diff --git a/ffmpeg-definitions.rkt b/ffmpeg-definitions.rkt
index af5e6e9..2f1d257 100644
--- a/ffmpeg-definitions.rkt
+++ b/ffmpeg-definitions.rkt
@@ -1378,15 +1378,12 @@
 (define (call-with-swr-output-buffer max-bytes proc)
   (early-return
    ;; Both allocations are native because swr_convert reads/writes C pointers.
-   ((tmp (malloc max-bytes 'raw) ? (eq? tmp #f) => #f)
-    (out-planes (malloc _pointer 1 'raw) 
-                ? (eq? out-planes #f) => #f
-                ~ (free tmp))
+   ((tmp (malloc max-bytes 'atomic-interior) ? (eq? tmp #f) => #f)
+    (out-planes (malloc _pointer 1 'atomic-interior) 
+                ? (eq? out-planes #f) => #f)
     ;; Interleaved output has one plane; out-planes[0] points to tmp.
     (do (ptr-set! out-planes _pointer 0 tmp))
     (result (proc tmp out-planes)))
-   (free out-planes)
-   (free tmp)
    result)
   )
 
@@ -1511,27 +1508,20 @@
                ? (<= delay 0) => produced)
         (max-bytes (av_samples_get_buffer_size #f channels delay FMPG_OUTPUT_FMT 1)
                    ? (<= max-bytes 0) => produced)
-        (tmp (malloc max-bytes 'raw)
+        (tmp (malloc max-bytes 'atomic-interior)
              ? (eq? tmp #f) => -1)
-        (out-planes (malloc _pointer 1 'raw)
-                    ? (eq? out-planes #f) => -1
-                    ~ (free tmp))
+        (out-planes (malloc _pointer 1 'atomic-interior)
+                    ? (eq? out-planes #f) => -1)
 
         (do (ptr-set! out-planes _pointer 0 tmp))
 
         ;; Null input with 0 samples asks swresample to flush delayed output.
         (out-samples (swr_convert swr-ctx out-planes delay #f 0)
-                     ? (<= out-samples 0) => produced
-                     ~ (begin
-                         (free out-planes)
-                         (free tmp)))
+                     ? (<= out-samples 0) => produced)
 
         (used-bytes (av_samples_get_buffer_size #f channels out-samples
                                                 FMPG_OUTPUT_FMT 1)
-                    ? (< used-bytes 0) => produced
-                    ~ (begin
-                        (free out-planes)
-                        (free tmp)))
+                    ? (< used-bytes 0) => produced)
 
         ;; If this is the first output, the buffer belongs to the current next-sample-pos.
         (do
@@ -1542,17 +1532,12 @@
                                   sample-rate*)))))
 
         (appended? (append-bytes! dec tmp used-bytes)
-                   ? (not appended?) => -1
-                   ~ (begin
-                       (free out-planes)
-                       (free tmp)))
+                   ? (not appended?) => -1)
         )
 
        (ds-last-samples! dec (+ (ds-last-samples dec) out-samples))
        (ds-next-sample-pos! dec (+ (ds-next-sample-pos dec)
                                    out-samples))
-       (free out-planes)
-       (free tmp)
        (loop 1))
       )
     )