Move deinterleave of OpenJPEGImage to Image into the prepare(), meaning

that it can be multi-threaded.  This allows the bit shift for non-12bpp
JPEG2000 sources to be done at the same time as the deinterleave.
Should speed up DCP playback in some cases.

2 files changed, 26 insertions, 38 deletions

diff --git a/src/lib/j2k_image_proxy.cc b/src/lib/j2k_image_proxy.cc
index 1ef00d946..1422b6948 100644
--- a/src/lib/j2k_image_proxy.cc
+++ b/src/lib/j2k_image_proxy.cc
@@ -118,7 +118,7 @@ J2KImageProxy::prepare (optional<dcp::Size> target_size) const
 {
 	boost::mutex::scoped_lock lm (_mutex);
 
-	if (_decompressed && target_size == _target_size) {
+	if (_image && target_size == _target_size) {
 		DCPOMATIC_ASSERT (_reduce);
 		return *_reduce;
 	}
@@ -136,54 +136,42 @@ J2KImageProxy::prepare (optional<dcp::Size> target_size) const
 		reduce = max (0, reduce);
 	}
 
-	_decompressed = dcp::decompress_j2k (const_cast<uint8_t*> (_data.data().get()), _data.size (), reduce);
-
-	if (_decompressed->precision(0) < 12) {
-		int const shift = 12 - _decompressed->precision (0);
-		for (int c = 0; c < 3; ++c) {
-			int* p = _decompressed->data (c);
-			for (int y = 0; y < _decompressed->size().height; ++y) {
-				for (int x = 0; x < _decompressed->size().width; ++x) {
-					*p++ <<= shift;
-				}
-			}
-		}
-	}
-
-	_target_size = target_size;
-	_reduce = reduce;
+	shared_ptr<dcp::OpenJPEGImage> decompressed = dcp::decompress_j2k (const_cast<uint8_t*> (_data.data().get()), _data.size (), reduce);
 
-	return reduce;
-}
-
-pair<shared_ptr<Image>, int>
-J2KImageProxy::image (optional<dcp::NoteHandler>, optional<dcp::Size> target_size) const
-{
-	int const reduce = prepare (target_size);
+	_image.reset (new Image (_pixel_format, decompressed->size(), true));
 
-	shared_ptr<Image> image (new Image (_pixel_format, _decompressed->size(), true));
+	int const shift = 16 - decompressed->precision (0);
 
 	/* Copy data in whatever format (sRGB or XYZ) into our Image; I'm assuming
 	   the data is 12-bit either way.
 	*/
 
-	int const width = _decompressed->size().width;
+	int const width = decompressed->size().width;
 
 	int p = 0;
-	int* decomp_0 = _decompressed->data (0);
-	int* decomp_1 = _decompressed->data (1);
-	int* decomp_2 = _decompressed->data (2);
-	for (int y = 0; y < _decompressed->size().height; ++y) {
-		uint16_t* q = (uint16_t *) (image->data()[0] + y * image->stride()[0]);
+	int* decomp_0 = decompressed->data (0);
+	int* decomp_1 = decompressed->data (1);
+	int* decomp_2 = decompressed->data (2);
+	for (int y = 0; y < decompressed->size().height; ++y) {
+		uint16_t* q = (uint16_t *) (_image->data()[0] + y * _image->stride()[0]);
 		for (int x = 0; x < width; ++x) {
-			*q++ = decomp_0[p] << 4;
-			*q++ = decomp_1[p] << 4;
-			*q++ = decomp_2[p] << 4;
+			*q++ = decomp_0[p] << shift;
+			*q++ = decomp_1[p] << shift;
+			*q++ = decomp_2[p] << shift;
 			++p;
 		}
 	}
 
-	return make_pair (image, reduce);
+	_target_size = target_size;
+	_reduce = reduce;
+
+	return reduce;
+}
+
+pair<shared_ptr<Image>, int>
+J2KImageProxy::image (optional<dcp::NoteHandler>, optional<dcp::Size> target_size) const
+{
+	return make_pair (_image, prepare(target_size));
 }
 
 void
@@ -232,9 +220,9 @@ size_t
 J2KImageProxy::memory_used () const
 {
 	size_t m = _data.size();
-	if (_decompressed) {
+	if (_image) {
 		/* 3 components, 16-bits per pixel */
-		m += 3 * 2 * _decompressed->size().width * _decompressed->size().height;
+		m += 3 * 2 * _image->size().width * _image->size().height;
 	}
 	return m;
 }
diff --git a/src/lib/j2k_image_proxy.h b/src/lib/j2k_image_proxy.h
index a67cc24de..8e9a0fa99 100644
--- a/src/lib/j2k_image_proxy.h
+++ b/src/lib/j2k_image_proxy.h
@@ -80,7 +80,7 @@ private:
 	dcp::Data _data;
 	dcp::Size _size;
 	boost::optional<dcp::Eye> _eye;
-	mutable boost::shared_ptr<dcp::OpenJPEGImage> _decompressed;
+	mutable boost::shared_ptr<Image> _image;
 	mutable boost::optional<dcp::Size> _target_size;
 	mutable boost::optional<int> _reduce;
 	AVPixelFormat _pixel_format;