af: don't require filters to allocate af_instance->data, redo buffers

Allocate af_instance->data in generic code before filter initialization.
Every filter needs af->data (since it contains the output
configuration), so there's no reason why every filter should allocate
and free it.

Remove RESIZE_LOCAL_BUFFER(), and replace it with mp_audio_realloc_min().
Interestingly, most code becomes simpler, because the new function takes
the size in samples, and not in bytes. There are larger change in
af_scaletempo.c and af_lavcac3enc.c, because these had copied and
modified versions of the RESIZE_LOCAL_BUFFER macro/function.

1 files changed, 2 insertions, 7 deletions

diff --git a/audio/filter/af_lavfi.c b/audio/filter/af_lavfi.c
index 381e2d0583..e77110c067 100644
--- a/audio/filter/af_lavfi.c
+++ b/audio/filter/af_lavfi.c
@@ -58,11 +58,6 @@ struct priv {
     AVFilterContext *in;
     AVFilterContext *out;
 
-    // Guarantee that the data stays valid until next filter call
-    char *out_buffer;
-
-    struct mp_audio temp;
-
     int64_t samples_in;
 
     AVRational timebase_out;
@@ -278,8 +273,8 @@ static struct mp_audio *play(struct af_instance *af, struct mp_audio *data)
         af->delay = (in_time - out_time) * r->rate * r->sstride;
     }
 
-    p->temp = *r;
-    return &p->temp;
+    *data = *r;
+    return data;
 }
 
 static void uninit(struct af_instance *af)