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Diffstat (limited to 'pica-client/capturegain.h')
| -rw-r--r-- | pica-client/capturegain.h | 81 |
1 files changed, 0 insertions, 81 deletions
diff --git a/pica-client/capturegain.h b/pica-client/capturegain.h deleted file mode 100644 index a0d3bdc..0000000 --- a/pica-client/capturegain.h +++ /dev/null @@ -1,81 +0,0 @@ -/* - (c) Copyright 2012 - 2026 Anton Sviridenko - https://picapica.im - - 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, version 3. - - 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, see <https://www.gnu.org/licenses/>. -*/ -#ifndef CAPTUREGAIN_H -#define CAPTUREGAIN_H - -#include <QString> -#include <QtGlobal> - -// The capture device's own gain control - the mixer slider, not a multiplier -// applied to samples we already have. -// -// The distinction is the entire point of this class. Clipping happens in the -// converter, before any buffer reaches us; by then the peaks are flat and the -// harmonics they generated are in the signal for good. Scaling that buffer -// down produces a quieter clipped buffer and nothing else - in particular it -// does not help the echo canceller, whose adaptive filter is linear and -// therefore scale invariant. What defeats the filter is the non-linearity, and -// the only place to prevent one is ahead of the ADC. That is this control. -// -// Gain is expressed as a 0.0 to 1.0 fraction of the control's travel, which is -// what WASAPI and CoreAudio use natively and what ALSA and PulseAudio's ranges -// map onto cleanly. The mapping from that fraction to decibels is the -// platform's business and is not the same on all of them, so callers should -// treat a step as "somewhat quieter" and close the loop by measuring again -// rather than doing arithmetic in dB. -// -// Not thread safe, and deliberately so: AudioVideoCallController owns one of -// these and touches it only from the GUI thread, driven by a queued signal -// from the capture thread. Some of the implementations below need a message -// loop or a COM apartment and have no business being called from an audio -// callback. -class CaptureGainControl -{ -public: - virtual ~CaptureGainControl(); - - // Current position of the control, 0.0 to 1.0. False if it could not be - // read, in which case *out is untouched. - virtual bool gain(double *out) = 0; - - // The same position in decibels, where the platform can say. This is what - // a caller should bound itself by: the fraction above is a position on a - // slider whose relationship to loudness differs per backend - linear in dB - // on an ALSA hardware control, roughly cubic on PulseAudio and WASAPI - so - // "5% of travel" is a mild cut on one and near silence on another. Decibels - // mean the same thing everywhere. - // - // False when the platform will not say, and then the caller has nothing to - // go on but a step count. - virtual bool gainDb(double *out) { Q_UNUSED(out) return false; } - - // Moves the control. Values outside 0.0 to 1.0 are clamped. - virtual bool setGain(double value) = 0; - - // What was actually found - the mixer element or endpoint name - for the - // log line that says the gain is being taken over. - virtual QString description() const = 0; - - // driver is a name from AudioDevice::PlatformDriverName(), device the - // capture device string that goes with it. Returns null when this build - // or this platform has no way to reach the control, which is not an - // error: the caller carries on without automatic gain and the clipping - // warning still gets shown. - static CaptureGainControl *create(const QString &driver, const QString &device); -}; - -#endif // CAPTUREGAIN_H |