Untested code to optionally reduce resolution on extracting image frames.

5 files changed, 25 insertions, 14 deletions

diff --git a/src/picture_asset.cc b/src/picture_asset.cc
index 21da250a..4c66bd02 100644
--- a/src/picture_asset.cc
+++ b/src/picture_asset.cc
@@ -149,8 +149,8 @@ PictureAsset::equals (shared_ptr<const Asset> other, EqualityOptions opt) const
 				}
 				
 				/* Decompress the images to bitmaps */
-				opj_image_t* image_A = decompress_j2k (const_cast<uint8_t*> (buffer_A.RoData()), buffer_A.Size ());
-				opj_image_t* image_B = decompress_j2k (const_cast<uint8_t*> (buffer_B.RoData()), buffer_B.Size ());
+				opj_image_t* image_A = decompress_j2k (const_cast<uint8_t*> (buffer_A.RoData()), buffer_A.Size (), 0);
+				opj_image_t* image_B = decompress_j2k (const_cast<uint8_t*> (buffer_B.RoData()), buffer_B.Size (), 0);
 
 				/* Compare them */
 				
diff --git a/src/picture_frame.cc b/src/picture_frame.cc
index 87502e5e..06788da5 100644
--- a/src/picture_frame.cc
+++ b/src/picture_frame.cc
@@ -54,14 +54,19 @@ MonoPictureFrame::~MonoPictureFrame ()
 	delete _buffer;
 }
 
-/** @return An ARGB representation of this frame.  This is ARGB in the
+/** @param reduce a factor by which to reduce the resolution
+ *  of the image, expressed as a power of two (pass 0 for no
+ *  reduction).
+ *
+ *  @return An ARGB representation of this frame.  This is ARGB in the
  *  Cairo sense, so that each pixel takes up 4 bytes; the first byte
  *  is blue, second green, third red and fourth alpha (always 255).
+ *
  */
 shared_ptr<ARGBFrame>
-MonoPictureFrame::argb_frame () const
+MonoPictureFrame::argb_frame (int reduce) const
 {
-	opj_image_t* xyz_frame = decompress_j2k (const_cast<uint8_t*> (_buffer->RoData()), _buffer->Size());
+	opj_image_t* xyz_frame = decompress_j2k (const_cast<uint8_t*> (_buffer->RoData()), _buffer->Size(), reduce);
 	assert (xyz_frame->numcomps == 3);
 	shared_ptr<ARGBFrame> f = xyz_to_rgb (xyz_frame);
 	opj_image_destroy (xyz_frame);
@@ -92,23 +97,28 @@ StereoPictureFrame::~StereoPictureFrame ()
 	delete _buffer;
 }
 
-/** @return An ARGB representation of one of the eyes (left or right)
+/** @param reduce a factor by which to reduce the resolution
+ *  of the image, expressed as a power of two (pass 0 for no
+ *  reduction).
+ *
+ *  @param eye Eye to return (EYE_LEFT or EYE_RIGHT).
+ *
+ *  @return An ARGB representation of one of the eyes (left or right)
  *  of this frame.  This is ARGB in the Cairo sense, so that each
  *  pixel takes up 4 bytes; the first byte is blue, second green,
  *  third red and fourth alpha (always 255).
  *
- *  @param eye Eye to return (EYE_LEFT or EYE_RIGHT).
  */
 shared_ptr<ARGBFrame>
-StereoPictureFrame::argb_frame (Eye eye) const
+StereoPictureFrame::argb_frame (Eye eye, int reduce) const
 {
 	opj_image_t* xyz_frame = 0;
 	switch (eye) {
 	case LEFT:
-		xyz_frame = decompress_j2k (const_cast<uint8_t*> (_buffer->Left.RoData()), _buffer->Left.Size());
+		xyz_frame = decompress_j2k (const_cast<uint8_t*> (_buffer->Left.RoData()), _buffer->Left.Size(), reduce);
 		break;
 	case RIGHT:
-		xyz_frame = decompress_j2k (const_cast<uint8_t*> (_buffer->Right.RoData()), _buffer->Right.Size());
+		xyz_frame = decompress_j2k (const_cast<uint8_t*> (_buffer->Right.RoData()), _buffer->Right.Size(), reduce);
 		break;
 	}
 	
diff --git a/src/picture_frame.h b/src/picture_frame.h
index d207333a..07519455 100644
--- a/src/picture_frame.h
+++ b/src/picture_frame.h
@@ -40,7 +40,7 @@ public:
 	MonoPictureFrame (std::string mxf_path, int n);
 	~MonoPictureFrame ();
 
-	boost::shared_ptr<ARGBFrame> argb_frame () const;
+	boost::shared_ptr<ARGBFrame> argb_frame (int reduce = 0) const;
 
 private:
 	ASDCP::JP2K::FrameBuffer* _buffer;
@@ -53,7 +53,7 @@ public:
 	StereoPictureFrame (std::string mxf_path, int n);
 	~StereoPictureFrame ();
 
-	boost::shared_ptr<ARGBFrame> argb_frame (Eye eye) const;
+	boost::shared_ptr<ARGBFrame> argb_frame (Eye eye, int reduce = 0) const;
 
 private:
 	ASDCP::JP2K::SFrameBuffer* _buffer;
diff --git a/src/util.cc b/src/util.cc
index 360974a6..c171b2c7 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -159,11 +159,12 @@ libdcp::ends_with (string big, string little)
 }
 
 opj_image_t *
-libdcp::decompress_j2k (uint8_t* data, int64_t size)
+libdcp::decompress_j2k (uint8_t* data, int64_t size, int reduce)
 {
 	opj_dinfo_t* decoder = opj_create_decompress (CODEC_J2K);
 	opj_dparameters_t parameters;
 	opj_set_default_decoder_parameters (&parameters);
+	parameters.cp_reduce = reduce;
 	opj_setup_decoder (decoder, &parameters);
 	opj_cio_t* cio = opj_cio_open ((opj_common_ptr) decoder, data, size);
 	opj_image_t* image = opj_decode (decoder, cio);
diff --git a/src/util.h b/src/util.h
index 75115272..af6a08d6 100644
--- a/src/util.h
+++ b/src/util.h
@@ -48,7 +48,7 @@ extern std::string content_kind_to_string (ContentKind kind);
 extern ContentKind content_kind_from_string (std::string kind);
 extern bool ends_with (std::string big, std::string little);
 
-extern opj_image_t* decompress_j2k (uint8_t* data, int64_t size);
+extern opj_image_t* decompress_j2k (uint8_t* data, int64_t size, int reduce);
 extern boost::shared_ptr<ARGBFrame> xyz_to_rgb (opj_image_t* xyz_frame);
 
 }