1 files changed, 35 insertions, 30 deletions
diff --git a/engines/sword1/sound.cpp b/engines/sword1/sound.cpp
index ddde7f4235..9140bddb65 100644
--- a/engines/sword1/sound.cpp
+++ b/engines/sword1/sound.cpp
@@ -116,7 +116,7 @@ void Sound::checkSpeechFileEndianness() {
 		return;
 
 	// I picked the sample to use randomly (I just made sure it is long enough so that there is
-	// a fair change of the heuristic to have a stable result and work for every language).
+	// a fair chance of the heuristic to have a stable result and work for every language).
 	int roomNo = _currentCowFile == 1 ? 1 : 129;
 	int localNo = _currentCowFile == 1 ? 2 : 933;
 	// Get the speech data and apply the heuristic
@@ -128,37 +128,42 @@ void Sound::checkSpeechFileEndianness() {
 		// Compute average of difference between two consecutive samples for both BE and LE
 		_bigEndianSpeech = false;
 		int16 *data = uncompressSpeech(index + _cowHeaderSize, sampleSize, &size);
-		if (data) {
-			if (size > 4000)
-				size = 2000;
-			else
-				size /= 2;
-			double le_diff_sum = 0.;
-			for (uint32 i = 1; i < size; ++i)
-				le_diff_sum += fabs((double)(data[i] - data[i - 1]));
-			delete[] data;
-			_bigEndianSpeech = true;
-			data = uncompressSpeech(index + _cowHeaderSize, sampleSize, &size);
-			if (data) {
-				if (size > 4000)
-					size = 2000;
-				else
-					size /= 2;
-				double be_diff_sum = 0.;
-				for (uint32 i = 1; i < size; ++i)
-					be_diff_sum += fabs((double)(data[i] - data[i - 1]));
-				delete [] data;
-				// Set the big endian flag
-				_bigEndianSpeech = (be_diff_sum < le_diff_sum);
-				if (_bigEndianSpeech)
-					debug(6, "Mac version: using big endian speech file");
-				else
-					debug(6, "Mac version: using little endian speech file");
-				debug(8, "Speech endianness heuristic: average = %f for BE and %f for LE, computed on %d samples)", be_diff_sum / (size - 1), le_diff_sum / (size - 1), size);
-			} else
-				_bigEndianSpeech = false;
+		uint32 maxSamples = size > 2000 ? 2000 : size;
+		double le_diff = endiannessHeuristicValue(data, size, maxSamples);
+		delete[] data;
+		_bigEndianSpeech = true;
+		data = uncompressSpeech(index + _cowHeaderSize, sampleSize, &size);
+		double be_diff = endiannessHeuristicValue(data, size, maxSamples);
+		delete [] data;
+		// Set the big endian flag
+		_bigEndianSpeech = (be_diff < le_diff);
+		if (_bigEndianSpeech)
+			debug(6, "Mac version: using big endian speech file");
+		else
+			debug(6, "Mac version: using little endian speech file");
+		debug(8, "Speech endianness heuristic: average = %f for BE and %f for LE (%d samples)", be_diff, le_diff, maxSamples);
+	}
+}
+											   
+double Sound::endiannessHeuristicValue(int16* data, uint32 dataSize, uint32 &maxSamples) {
+	if (!data)
+		return 50000.; // the heuristic value for the wrong endianess is about 21000 (1/3rd of the 16 bits range)
+
+	double diff_sum = 0.;
+	uint32 cpt = 0;
+	int16 prev_value = (int16)FROM_LE_16(*((uint16 *)(data)));
+	for (uint32 i = 1; i < dataSize && cpt < maxSamples; ++i) {
+		int16 value = (int16)FROM_LE_16(*((uint16 *)(data + i)));
+		if (value != prev_value) {
+			diff_sum += fabs((double)(value - prev_value));
+			++cpt;
+			prev_value = value;
 		}
 	}
+	if (cpt == 0)
+		return 50000.;
+	maxSamples = cpt;
+	return diff_sum / cpt;
 }