Thread: SDL read error

I'm making my own lossy image compression codec in c++ w/ SDL, and the decoder isn't reading the header correctly (or more likely the encoder isn't writing it right)

Code:

#include <SDL.h>
#include <SDL_image.h>
#include <iostream>
#include <fstream>
#include <windows.h>
using namespace std;
int ICEC();
int DICEC();
void Slock(SDL_Surface *dest);
void Sulock(SDL_Surface *dest);
int main(int argc, char *argv[])
{
	if(SDL_Init(SDL_INIT_VIDEO) == -1)
		return -1;
	atexit(SDL_Quit);
	ICEC();
	DICEC();
}
int ICEC()
{
	SDL_Surface * inimage = IMG_Load("Image\\test.bmp");

	// vars
	Slock(inimage);
	int w = inimage->w;
	int h = inimage->h;
	Uint8 bpp = inimage->format->BytesPerPixel;
	bool subsample = true;
	ofstream out;

	//write width, height, and bytes per pixel as a header
	out.open("Image\\test.ice", ios::binary);
	out.write(reinterpret_cast<char*>(&w), sizeof(int));
	out.write(reinterpret_cast<char*>(&h), sizeof(int));
	out.write(reinterpret_cast<char*>(&bpp), sizeof(Uint8));
	Sulock(inimage);
	out.close();
	return 0;
}
void Slock(SDL_Surface *dest)
{
  if ( SDL_MUSTLOCK(dest) )
  {
    if ( SDL_LockSurface(dest) < 0 )
    {
      return;
    }
  }
}
void Sulock(SDL_Surface *dest)
{
	if ( SDL_MUSTLOCK(dest) )
	{
		SDL_UnlockSurface(dest);
	}
}

If I replace w = inimage->w with w = 512, the reader still doesn't give the correct number
Also, the call to Slock is causing an access violation.
I can't figure out the source of all these problems

Thanks,
MC

Hmm..."Image\\test.bmp" is valid (it's the famous 512X512 Lena test image)
so I still don't know
If anyone would be so nice, here is my full code
The call to printf in DICEC reveals that the width, height, and bpp are crazy
With that in mind I have to be suspicious of the rest of the data

For clarification, this code should convert an image from RGB into the YUV color space, and then subsample it with 4 lumas to a chroma

Code:

#include <SDL.h>
#include "engine.h"
#include "SDL_image.h"
#include "SDL_mixer.h"
#include <iostream>
#include <fstream>
#include <windows.h>

using namespace std;

int ICEC();
int DICEC();

SDL_Surface * screen, * inimage;

int main(int argc, char *argv[])
{
	if(SDL_Init(SDL_INIT_VIDEO|SDL_INIT_AUDIO|SDL_INIT_TIMER) == -1)
		return -1;
	atexit(SDL_Quit);
	screen = SDL_SetVideoMode(512, 512, 32, SDL_HWSURFACE|SDL_DOUBLEBUF);
	ICEC();
	DICEC();
	return 0;
}
int ICEC()
{
	SDL_Surface * inimage = IMG_Load("Image\\test.bmp");

	// vars
	int w = inimage->w;
	int h = inimage->h;
	Uint8 bpp = inimage->format->BytesPerPixel;
	bool subsample = true;
	ofstream out;

	//write width, height, and bytes per pixel as a header
	out.open("Image\\test.ice", ios::binary);
	out.write(reinterpret_cast<char*>(&w), sizeof(int));
	out.write(reinterpret_cast<char*>(&h), sizeof(int));
	out.write(reinterpret_cast<char*>(&bpp), sizeof(Uint8));
	switch (bpp)
	{
	case 3:
		Uint8 R, G, B, Y1,Y2,Y3,Y4;
		Uint32 U, V;
		Uint8 U2, V2;
		if (subsample == true)
		{
			for (int x = 0; x < w; x+=2)
			{
				for (int y = 0; y < h; y+=2)
				{
					U = 0; V = 0;

					Slock(inimage);
					SDL_GetRGB((Uint32)inimage->pixels + y*inimage->pitch + x * 3, inimage->format, &R, &G, &B);
					Y1 = (0.299*R + 0.587*G + 0.114*B);
					U+=(- 0.147*R - 0.289*G + 0.436*B);
					V+=(0.615*R - 0.515*G - 0.100*B);

					SDL_GetRGB((Uint32)inimage->pixels + y*inimage->pitch + (x+1) * 3, inimage->format, &R, &G, &B);
					Y2 = (0.299*R + 0.587*G + 0.114*B);
					U+=(- 0.147*R - 0.289*G + 0.436*B);
					V+=(0.615*R - 0.515*G - 0.100*B);

					SDL_GetRGB((Uint32)inimage->pixels + (y+1)*inimage->pitch + (x+1) * 3, inimage->format, &R, &G, &B);
					Y3 = (0.299*R + 0.587*G + 0.114*B);
					U+=(- 0.147*R - 0.289*G + 0.436*B);
					V+=(0.615*R - 0.515*G - 0.100*B);

					SDL_GetRGB((Uint32)inimage->pixels + (y+1)*inimage->pitch + x * 3, inimage->format, &R, &G, &B);
					Y4 = (0.299*R + 0.587*G + 0.114*B);
					U+=(- 0.147*R - 0.289*G + 0.436*B);
					V+=(0.615*R - 0.515*G - 0.100*B);
					Sulock(inimage);

					out.write(reinterpret_cast<char*>(&Y1), sizeof(Uint8));
					out.write(reinterpret_cast<char*>(&Y2), sizeof(Uint8));
					out.write(reinterpret_cast<char*>(&Y3), sizeof(Uint8));
					out.write(reinterpret_cast<char*>(&Y4), sizeof(Uint8));
					U2 = (Uint8)(U/4);
					V2 = (Uint8)(V/4);
					out.write(reinterpret_cast<char*>(&U2), sizeof(Uint8));
					out.write(reinterpret_cast<char*>(&V2), sizeof(Uint8));
				}
			}
		}
		break;
	}
	out.close();
	return 0;
}
int DICEC()
{
	//vars
	ifstream read;
	int w, h;
	Uint8 R, G, B, Y1,Y2,Y3,Y4,U,V;
	Uint8 bpp;
	bool subsample = true;

	//header
	read.open("Images\\test.ice", ios::binary);
	read.read(reinterpret_cast<char*>(&w), sizeof(int));
	read.read(reinterpret_cast<char*>(&h), sizeof(int));
	read.read(reinterpret_cast<char*>(&bpp), sizeof(Uint8));
	printf("%d%d%d", w, h, bpp);

	//main
	switch (bpp)
	{
	case 3:
		if (subsample == true)
		{
			for (int x = 0; x < w; x+=2)
			{
				for (int y = 0; y < h; y+=2)
				{
					 read.read(reinterpret_cast<char*>(&Y1), sizeof(Uint8));
					 read.read(reinterpret_cast<char*>(&Y2), sizeof(Uint8));
					 read.read(reinterpret_cast<char*>(&Y3), sizeof(Uint8));
					 read.read(reinterpret_cast<char*>(&Y4), sizeof(Uint8));
					 read.read(reinterpret_cast<char*>(&U), sizeof(Uint8));
					 read.read(reinterpret_cast<char*>(&V), sizeof(Uint8));
					 Slock(screen);
					 R = Y1 + 1.140*V;G = Y1 - 0.395*U - 0.581*V;B = Y1 + 2.032*U;
					 DrawPixel(screen, x, y, R, G, B);
					 R = Y2 + 1.140*V;G = Y2 - 0.395*U - 0.581*V;B = Y2 + 2.032*U;
					 DrawPixel(screen, x+1, y, R, G, B);
					 R = Y3 + 1.140*V;G = Y3 - 0.395*U - 0.581*V;B = Y3 + 2.032*U;
					 DrawPixel(screen, x+1, y+1, R, G, B);
					 R = Y4 + 1.140*V;G = Y4 - 0.395*U - 0.581*V;B = Y4 + 2.032*U;
					 DrawPixel(screen, x, y+1, R, G, B);
					 Sulock(screen);
				}
			}
		}
		else
		{
		}
		break;
	}
	read.close();
	while (!GetAsyncKeyState(VK_ESCAPE))
	{
		SDL_Flip(screen);
		SDL_Delay(1000);
	}
	return 0;
}