diff --git a/libavcodec/ac3enc.c b/libavcodec/ac3enc.c
index 031718afa4..b10c2d2ae9 100644
--- a/libavcodec/ac3enc.c
+++ b/libavcodec/ac3enc.c
@@ -56,6 +56,7 @@ typedef struct IComplex {
 } IComplex;
 
 typedef struct AC3MDCTContext {
+    const int16_t *window;                  ///< MDCT window function
     int nbits;                              ///< log2(transform size)
     int16_t *costab;                        ///< FFT cos table
     int16_t *sintab;                        ///< FFT sin table
@@ -262,6 +263,8 @@ static av_cold int mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct,
     if (ret)
         return ret;
 
+    mdct->window = ff_ac3_window;
+
     FF_ALLOC_OR_GOTO(avctx, mdct->xcos1,    n4 * sizeof(*mdct->xcos1),    mdct_alloc_fail);
     FF_ALLOC_OR_GOTO(avctx, mdct->xsin1,    n4 * sizeof(*mdct->xsin1),    mdct_alloc_fail);
     FF_ALLOC_OR_GOTO(avctx, mdct->rot_tmp,  n  * sizeof(*mdct->rot_tmp),  mdct_alloc_fail);
@@ -498,7 +501,7 @@ static void apply_mdct(AC3EncodeContext *s)
             AC3Block *block = &s->blocks[blk];
             const int16_t *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE];
 
-            apply_window(s->windowed_samples, input_samples, ff_ac3_window, AC3_WINDOW_SIZE);
+            apply_window(s->windowed_samples, input_samples, s->mdct.window, AC3_WINDOW_SIZE);
 
             block->exp_shift[ch] = normalize_samples(s);