[vlc-devel] [PATCH 1/2] Add new API to libvlc for persistent equalizer settings.

Mark Lee mark.lee at capricasoftware.co.uk
Sun Aug 12 10:30:45 CEST 2012


New methods are provided to:

 - get the available equalizer presets;
 - get the available frequency bands (useful for creating a UI);
 - create a new default equalizer, or create a new equalizer from a preset;
 - release a previously created equalizer;
 - get/set preamp and individual frequency amplification values;
 - get/set an equalizer on a media player.

Equalizer settings are persistent, can be made whether media is currently playing or not and will automatically be applied to subsequently played media.
---
 include/vlc/libvlc_media_player.h        |  185 ++++++++++++++++++++++++++++++
 lib/audio.c                              |  152 ++++++++++++++++++++++++
 lib/libvlc.sym                           |   13 +++
 lib/media_player.c                       |   52 +++++++++
 lib/media_player_internal.h              |   13 +++
 modules/audio_filter/equalizer.c         |   11 --
 modules/audio_filter/equalizer_presets.h |   16 +++
 src/audio_output/common.c                |    7 ++
 8 files changed, 438 insertions(+), 11 deletions(-)

diff --git a/include/vlc/libvlc_media_player.h b/include/vlc/libvlc_media_player.h
index 809ed5f..f797b8d 100644
--- a/include/vlc/libvlc_media_player.h
+++ b/include/vlc/libvlc_media_player.h
@@ -110,6 +110,13 @@ typedef enum libvlc_navigate_mode_t
 } libvlc_navigate_mode_t;
 
 /**
+ * Opaque equalizer handle.
+ *
+ * An equalizer can be associated with a media player.
+ */
+typedef struct libvlc_equalizer_t libvlc_equalizer_t;
+
+/**
  * Create an empty Media Player object
  *
  * \param p_libvlc_instance the libvlc instance in which the Media Player
@@ -1578,6 +1585,184 @@ LIBVLC_API int64_t libvlc_audio_get_delay( libvlc_media_player_t *p_mi );
  */
 LIBVLC_API int libvlc_audio_set_delay( libvlc_media_player_t *p_mi, int64_t i_delay );
 
+/**
+ * Get the number of equalizer presets.
+ *
+ * \return number of presets
+ * \version LibVLC 2.1.0 or later
+ */
+LIBVLC_API unsigned libvlc_audio_equalizer_get_preset_count( void );
+
+/**
+ * Get the name of a particular equalizer preset.
+ *
+ * This name can be used, for example, to prepare a preset label or menu in a user
+ * interface.
+ *
+ * \param i_index index of the preset, counting from zero
+ * \return preset name, or NULL if there is no such preset
+ * \version LibVLC 2.1.0 or later
+ */
+LIBVLC_API const char *libvlc_audio_equalizer_get_preset_name( int i_index );
+
+/**
+ * Get the number of distinct frequency bands for an equalizer.
+ *
+ * \return number of frequency bands
+ * \version LibVLC 2.1.0 or later
+ */
+LIBVLC_API unsigned libvlc_audio_equalizer_get_band_count( void );
+
+/**
+ * Get a particular equalizer frequency band.
+ *
+ * This value can be used, for example, to create a label for an equalizer band control
+ * in a user interface.
+ *
+ * \param i_index index of the band, counting from zero
+ * \return equalizer band frequency, or -1 if there is no such band
+ * \version LibVLC 2.1.0 or later
+ */
+LIBVLC_API float libvlc_audio_equalizer_get_band_frequency( int i_index );
+
+/**
+ * Create a new default equalizer, with all frequency values zeroed.
+ *
+ * The new equalizer can subsequently be associated with a media player by using
+ * libvlc_media_player_set_equalizer().
+ *
+ * When the application is finished with a particular equalizer instance it should
+ * disassociate it from the media player by invoking libvlc_media_player_set_equalizer(NULL)
+ * and then free it by using libvlc_audio_equalizer_release().
+ *
+ * It is the responsibility of the application itself to deal wth the lifecycle management
+ * of equalizer instances, and not the responsibilty of libvlc.
+ *
+ * \return opaque equalizer handle, or NULL on error
+ * \version LibVLC 2.1.0 or later
+ */
+LIBVLC_API libvlc_equalizer_t *libvlc_audio_equalizer_new( void );
+
+/**
+ * Create a new equalizer, with initial frequency values copied from an existing
+ * preset.
+ *
+ * The new equalizer can subsequently be associated with a media player by using
+ * libvlc_media_player_set_equalizer().
+ *
+ * When the application is finished with a particular equalizer instance it should
+ * disassociate it from the media player by invoking libvlc_media_player_set_equalizer(NULL)
+ * and then free it by using libvlc_audio_equalizer_release().
+ *
+ * It is the responsibility of the application itself to deal with the lifecycle management
+ * of equalizer instances, and not the responsibilty of libvlc.
+ *
+ * \param i_index index of the preset, counting from zero
+ * \return opaque equalizer handle, or NULL on error
+ * \version LibVLC 2.1.0 or later
+ */
+LIBVLC_API libvlc_equalizer_t *libvlc_audio_equalizer_new_from_preset( int i_index );
+
+/**
+ * Free a previously created equalizer.
+ *
+ * The equalizer was previously created by using libvlc_audio_equalizer_new() or
+ * libvlc_audio_equalizer_new_from_preset().
+ *
+ * An application must first disassociate the equalizer from any media player to which
+ * it is attached, by invoking libvlc_media_player_set_equalizer(NULL), before releasing
+ * the equalizer.
+ *
+ * \param p_equalizer opaque equalizer handle
+ * \version LibVLC 2.1.0 or later
+ */
+LIBVLC_API void libvlc_audio_equalizer_release( libvlc_equalizer_t *p_equalizer );
+
+/**
+ * Set a new pre-amplification value for an equalizer.
+ *
+ * The new value will be stored in the equalizer immediately, but will not be applied to
+ * any associated media player audio output until libvlc_media_player_set_equalizer() is
+ * invoked, or media is played via libvlc_media_player_play().
+ *
+ * \param p_equalizer opaque equalizer handle
+ * \param f_preamp preamp value
+ * \return zero on success, -1 on error
+ * \version LibVLC 2.1.0 or later
+ */
+LIBVLC_API int libvlc_audio_equalizer_set_preamp( libvlc_equalizer_t *p_equalizer, float f_preamp );
+
+/**
+ * Get the current pre-amplification value from an equalizer.
+ *
+ * \param p_equalizer opaque equalizer handle
+ * \return preamp value
+ * \version LibVLC 2.1.0 or later
+ */
+LIBVLC_API float libvlc_audio_equalizer_get_preamp( libvlc_equalizer_t *p_equalizer );
+
+/**
+ * Set a new amplification value for a particular equalizer frequency band.
+ *
+ * The new value will be stored in the equalizer immediately, but will not be applied to
+ * any associated media player audio output until libvlc_media_player_set_equalizer() is
+ * invoked, or new media is played via libvlc_media_player_play().
+ *
+ * \param p_equalizer opaque equalizer handle
+ * \param f_amp amplification value
+ * \param i_band index, counting from zero, of the frequency band to set
+ * \return zero on success, -1 on error
+ * \version LibVLC 2.1.0 or later
+ */
+LIBVLC_API int libvlc_audio_equalizer_set_amp_at_index( libvlc_equalizer_t *p_equalizer, float f_amp, int i_band );
+
+/**
+ * Get the amplification value for a particular equalizer frequency band.
+ *
+ * \param p_equalizer opaque equalizer handle
+ * \param i_band index, counting from zero, of the frequency band to get
+ * \return amplification value; this will also return zero if there is no such frequency band
+ * \version LibVLC 2.1.0 or later
+ */
+LIBVLC_API float libvlc_audio_equalizer_get_amp_at_index( libvlc_equalizer_t *p_equalizer, int i_band );
+
+/**
+ * Associate an equalizer with a media player.
+ *
+ * The equalizer is first created by using libvlc_audio_equalizer_new() or
+ * libvlc_audio_equalizer_new_from_preset().
+ *
+ * It is possible to associate new equalizer settings with a media player whether the
+ * media player is currently playing media or not.
+ *
+ * Invoking this method will immediately apply the new equalizer settings to the audio
+ * output of the currently playing media if there is any.
+ *
+ * If there is no currently playing media, the new equalizer settings will be applied
+ * later if and when new media is played.
+ *
+ * Equalizer settings will automatically be applied to subsequently played media.
+ *
+ * To disassociate an equalizer from a media player, for example before freeing a no-
+ * longer needed equalizer instance or simply to disable the equalizer, invoke this
+ * method passing NULL for the p_equalizer parameter.
+ *
+ * \param p_mi opaque media player handle
+ * \param p_equalizer opaque equalizer handle, or NULL to disable the equalizer for this media player
+ * \return zero on success, -1 on error
+ * \version LibVLC 2.1.0 or later
+ */
+LIBVLC_API int libvlc_media_player_set_equalizer( libvlc_media_player_t *p_mi, libvlc_equalizer_t *p_equalizer );
+
+/**
+ * Get the current equalizer associated with a media player.
+ *
+ * \param p_mi opaque media player handle
+ * \return opaque equalizer handle, or NULL if there is no equalizer associated with this media player
+ * \version LibVLC 2.1.0 or later
+ */
+LIBVLC_API libvlc_equalizer_t *libvlc_media_player_get_equalizer( libvlc_media_player_t *p_mi );
+
 /** @} audio */
 
 /** @} media_player */
diff --git a/lib/audio.c b/lib/audio.c
index 27d7cd4..8e7b959 100644
--- a/lib/audio.c
+++ b/lib/audio.c
@@ -42,6 +42,8 @@
 #include "libvlc_internal.h"
 #include "media_player_internal.h"
 
+#include "modules/audio_filter/equalizer_presets.h"
+
 /*
  * Remember to release the returned audio_output_t since it is locked at
  * the end of this function.
@@ -507,3 +509,153 @@ int libvlc_audio_set_delay( libvlc_media_player_t *p_mi, int64_t i_delay )
     }
     return ret;
 }
+
+/*****************************************************************************
+ * libvlc_audio_equalizer_get_preset_count : Get the number of equalizer presets
+ *****************************************************************************/
+unsigned libvlc_audio_equalizer_get_preset_count( void )
+{
+    return NB_PRESETS;
+}
+
+/*****************************************************************************
+ * libvlc_audio_equalizer_get_preset_name : Get the name for a preset
+ *****************************************************************************/
+const char *libvlc_audio_equalizer_get_preset_name( int i_index )
+{
+    if ( i_index < 0 || i_index >= NB_PRESETS )
+        return NULL;
+
+    return preset_list_text[ i_index ];
+}
+
+/*****************************************************************************
+ * libvlc_audio_equalizer_get_band_count : Get the number of equalizer frequency bands
+ *****************************************************************************/
+unsigned libvlc_audio_equalizer_get_band_count( void )
+{
+    return EQZ_BANDS_MAX;
+}
+
+/*****************************************************************************
+ * libvlc_audio_equalizer_get_band_frequency : Get the frequency for a band
+ *****************************************************************************/
+float libvlc_audio_equalizer_get_band_frequency( int i_index )
+{
+    if ( i_index < 0 || i_index >= EQZ_BANDS_MAX )
+        return -1;
+
+    return f_vlc_frequency_table_10b[ i_index ];
+}
+
+/*****************************************************************************
+ * libvlc_audio_equalizer_new : Create a new audio equalizer with zeroed values
+ *****************************************************************************/
+libvlc_equalizer_t *libvlc_audio_equalizer_new( void )
+{
+    libvlc_equalizer_t *p_equalizer;
+
+    p_equalizer = malloc( sizeof( *p_equalizer ) );
+    if ( p_equalizer == NULL )
+        return NULL;
+
+    p_equalizer->f_preamp = 0.0;
+
+    for ( int i = 0; i < EQZ_BANDS_MAX; i++ )
+        p_equalizer->f_amp[ i ] = 0.0;
+
+    return p_equalizer;
+}
+
+/*****************************************************************************
+ * libvlc_audio_equalizer_new_from_preset : Create a new audio equalizer based on a preset
+ *****************************************************************************/
+libvlc_equalizer_t *libvlc_audio_equalizer_new_from_preset( int i_index )
+{
+    libvlc_equalizer_t *p_equalizer;
+
+    if ( i_index < 0 || i_index >= NB_PRESETS )
+        return NULL;
+
+    p_equalizer = libvlc_audio_equalizer_new();
+    if ( !p_equalizer )
+        return NULL;
+
+    p_equalizer->f_preamp = eqz_preset_10b[ i_index ].f_preamp;
+
+    for ( int i = 0; i < EQZ_BANDS_MAX; i++ )
+        p_equalizer->f_amp[ i ] = eqz_preset_10b[ i_index ].f_amp[ i ];
+
+    return p_equalizer;
+}
+
+/*****************************************************************************
+ * libvlc_audio_equalizer_release : Release a previously created equalizer
+ *****************************************************************************/
+void libvlc_audio_equalizer_release( libvlc_equalizer_t *p_equalizer )
+{
+    if ( p_equalizer )
+        free( p_equalizer );
+}
+
+/*****************************************************************************
+ * libvlc_audio_equalizer_set_preamp : Set the preamp value for an equalizer
+ *****************************************************************************/
+int libvlc_audio_equalizer_set_preamp( libvlc_equalizer_t *p_equalizer, float f_preamp )
+{
+    if ( !p_equalizer )
+        return -1;
+
+    if ( f_preamp < -20.0 )
+        f_preamp = -20.0;
+    else if ( f_preamp > 20.0 )
+        f_preamp = 20.0;
+
+    p_equalizer->f_preamp = f_preamp;
+    return 0;
+}
+
+/*****************************************************************************
+ * libvlc_audio_equalizer_get_preamp : Get the preamp value for an equalizer
+ *****************************************************************************/
+float libvlc_audio_equalizer_get_preamp( libvlc_equalizer_t *p_equalizer )
+{
+    if ( !p_equalizer )
+        return 0;
+
+    return p_equalizer->f_preamp;
+}
+
+/*****************************************************************************
+ * 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, int i_band )
+{
+    if ( !p_equalizer )
+        return -1;
+
+    if ( i_band < 0 || i_band >= EQZ_BANDS_MAX )
+        return -1;
+
+    if ( f_amp < -20.0 )
+        f_amp = -20.0;
+    else if ( f_amp > 20.0 )
+        f_amp = 20.0;
+
+    p_equalizer->f_amp[ i_band ] = f_amp;
+    return 0;
+}
+
+/*****************************************************************************
+ * libvlc_audio_equalizer_get_amp_at_index : Get the amplification value for an equalizer band
+ *****************************************************************************/
+float libvlc_audio_equalizer_get_amp_at_index( libvlc_equalizer_t *p_equalizer, int i_band )
+{
+    if ( !p_equalizer )
+        return 0;
+
+    if ( i_band < 0 || i_band >= EQZ_BANDS_MAX )
+        return 0;
+
+    return p_equalizer->f_amp[ i_band ];
+}
diff --git a/lib/libvlc.sym b/lib/libvlc.sym
index 974e04f..93238f7 100644
--- a/lib/libvlc.sym
+++ b/lib/libvlc.sym
@@ -3,6 +3,17 @@ libvlc_clearerr
 libvlc_printerr
 libvlc_vprinterr
 libvlc_add_intf
+libvlc_audio_equalizer_get_amp_at_index
+libvlc_audio_equalizer_get_band_count
+libvlc_audio_equalizer_get_band_frequency
+libvlc_audio_equalizer_get_preamp
+libvlc_audio_equalizer_get_preset_count
+libvlc_audio_equalizer_get_preset_name
+libvlc_audio_equalizer_new
+libvlc_audio_equalizer_new_from_preset
+libvlc_audio_equalizer_release
+libvlc_audio_equalizer_set_amp_at_index
+libvlc_audio_equalizer_set_preamp
 libvlc_audio_output_device_count
 libvlc_audio_output_device_id
 libvlc_audio_output_device_longname
@@ -122,6 +133,7 @@ libvlc_media_player_get_agl
 libvlc_media_player_get_chapter
 libvlc_media_player_get_chapter_count
 libvlc_media_player_get_chapter_count_for_title
+libvlc_media_player_get_equalizer
 libvlc_media_player_get_fps
 libvlc_media_player_get_hwnd
 libvlc_media_player_get_length
@@ -148,6 +160,7 @@ libvlc_media_player_release
 libvlc_media_player_retain
 libvlc_media_player_set_agl
 libvlc_media_player_set_chapter
+libvlc_media_player_set_equalizer
 libvlc_media_player_set_hwnd
 libvlc_media_player_set_media
 libvlc_media_player_set_nsobject
diff --git a/lib/media_player.c b/lib/media_player.c
index a41b8c7..f2cb46d 100644
--- a/lib/media_player.c
+++ b/lib/media_player.c
@@ -34,11 +34,14 @@
 #include <vlc_input.h>
 #include <vlc_vout.h>
 #include <vlc_keys.h>
+#include <vlc_aout_intf.h>
 
 #include "libvlc_internal.h"
 #include "media_internal.h" // libvlc_media_set_state()
 #include "media_player_internal.h"
 
+#include "modules/audio_filter/equalizer_presets.h"
+
 /*
  * mapping of libvlc_navigate_mode_t to vlc_action_t
  */
@@ -482,6 +485,9 @@ libvlc_media_player_new( libvlc_instance_t *instance )
     var_Create (mp, "amem-rate", VLC_VAR_INTEGER | VLC_VAR_DOINHERIT);
     var_Create (mp, "amem-channels", VLC_VAR_INTEGER | VLC_VAR_DOINHERIT);
 
+    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;
@@ -1409,3 +1415,49 @@ void libvlc_media_player_next_frame( libvlc_media_player_t *p_mi )
         vlc_object_release( p_input_thread );
     }
 }
+
+int libvlc_media_player_set_equalizer( libvlc_media_player_t *p_mi, libvlc_equalizer_t *p_equalizer )
+{
+    if ( !p_mi )
+        return -1;
+
+    p_mi->p_equalizer = p_equalizer;
+
+    if ( p_equalizer )
+    {
+        aout_EnableFilter( p_mi, "equalizer", true );
+
+        var_SetFloat( p_mi, "equalizer-preamp", p_equalizer->f_preamp );
+
+        // This implementation slightly adapted from modules/audio_filter/equalizer.c
+        char *psz_bands = NULL;
+        for ( int i = 0; i < EQZ_BANDS_MAX; i++ )
+        {
+            lldiv_t d;
+            char *psz;
+
+            d = lldiv( p_equalizer->f_amp[i] * 10000000, 10000000 );
+            if ( asprintf( &psz, "%s %lld.%07llu", psz_bands ? psz_bands : "", d.quot, d.rem ) == -1 )
+            {
+                free( psz_bands );
+                return -1;
+            }
+            free( psz_bands );
+            psz_bands = psz;
+        }
+        var_SetString( p_mi, "equalizer-bands", psz_bands );
+        free( psz_bands );
+    }
+    else
+        aout_EnableFilter( p_mi, "equalizer", false );
+
+    return 0;
+}
+
+libvlc_equalizer_t *libvlc_media_player_get_equalizer( libvlc_media_player_t *p_mi )
+{
+    if ( !p_mi )
+        return NULL;
+
+    return p_mi->p_equalizer;
+}
diff --git a/lib/media_player_internal.h b/lib/media_player_internal.h
index 185f183..ecf994c 100644
--- a/lib/media_player_internal.h
+++ b/lib/media_player_internal.h
@@ -34,6 +34,8 @@
 #include <vlc/libvlc_media.h>
 #include <vlc_input.h>
 
+#include "modules/audio_filter/equalizer_presets.h"
+
 struct libvlc_media_player_t
 {
     VLC_COMMON_MEMBERS
@@ -52,6 +54,8 @@ struct libvlc_media_player_t
     libvlc_media_t * p_md; /* current media descriptor */
     libvlc_event_manager_t * p_event_manager;
     libvlc_state_t state;
+
+    libvlc_equalizer_t *p_equalizer;
 };
 
 /* Media player - audio, video */
@@ -62,4 +66,13 @@ libvlc_track_description_t * libvlc_get_track_description(
         libvlc_media_player_t *p_mi,
         const char *psz_variable );
 
+/**
+ * Internal equalizer structure.
+ */
+struct libvlc_equalizer_t
+{
+    float f_preamp;
+    float f_amp[EQZ_BANDS_MAX];
+};
+
 #endif
diff --git a/modules/audio_filter/equalizer.c b/modules/audio_filter/equalizer.c
index 1f88a15..c152d2d 100644
--- a/modules/audio_filter/equalizer.c
+++ b/modules/audio_filter/equalizer.c
@@ -232,17 +232,6 @@ typedef struct
 
 } eqz_config_t;
 
-/* The frequency tables */
-static const float f_vlc_frequency_table_10b[EQZ_BANDS_MAX] =
-{
-    60, 170, 310, 600, 1000, 3000, 6000, 12000, 14000, 16000,
-};
-
-static const float f_iso_frequency_table_10b[EQZ_BANDS_MAX] =
-{
-    31.25, 62.5, 125, 250, 500, 1000, 2000, 4000, 8000, 16000,
-};
-
 /* Equalizer coefficient calculation function based on equ-xmms */
 static void EqzCoeffs( int i_rate, float f_octave_percent,
                        bool b_use_vlc_freqs,
diff --git a/modules/audio_filter/equalizer_presets.h b/modules/audio_filter/equalizer_presets.h
index 0c0c812..f0830ad 100644
--- a/modules/audio_filter/equalizer_presets.h
+++ b/modules/audio_filter/equalizer_presets.h
@@ -21,6 +21,9 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  *****************************************************************************/
 
+#ifndef _EQUALIZER_PRESETS_H
+#define _EQUALIZER_PRESETS_H 1
+
 /*****************************************************************************
  * Equalizer presets
  *****************************************************************************/
@@ -30,6 +33,17 @@
 
 #define EQZ_BANDS_MAX 10
 
+/* The frequency tables */
+static const float f_vlc_frequency_table_10b[EQZ_BANDS_MAX] =
+{
+    60, 170, 310, 600, 1000, 3000, 6000, 12000, 14000, 16000,
+};
+
+static const float f_iso_frequency_table_10b[EQZ_BANDS_MAX] =
+{
+    31.25, 62.5, 125, 250, 500, 1000, 2000, 4000, 8000, 16000,
+};
+
 #define NB_PRESETS 18
 static const char *const preset_list[NB_PRESETS] = {
     "flat", "classical", "club", "dance", "fullbass", "fullbasstreble",
@@ -132,3 +146,5 @@ static const eqz_preset_t eqz_preset_10b[NB_PRESETS] =
         { 8, 5.6, -1.11022e-15, -5.6, -4.8, -1.11022e-15, 8, 9.6, 9.6, 8.8 }
     },
 };
+
+#endif
diff --git a/src/audio_output/common.c b/src/audio_output/common.c
index c50883b..25f6ad0 100644
--- a/src/audio_output/common.c
+++ b/src/audio_output/common.c
@@ -88,6 +88,9 @@ audio_output_t *aout_New( vlc_object_t * p_parent )
     var_Create (aout, "mute", VLC_VAR_BOOL | VLC_VAR_DOINHERIT);
     var_AddCallback (aout, "mute", var_Copy, p_parent);
 
+    var_AddCallback (p_parent, "equalizer-preamp", var_Copy, aout );
+    var_AddCallback (p_parent, "equalizer-bands", var_Copy, aout );
+
     /* Visualizations */
     var_Create (aout, "visual", VLC_VAR_STRING | VLC_VAR_HASCHOICE);
     text.psz_string = _("Visualizations");
@@ -197,6 +200,10 @@ void aout_Destroy (audio_output_t *aout)
     var_DelCallback (aout, "mute", var_Copy, aout->p_parent);
     var_SetFloat (aout, "volume", -1.f);
     var_DelCallback (aout, "volume", var_Copy, aout->p_parent);
+
+    var_DelCallback (aout->p_parent, "equalizer-bands", var_Copy, aout);
+    var_DelCallback (aout->p_parent, "equalizer-preamp", var_Copy, aout);
+
     vlc_object_release (aout);
 }
 
-- 
1.7.9.5




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