From 0cb4b1b6542666919ae8b177f7bdb045e84e55ab Mon Sep 17 00:00:00 2001
From: Juho Hiltunen <jaacoppi@kapsi.fi>
Date: Sat, 27 Feb 2021 12:51:23 +0200
Subject: [PATCH] docs: add sox as an optional dependency.

using sox for ssml <audio> tag is hardcoded in readclause.c and for
--compile-phonemes in compiledict.c

Currently, --compile-phoneme doesn't need to run sox since the
samplerate for the specific file is correct. There might be a lot of
dead code in compiledata.c
---
 docs/building.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/docs/building.md b/docs/building.md
index 858b14ef..b5c0fe64 100644
--- a/docs/building.md
+++ b/docs/building.md
@@ -32,6 +32,10 @@ To build eSpeak NG on Windows, you will need:
 4. the [pcaudiolib](https://github.com/espeak-ng/pcaudiolib) project checked out to
    `src` (as `src/pcaudiolib`).
 
+Optionally, you need:
+
+1. sox (http://sox.sourceforge.net/) to enable audio output for SSML <audio> tag
+
 __NOTE:__ SAPI 5 voices are not currently available in this release of eSpeak NG.
 There is an [issue](https://github.com/espeak-ng/espeak-ng/issues/7) to track
 support for this feature.
@@ -77,6 +81,7 @@ Optionally, you need:
 3.  the [sonic](https://github.com/espeak-ng/sonic) development library to
     enable sonic audio speed up support;
 4.  the `ronn` man-page markdown processor to build the man pages.
+5. sox (http://sox.sourceforge.net/) to enable audio output for SSML <audio> tag
 
 To build the documentation, you need: