audio: refactor some aspects of filter chain setup

There's no real reason why audio_init_filter() should exist. Just use
af_init or af_reinit directly. (We lose a useless message; the same
information is printed in a quite close place with more details.)

Requires less code, and the way the filter chain is marked as having
failed to initialize allows just switching off audio instead of
crashing if trying to insert a volume filter in mixer.c fails, and
recreating the old filter chain fails too.

2 files changed, 15 insertions, 13 deletions

diff --git a/audio/filter/af.c b/audio/filter/af.c
index 72029f1013..176946b6d4 100644
--- a/audio/filter/af.c
+++ b/audio/filter/af.c
@@ -558,22 +558,27 @@ static int af_reinit(struct af_stream *s)
             MP_ERR(s, "Reinitialization did not work, "
                    "audio filter '%s' returned error code %i\n",
                    af->info->name, rv);
-            af_print_filter_chain(s, af, MSGL_ERR);
-            return AF_ERROR;
+            goto error;
         }
     }
 
-    af_print_filter_chain(s, NULL, MSGL_V);
-
     /* Set previously unset fields in s->output to those of the filter chain
      * output. This is used to make the output format fixed, and even if you
      * insert new filters or change the input format, the output format won't
      * change. (Audio outputs generally can't change format at runtime.) */
     af_copy_unset_fields(&s->output, &s->filter_output);
-    return af_config_equals(&s->output, &s->filter_output) ? AF_OK : AF_ERROR;
+    if (af_config_equals(&s->output, &s->filter_output)) {
+        s->initialized = 1;
+        af_print_filter_chain(s, NULL, MSGL_V);
+        return AF_OK;
+    }
+
+    goto error;
 
 negotiate_error:
     MP_ERR(s, "Unable to convert audio input format to output format.\n");
+error:
+    s->initialized = -1;
     af_print_filter_chain(s, af, MSGL_ERR);
     return AF_ERROR;
 }
@@ -583,6 +588,7 @@ void af_uninit(struct af_stream *s)
 {
     while (s->first->next && s->first->next != s->last)
         af_remove(s, s->first->next);
+    s->initialized = 0;
 }
 
 struct af_stream *af_new(struct mpv_global *global)
@@ -632,10 +638,6 @@ void af_destroy(struct af_stream *s)
    The return value is 0 if success and -1 if failure */
 int af_init(struct af_stream *s)
 {
-    // Sanity check
-    if (!s)
-        return -1;
-
     // Precaution in case caller is misbehaving
     mp_audio_set_null_data(&s->input);
     mp_audio_set_null_data(&s->output);
@@ -647,6 +649,7 @@ int af_init(struct af_stream *s)
         for (int i = 0; list && list[i].name; i++) {
             if (!af_prepend(s, s->last, list[i].name, list[i].attribs)) {
                 af_uninit(s);
+                s->initialized = -1;
                 return -1;
             }
         }
@@ -655,7 +658,6 @@ int af_init(struct af_stream *s)
     if (af_reinit(s) != AF_OK) {
         // Something is stuffed audio out will not work
         MP_ERR(s, "Could not create audio filter chain.\n");
-        af_uninit(s);
         return -1;
     }
     return 0;
@@ -668,9 +670,6 @@ int af_init(struct af_stream *s)
 struct af_instance *af_add(struct af_stream *s, char *name, char **args)
 {
     struct af_instance *new;
-    // Sanity check
-    if (!s || !s->first || !name)
-        return NULL;
     // Insert the filter somewhere nice
     if (af_is_conversion_filter(s->first->next))
         new = af_append(s, s->first->next, name, args);
@@ -698,6 +697,7 @@ struct af_instance *af_add(struct af_stream *s, char *name, char **args)
 int af_filter(struct af_stream *s, struct mp_audio *data, int flags)
 {
     struct af_instance *af = s->first;
+    assert(s->initialized > 0);
     assert(mp_audio_config_equals(af->data, data));
     // Iterate through all filters
     while (af) {
diff --git a/audio/filter/af.h b/audio/filter/af.h
index bec0e823fe..579ac271ef 100644
--- a/audio/filter/af.h
+++ b/audio/filter/af.h
@@ -80,6 +80,8 @@ struct af_instance {
 
 // Current audio stream
 struct af_stream {
+    int initialized; // 0: no, 1: yes, -1: attempted to, but failed
+
     // The first and last filter in the list
     struct af_instance *first;
     struct af_instance *last;