WaveClipUtilities Namespace Reference

Functions
WAVE_TRACK_API bool	GetFloatAtTime (const WaveClip &clip, double t, size_t iChannel, float &value, bool mayThrow)
WAVE_TRACK_API void	SetFloatsFromTime (WaveClip &clip, double t, size_t iChannel, const float *buffer, size_t numSamples, sampleFormat effectiveFormat)
	Considers buffer as audio starting at TimeToSamples(t) (relative to clip play start time) and with equal stretch ratio. Samples at intersecting indices are then copied, leaving non-intersecting clip samples untouched. E.g., buffer: [a b c d e] clip : [x y z] result: [d e z]. More...
WAVE_TRACK_API bool	SharesBoundaryWithNextClip (const WaveTrack::Interval &prev, const WaveTrack::Interval &next)
	used by commands which interact with clips using the keyboard More...

Function Documentation

GetFloatAtTime()

bool WaveClipUtilities::GetFloatAtTime	(	const WaveClip &	clip,
		double	t,
		size_t	iChannel,
		float &	value,
		bool	mayThrow
	)

Parameters

t	relative to clip start sample

---

Audacity: A Digital Audio Editor

WaveClipUtilities.cpp

Paul Licameli split from WaveClip.cpp

Definition at line 15 of file WaveClipUtilities.cpp.

{
   if (!clip.WithinPlayRegion(t))
      return false;
   const auto start = clip.TimeToSamples(t);
   return clip.GetSamples(
      iChannel, reinterpret_cast<samplePtr>(&value), floatSample, start, 1u,
      mayThrow);
}

References floatSample, WaveClip::GetSamples(), anonymous_namespace{StretchingSequenceIntegrationTest.cpp}::iChannel, WaveClip::TimeToSamples(), and WaveClip::WithinPlayRegion().

Referenced by WaveChannelUtilities::GetFloatAtTime().

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SetFloatsFromTime()

void WaveClipUtilities::SetFloatsFromTime	(	WaveClip &	clip,
		double	t,
		size_t	iChannel,
		const float *	buffer,
		size_t	numSamples,
		sampleFormat	effectiveFormat
	)

Considers buffer as audio starting at TimeToSamples(t) (relative to clip play start time) and with equal stretch ratio. Samples at intersecting indices are then copied, leaving non-intersecting clip samples untouched. E.g., buffer: [a b c d e] clip : [x y z] result: [d e z].

Succeed with out-of-bounds requests, only changing what is in bounds.

Definition at line 26 of file WaveClipUtilities.cpp.

{
   const auto maybeNegativeStart = clip.TimeToSamples(t);
   const auto maybeOutOfBoundEnd = maybeNegativeStart + numFloats;
   const auto effectiveStart = std::max(sampleCount { 0 }, maybeNegativeStart);
   const auto effectiveEnd =
      std::min(clip.GetVisibleSampleCount(), maybeOutOfBoundEnd);
   if (effectiveStart >= effectiveEnd)
      return;
   // Cannot be greater than `numFloats` -> safe cast
   const auto effectiveLen = (effectiveEnd - effectiveStart).as_size_t();
   // Cannot be greater than `numFloats` -> safe cast
   const auto numLeadingZeros =
      (effectiveStart - maybeNegativeStart).as_size_t();
   const auto offsetBuffer =
      reinterpret_cast<const char*>(buffer + numLeadingZeros);
   clip.SetSamples(
      iChannel, offsetBuffer, floatSample, effectiveStart, effectiveLen,
      effectiveFormat);
}

References floatSample, WaveClip::GetVisibleSampleCount(), anonymous_namespace{StretchingSequenceIntegrationTest.cpp}::iChannel, min(), WaveClip::SetSamples(), and WaveClip::TimeToSamples().

Referenced by WaveChannelUtilities::SetFloatsWithinTimeRange().

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SharesBoundaryWithNextClip()

bool WaveClipUtilities::SharesBoundaryWithNextClip	(	const WaveTrack::Interval &	prev,
		const WaveTrack::Interval &	next
	)

used by commands which interact with clips using the keyboard

When two clips are immediately next to each other, the GetPlayEndTime() of the first clip and the GetPlayStartTime() of the second clip may not be exactly equal due to rounding errors.

Definition at line 49 of file WaveClipUtilities.cpp.

{
   double endThis = prev.GetRate() * prev.GetPlayStartTime() +
      prev.GetVisibleSampleCount().as_double() * prev.GetStretchRatio();
   double startNext = next.GetRate() * next.GetPlayStartTime();
 
   // given that a double has about 15 significant digits, using a criterion
   // of half a sample should be safe in all normal usage.
   return fabs(startNext - endThis) < 0.5;
}

References sampleCount::as_double(), WaveClip::GetPlayStartTime(), WaveClip::GetRate(), WaveClip::GetStretchRatio(), and WaveClip::GetVisibleSampleCount().

Referenced by anonymous_namespace{ClipMenus.cpp}::AdjustForFindingEndTimes(), anonymous_namespace{ClipMenus.cpp}::AdjustForFindingStartTimes(), anonymous_namespace{ClipMenus.cpp}::FindNextClipBoundary(), and anonymous_namespace{ClipMenus.cpp}::FindPrevClipBoundary().

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