diff a/src/dop_packer.cpp b/src/dop_packer.cpp
--- a/src/dop_packer.cpp
+++ b/src/dop_packer.cpp
@@ -99,14 +99,14 @@ unsigned char reverse(unsigned char x)
 
 void DopPacker::pack_buffer(dsf2flac_int32 *buffer, dsf2flac_uint32 bufferLen) {
 	// check the buffer seems sensible
-	div_t d = div(bufferLen,reader->getNumChannels());
+	ldiv_t d = div(dsf2flac_int64(bufferLen),reader->getNumChannels());
 	if (d.rem) {
 		fputs("Buffer length is not a multiple of getNumChannels()",stderr);
 		exit(EXIT_FAILURE);
 	}
 	// get the sample buffer
 	boost::circular_buffer<dsf2flac_uint8>* buff = reader->getBuffer();
-	for (int i=0; i<d.quot ; i++) {
+	for (dsf2flac_int64 i=0; i<d.quot ; i++) {
 
 		dsf2flac_int32 packed_sample;
 		dsf2flac_uint8 byte1;
diff a/src/dsd_decimator.cpp b/src/dsd_decimator.cpp
--- a/src/dsd_decimator.cpp
+++ b/src/dsd_decimator.cpp
@@ -179,7 +179,7 @@ template <typename sampleType> void DsdDecimator::getSamplesInternal(
 		bool roundToInt)
 {
 	// check the buffer seems sensible
-	div_t d = div(bufferLen,getNumChannels());
+	ldiv_t d = div(dsf2flac_int64(bufferLen),getNumChannels());
 	if (d.rem) {
 		fputs("Buffer length is not a multiple of getNumChannels()",stderr);
 		exit(EXIT_FAILURE);
@@ -188,7 +188,7 @@ template <typename sampleType> void DsdDecimator::getSamplesInternal(
 	bool clip = clipAmplitude > 0;
 	// get the sample buffer
 	boost::circular_buffer<dsf2flac_uint8>* buff = reader->getBuffer();
-	for (int i=0; i<d.quot ; i++) {
+	for (dsf2flac_int64 i=0; i<d.quot ; i++) {
 		// filter each chan in turn
 		for (dsf2flac_uint32 c=0; c<getNumChannels(); c++) {
 			calc_type sum = 0.0;