Basics of forced reduction of JPEG2000 decode resolution.

[dcpomatic.git] / src / lib / j2k_image_proxy.cc

diff --git a/src/lib/j2k_image_proxy.cc b/src/lib/j2k_image_proxy.cc
index f7e6dd5f4dd52f25ffc444f79de58e71376e4457..a60af1eb26182e299261a4a4fdf00b79e1b8f8a5 100644 (file)
--- a/src/lib/j2k_image_proxy.cc
+++ b/src/lib/j2k_image_proxy.cc
@@ -53,18 +53,31 @@ J2KImageProxy::J2KImageProxy (boost::filesystem::path path, dcp::Size size, AVPi
 
 }
 
-J2KImageProxy::J2KImageProxy (shared_ptr<const dcp::MonoPictureFrame> frame, dcp::Size size, AVPixelFormat pixel_format)
+J2KImageProxy::J2KImageProxy (
+       shared_ptr<const dcp::MonoPictureFrame> frame,
+       dcp::Size size,
+       AVPixelFormat pixel_format,
+       optional<int> forced_reduction
+       )
        : _data (frame->j2k_size ())
        , _size (size)
        , _pixel_format (pixel_format)
+       , _forced_reduction (forced_reduction)
 {
        memcpy (_data.data().get(), frame->j2k_data(), _data.size ());
 }
 
-J2KImageProxy::J2KImageProxy (shared_ptr<const dcp::StereoPictureFrame> frame, dcp::Size size, dcp::Eye eye, AVPixelFormat pixel_format)
+J2KImageProxy::J2KImageProxy (
+       shared_ptr<const dcp::StereoPictureFrame> frame,
+       dcp::Size size,
+       dcp::Eye eye,
+       AVPixelFormat pixel_format,
+       optional<int> forced_reduction
+       )
        : _size (size)
        , _eye (eye)
        , _pixel_format (pixel_format)
+       , _forced_reduction (forced_reduction)
 {
        switch (eye) {
        case dcp::EYE_LEFT:
@@ -93,35 +106,50 @@ J2KImageProxy::J2KImageProxy (shared_ptr<cxml::Node> xml, shared_ptr<Socket> soc
        socket->read (_data.data().get (), _data.size ());
 }
 
-shared_ptr<Image>
-J2KImageProxy::image (optional<dcp::NoteHandler>, optional<dcp::Size> target_size) const
+void
+J2KImageProxy::prepare (optional<dcp::Size> target_size) const
 {
-       if (!_decompressed || target_size != _target_size) {
-               int reduce = 0;
+       boost::mutex::scoped_lock lm (_mutex);
+
+       if (_decompressed && target_size == _target_size) {
+               return;
+       }
+
+       int reduce = 0;
 
+       if (_forced_reduction) {
+               reduce = *_forced_reduction;
+       } else {
                while (target_size && (_size.width / pow(2, reduce)) > target_size->width && (_size.height / pow(2, reduce)) > target_size->height) {
                        ++reduce;
                }
 
                --reduce;
                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;
-                                       }
+       _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;
        }
 
+       _target_size = target_size;
+}
+
+shared_ptr<Image>
+J2KImageProxy::image (optional<dcp::NoteHandler>, optional<dcp::Size> target_size) const
+{
+       prepare (target_size);
+
        shared_ptr<Image> image (new Image (_pixel_format, _decompressed->size(), true));
 
        /* Copy data in whatever format (sRGB or XYZ) into our Image; I'm assuming