diff --git a/src/device.c b/src/device.c
index c4881a3..f016216 100644
--- a/src/device.c
+++ b/src/device.c
@@ -173,11 +173,15 @@ void device_close(struct device_t *dev) {
 	if (dev->run->hw_buffers) {
 		LOG_DEBUG("Unmapping HW buffers ...");
 		for (unsigned index = 0; index < dev->run->n_buffers; ++index) {
-			if (dev->run->hw_buffers[index].start != MAP_FAILED) {
-				if (munmap(dev->run->hw_buffers[index].start, dev->run->hw_buffers[index].length) < 0) {
+#			define HW_BUFFER(_next) dev->run->hw_buffers[index]._next
+
+			if (HW_BUFFER(size) > 0 && HW_BUFFER(data) != MAP_FAILED) {
+				if (munmap(HW_BUFFER(data), HW_BUFFER(size)) < 0) {
 					LOG_PERROR("Can't unmap device buffer %u", index);
 				}
 			}
+
+#			undef HW_BUFFER
 		}
 		dev->run->n_buffers = 0;
 		free(dev->run->hw_buffers);
@@ -395,13 +399,17 @@ static int _device_open_mmap(struct device_t *dev) {
 			return -1;
 		}
 
+#		define HW_BUFFER(_next) dev->run->hw_buffers[dev->run->n_buffers]._next
+
 		LOG_DEBUG("Mapping device buffer %u ...", dev->run->n_buffers);
-		dev->run->hw_buffers[dev->run->n_buffers].length = buf_info.length;
-		dev->run->hw_buffers[dev->run->n_buffers].start = mmap(NULL, buf_info.length, PROT_READ|PROT_WRITE, MAP_SHARED, dev->run->fd, buf_info.m.offset);
-		if (dev->run->hw_buffers[dev->run->n_buffers].start == MAP_FAILED) {
+		HW_BUFFER(data) = mmap(NULL, buf_info.length, PROT_READ|PROT_WRITE, MAP_SHARED, dev->run->fd, buf_info.m.offset);
+		if (HW_BUFFER(data) == MAP_FAILED) {
 			LOG_PERROR("Can't map device buffer %u", dev->run->n_buffers);
 			return -1;
 		}
+		HW_BUFFER(size) = buf_info.length;
+
+#		undef HW_BUFFER
 	}
 	return 0;
 }
diff --git a/src/device.h b/src/device.h
index a5dfafd..bcf5081 100644
--- a/src/device.h
+++ b/src/device.h
@@ -43,8 +43,8 @@
 
 
 struct hw_buffer_t {
-	void	*start;
-	size_t	length;
+	unsigned char	*data;
+	size_t			size;
 };
 
 struct picture_t {
diff --git a/src/encoders/cpu/encoder.c b/src/encoders/cpu/encoder.c
index 0c30a97..4fbe23c 100644
--- a/src/encoders/cpu/encoder.c
+++ b/src/encoders/cpu/encoder.c
@@ -95,7 +95,7 @@ void cpu_encoder_compress_buffer(struct device_t *dev, unsigned index, unsigned
 	jpeg_start_compress(&jpeg, TRUE);
 
 #	define WRITE_SCANLINES(_format, _func) \
-		case _format: { _func(&jpeg, dev->run->hw_buffers[index].start, dev->run->width, dev->run->height); break; }
+		case _format: { _func(&jpeg, dev->run->hw_buffers[index].data, dev->run->width, dev->run->height); break; }
 
 	switch (dev->run->format) {
 		// https://www.fourcc.org/yuv.php
diff --git a/src/encoders/hw/encoder.c b/src/encoders/hw/encoder.c
index 789eda4..77afd8a 100644
--- a/src/encoders/hw/encoder.c
+++ b/src/encoders/hw/encoder.c
@@ -69,8 +69,8 @@ void hw_encoder_compress_buffer(struct device_t *dev, unsigned index) {
 #	define PICTURE(_next)	dev->run->pictures[index]._next
 #	define HW_BUFFER(_next)	dev->run->hw_buffers[index]._next
 
-	assert(PICTURE(allocated) >= HW_BUFFER(length) + sizeof(HUFFMAN_TABLE));
-	PICTURE(size) = _memcpy_with_huffman(PICTURE(data), HW_BUFFER(start), HW_BUFFER(length));
+	assert(PICTURE(allocated) >= HW_BUFFER(size) + sizeof(HUFFMAN_TABLE));
+	PICTURE(size) = _memcpy_with_huffman(PICTURE(data), HW_BUFFER(data), HW_BUFFER(size));
 
 #	undef HW_BUFFER
 #	undef PICTURE
diff --git a/src/encoders/omx/encoder.c b/src/encoders/omx/encoder.c
index fed33e8..9469fa7 100644
--- a/src/encoders/omx/encoder.c
+++ b/src/encoders/omx/encoder.c
@@ -216,18 +216,18 @@ int omx_encoder_compress_buffer(struct omx_encoder_t *omx, struct device_t *dev,
 		if (omx->input_required) {
 			omx->input_required = false;
 
-			if (pos == HW_BUFFER(length)) {
+			if (pos == HW_BUFFER(size)) {
 				continue;
 			}
 
-			memcpy(IN(pBuffer), HW_BUFFER(start) + pos, slice_size);
+			memcpy(IN(pBuffer), HW_BUFFER(data) + pos, slice_size);
 			IN(nOffset) = 0;
 			IN(nFilledLen) = slice_size;
 
 			pos += slice_size;
 
-			if (pos + slice_size > HW_BUFFER(length)) {
-				slice_size = HW_BUFFER(length) - pos;
+			if (pos + slice_size > HW_BUFFER(size)) {
+				slice_size = HW_BUFFER(size) - pos;
 			}
 
 			if ((error = OMX_EmptyThisBuffer(omx->encoder, omx->input_buffer)) != OMX_ErrorNone) {