ * concrete subclass.
+ */
+
+class AudioPlaySource
+{
+public:
+    /**
+     * Start playing from the given frame.  If playback is already
+     * under way, reseek to the given frame and continue.
+     */
+    virtual void play(size_t startFrame) = 0;
+
+    /**
+     * Stop playback.
+     */
+    virtual void stop() = 0;
+
+    /**
+     * Return whether playback is currently supposed to be happening.
+     */
+    virtual bool isPlaying() const = 0;
+
+    /**
+     * Return the frame number that is currently expected to be coming
+     * out of the speakers.  (i.e. compensating for playback latency.)
+     */
+    virtual size_t getCurrentPlayingFrame() = 0;
+
+    /**
+     * Return the current (or thereabouts) output levels in the range
+     * 0.0 -> 1.0, for metering purposes.
+     */
+    virtual bool getOutputLevels(float &left, float &right) = 0;
+};
+
+#endif