[vlc-devel] [RFC PATCH 8/9] decoder: reload module if aout device changes

[Thomas Guillem]

In order to be able to change from PCM to SPDIF and from SPDIF to PCM.

There is a Time of check to time of use issue here. DecoderPlayAudio() can
still be called when the decoder is configured with a wrong audio device. This
will result in a loss of few audio blocks. This is hard to avoid when the user
choose to change audio devices.
---
 src/input/decoder.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/src/input/decoder.c b/src/input/decoder.c
index de03dd6..a437930 100644
--- a/src/input/decoder.c
+++ b/src/input/decoder.c
@@ -82,6 +82,7 @@ struct decoder_owner_sys_t
     /* */
     bool           b_fmt_description;
     vlc_meta_t     *p_description;
+    atomic_bool    aout_device_changed;
 
     /* fifo */
     block_fifo_t *p_fifo;
@@ -270,6 +271,20 @@ static vout_thread_t *aout_request_vout( void *p_private,
     return p_vout;
 }
 
+static int aout_device_changed( vlc_object_t *p_obj, const char *p_var,
+                                vlc_value_t prev, vlc_value_t cur, void *p_data)
+{
+    (void) p_obj; (void) p_var;
+    decoder_t *p_dec = p_data;
+    decoder_owner_sys_t *p_owner = p_dec->p_owner;
+
+    if( prev.psz_string == NULL || cur.psz_string == NULL
+     || strcmp( prev.psz_string, cur.psz_string ) != 0 )
+        atomic_store( &p_owner->aout_device_changed, true );
+
+    return VLC_SUCCESS;
+}
+
 static int aout_update_format( decoder_t *p_dec )
 {
     decoder_owner_sys_t *p_owner = p_dec->p_owner;
@@ -283,6 +298,7 @@ static int aout_update_format( decoder_t *p_dec )
         vlc_mutex_lock( &p_owner->lock );
         p_owner->p_aout = NULL;
         vlc_mutex_unlock( &p_owner->lock );
+        var_DelCallback( p_aout, "device", aout_device_changed, p_dec );
         aout_DecDelete( p_aout );
 
         input_resource_PutAout( p_owner->p_resource, p_aout );
@@ -328,6 +344,8 @@ static int aout_update_format( decoder_t *p_dec )
                 input_resource_PutAout( p_owner->p_resource, p_aout );
                 p_aout = NULL;
             }
+            else
+                var_AddCallback( p_aout, "device", aout_device_changed, p_dec );
         }
 
         vlc_mutex_lock( &p_owner->lock );
@@ -1418,6 +1436,14 @@ static void DecoderProcess( decoder_t *p_dec, block_t *p_block )
     if( p_dec->b_error )
         goto error;
 
+    if( atomic_exchange( &p_owner->aout_device_changed, false ) )
+    {
+        msg_Warn( p_dec, "Restarting decoder since the audio device changed" );
+
+        if( ReloadDecoder( p_dec, NULL, &p_dec->fmt_in ) != VLC_SUCCESS )
+            goto error;
+    }
+
     if( p_block )
     {
         if( p_block->i_buffer <= 0 )
@@ -1668,6 +1694,7 @@ static decoder_t * CreateDecoder( vlc_object_t *p_parent,
     p_owner->flushing = false;
     p_owner->b_draining = false;
     atomic_init( &p_owner->drained, false );
+    atomic_init( &p_owner->aout_device_changed, false );
     p_owner->b_idle = false;
 
     es_format_Init( &p_owner->fmt, UNKNOWN_ES, 0 );
-- 
2.8.1