mirror of https://code.videolan.org/videolan/vlc
137 lines
4.5 KiB
C
137 lines
4.5 KiB
C
/*****************************************************************************
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* gain.c : gain control filter
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*****************************************************************************
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* Copyright © 2012 VLC authors and VideoLAN
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*
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* Authors: Ludovic Fauvet <etix@videolan.org>
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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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/*****************************************************************************
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* Preamble
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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 <vlc_common.h>
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#include <vlc_aout.h>
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#include <vlc_aout_volume.h>
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#include <vlc_filter.h>
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#include <vlc_modules.h>
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#include <vlc_plugin.h>
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/*****************************************************************************
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* Local prototypes
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*****************************************************************************/
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static int Open ( vlc_object_t * );
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static void Close ( vlc_object_t * );
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static block_t *Process ( filter_t *, block_t * );
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struct filter_sys_t
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{
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audio_volume_t volume;
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float f_gain;
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module_t *module;
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};
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/*****************************************************************************
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* Module descriptor
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*****************************************************************************/
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#define GAIN_VALUE_TEXT N_( "Gain multiplier" )
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#define GAIN_VALUE_LONGTEXT N_( "Increase or decrease the gain (default 1.0)" )
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vlc_module_begin()
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set_shortname( N_("Gain") )
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set_description( N_("Gain control filter") )
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set_category( CAT_AUDIO )
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set_subcategory( SUBCAT_AUDIO_AFILTER )
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add_float( "gain-value", 1.0, GAIN_VALUE_TEXT,
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GAIN_VALUE_LONGTEXT, false )
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set_capability( "audio filter", 0 )
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set_callbacks( Open, Close )
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vlc_module_end()
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/*****************************************************************************
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* Open: initialize filter
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*****************************************************************************/
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static int Open( vlc_object_t *p_this )
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{
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filter_t *p_filter = (filter_t *)p_this;
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filter_sys_t *p_sys;
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if ( !AOUT_FMTS_IDENTICAL( &p_filter->fmt_in.audio, &p_filter->fmt_out.audio ) )
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{
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msg_Warn( p_filter, "bad input or output format" );
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return VLC_EGENERIC;
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}
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p_sys = vlc_object_create( p_this, sizeof( *p_sys ) );
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if( unlikely( p_sys == NULL ) )
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return VLC_ENOMEM;
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p_filter->p_sys = p_sys;
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p_sys->volume.format = p_filter->fmt_in.audio.i_format;
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p_sys->module = module_need( &p_sys->volume, "audio volume", NULL, false );
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if( p_sys->module == NULL )
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{
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msg_Warn( p_filter, "unsupported format" );
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vlc_object_release( &p_sys->volume );
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return VLC_EGENERIC;
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}
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p_sys->f_gain = var_InheritFloat( p_filter->p_parent, "gain-value" );
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msg_Dbg( p_filter, "gain multiplier sets to %.2fx", p_sys->f_gain );
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p_filter->pf_audio_filter = Process;
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return VLC_SUCCESS;
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}
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/*****************************************************************************
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* Process: process samples buffer
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*****************************************************************************/
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static block_t *Process( filter_t *p_filter, block_t *p_block )
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{
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filter_sys_t *p_sys = p_filter->p_sys;
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p_sys->volume.amplify( &p_sys->volume, p_block, p_sys->f_gain );
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return p_block;
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}
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/*****************************************************************************
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* Close: close filter
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*****************************************************************************/
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static void Close( vlc_object_t *p_this )
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{
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filter_t *p_filter = (filter_t*)p_this;
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filter_sys_t *p_sys = p_filter->p_sys;
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module_unneed( &p_sys->volume, p_sys->module );
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vlc_object_release( &p_sys->volume );
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}
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