Implement YUV 4:2:2 8bit support for QtQuick

This patch implements support for rendering of UYVY and YUYV sources when using
QtQuick for preview.

[ChangeLog][QtQuick][Rendering] Support for YUV 4:2:2 8bit has
been implemented for the QtQuick viewfinder.

Change-Id: I4d98f3c44240ee53f7708bc6bd84e7fb83aac069
Reviewed-by: Yoann Lopes <yoann.lopes@qt.io>

1 files changed, 22 insertions, 0 deletions

diff --git a/src/qtmultimediaquicktools/shaders/uyvyvideo.frag b/src/qtmultimediaquicktools/shaders/uyvyvideo.frag
new file mode 100644
index 000000000..8e34f7d33
--- /dev/null
+++ b/src/qtmultimediaquicktools/shaders/uyvyvideo.frag
@@ -0,0 +1,22 @@
+uniform sampler2D yuvTexture; // UYVY macropixel texture passed as RGBA format
+uniform float imageWidth; // The UYVY texture appears to the shader with 1/2 the image width since we use the RGBA format to pass UYVY
+uniform mediump mat4 colorMatrix;
+uniform lowp float opacity;
+
+varying highp vec2 qt_TexCoord;
+
+void main()
+{
+   // For U0 Y0 V0 Y1 macropixel, lookup Y0 or Y1 based on whether
+   // the original texture x coord is even or odd.
+   mediump float Y;
+   if (fract(floor(qt_TexCoord.x * imageWidth + 0.5) / 2.0) > 0.0)
+       Y = texture2D(yuvTexture, qt_TexCoord).a;       // odd so choose Y1
+   else
+       Y = texture2D(yuvTexture, qt_TexCoord).g;       // even so choose Y0
+   mediump float Cb = texture2D(yuvTexture, qt_TexCoord).r;
+   mediump float Cr = texture2D(yuvTexture, qt_TexCoord).b;
+
+   mediump vec4 color = vec4(Y, Cb, Cr, 1.0);
+   gl_FragColor = colorMatrix * color * opacity;
+}