equalizer.c

VLC Player Source Code

/*****************************************************************************
 * equalizer.c:
 *****************************************************************************
 * Copyright (C) 2004, 2006 the VideoLAN team
 * $Id$
 *
 * Authors: Laurent Aimar <[e-mail]>
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

/*****************************************************************************
 * Preamble
 *****************************************************************************/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <math.h>

#include <vlc_common.h>
#include <vlc_plugin.h>

#include "vlc_aout.h"

#include "equalizer_presets.h"
/* TODO:
 *  - add tables for other rates ( 22500, 11250, ...)
 *  - optimize a bit (you can hardly do slower ;)
 *  - add tables for more bands (15 and 32 would be cool), maybe with auto coeffs
 *  computation (not too hard once the Q is found).
 *  - support for external preset
 *  - callback to handle preset changes on the fly
 *  - ...
 */

/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
static int  Open ( vlc_object_t * );
static void Close( vlc_object_t * );

#define PRESET_TEXT N_( "Equalizer preset" )
#define PRESET_LONGTEXT N_("Preset to use for the equalizer." )

#define BANDS_TEXT N_( "Bands gain")
#define BANDS_LONGTEXT N_( \
         "Don't use presets, but manually specified bands. You need to " \
         "provide 10 values between -20dB and 20dB, separated by spaces, " \
         "e.g. \"0 2 4 2 0 -2 -4 -2 0\"." )

#define TWOPASS_TEXT N_( "Two pass" )
#define TWOPASS_LONGTEXT N_( "Filter the audio twice. This provides a more "  \
         "intense effect.")

#define PREAMP_TEXT N_("Global gain" )
#define PREAMP_LONGTEXT N_("Set the global gain in dB (-20 ... 20)." )

vlc_module_begin();
    set_description( N_("Equalizer with 10 bands") );
    set_shortname( N_("Equalizer" ) );
    set_capability( "audio filter", 0 );
    set_category( CAT_AUDIO );
    set_subcategory( SUBCAT_AUDIO_AFILTER );

    add_string( "equalizer-preset", "flat", NULL, PRESET_TEXT,
                PRESET_LONGTEXT, false );
        change_string_list( preset_list, preset_list_text, 0 );
    add_string( "equalizer-bands", NULL, NULL, BANDS_TEXT,
                BANDS_LONGTEXT, true );
    add_bool( "equalizer-2pass", 0, NULL, TWOPASS_TEXT,
              TWOPASS_LONGTEXT, true );
    add_float( "equalizer-preamp", 12.0, NULL, PREAMP_TEXT,
               PREAMP_LONGTEXT, true );
    set_callbacks( Open, Close );
    add_shortcut( "equalizer" );
vlc_module_end();

/*****************************************************************************
 * Local prototypes
 *****************************************************************************/
typedef struct aout_filter_sys_t
{
    /* Filter static config */
    int i_band;
    float *f_alpha;
    float *f_beta;
    float *f_gamma;

    float f_newpreamp;
    char *psz_newbands;
    bool b_first;

    /* Filter dyn config */
    float *f_amp;   /* Per band amp */
    float f_gamp;   /* Global preamp */
    bool b_2eqz;

    /* Filter state */
    float x[32][2];
    float y[32][128][2];

    /* Second filter state */
    float x2[32][2];
    float y2[32][128][2];

} aout_filter_sys_t;

static void DoWork( aout_instance_t *, aout_filter_t *,
                    aout_buffer_t *, aout_buffer_t * );

#define EQZ_IN_FACTOR (0.25)
static int  EqzInit( aout_filter_t *, int );
static void EqzFilter( aout_filter_t *, float *, float *,
                        int, int );
static void EqzClean( aout_filter_t * );

static int PresetCallback( vlc_object_t *, char const *,
                                           vlc_value_t, vlc_value_t, void * );
static int PreampCallback( vlc_object_t *, char const *,
                                           vlc_value_t, vlc_value_t, void * );
static int BandsCallback ( vlc_object_t *, char const *,
                                           vlc_value_t, vlc_value_t, void * );



/*****************************************************************************
 * Open:
 *****************************************************************************/
static int Open( vlc_object_t *p_this )
{
    aout_filter_t     *p_filter = (aout_filter_t *)p_this;
    aout_filter_sys_t *p_sys;
    bool         b_fit = true;

    if( p_filter->input.i_format != VLC_FOURCC('f','l','3','2' ) ||
        p_filter->output.i_format != VLC_FOURCC('f','l','3','2') )
    {
        b_fit = false;
        p_filter->input.i_format = VLC_FOURCC('f','l','3','2');
        p_filter->output.i_format = VLC_FOURCC('f','l','3','2');
        msg_Warn( p_filter, "bad input or output format" );
    }
    if ( !AOUT_FMTS_SIMILAR( &p_filter->input, &p_filter->output ) )
    {
        b_fit = false;
        memcpy( &p_filter->output, &p_filter->input,
                sizeof(audio_sample_format_t) );
        msg_Warn( p_filter, "input and output formats are not similar" );
    }

    if ( ! b_fit )
    {
        return VLC_EGENERIC;
    }

    p_filter->pf_do_work = DoWork;
    p_filter->b_in_place = true;

    /* Allocate structure */
    p_sys = p_filter->p_sys = malloc( sizeof( aout_filter_sys_t ) );
    if( !p_sys )
        return VLC_ENOMEM;

    if( EqzInit( p_filter, p_filter->input.i_rate ) != VLC_SUCCESS )
    {
        free( p_sys );
        return VLC_EGENERIC;
    }

    return VLC_SUCCESS;
}

/*****************************************************************************
 * Close: close the plugin
 *****************************************************************************/
static void Close( vlc_object_t *p_this )
{
    aout_filter_t     *p_filter = (aout_filter_t *)p_this;
    aout_filter_sys_t *p_sys = p_filter->p_sys;

    EqzClean( p_filter );
    free( p_sys );
}

/*****************************************************************************
 * DoWork: process samples buffer
 *****************************************************************************
 *
 *****************************************************************************/
static void DoWork( aout_instance_t * p_aout, aout_filter_t * p_filter,
                    aout_buffer_t * p_in_buf, aout_buffer_t * p_out_buf )
{
    VLC_UNUSED(p_aout);
    p_out_buf->i_nb_samples = p_in_buf->i_nb_samples;
    p_out_buf->i_nb_bytes = p_in_buf->i_nb_bytes;

    EqzFilter( p_filter, (float*)p_out_buf->p_buffer,
               (float*)p_in_buf->p_buffer, p_in_buf->i_nb_samples,
               aout_FormatNbChannels( &p_filter->input ) );
}

/*****************************************************************************
 * Equalizer stuff
 *****************************************************************************/
typedef struct
{
    int   i_band;

    struct
    {
        float f_frequency;
        float f_alpha;
        float f_beta;
        float f_gamma;
    } band[EQZ_BANDS_MAX];

} eqz_config_t;

/* Value from equ-xmms */
static const eqz_config_t eqz_config_44100_10b =
{
    10,
    {
        {    60, 0.003013, 0.993973, 1.993901 },
        {   170, 0.008490, 0.983019, 1.982437 },
        {   310, 0.015374, 0.969252, 1.967331 },
        {   600, 0.029328, 0.941343, 1.934254 },
        {  1000, 0.047918, 0.904163, 1.884869 },
        {  3000, 0.130408, 0.739184, 1.582718 },
        {  6000, 0.226555, 0.546889, 1.015267 },
        { 12000, 0.344937, 0.310127, -0.181410 },
        { 14000, 0.366438, 0.267123, -0.521151 },
        { 16000, 0.379009, 0.241981, -0.808451 },
    }
};
static const eqz_config_t eqz_config_48000_10b =
{
    10,
    {
        {    60, 0.002769, 0.994462, 1.994400 },
        {   170, 0.007806, 0.984388, 1.983897 },
        {   310, 0.014143, 0.971714, 1.970091 },
        {   600, 0.027011, 0.945978, 1.939979 },
        {  1000, 0.044203, 0.911595, 1.895241 },
        {  3000, 0.121223, 0.757553, 1.623767 },
        {  6000, 0.212888, 0.574224, 1.113145 },
        { 12000, 0.331347, 0.337307, 0.000000 },
        { 14000, 0.355263, 0.289473, -0.333740 },
        { 16000, 0.371900, 0.256201, -0.628100 }
    }
};

static inline float EqzConvertdB( float db )
{
    /* Map it to gain,
     * (we do as if the input of iir is /EQZ_IN_FACTOR, but in fact it's the non iir data that is *EQZ_IN_FACTOR)
     * db = 20*log( out / in ) with out = in + amp*iir(i/EQZ_IN_FACTOR)
     * or iir(i) == i for the center freq so
     * db = 20*log( 1 + amp/EQZ_IN_FACTOR )
     * -> amp = EQZ_IN_FACTOR*(10^(db/20) - 1)
     **/

    if( db < -20.0 )
        db = -20.0;
    else if(  db > 20.0 )
        db = 20.0;
    return EQZ_IN_FACTOR * ( pow( 10, db / 20.0 ) - 1.0 );
}

static int EqzInit( aout_filter_t *p_filter, int i_rate )
{
    aout_filter_sys_t *p_sys = p_filter->p_sys;
    const eqz_config_t *p_cfg;
    int i, ch;
    vlc_value_t val1, val2, val3;
    aout_instance_t *p_aout = (aout_instance_t *)p_filter->p_parent;

    /* Select the config */
    if( i_rate == 48000 )
    {
        p_cfg = &eqz_config_48000_10b;
    }
    else if( i_rate == 44100 )
    {
        p_cfg = &eqz_config_44100_10b;
    }
    else
    {
        /* TODO compute the coeffs on the fly */
        msg_Err( p_filter, "rate not supported" );