diff --git a/src/lib/openjp2/dwt.c b/src/lib/openjp2/dwt.c
index 2b9b9e92..1899af27 100644
--- a/src/lib/openjp2/dwt.c
+++ b/src/lib/openjp2/dwt.c
@@ -2123,7 +2123,7 @@ static OPJ_BOOL opj_dwt_decode_tile(opj_thread_pool_t* tp,
                 opj_idwt53_h(&h, &tiledp[(OPJ_SIZE_T)j * w]);
             }
         } else {
-            OPJ_UINT32 num_jobs = (OPJ_UINT32)num_threads;
+            OPJ_UINT32 num_jobs = (OPJ_UINT32)num_threads * 2;
             OPJ_UINT32 step_j;
 
             if (rh < num_jobs) {