diff options
Diffstat (limited to 'libs/ardour/meter.cc')
-rw-r--r-- | libs/ardour/meter.cc | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/libs/ardour/meter.cc b/libs/ardour/meter.cc new file mode 100644 index 0000000000..c574ff0bdb --- /dev/null +++ b/libs/ardour/meter.cc @@ -0,0 +1,110 @@ +/* + Copyright (C) 2006 Paul Davis + + This program is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by the Free + Software Foundation; either version 2 of the License, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, but WITHOUT + ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + for more details. + + You should have received a copy of the GNU General Public License along + with this program; if not, write to the Free Software Foundation, Inc., + 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#include <ardour/meter.h> +#include <algorithm> +#include <cmath> +#include <ardour/buffer_set.h> +#include <ardour/peak.h> +#include <ardour/dB.h> +#include <ardour/session.h> + +namespace ARDOUR { + + +/** Get peaks from @a bufs + * Input acceptance is lenient - the first n audio buffers from @a bufs will + * be metered, where n was set by the last call to setup(), excess meters will + * be set to 0. + */ +void +PeakMeter::run (BufferSet& bufs, jack_nframes_t nframes, jack_nframes_t offset) +{ + size_t meterable = std::min(bufs.count().get(DataType::AUDIO), _peak_power.size()); + + // Meter what we have + for (size_t n = 0; n < meterable; ++n) { + _peak_power[n] = compute_peak (bufs.get_audio(n).data(nframes, offset), nframes, _peak_power[n]); + } + + // Zero any excess peaks + for (size_t n = meterable; n < _peak_power.size(); ++n) { + _peak_power[n] = 0; + } +} + +void +PeakMeter::reset () +{ + for (size_t i = 0; i < _peak_power.size(); ++i) { + _peak_power[i] = 0; + } +} + +void +PeakMeter::setup (const ChanCount& in) +{ + uint32_t limit = in.get(DataType::AUDIO); + + while (_peak_power.size() < limit) { + _peak_power.push_back (0); + _visible_peak_power.push_back (0); + } + + assert(_peak_power.size() == limit); + assert(_visible_peak_power.size() == limit); +} + +/** To be driven by the Meter signal from IO. + * Caller MUST hold io_lock! + */ +void +PeakMeter::meter () +{ + assert(_visible_peak_power.size() == _peak_power.size()); + + const size_t limit = _peak_power.size(); + + for (size_t n = 0; n < limit; ++n) { + + /* XXX we should use atomic exchange here */ + + /* grab peak since last read */ + + float new_peak = _peak_power[n]; + _peak_power[n] = 0; + + /* compute new visible value using falloff */ + + if (new_peak > 0.0) { + new_peak = coefficient_to_dB (new_peak); + } else { + new_peak = minus_infinity(); + } + + if (_session.meter_falloff() == 0.0f || new_peak > _visible_peak_power[n]) { + _visible_peak_power[n] = new_peak; + } else { + // do falloff + new_peak = _visible_peak_power[n] - _session.meter_falloff(); + _visible_peak_power[n] = std::max (new_peak, -INFINITY); + } + } +} + +} // namespace ARDOUR |