diff -urN a/libavfilter/af_aformat.c b/libavfilter/af_aformat.c
--- a/libavfilter/af_aformat.c	2019-12-02 08:48:03.060361273 -0700
+++ b/libavfilter/af_aformat.c	2019-12-02 08:52:25.619248884 -0700
@@ -109,6 +109,16 @@
     return 0;
 }
 
+#define DEL_FIELD(p,mem,fld) if( p->mem ) { av_freep(&p->mem->fld); av_freep(&p->mem); }
+
+static av_cold void uninit(AVFilterContext *ctx)
+{
+    AFormatContext *s = ctx->priv;
+    DEL_FIELD(s, formats, formats);
+    DEL_FIELD(s, sample_rates, formats);
+    DEL_FIELD(s, channel_layouts, channel_layouts);
+}
+
 static int query_formats(AVFilterContext *ctx)
 {
     AFormatContext *s = ctx->priv;
@@ -146,6 +156,7 @@
     .name          = "aformat",
     .description   = NULL_IF_CONFIG_SMALL("Convert the input audio to one of the specified formats."),
     .init          = init,
+    .uninit        = uninit,
     .query_formats = query_formats,
     .priv_size     = sizeof(AFormatContext),
     .priv_class    = &aformat_class,