diff --git a/src/RageSoundMixBuffer.cpp b/src/RageSoundMixBuffer.cpp
index ca5ecc91f3..7b5226bb28 100644
--- a/src/RageSoundMixBuffer.cpp
+++ b/src/RageSoundMixBuffer.cpp
@@ -92,7 +92,7 @@ void RageSoundMixBuffer::read( float *pBuf )
 
 void RageSoundMixBuffer::read_deinterlace( float **pBufs, int channels )
 {
-	for( int i = 0; i < m_iBufUsed; ++i )
+	for( int i = 0; i < m_iBufUsed / channels; ++i )
 		for( int ch = 0; ch < channels; ++ch )
 			pBufs[ch][i] = m_pMixbuf[channels * i + ch];
 	m_iBufUsed = 0;