audio: add some setters for mp_audio, and require filters to use them

mp_audio has some redundant fields. Setters like mp_audio_set_format()
initialize these properly.

Also move the mp_audio struct to a the file audio.c.

We can remove a mysterious line of code from af.c:

    in.format |= af_bits2fmt(in.bps * 8);

I'm not sure if this was ever actually needed, or if it was some kind of
"make it work" quick-fix that works against the way things were supposed
to work. All filters etc. now set the format correctly, so if there ever
was a need for this code, it's definitely gone.

1 files changed, 4 insertions, 9 deletions

diff --git a/audio/filter/af_drc.c b/audio/filter/af_drc.c
index ba1e10c0a7..e293f7f616 100644
--- a/audio/filter/af_drc.c
+++ b/audio/filter/af_drc.c
@@ -87,15 +87,10 @@ static int control(struct af_instance* af, int cmd, void* arg)
     // Sanity check
     if(!arg) return AF_ERROR;
 
-    af->data->rate   = ((struct mp_audio*)arg)->rate;
-    af->data->nch    = ((struct mp_audio*)arg)->nch;
-
-    if(((struct mp_audio*)arg)->format == (AF_FORMAT_S16_NE)){
-      af->data->format = AF_FORMAT_S16_NE;
-      af->data->bps    = 2;
-    }else{
-      af->data->format = AF_FORMAT_FLOAT_NE;
-      af->data->bps    = 4;
+    mp_audio_copy_config(af->data, (struct mp_audio*)arg);
+
+    if(((struct mp_audio*)arg)->format != (AF_FORMAT_S16_NE)){
+      mp_audio_set_format(af->data, AF_FORMAT_FLOAT_NE);
     }
     return af_test_output(af,(struct mp_audio*)arg);
   case AF_CONTROL_COMMAND_LINE:{