mirror of https://code.videolan.org/videolan/vlc
93 lines
3.0 KiB
C
93 lines
3.0 KiB
C
/*****************************************************************************
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* volume.c : helper for software audio amplification
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*****************************************************************************
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* Copyright (C) 2012 Rémi Denis-Courmont
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
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*****************************************************************************/
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <stdio.h>
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#include <math.h>
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#include <vlc_common.h>
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#include <vlc_aout.h>
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#define add_sw_gain() \
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add_float(MODULE_STRING"-gain", 1., N_("Software gain"), \
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N_("This linear gain will be applied in software.")) \
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change_float_range(0., 8.)
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static int aout_SoftVolumeSet(audio_output_t *aout, float volume)
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{
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aout_sys_t *sys = aout->sys;
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/*
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* Cubic mapping from software volume to amplification factor.
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* This provides a good tradeoff between low and high volume ranges.
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*
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* This code is only used for the VLC software mixer. If you change this
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* formula, be sure to update the volume-capable plugins also.
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*/
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float gain = volume * volume * volume;
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if (!sys->soft_mute && aout_GainRequest(aout, gain))
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return -1;
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sys->soft_gain = gain;
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if (var_InheritBool(aout, "volume-save"))
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config_PutFloat(MODULE_STRING"-gain", gain);
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aout_VolumeReport(aout, volume);
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return 0;
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}
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static int aout_SoftMuteSet (audio_output_t *aout, bool mute)
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{
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aout_sys_t *sys = aout->sys;
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if (aout_GainRequest(aout, mute ? 0.f : sys->soft_gain))
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return -1;
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sys->soft_mute = mute;
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aout_MuteReport(aout, mute);
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return 0;
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}
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static void aout_SoftVolumeInit(audio_output_t *aout)
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{
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aout_sys_t *sys = aout->sys;
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float gain = var_InheritFloat(aout, MODULE_STRING"-gain");
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bool mute = var_InheritBool(aout, "mute");
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aout->volume_set = aout_SoftVolumeSet;
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aout->mute_set = aout_SoftMuteSet;
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sys->soft_gain = gain;
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sys->soft_mute = mute;
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aout_MuteReport(aout, mute);
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aout_VolumeReport(aout, cbrtf(gain));
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}
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static void aout_SoftVolumeStart (audio_output_t *aout)
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{
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aout_sys_t *sys = aout->sys;
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if (aout_GainRequest(aout, sys->soft_mute ? 0.f : sys->soft_gain))
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{
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aout_MuteReport(aout, false);
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aout_VolumeReport(aout, 1.f);
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}
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}
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