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authorChris Robinson <[email protected]>2019-07-28 18:56:04 -0700
committerChris Robinson <[email protected]>2019-07-28 18:56:04 -0700
commitcb3e96e75640730b9391f0d2d922eecd9ee2ce79 (patch)
tree23520551bddb2a80354e44da47f54201fdc084f0 /Alc/uhjfilter.h
parent93e60919c8f387c36c267ca9faa1ac653254aea6 (diff)
Rename Alc to alc
Diffstat (limited to 'Alc/uhjfilter.h')
-rw-r--r--Alc/uhjfilter.h54
1 files changed, 0 insertions, 54 deletions
diff --git a/Alc/uhjfilter.h b/Alc/uhjfilter.h
deleted file mode 100644
index 53e4f89e..00000000
--- a/Alc/uhjfilter.h
+++ /dev/null
@@ -1,54 +0,0 @@
-#ifndef UHJFILTER_H
-#define UHJFILTER_H
-
-#include "AL/al.h"
-
-#include "alcmain.h"
-#include "almalloc.h"
-
-
-struct AllPassState {
- ALfloat z[2]{0.0f, 0.0f};
-};
-
-/* Encoding 2-channel UHJ from B-Format is done as:
- *
- * S = 0.9396926*W + 0.1855740*X
- * D = j(-0.3420201*W + 0.5098604*X) + 0.6554516*Y
- *
- * Left = (S + D)/2.0
- * Right = (S - D)/2.0
- *
- * where j is a wide-band +90 degree phase shift.
- *
- * The phase shift is done using a Hilbert transform, described here:
- * https://web.archive.org/web/20060708031958/http://www.biochem.oulu.fi/~oniemita/dsp/hilbert/
- * It works using 2 sets of 4 chained filters. The first filter chain produces
- * a phase shift of varying magnitude over a wide range of frequencies, while
- * the second filter chain produces a phase shift 90 degrees ahead of the
- * first over the same range.
- *
- * Combining these two stages requires the use of three filter chains. S-
- * channel output uses a Filter1 chain on the W and X channel mix, while the D-
- * channel output uses a Filter1 chain on the Y channel plus a Filter2 chain on
- * the W and X channel mix. This results in the W and X input mix on the D-
- * channel output having the required +90 degree phase shift relative to the
- * other inputs.
- */
-
-struct Uhj2Encoder {
- AllPassState mFilter1_Y[4];
- AllPassState mFilter2_WX[4];
- AllPassState mFilter1_WX[4];
- ALfloat mLastY{0.0f}, mLastWX{0.0f};
-
- /* Encodes a 2-channel UHJ (stereo-compatible) signal from a B-Format input
- * signal. The input must use FuMa channel ordering and scaling.
- */
- void encode(FloatBufferLine &LeftOut, FloatBufferLine &RightOut, FloatBufferLine *InSamples,
- const ALsizei SamplesToDo);
-
- DEF_NEWDEL(Uhj2Encoder)
-};
-
-#endif /* UHJFILTER_H */