From d05aba55a86177f7a3d395c7a03c5c4e280b31fb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Erik=20Ronstro=CC=88m?= <erik.ronstrom@doremir.com>
Date: Mon, 25 Nov 2019 23:54:09 +0100
Subject: [PATCH] Don't call sox_write from output effect if input buffer is
 empty. This avoids issues with the vorbis encoder.

---
 src/output.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/output.c b/src/output.c
index c06ab7bd..fa92d5c3 100644
--- a/src/output.c
+++ b/src/output.c
@@ -31,6 +31,11 @@ static int flow(sox_effect_t *effp, sox_sample_t const * ibuf,
     sox_sample_t * obuf, size_t * isamp, size_t * osamp)
 {
   priv_t * p = (priv_t *)effp->priv;
+  /* Abort if there are no samples to write */
+  if (*isamp == 0) {
+    *osamp = 0;
+    return SOX_SUCCESS;
+  }
   /* Write out *isamp samples */
   size_t len = sox_write(p->file, ibuf, *isamp);