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Add AudioSynthWaveformDc

dds
PaulStoffregen 10 years ago
parent
a9a23d58a4
commit
6b6218bb90
6 changed files with 315 additions and 0 deletions
Split View Show Diff Stats
  1. +1
    -0
      Audio.h
  2. +44
    -0
      gui/list.html
  3. +1
    -0
      keywords.txt
  4. +108
    -0
      synth_dc.cpp
  5. +151
    -0
      synth_dc.h
  6. +10
    -0
      utility/dspinst.h

+ 1
- 0
Audio.h View File

@@ -72,6 +72,7 @@
#include "synth_tonesweep.h"
#include "synth_sine.h"
#include "synth_waveform.h"
#include "synth_dc.h"
#include "multiplier.h"

// TODO: more audio processing objects....

+ 44
- 0
gui/list.html View File

@@ -815,6 +815,50 @@
</script>


<script type="text/javascript">
RED.nodes.registerType('AudioSynthWaveformDc',{
shortName: "dc",
inputs:0,
outputs:1,
category: 'synth-function',
color:"#E6E0F8",
icon: "arrow-in.png"
});
</script>
<script type="text/x-red" data-help-name="AudioSynthWaveformDc">
<h3>Summary</h3>
<p>Create constant (DC) signal, useful for control of objects that take
a modulation or control input signal. This constant level can be
used to modify other waveforms using mixer or multiplier objects</p>
<h3>Audio Connections</h3>
<table class=doc align=center cellpadding=3>
<tr class=top><th>Port</th><th>Purpose</th></tr>
<tr class=odd><td align=center>Out 0</td><td>Output constant DC level</td></tr>
</table>
<h3>Functions</h3>
<p class=func><span class=keyword>amplitude</span>(level);</p>
<p class=desc>Set the output. Level is -1.0 to 1.0. The output is
changed immediately.
</p>
<p class=func><span class=keyword>amplitude</span>(level, milliseconds);</p>
<p class=desc>Set the output. Level is -1.0 to 1.0. The output is
gradually changed over a "milliseconds" time period. Any time may
be specified, but periods longer than 1 second may be automatically
shortened for small level changes, due to numerical precision limits.
</p>
<h3>Notes</h3>
<p>Of course, the term "DC", for Direct Current, doesn't properly apply
to a pure digital stream of numerical values. But the term is widely
understood in audio applications, so hopefully it's not too confusing?</p>
</script>
<script type="text/x-red" data-template-name="AudioSynthWaveformDc">
<div class="form-row">
<label for="node-input-name"><i class="fa fa-tag"></i> Name</label>
<input type="text" id="node-input-name" placeholder="Name">
</div>
</script>



<script type="text/javascript">
RED.nodes.registerType('AudioEffectFade',{

+ 1
- 0
keywords.txt View File

@@ -28,6 +28,7 @@ AudioSynthToneSweep KEYWORD2
AudioSynthWaveform KEYWORD2
AudioSynthWaveformSine KEYWORD2
AudioSynthWaveformSineModulated KEYWORD2
AudioSynthWaveformDc KEYWORD2
isPlaying KEYWORD2
positionMillis KEYWORD2
lengthMillis KEYWORD2

+ 108
- 0
synth_dc.cpp View File

@@ -0,0 +1,108 @@
/* Audio Library for Teensy 3.X
* Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
*
* Development of this audio library was funded by PJRC.COM, LLC by sales of
* Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop
* open source software by purchasing Teensy or other PJRC products.
*
* 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, development funding 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.
*/

#include "synth_dc.h"

void AudioSynthWaveformDc::update(void)
{
audio_block_t *block;
uint32_t *p, *end, val;
int32_t count, t1, t2, t3, t4;

block = allocate();
if (!block) return;
p = (uint32_t *)(block->data);
end = p + AUDIO_BLOCK_SAMPLES/2;

if (state == 0) {
// steady DC output, simply fill the buffer with fixed value
val = pack_16t_16t(magnitude, magnitude);
do {
*p++ = val;
*p++ = val;
*p++ = val;
*p++ = val;
*p++ = val;
*p++ = val;
*p++ = val;
*p++ = val;
} while (p < end);
} else {
// transitioning to a new DC level
//count = (target - magnitude) / increment;
count = substract_int32_then_divide_int32(target, magnitude, increment);
if (count >= 128) {
// this update will not reach the target
do {
magnitude += increment;
t1 = magnitude;
magnitude += increment;
t1 = pack_16t_16t(magnitude, t1);
magnitude += increment;
t2 = magnitude;
magnitude += increment;
t2 = pack_16t_16t(magnitude, t2);
magnitude += increment;
t3 = magnitude;
magnitude += increment;
t3 = pack_16t_16t(magnitude, t3);
magnitude += increment;
t4 = magnitude;
magnitude += increment;
t4 = pack_16t_16t(magnitude, t4);
*p++ = t1;
*p++ = t2;
*p++ = t3;
*p++ = t4;
} while (p < end);
} else {
// this update reaches the target
while (count >= 2) {
count -= 2;
magnitude += increment;
t1 = magnitude;
magnitude += increment;
t1 = pack_16t_16t(magnitude, t1);
*p++ = t1;
}
if (count) {
t1 = pack_16t_16t(target, magnitude + increment);
*p++ = t1;
}
magnitude = target;
state = 0;
val = pack_16t_16t(magnitude, magnitude);
while (p < end) {
*p++ = val;
}
}
}
transmit(block);
release(block);
}




+ 151
- 0
synth_dc.h View File

@@ -0,0 +1,151 @@
/* Audio Library for Teensy 3.X
* Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
*
* Development of this audio library was funded by PJRC.COM, LLC by sales of
* Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop
* open source software by purchasing Teensy or other PJRC products.
*
* 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, development funding 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.
*/

#ifndef synth_dc_h_
#define synth_dc_h_
#include "AudioStream.h"
#include "utility/dspinst.h"

// compute (a - b) / c
// handling 32 bit interger overflow at every step
// without resorting to slow 64 bit math
#if 0
// TODO: write this in assembly....
static inline int32_t substract_32_then_divide(int32_t a, int32_t b, int32_t c) __attribute__((always_inline, unused));
static inline int32_t substract_32_then_divide(int32_t a, int32_t b, int32_t c)
{
int32_t diff = substract_32_saturate(a, b);
// if only C language provided a way to test Q status bit....
if (diff != 0x7FFFFFFF && diff != 0x80000000) {
return diff / c;
} else {
diff = substract_32_saturate(a/2, b/2);
if (c == 1 || c == -1) c *= 2; // <-- horrible, incorrect hack
return (diff / c) * 2;
}
}
#else
static inline int32_t substract_int32_then_divide_int32(int32_t a, int32_t b, int32_t c) __attribute__((always_inline, unused));
static inline int32_t substract_int32_then_divide_int32(int32_t a, int32_t b, int32_t c)
{
uint32_t diff;
uint8_t negative;

if (a >= 0) {
if (b >= 0) {
if (a >= b) {
diff = a - b;
negative = 0;
} else {
diff = b - a;
negative = 1;
}
} else {
diff = a + (b * -1); // assumes 0x80000000 * -1 == 0x80000000
negative = 0;
}
} else {
if (b >= 0) {
diff = (a * -1) + b; // assumes 0x80000000 * -1 == 0x80000000
negative = 1;
} else {
if (a >= b) {
diff = a - b;
negative = 0;
} else {
diff = b - a;
negative = 1;
}
}
}
if (c >= 0) {
diff = diff / (uint32_t)c;
} else {
diff = diff / (uint32_t)(c * -1);
negative ^= 1;
}
if (negative) {
if (diff > 0x7FFFFFFF) return 0x80000000;
return (int32_t)diff * -1;
} else {
if (diff > 0x7FFFFFFF) return 0x7FFFFFFF;
return (int32_t)diff;
}
}

#endif

class AudioSynthWaveformDc : public AudioStream
{
public:
AudioSynthWaveformDc() : AudioStream(0, NULL), state(0), magnitude(0) {}
// immediately jump to the new DC level
void amplitude(float n) {
if (n > 1.0) n = 1.0;
else if (n < -1.0) n = -1.0;
int32_t m = (int32_t)(n * 2147418112.0);
__disable_irq();
magnitude = m;
state = 0;
__enable_irq();
}
// slowly transition to the new DC level
void amplitude(float n, float milliseconds) {
if (milliseconds <= 0.0) {
amplitude(n);
return;
}
if (n > 1.0) n = 1.0;
else if (n < -1.0) n = -1.0;
int32_t c = (int32_t)(milliseconds*(AUDIO_SAMPLE_RATE_EXACT/1000.0));
if (c == 0) {
amplitude(n);
return;
}
int32_t t = (int32_t)(n * 2147418112.0);
__disable_irq();
target = t;
if (target == magnitude) {
state = 0;
__enable_irq();
return;
}
increment = substract_int32_then_divide_int32(target, magnitude, c);
if (increment == 0) {
increment = (target > magnitude) ? 1 : -1;
}
state = 1;
__enable_irq();
}
virtual void update(void);
private:
uint8_t state; // 0=steady output, 1=transitioning
int32_t magnitude; // current output
int32_t target; // designed output (while transitiong)
int32_t increment; // adjustment per sample (while transitiong)
};

#endif

+ 10
- 0
utility/dspinst.h View File

@@ -218,5 +218,15 @@ static inline int32_t multiply_16tx16t(uint32_t a, uint32_t b)
return out;
}

// computes (a - b), result saturated to 32 bit integer range
static inline int32_t substract_32_saturate(uint32_t a, uint32_t b) __attribute__((always_inline, unused));
static inline int32_t substract_32_saturate(uint32_t a, uint32_t b)
{
int32_t out;
asm volatile("qsub %0, %1, %2" : "=r" (out) : "r" (a), "r" (b));
return out;
}



#endif

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