public static YCbCrImage RgbToYCbCr(RGBImage rgbImage)
{
Stopwatch stopwatch = Stopwatch.StartNew();
ColorChannel luminance = new ColorChannel(rgbImage.GetWidth(), rgbImage.GetHeight());
ColorChannel cbChannel = new ColorChannel(rgbImage.GetWidth(), rgbImage.GetHeight());
ColorChannel crChannel = new ColorChannel(rgbImage.GetWidth(), rgbImage.GetHeight());
int height = rgbImage.GetHeight();
if (height < 192)
{
for (int y = 0; y < rgbImage.GetHeight(); y++)
{
for (int x = 0; x < rgbImage.GetWidth(); x++)
{
YCbCr converted = ConvertRgbtoYCbCr(rgbImage.GetRGBAt(x, y));
luminance.SetPixel(x, y, converted.GetLuminanceChannel());
cbChannel.SetPixel(x, y, converted.GetCbChannel());
crChannel.SetPixel(x, y, converted.GetCrChannel());
}
}
}
else
{
int threadCount = 16;
if (height < 500)
{
threadCount = 4;
}
else if (height < 1000)
{
threadCount = 8;
}
CountdownEvent e = new CountdownEvent(1);
for (int i = 0; i < height; i += height / threadCount)
{
e.AddCount();
ThreadPool.QueueUserWorkItem(
state =>
{
object[] inp = state as object[];
//Console.WriteLine($"Thread with row {(int) inp[0]} to row {(int) inp[1]} started...");
int upper = (int)inp[1];
for (int row = (int)inp[0]; row < upper; row++)
{
for (int x = 0; x < rgbImage.GetWidth(); x++)
{
YCbCr converted = ConvertRgbtoYCbCr(rgbImage.GetRGBAt(x, row));
luminance.SetPixel(x, row, converted.GetLuminanceChannel());
cbChannel.SetPixel(x, row, converted.GetCbChannel());
crChannel.SetPixel(x, row, converted.GetCrChannel());
}
}
e.Signal();
}, new object[] { i, i + (height / threadCount) });
}
e.Signal();
e.Wait();
}
Console.WriteLine("Finished RGB to YCbCr conversion in "
+ stopwatch.ElapsedMilliseconds / 1000d
+ " seconds");
stopwatch.Stop();
return(new YCbCrImage(luminance,
cbChannel,
crChannel,
rgbImage.GetOriginalWidth(),
rgbImage.GetOriginalHeight()));
}