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Change Delayline to use power-of-two size and bitmasking

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This commit is contained in:
Robin Gareus 2017-11-04 16:39:08 +01:00
parent 06abdee652
commit 8366fbaa62
2 changed files with 21 additions and 15 deletions
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1
libs/ardour/ardour/delayline.h
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@ -63,6 +63,7 @@ private:
friend class IO;
samplecnt_t _bsiz;
samplecnt_t _bsiz_mask;
samplecnt_t _delay, _pending_delay;
sampleoffset_t _roff, _woff;
bool _pending_flush;

35
libs/ardour/delayline.cc
View File

@ -93,7 +93,7 @@ DelayLine::run (BufferSet& bufs, samplepos_t /* start_sample */, samplepos_t /*
Sample* rb = (*bi).get ();
write_to_rb (rb, i->data (), add);
}
_woff = (_woff + add) % _bsiz;
_woff = (_woff + add) & _bsiz_mask;
delay_diff += add;
}
} else {
@ -104,18 +104,18 @@ DelayLine::run (BufferSet& bufs, samplepos_t /* start_sample */, samplepos_t /*
for (AudioDlyBuf::iterator i = _buf.begin(); i != _buf.end (); ++i) {
Sample* rb = (*i).get ();
for (uint32_t s = 0; s < fade_out_len; ++s) {
sampleoffset_t off = (_woff + _bsiz - s) % _bsiz;
sampleoffset_t off = (_woff + _bsiz - s) & _bsiz_mask;
rb[off] *= s / (float) fade_out_len;
}
/* clear data in rb */
// TODO optimize this using memset
for (uint32_t s = 0; s < -delay_diff; ++s) {
sampleoffset_t off = (_woff + _bsiz + s) % _bsiz;
sampleoffset_t off = (_woff + _bsiz + s) & _bsiz_mask;
rb[off] = 0.f;
}
}
_woff = (_woff - delay_diff) % _bsiz;
_woff = (_woff - delay_diff) & _bsiz_mask;
/* fade-in, directly apply to input buffer */
for (BufferSet::audio_iterator i = bufs.audio_begin (); i != bufs.audio_end (); ++i) {
@ -138,7 +138,7 @@ DelayLine::run (BufferSet& bufs, samplepos_t /* start_sample */, samplepos_t /*
// TODO consider handling fade_out & fade_in separately
// if fade_out_len < fade_in_len.
for (uint32_t s = 0; s < xfade_len; ++s) {
sampleoffset_t off = (_roff + s) % _bsiz;
sampleoffset_t off = (_roff + s) & _bsiz_mask;
const gain_t g = s / (float) xfade_len;
src[s] *= g;
src[s] += (1.f - g) * rb[off];
@ -146,9 +146,9 @@ DelayLine::run (BufferSet& bufs, samplepos_t /* start_sample */, samplepos_t /*
}
#ifndef NDEBUG
sampleoffset_t check = (_roff + delay_diff) % _bsiz;
sampleoffset_t check = (_roff + delay_diff) & _bsiz_mask;
#endif
_roff = (_woff + _bsiz - pending_delay) % _bsiz;
_roff = (_woff + _bsiz - pending_delay) & _bsiz_mask;
#ifndef NDEBUG
assert (_roff == check);
#endif
@ -165,20 +165,20 @@ DelayLine::run (BufferSet& bufs, samplepos_t /* start_sample */, samplepos_t /*
Sample* rb = (*i).get ();
uint32_t s = 0;
for (; s < fade_out_len; ++s) {
sampleoffset_t off = (_roff + s) % _bsiz;
sampleoffset_t off = (_roff + s) & _bsiz_mask;
rb[off] *= 1. - (s / (float) fade_out_len);
}
for (; s < _delay; ++s) {
sampleoffset_t off = (_roff + s) % _bsiz;
sampleoffset_t off = (_roff + s) & _bsiz_mask;
rb[off] = 0;
}
assert (_woff == ((_roff + s) % _bsiz));
assert (_woff == ((_roff + s) & _bsiz_mask));
}
// TODO consider adding a fade-in to bufs
}
/* delay audio buffers */
assert (_delay == ((_woff - _roff + _bsiz) % _bsiz));
assert (_delay == ((_woff - _roff + _bsiz) & _bsiz_mask));
AudioDlyBuf::iterator bi = _buf.begin ();
if (_delay == 0) {
/* do nothing */
@ -189,8 +189,8 @@ DelayLine::run (BufferSet& bufs, samplepos_t /* start_sample */, samplepos_t /*
write_to_rb (rb, i->data (), n_samples);
read_from_rb (rb, i->data (), n_samples);
}
_roff = (_roff + n_samples) % _bsiz;
_woff = (_woff + n_samples) % _bsiz;
_roff = (_roff + n_samples) & _bsiz_mask;
_woff = (_woff + n_samples) & _bsiz_mask;
} else {
/* only write _delay samples to ringbuffer, memmove buffer */
samplecnt_t tail = n_samples - _delay;
@ -201,8 +201,8 @@ DelayLine::run (BufferSet& bufs, samplepos_t /* start_sample */, samplepos_t /*
memmove (&src[_delay], src, tail * sizeof(Sample));
read_from_rb (rb, src, _delay);
}
_roff = (_roff + _delay) % _bsiz;
_woff = (_woff + _delay) % _bsiz;
_roff = (_roff + _delay) & _bsiz_mask;
_woff = (_woff + _delay) & _bsiz_mask;
}
} else {
/* set new delay for MIDI only */
@ -319,6 +319,10 @@ DelayLine::allocate_pending_buffers (samplecnt_t signal_delay, ChanCount const&
samplecnt_t rbs = signal_delay + 8192 + 1;
rbs = std::max (_bsiz, rbs);
uint64_t power_of_two;
for (power_of_two = 1; 1 << power_of_two < rbs; ++power_of_two) {}
rbs = 1 << power_of_two;
if (cc.n_audio () == _buf.size () && _bsiz == rbs) {
return;
}
@ -356,6 +360,7 @@ DelayLine::allocate_pending_buffers (samplecnt_t signal_delay, ChanCount const&
}
}
_bsiz = rbs;
_bsiz_mask = _bsiz - 1;
_buf.swap (pending_buf);
}