[PATCH] qcap: Don't clip intermediate values in YUV to RGB conversion code.

[Lei Zhang]

Hi,

The YUV to RGB conversion code follows the formula here. [1] But it's
rounding some of the intermediate values. I.e. yuv_gu and yuv_gv will
never be negative.


[1] http://www.fourcc.org/fccyvrgb.php
-------------- next part --------------
From 77050ce10b1e9da022451e93a6af22e722494dee Mon Sep 17 00:00:00 2001
From: Lei Zhang <thestig at google.com>
Date: Tue, 9 Dec 2008 16:35:32 -0800
Subject: [PATCH] qcap: Don't clip intermediate values in YUV to RGB conversion code.

---
 dlls/qcap/yuv.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/dlls/qcap/yuv.c b/dlls/qcap/yuv.c
index 358a711..04ca58e 100644
--- a/dlls/qcap/yuv.c
+++ b/dlls/qcap/yuv.c
@@ -68,21 +68,21 @@ void YUV_Init(void) {
    for (y_ = 0; y_ <= 255; y_++)
    {
       y = ((float) 255 / 219) * (y_ - 16);
-      yuv_xy[y_] = ValidRange((int) (y));
+      yuv_xy[y_] = (int) (y);
    }
 
    for (cb = 0; cb <= 255; cb++)
    {
       u = ((float) 255 / 224) * (cb - 128);
-      yuv_gu[cb] = - ValidRange((int) (0.344 * u));
-      yuv_bu[cb] =   ValidRange((int) (1.772 * u));
+      yuv_gu[cb] = (int) (-0.344 * u);
+      yuv_bu[cb] = (int) (1.772 * u);
    }
 
    for (cr = 0; cr <= 255; cr++)
    {
       v = ((float) 255 / 224) * (cr - 128);
-      yuv_rv[cr] =   ValidRange((int) (1.402 * v));
-      yuv_gv[cr] = - ValidRange((int) (0.714 * v));
+      yuv_rv[cr] = (int) (1.402 * v);
+      yuv_gv[cr] = (int) (-0.714 * v);
    }
    TRACE("Filled hash table\n");
 }
-- 
1.5.4.5