diff --git a/src/ao.c b/src/ao.c

index 4791d4e..3d6431d 100644

--- a/src/ao.c

+++ b/src/ao.c

@@ -34,9 +34,21 @@ typedef struct {

 static int startwrite(sox_format_t * ft)

 {

   priv_t * ao = (priv_t *)ft->priv;

+  unsigned bytes_per_sample = (ft->encoding.bits_per_sample + 7) >> 3;

-  ao->buf_size = sox_globals.bufsiz - (sox_globals.bufsiz % (ft->encoding.bits_per_sample >> 3));

-  ao->buf_size *= (ft->encoding.bits_per_sample >> 3);

+  if (bytes_per_sample == 0)

+  {

+      lsx_fail("startwrite [ao driver]: Corrupted encoding data (bits per sample should not be zero)");

+      return SOX_EOF;

+  }

+

+  /* Since sox_sw_write_buf works with 16-bit samples, ensure there is an enough room */

+  if (bytes_per_sample < 2)

+    bytes_per_sample = 2;

+  /* Align the buffer size to the boundary divisible by bytes_per_sample */

+  ao->buf_size = sox_globals.bufsiz - (sox_globals.bufsiz % bytes_per_sample);

+  /* - add back possibly truncated bytes */

+  ao->buf_size += bytes_per_sample;

   ao->buf = lsx_malloc(ao->buf_size);

   if (!ao->buf)

@@ -90,12 +102,17 @@ static void sox_sw_write_buf(char *buf1, sox_sample_t const * buf2, size_t len,

 static size_t write_samples(sox_format_t *ft, const sox_sample_t *buf, size_t len)

 {

   priv_t * ao = (priv_t *)ft->priv;

+  /* This will be always > 0 in the case the format handler is properly used */

+  unsigned bytes_per_sample = (ft->encoding.bits_per_sample + 7) >> 3;

   uint_32 aobuf_size;

-  if (len > ao->buf_size / (ft->encoding.bits_per_sample >> 3))

-      len = ao->buf_size / (ft->encoding.bits_per_sample >> 3);

+  /* Normalize the number of samples */

+  if (bytes_per_sample < 2)

+      bytes_per_sample = 2;

+  if (len > ao->buf_size / bytes_per_sample)

+      len = ao->buf_size / bytes_per_sample;

-  aobuf_size = (ft->encoding.bits_per_sample >> 3) * len;

+  aobuf_size = bytes_per_sample * len;

   sox_sw_write_buf(ao->buf, buf, len, ft->encoding.reverse_bytes,

                    &(ft->clips));