From fb396395e99fcf9058ffac27c6445a5c24597b6c Mon Sep 17 00:00:00 2001
From: luckytyphlosion <10688458+luckytyphlosion@users.noreply.github.com>
Date: Tue, 5 Jan 2021 11:34:38 -0500
Subject: [PATCH] Fix bug in pcm delta compression.

error wasn't being correctly calculated for when new_sample was negative and sample was positive.
---
 tools/aif2pcm/main.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/aif2pcm/main.c b/tools/aif2pcm/main.c
index cd5ac4a50..b9709bee8 100644
--- a/tools/aif2pcm/main.c
+++ b/tools/aif2pcm/main.c
@@ -426,7 +426,9 @@ int get_delta_index(uint8_t sample, uint8_t prev_sample)
 	for (int i = 0; i < 16; i++)
 	{
 		uint8_t new_sample = prev_sample + gDeltaEncodingTable[i];
-		int error = sample > new_sample ? sample - new_sample : new_sample - sample;
+		uint8_t sample_diff_1 = (sample - new_sample) & 0xff;
+		uint8_t sample_diff_2 = (new_sample - sample) & 0xff;
+		int error = sample_diff_1 < sample_diff_2 ? sample_diff_1 : sample_diff_2;
 
 		if (error < best_error)
 		{