1 files changed, 0 insertions, 218 deletions
diff --git a/portaudio/src/common/pa_dither.c b/portaudio/src/common/pa_dither.c
deleted file mode 100644
index 0d1666a..0000000
--- a/portaudio/src/common/pa_dither.c
+++ /dev/null
@@ -1,218 +0,0 @@
-/*
- * $Id$
- * Portable Audio I/O Library triangular dither generator
- *
- * Based on the Open Source API proposed by Ross Bencina
- * Copyright (c) 1999-2002 Phil Burk, Ross Bencina
- *
- * Permission is hereby granted, free of charge, to any person obtaining
- * a copy of this software and associated documentation files
- * (the "Software"), to deal in the Software without restriction,
- * including without limitation the rights to use, copy, modify, merge,
- * publish, distribute, sublicense, and/or sell copies of the Software,
- * and to permit persons to whom the Software is furnished to do so,
- * subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be
- * included in all copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
- * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
- * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
- * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
- * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
- */
-
-/*
- * The text above constitutes the entire PortAudio license; however,
- * the PortAudio community also makes the following non-binding requests:
- *
- * Any person wishing to distribute modifications to the Software is
- * requested to send the modifications to the original developer so that
- * they can be incorporated into the canonical version. It is also
- * requested that these non-binding requests be included along with the
- * license above.
- */
-
-/** @file
- @ingroup common_src
-
- @brief Functions for generating dither noise
-*/
-
-#include "pa_types.h"
-#include "pa_dither.h"
-
-
-/* Note that the linear congruential algorithm requires 32 bit integers
- * because it uses arithmetic overflow. So use PaUint32 instead of
- * unsigned long so it will work on 64 bit systems.
- */
-
-#define PA_DITHER_BITS_   (15)
-
-
-void PaUtil_InitializeTriangularDitherState( PaUtilTriangularDitherGenerator *state )
-{
-    state->previous = 0;
-    state->randSeed1 = 22222;
-    state->randSeed2 = 5555555;
-}
-
-
-PaInt32 PaUtil_Generate16BitTriangularDither( PaUtilTriangularDitherGenerator *state )
-{
-    PaInt32 current, highPass;
-
-    /* Generate two random numbers. */
-    state->randSeed1 = (state->randSeed1 * 196314165) + 907633515;
-    state->randSeed2 = (state->randSeed2 * 196314165) + 907633515;
-
-    /* Generate triangular distribution about 0.
-     * Shift before adding to prevent overflow which would skew the distribution.
-     * Also shift an extra bit for the high pass filter.
-     */
-#define DITHER_SHIFT_  ((sizeof(PaInt32)*8 - PA_DITHER_BITS_) + 1)
-
-    current = (((PaInt32)state->randSeed1)>>DITHER_SHIFT_) +
-              (((PaInt32)state->randSeed2)>>DITHER_SHIFT_);
-
-    /* High pass filter to reduce audibility. */
-    highPass = current - state->previous;
-    state->previous = current;
-    return highPass;
-}
-
-
-/* Multiply by PA_FLOAT_DITHER_SCALE_ to get a float between -2.0 and +1.99999 */
-#define PA_FLOAT_DITHER_SCALE_  (1.0f / ((1<<PA_DITHER_BITS_)-1))
-static const float const_float_dither_scale_ = PA_FLOAT_DITHER_SCALE_;
-
-float PaUtil_GenerateFloatTriangularDither( PaUtilTriangularDitherGenerator *state )
-{
-    PaInt32 current, highPass;
-
-    /* Generate two random numbers. */
-    state->randSeed1 = (state->randSeed1 * 196314165) + 907633515;
-    state->randSeed2 = (state->randSeed2 * 196314165) + 907633515;
-
-    /* Generate triangular distribution about 0.
-     * Shift before adding to prevent overflow which would skew the distribution.
-     * Also shift an extra bit for the high pass filter.
-     */
-    current = (((PaInt32)state->randSeed1)>>DITHER_SHIFT_) +
-              (((PaInt32)state->randSeed2)>>DITHER_SHIFT_);
-
-    /* High pass filter to reduce audibility. */
-    highPass = current - state->previous;
-    state->previous = current;
-    return ((float)highPass) * const_float_dither_scale_;
-}
-
-
-/*
-The following alternate dither algorithms (from musicdsp.org) could be
-considered
-*/
-
-/*Noise shaped dither  (March 2000)
--------------------
-
-This is a simple implementation of highpass triangular-PDF dither with
-2nd-order noise shaping, for use when truncating floating point audio
-data to fixed point.
-
-The noise shaping lowers the noise floor by 11dB below 5kHz (@ 44100Hz
-sample rate) compared to triangular-PDF dither. The code below assumes
-input data is in the range +1 to -1 and doesn't check for overloads!
-
-To save time when generating dither for multiple channels you can do
-things like this:  r3=(r1 & 0x7F)<<8; instead of calling rand() again.
-
-
-
-  int   r1, r2;                //rectangular-PDF random numbers
-  float s1, s2;                //error feedback buffers
-  float s = 0.5f;              //set to 0.0f for no noise shaping
-  float w = pow(2.0,bits-1);   //word length (usually bits=16)
-  float wi= 1.0f/w;
-  float d = wi / RAND_MAX;     //dither amplitude (2 lsb)
-  float o = wi * 0.5f;         //remove dc offset
-  float in, tmp;
-  int   out;
-
-
-//for each sample...
-
-  r2=r1;                               //can make HP-TRI dither by
-  r1=rand();                           //subtracting previous rand()
-
-  in += s * (s1 + s1 - s2);            //error feedback
-  tmp = in + o + d * (float)(r1 - r2); //dc offset and dither
-
-  out = (int)(w * tmp);                //truncate downwards
-  if(tmp<0.0f) out--;                  //this is faster than floor()
-
-  s2 = s1;
-  s1 = in - wi * (float)out;           //error
-
-
-
---
-paul.kellett@maxim.abel.co.uk
-http://www.maxim.abel.co.uk
-*/
-
-
-/*
-16-to-8-bit first-order dither
-
-Type : First order error feedforward dithering code
-References : Posted by Jon Watte
-
-Notes :
-This is about as simple a dithering algorithm as you can implement, but it's
-likely to sound better than just truncating to N bits.
-
-Note that you might not want to carry forward the full difference for infinity.
-It's probably likely that the worst performance hit comes from the saturation
-conditionals, which can be avoided with appropriate instructions on many DSPs
-and integer SIMD type instructions, or CMOV.
-
-Last, if sound quality is paramount (such as when going from > 16 bits to 16
-bits) you probably want to use a higher-order dither function found elsewhere
-on this site.
-
-
-Code :
-// This code will down-convert and dither a 16-bit signed short
-// mono signal into an 8-bit unsigned char signal, using a first
-// order forward-feeding error term dither.
-
-#define uchar unsigned char
-
-void dither_one_channel_16_to_8( short * input, uchar * output, int count, int * memory )
-{
-  int m = *memory;
-  while( count-- > 0 ) {
-    int i = *input++;
-    i += m;
-    int j = i + 32768 - 128;
-    uchar o;
-    if( j < 0 ) {
-      o = 0;
-    }
-    else if( j > 65535 ) {
-      o = 255;
-    }
-    else {
-      o = (uchar)((j>>8)&0xff);
-    }
-    m = ((j-32768+128)-i);
-    *output++ = o;
-  }
-  *memory = m;
-}
-*/