[vlc-devel] [PATCH 1/2] libvlc: add equalizer API

[Rémi Denis-Courmont]

Le mercredi 10 juillet 2013 21:54:18, Mark Lee a écrit :
> +/*************************************************************************
> **** + * libvlc_audio_equalizer_set_amp_at_index : Set the amplification
> value for an equalizer band +
> **************************************************************************
> ***/ +int libvlc_audio_equalizer_set_amp_at_index( libvlc_equalizer_t
> *p_equalizer, float f_amp, unsigned u_band ) +{
> +    if ( !p_equalizer )
> +        return -1;

Whenever you accept NULL, please document it. Alternatively, do not accept 
NULL.

> +
> +    if ( u_band >= EQZ_BANDS_MAX )
> +        return -1;
> +
> +    if ( f_amp < -20.0f )
> +        f_amp = -20.0f;
> +    else if ( f_amp > 20.0f )
> +        f_amp = 20.0f;
> +
> +    p_equalizer->f_amp[ u_band ] = f_amp;
> +    return 0;
> +}
> +
> diff --git a/lib/media_player.c b/lib/media_player.c
> index 376159f..bb43a82 100644
> --- a/lib/media_player.c
> +++ b/lib/media_player.c
> @@ -33,6 +33,7 @@
>  #include <vlc_demux.h>
>  #include <vlc_input.h>
>  #include <vlc_vout.h>
> +#include <vlc_aout.h>
>  #include <vlc_keys.h>
> 
>  #include "libvlc_internal.h"
> @@ -462,6 +463,10 @@ libvlc_media_player_new( libvlc_instance_t *instance )
>      var_Create (mp, "video-title-position", VLC_VAR_INTEGER);
>      var_Create (mp, "video-title-timeout", VLC_VAR_INTEGER);
> 
> +    /* Equalizer */
> +    var_Create (mp, "equalizer-preamp", VLC_VAR_FLOAT);
> +    var_Create (mp, "equalizer-bands", VLC_VAR_STRING);
> +
>      mp->p_md = NULL;
>      mp->state = libvlc_NothingSpecial;
>      mp->p_libvlc_instance = instance;
> @@ -1404,3 +1409,46 @@ void libvlc_media_player_set_video_title_display(
> libvlc_media_player_t *p_mi, l var_SetBool( p_mi, "video-title-show",
> false );
>      }
>  }
> +
> +int libvlc_media_player_set_equalizer( libvlc_media_player_t *p_mi,
> libvlc_equalizer_t *p_equalizer ) +{
> +    float f_preamp;
> +    char *psz_bands;
> +
> +    if ( p_equalizer )
> +    {
> +        f_preamp = p_equalizer->f_preamp;
> +        psz_bands = NULL;
> +        for ( int i = 0; i < EQZ_BANDS_MAX; i++ )
> +        {
> +            char *psz;
> +            if ( asprintf( &psz, "%s %.07f", psz_bands ? psz_bands : "",
> p_equalizer ? p_equalizer->f_amp[i] : 0.f ) == -1 )
> +            {
> +                free( psz_bands );
> +                return -1;
> +            }

How large can this get? Pre-allocating the buffer would be faster and simpler, 
especially on the stack.

> +            free( psz_bands );
> +            psz_bands = psz;
> +        }
> +    }
> +    else
> +    {
> +        f_preamp = 0.f;
> +        psz_bands = NULL;
> +    }
> +
> +    var_SetFloat( p_mi, "equalizer-preamp", f_preamp );
> +    var_SetString( p_mi, "equalizer-bands", psz_bands );
> +
> +    audio_output_t *p_aout = input_resource_HoldAout(
> p_mi->input.p_resource ); +    if ( p_aout )
> +    {
> +        var_SetFloat( p_aout, "equalizer-preamp", f_preamp );
> +        var_SetString( p_aout, "equalizer-bands", psz_bands );
> +
> +        vlc_object_release( p_aout );
> +    }
> +
> +    free( psz_bands );
> +    return 0;
> +}
> diff --git a/src/audio_output/filters.c b/src/audio_output/filters.c
> index 41b23b4..ea451a3 100644
> --- a/src/audio_output/filters.c
> +++ b/src/audio_output/filters.c
> @@ -314,8 +314,7 @@ static int EqualizerCallback (vlc_object_t *obj, const
> char *var, void *data)
>  {
>      const char *val = newval.psz_string;
> -
> -    if (*val)
> +    if (!strcmp("equalizer", var) && *val)

Tautology.

>      {
>          var_Create (obj, "equalizer-preset", VLC_VAR_STRING);
>          var_SetString (obj, "equalizer-preset", val);

-- 
Rémi Denis-Courmont
http://www.remlab.net/