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* Consume output when running stretcher in RT mode from Vamp plugin;

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start some documentation
This commit is contained in:
Chris Cannam
2007-11-23 22:22:31 +00:00
parent a0c7b04c3d
commit 89ce4223ee
2 changed files with 151 additions and 2 deletions
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129
rubberband/RubberBandStretcher.h
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@@ -26,6 +26,125 @@ class RubberBandStretcher : public TimeStretcher
{
public:
/**
* Processing options for the timestretcher. The preferred
* options should normally be set in the constructor, as a bitwise
* OR of the option flags. The default value (DefaultOptions) is
* intended to give good results in most situations.
*
* 1. Flags prefixed OptionProcess determine how the timestretcher
* will be invoked. These options may not be changed after
* construction.
*
* OptionProcessOffline - Run the stretcher in offline mode. In
* this mode the input data needs to be provided twice, once to
* study(), which calculates a stretch profile for the audio,
* and once to process(), which stretches it.
*
* OptionProcessRealTime - Run the stretcher in real-time mode.
* In this mode only process() should be called, and the
* stretcher adjusts dynamically in response to the input audio.
*
* The Process setting is likely to depend on your architecture:
* non-real-time operation on seekable files: Offline; real-time
* or streaming operation: RealTime.
*
* 2. Flags prefixed OptionStretch control the profile used for
* variable timestretching. Rubber Band always adjusts the
* stretch profile to minimise stretching of busy broadband
* transient sounds, but the degree to which it does so is
* adjustable. These options may not be changed after
* construction.
*
* OptionStretchElastic - Only meaningful in offline mode, and
* the default in that mode. The audio will be stretched at a
* variable rate, aimed at preserving the quality of transient
* sounds as much as possible. The timings of low activity
* regions between transients may be less exact than when the
* precise flag is set.
*
* OptionStretchPrecise - Although still using a variable
* stretch rate, the audio will be stretched so as to maintain
* as close as possible to a linear stretch ratio throughout.
* Timing may be better than when using OptionStretchElastic, at
* slight cost to the sound quality of transients. This setting
* is always used when running in real-time mode.
*
* 3. Flags prefixed OptionTransients control the component
* frequency phase-reset mechanism that may be used at transient
* points to provide clarity and realism to percussion and other
* significant transient sounds. These options may be changed
* after construction when running in real-time mode, but not when
* running in offline mode.
*
* OptionTransientsCrisp - Reset component phases at the peak of
* each transient (the start of a significant note or percussive
* event). This, the default setting, usually results in a
* clear-sounding output; but it is not always consistent, and
* may cause interruptions in stable sounds present at the same
* time as transient events.
*
* OptionTransientsMixed - Reset component phases at the peak of
* each transient, outside a frequency range typical of musical
* fundamental frequencies. The results may be more regular for
* mixed stable and percussive notes than OptionTransientsCrisp,
* but with a "phasier" sound. The balance may sound very good
* for certain types of music and fairly bad for others.
*
* OptionTransientsSmooth - Do not reset component phases at any
* point. The results will be smoother and more regular but may
* be less clear than with either of the other transients flags.
*
* 4. Flags prefixed OptionPhase control the adjustment of
* component frequency phases from one analysis window to the next
* during non-transient segments. These options may be changed at
* any time.
*
* OptionPhaseAdaptive - Lock the adjustments of phase for
* frequencies close to peak frequencies to those of the peak,
* but reduce the degree of locking as the stretch ratio gets
* longer. This, the default setting, should give a good
* balance between clarity and smoothness in most situations.
*
* OptionPhasePeakLocked - Lock the adjustments of phase for
* frequencies close to peak frequencies to those of the peak.
* This should give a clear result in situations with relatively
* low stretch ratios, but a relatively metallic sound at longer
* stretches.
*
* OptionPhaseIndependent - Do not lock phase adjustments to
* peak frequencies. This usually results in a softer, phasier
* sound.
*
* 5. Options prefixed OptionThreading control the threading model
* of the stretcher. These options may not be changed after
* construction.
*
* OptionThreadingAuto - Permit the stretcher to determine its
* own threading model. Usually this means using one processing
* thread per audio channel in offline mode, and one thread only
* in realtime mode.
*
* OptionThreadingNone - Never use more than one thread.
*
* 6. Options prefixed OptionWindow control the window size for
* FFT processing. The window size actually used will depend on
* many factors, but it can be influenced. These options may not
* be changed after construction.
*
* OptionWindowStandard - Use the default window size. The
* actual size will vary depending on other parameters. This
* option is expected to produce better results than the other
* window options in most situations.
*
* OptionWindowShort - Use a shorter window. This may result in
* crisper sound for audio that depends strongly on its timing
* qualities.
*
* OptionWindowLong - Use a longer window. This is likely to
* result in a smoother sound at the expense of clarity and
* timing.
*/
typedef int Options;
static const int OptionProcessOffline = 0x00000000;
@@ -53,6 +172,14 @@ public:
static const int PercussiveOptions = OptionWindowShort | \
OptionPhaseIndependent;
/**
* Construct a time-and-pitch-scaling object to run at the given
* sample rate, with the given number of channels. Processing
* options and the time and pitch scaling ratios may be provided.
* The time and pitch ratios may be changed after construction,
* but most of the options may not. See the option documentation
* above for more details.
*/
RubberBandStretcher(size_t sampleRate,
size_t channels,
Options options = DefaultOptions,
@@ -62,7 +189,7 @@ public:
virtual void reset();
virtual void setTimeRatio(double ratio);
virtual void setPitchScale(double scale); //!!!??? pitch ratio?
virtual void setPitchScale(double scale);
virtual double getTimeRatio() const;
virtual double getPitchScale() const;