[vlc-devel] [PATCH 08/12] aout: support unknown channel layout

[Thomas Guillem]

if the input doesn't have a valid channel layout, use the default one (wg4) and
drop extra channels via the trivial mixer.
---
 src/audio_output/dec.c     | 18 ++++++++++++++----
 src/audio_output/filters.c | 26 ++++++++++++++++++++++++--
 2 files changed, 38 insertions(+), 6 deletions(-)

diff --git a/src/audio_output/dec.c b/src/audio_output/dec.c
index 157443635e..dbf707113a 100644
--- a/src/audio_output/dec.c
+++ b/src/audio_output/dec.c
@@ -45,11 +45,14 @@ int aout_DecNew( audio_output_t *p_aout,
                  const audio_replay_gain_t *p_replay_gain,
                  const aout_request_vout_t *p_request_vout )
 {
-    /* Sanitize audio format */
-    unsigned i_channels = aout_FormatNbChannels( p_format );
-    if( i_channels != p_format->i_channels && AOUT_FMT_LINEAR( p_format ) )
+
+    /* Sanitize audio format, input need to have a valid physical channels
+     * layout or a valid number of channels. */
+    int i_map_channels = aout_FormatNbChannels( p_format );
+    if( ( i_map_channels == 0 && p_format->i_channels == 0 )
+       || i_map_channels > AOUT_CHAN_MAX )
     {
-        msg_Err( p_aout, "incompatible audio channels count with layout mask" );
+        msg_Err( p_aout, "invalid audio channels count" );
         return -1;
     }
 
@@ -82,6 +85,13 @@ int aout_DecNew( audio_output_t *p_aout,
     atomic_store (&owner->restart, 0);
     owner->input_format = *p_format;
     owner->mixer_format = owner->input_format;
+
+    if (i_map_channels == 0)
+    {
+        /* The output channel map is unknown, use the default one (wg4) */
+        assert(owner->mixer_format.i_channels > 0);
+        aout_SetDefaultPhysicalChannels(&owner->mixer_format);
+    }
     owner->request_vout = *p_request_vout;
 
     if (aout_OutputNew (p_aout, &owner->mixer_format))
diff --git a/src/audio_output/filters.c b/src/audio_output/filters.c
index 400d6e72f7..ec868d4a43 100644
--- a/src/audio_output/filters.c
+++ b/src/audio_output/filters.c
@@ -442,12 +442,34 @@ aout_filters_t *aout_FiltersNew (vlc_object_t *obj,
         }
         return filters;
     }
-    if (aout_FormatNbChannels(infmt) == 0 || aout_FormatNbChannels(outfmt) == 0)
+    if (aout_FormatNbChannels(outfmt) == 0)
     {
-        msg_Warn (obj, "No channel mask, cannot setup filters");
+        msg_Warn (obj, "No ouput channel mask, cannot setup filters");
         goto error;
     }
 
+    if (aout_FormatNbChannels(&input_format) == 0)
+    {
+        /* The input channel map is unknown, use the default one (wg4) and add
+         * a converter that will drop extra channels that are not handled by
+         * VLC */
+        msg_Info(obj, "unknown channel map, using the wg4 one.");
+
+        assert(input_format.i_channels > 0);
+        audio_sample_format_t input_phys_format = input_format;
+        aout_SetDefaultPhysicalChannels(&input_phys_format);
+
+        filter_t *f = FindConverter (obj, &input_format, &input_phys_format);
+        if (f == NULL)
+        {
+            msg_Err (obj, "cannot find channel converter");
+            goto error;
+        }
+
+        input_format = input_phys_format;
+        filters->tab[filters->count++] = f;
+    }
+
     /* parse user filter lists */
     if (var_InheritBool (obj, "audio-time-stretch"))
     {
-- 
2.11.0