From b0519667da8edcea1592a0ba7b0dfa4b4709e034 Mon Sep 17 00:00:00 2001
From: Simon Howard
Date: Sun, 6 Mar 2011 20:59:51 +0000
Subject: Discard very short sound effects and strip lead-in / lead-out samples
 that apparently aren't played by Vanilla Doom (thanks Quasar).

Subversion-branch: /trunk/chocolate-doom
Subversion-revision: 2291
---
 src/i_sdlsound.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/i_sdlsound.c b/src/i_sdlsound.c
index a26a81dd..14a5147f 100644
--- a/src/i_sdlsound.c
+++ b/src/i_sdlsound.c
@@ -359,7 +359,13 @@ static boolean LoadSoundLump(int sound,
     // greater than the length of the lump itself, this is an invalid
     // sound lump.
 
-    if (*length > lumplen - 8)
+    // We also discard sound lumps that are less than 49 samples long,
+    // as this is how DMX behaves - although the actual cut-off length
+    // seems to vary slightly depending on the sample rate.  This needs
+    // further investigation to better understand the correct
+    // behavior.
+
+    if (*length > lumplen - 8 || *length <= 48)
     {
 	W_ReleaseLumpNum(*lumpnum);
 	return false;
@@ -368,6 +374,12 @@ static boolean LoadSoundLump(int sound,
     // Prune header
     *data_ref += 8;
 
+    // The DMX sound library seems to skip the first 16 and last 16
+    // bytes of the lump - reason unknown.
+
+    *data_ref += 16;
+    *length -= 32;
+
     return true;
 }
 
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