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Commit acd619a9 authored by Jim Kaye's avatar Jim Kaye
Browse files

Adjust RGB-to-YUV conversion 

Round values rather than truncate them. ITU-R BT.601 indicates that
values should be rounded. Also, correct one coefficient value that
was slightly off.

These errors caused some CTS test failures for the Emulator.

BUG: http://b/31497838
Change-Id: I4c15e02dac266e243d3baf015fd3939877ab930c
(cherry picked from commit 36402501e4d94108db9e35fd3bb03c455d6a1635)
parent c5fae20b

media/libstagefright/omx/SoftVideoEncoderOMXComponent.cpp

+11 −4
Original line number Diff line number Diff line
@@ -480,18 +480,25 @@ void SoftVideoEncoderOMXComponent::ConvertRGB32ToPlanar( 
            unsigned green = src[greenOffset];

            unsigned blue  = src[blueOffset];



            // using ITU-R BT.601 conversion matrix

            // Using ITU-R BT.601-7 (03/2011)

            //   2.5.1: Ey'  = ( 0.299*R + 0.587*G + 0.114*B)

            //   2.5.2: ECr' = ( 0.701*R - 0.587*G - 0.114*B) / 1.402

            //          ECb' = (-0.299*R - 0.587*G + 0.886*B) / 1.772

            //   2.5.3: Y  = 219 * Ey'  +  16

            //          Cr = 224 * ECr' + 128

            //          Cb = 224 * ECb' + 128



            unsigned luma =

                ((red * 66 + green * 129 + blue * 25) >> 8) + 16;

                ((red * 65 + green * 129 + blue * 25 + 128) >> 8) + 16;



            dstY[x] = luma;



            if ((x & 1) == 0 && (y & 1) == 0) {

                unsigned U =

                    ((-red * 38 - green * 74 + blue * 112) >> 8) + 128;

                    ((-red * 38 - green * 74 + blue * 112 + 128) >> 8) + 128;



                unsigned V =

                    ((red * 112 - green * 94 - blue * 18) >> 8) + 128;

                    ((red * 112 - green * 94 - blue * 18 + 128) >> 8) + 128;



                dstU[x >> 1] = U;

                dstV[x >> 1] = V;