Add an effect for 4:2:2 interleaved YCbCr input (UYVY).

[movit] / ycbcr.h

diff --git a/ycbcr.h b/ycbcr.h
new file mode 100644 (file)
index 0000000..7e5891f
--- /dev/null
+++ b/ycbcr.h
@@ -0,0 +1,44 @@
+#ifndef _MOVIT_YCBCR_H
+#define _MOVIT_YCBCR_H 1
+
+// Shared utility functions between YCbCrInput and YCbCr422InterleavedInput.
+
+#include "image_format.h"
+
+#include <Eigen/Core>
+
+namespace movit {
+
+struct YCbCrFormat {
+       // Which formula for Y' to use.
+       YCbCrLumaCoefficients luma_coefficients;
+
+       // If true, assume Y'CbCr coefficients are full-range, ie. go from 0 to 255
+       // instead of the limited 220/225 steps in classic MPEG. For instance,
+       // JPEG uses the Rec. 601 luma coefficients, but full range.
+       bool full_range;
+
+       // Sampling factors for chroma components. For no subsampling (4:4:4),
+       // set both to 1.
+       unsigned chroma_subsampling_x, chroma_subsampling_y;
+
+       // Positioning of the chroma samples. MPEG-1 and JPEG is (0.5, 0.5);
+       // MPEG-2 and newer typically are (0.0, 0.5).
+       float cb_x_position, cb_y_position;
+       float cr_x_position, cr_y_position;
+};
+
+// Convert texel sampling offset for the given chroma channel, given that
+// chroma position is <pos> (0..1), we are downsampling this chroma channel
+// by a factor of <subsampling_factor> and the texture we are sampling from
+// is <resolution> pixels wide/high.
+float compute_chroma_offset(float pos, unsigned subsampling_factor, unsigned resolution);
+
+// Given <ycbcr_format>, compute the values needed to turn Y'CbCr into R'G'B';
+// first subtract the returned offset, then left-multiply the returned matrix
+// (the scaling is already folded into it).
+void compute_ycbcr_matrix(YCbCrFormat ycbcr_format, float *offset, Eigen::Matrix3d *ycbcr_to_rgb);
+
+}  // namespace movit
+
+#endif // !defined(_MOVIT_YCBCR_INPUT_H)