color decoding added; size decimation added

Author: poljvd

test/v4l2png/V4L2Grabber.cpp

@@ -19,15 +19,33 @@
 
 #define CLEAR(x) memset(&(x), 0, sizeof(x))
 
+static inline uint8_t clamp(int x)
+{
+	return (x<0) ? 0 : ((x>255) ? 255 : uint8_t(x));
+}
+
+static void yuv2rgb(uint8_t y, uint8_t u, uint8_t v, uint8_t & r, uint8_t & g, uint8_t & b)
+{
+	// see: http://en.wikipedia.org/wiki/YUV#Y.27UV444_to_RGB888_conversion
+	int c = y - 16;
+	int d = u - 128;
+	int e = v - 128;
+
+	r = clamp((298 * c + 409 * e + 128) >> 8);
+	g = clamp((298 * c - 100 * d - 208 * e + 128) >> 8);
+	b = clamp((298 * c + 516 * d + 128) >> 8);
+}
+
+
 V4L2Grabber::V4L2Grabber(const std::string &device, int input, VideoStandard videoStandard, int frameDecimation, int pixelDecimation) :
 	_deviceName(device),
 	_ioMethod(IO_METHOD_MMAP),
 	_fileDescriptor(-1),
 	_buffers(),
 	_width(0),
 	_height(0),
-	_frameDecimation(frameDecimation),
-	_pixelDecimation(pixelDecimation),
+	_frameDecimation(std::max(1, frameDecimation)),
+	_pixelDecimation(std::max(1, pixelDecimation)),
 	_currentFrame(0)
 {
 	open_device();
@@ -569,15 +587,24 @@ void V4L2Grabber::process_image(const uint8_t * data)
 {
 	std::cout << "process image" << std::endl;
 
-	QImage image(_width, _height, QImage::Format_RGB888);
+	int width = (_width + _pixelDecimation/2) / _pixelDecimation;
+	int height = (_height + _pixelDecimation/2) / _pixelDecimation;
+
+	QImage image(width, height, QImage::Format_RGB888);
 
-	for (int y = 0; y < image.height(); ++y)
+	for (int ySource = _pixelDecimation/2, yDest = 0; ySource < _height; ySource += _pixelDecimation, ++yDest)
 	{
-		for (int x = 0; x < image.width(); ++x)
+		for (int xSource = _pixelDecimation/2, xDest = 0; xSource < _width; xSource += _pixelDecimation, ++xDest)
 		{
-			uint8_t value = data[(image.width() * y + x) * 2 + 1];
-			//std::cout << "data = " << int(value) << std::endl;
-			image.setPixel(x, y, qRgb(value, value, value));
+			int index = (_width * ySource + xSource) * 2;
+			uint8_t y = data[index+1];
+			uint8_t u = (xSource%2 == 0) ? data[index] : data[index-2];
+			uint8_t v = (xSource%2 == 0) ? data[index+2] : data[index];
+
+			uint8_t r, g, b;
+			yuv2rgb(y, u, v, r, g, b);
+
+			image.setPixel(xDest, yDest, qRgb(r, g, b));
 		}
 	}
 

test/v4l2png/v4l2png.cpp

@@ -13,6 +13,39 @@
 
 using namespace vlofgren;
 
+/// Data parameter for the video standard
+typedef vlofgren::PODParameter<V4L2Grabber::VideoStandard> VideoStandardParameter;
+
+namespace vlofgren {
+	/// Translates a string (as passed on the commandline) to a color standard
+	///
+	/// @param[in] s The string (as passed on the commandline)
+	/// @return The color standard
+	/// @throws Parameter::ParameterRejected If the string did not result in a video standard
+	template<>
+	V4L2Grabber::VideoStandard VideoStandardParameter::validate(const std::string& s) throw (Parameter::ParameterRejected)
+	{
+		QString input = QString::fromStdString(s).toLower();
+
+		if (input == "pal")
+		{
+			return V4L2Grabber::PAL;
+		}
+		else if (input == "ntsc")
+		{
+			return V4L2Grabber::NTSC;
+		}
+		else if (input == "no-change")
+		{
+			return V4L2Grabber::NO_CHANGE;
+		}
+
+		throw Parameter::ParameterRejected("Invalid value for video standard. Valid values are: PAL, NTSC, and NO-CHANGE");
+		return V4L2Grabber::NO_CHANGE;
+	}
+}
+
+
 int main(int argc, char** argv)
 {
 	try
@@ -21,7 +54,17 @@ int main(int argc, char** argv)
 		OptionsParser optionParser("Simple application to send a command to hyperion using the Json interface");
 		ParameterSet & parameters = optionParser.getParameters();
 
-		SwitchParameter<> & argHelp  = parameters.add<SwitchParameter<> >('h', "help",  "Show this help message and exit");
+		StringParameter &   argDevice             = parameters.add<StringParameter>       ('d', "device",         "The device to use [default=/dev/video0]");
+		VideoStandardParameter & argVideoStandard = parameters.add<VideoStandardParameter>('v', "video-standard", "The used video standard. Valid values are PAL. NYSC, or NO-CHANGE [default=PAL]");
+		IntParameter &      argInput              = parameters.add<IntParameter>          ('i', "input",          "Input channel [default=0]");
+		IntParameter &      argSizeDecimation     = parameters.add<IntParameter>          ('s', "size-decimator", "Decimation factor for the output size [default=1]");
+		SwitchParameter<> & argHelp               = parameters.add<SwitchParameter<> >    ('h', "help",           "Show this help message and exit");
+
+		// set defaults
+		argDevice.setDefault("/dev/video0");
+		argVideoStandard.setDefault(V4L2Grabber::PAL);
+		argInput.setDefault(0);
+		argSizeDecimation.setDefault(1);
 
 		// parse all options
 		optionParser.parse(argc, const_cast<const char **>(argv));
@@ -32,6 +75,17 @@ int main(int argc, char** argv)
 			optionParser.usage();
 			return 0;
 		}
+
+		V4L2Grabber grabber(
+					argDevice.getValue(),
+					argInput.getValue(),
+					argVideoStandard.getValue(),
+					1,
+					argSizeDecimation.getValue());
+
+		grabber.start();
+		grabber.capture(1);
+		grabber.stop();
 	}
 	catch (const std::runtime_error & e)
 	{
@@ -40,10 +94,5 @@ int main(int argc, char** argv)
 		return 1;
 	}
 
-	V4L2Grabber grabber("/dev/video0", 0, V4L2Grabber::PAL, 25, 8);
-	grabber.start();
-	grabber.capture(250);
-	grabber.stop();
-
 	return 0;
 }