aout: partly rewrite and move filters initialization code

 - simplify "audio-filter" parser and fix a tautology
 - keep a single pointer for the resampler instead of a table

src/audio_output/aout_internal.h

@@ -51,15 +51,6 @@ struct aout_input_t
 {
     unsigned            samplerate; /**< Input sample rate */
 
-    /* filters */
-    filter_t *              pp_filters[AOUT_MAX_FILTERS];
-    unsigned                i_nb_filters;
-
-    filter_t *              p_playback_rate_filter;
-
-    /* Resampler + converter to mixer */
-    filter_t *              pp_resamplers[5];
-    unsigned                i_nb_resamplers;
     int                     i_resampling_type;
     mtime_t                 i_resamp_start_date;
     int                     i_resamp_start_drift;
@@ -69,10 +60,6 @@ struct aout_input_t
 
     /* */
     int               i_buffer_lost;
-
-    /* */
-    bool                b_recycle_vout;
-    aout_request_vout_t request_vout;
 };
 
 typedef struct
@@ -87,12 +74,20 @@ typedef struct
         date_t date;
     } sync;
 
-    audio_sample_format_t mixer_format;
     audio_sample_format_t input_format;
+    audio_sample_format_t mixer_format;
 
-    /* Filters between mixer and output */
-    filter_t *filters[5];
-    unsigned  nb_filters;
+    filter_t *rate_filter; /**< The filter adjusting samples count
+        (either the scaletempo filter or a resampler) */
+    filter_t *resampler; /**< The resampler */
+    filter_t *filters[AOUT_MAX_FILTERS]; /**< Configured user filters
+        (e.g. equalization) and their conversions */
+    unsigned nb_filters;
+    unsigned nb_converters;
+    filter_t *converters[5]; /**< Converters to the output */
+
+    aout_request_vout_t request_vout;
+    bool recycle_vout;
 
     vlc_atomic_t restart;
 } aout_owner_t;
@@ -128,6 +123,10 @@ int aout_FiltersCreatePipeline( vlc_object_t *, filter_t **, unsigned *,
 void aout_FiltersDestroyPipeline( filter_t *const *, unsigned );
 void aout_FiltersPlay( filter_t *const *, unsigned, block_t ** );
 
+int aout_FiltersNew(audio_output_t *, const audio_sample_format_t *,
+                   const audio_sample_format_t *, const aout_request_vout_t *);
+void aout_FiltersDestroy(audio_output_t *);
+
 /* From mixer.c : */
 aout_volume_t *aout_volume_New(vlc_object_t *, const audio_replay_gain_t *);
 #define aout_volume_New(o, g) aout_volume_New(VLC_OBJECT(o), g)

src/audio_output/dec.c

@@ -138,7 +138,7 @@ static void aout_CheckRestart (audio_output_t *aout)
 
     assert (restart & AOUT_RESTART_INPUT);
 
-    const aout_request_vout_t request_vout = owner->input->request_vout;
+    const aout_request_vout_t request_vout = owner->request_vout;
 
     if (likely(owner->input != NULL))
         aout_InputDelete (aout, owner->input);

src/audio_output/output.c

@@ -403,11 +403,11 @@ int aout_OutputNew (audio_output_t *aout, const audio_sample_format_t *fmtp)
     aout_FormatPrepare (&owner->mixer_format);
     aout_FormatPrint (aout, "mixer", &owner->mixer_format);
 
-    /* Create filters. */
-    owner->nb_filters = 0;
-    if (aout_FiltersCreatePipeline (aout, owner->filters, &owner->nb_filters,
-                                    sizeof (owner->filters)
-                                                  / sizeof (owner->filters[0]),
+    /* Create converters. */
+    owner->nb_converters = 0;
+    if (aout_FiltersCreatePipeline (aout, owner->converters,
+                                    &owner->nb_converters,
+                    sizeof (owner->converters) / sizeof (owner->converters[0]),
                                     &owner->mixer_format, &fmt) < 0)
     {
         msg_Err (aout, "couldn't create audio output pipeline");
@@ -431,7 +431,7 @@ void aout_OutputDelete (audio_output_t *aout)
     var_DelCallback (aout, "stereo-mode", aout_ChannelsRestart, NULL);
     if (aout->stop != NULL)
         aout->stop (aout);
-    aout_FiltersDestroyPipeline (owner->filters, owner->nb_filters);
+    aout_FiltersDestroyPipeline (owner->converters, owner->nb_converters);
 }
 
 /**
@@ -446,7 +446,7 @@ void aout_OutputPlay (audio_output_t *aout, block_t *block)
 
     aout_assert_locked (aout);
 
-    aout_FiltersPlay (owner->filters, owner->nb_filters, &block);
+    aout_FiltersPlay (owner->converters, owner->nb_converters, &block);
     if (block == NULL)
         return;
     if (block->i_buffer == 0)