Problem displaying YUV format

SDL Development
1

Hi all. I need help after 3 night of work and no result.
I have for v4l cam (fedora 4 core) and i’m trying to build a GTK
interface to show all cam’s frames in the same winwows. I chose to
display YUV2 format. I i try one cam all seem to work correctly. The
code i’m using is the follow:

SDL_Overlay *cam4Overlay;
int flags 	=  SDL_HWSURFACE|SDL_DOUBLEBUF; //SDL_SWSURFACE

| SDL_FULLSCREEN;
int nWidth = XWINDOWSIZE / cam4Struct->nRedim;
int nHeigth = YWINDOWSIZE / cam4Struct->nRedim;
int i = 0;

SDL_Rect rect4;
rect4.x = cam4Struct->nTopX;
rect4.y = cam4Struct->nTopY;
rect4.w = nWidth;
rect4.h = nHeigth;

cam4Overlay = SDL_CreateYUVOverlay(nWidth, nHeigth,

SDL_YUY2_OVERLAY, mainscreen);

while( !quit )
{
	....
	.....	
	
	SDL_LockYUVOverlay(cam4Overlay);

memcpy(cam4Overlay->pixels[0],buffer.data,buffer.buffer_size);

	cam4Overlay->pitches[0] = 320;
	
		SDL_UnlockYUVOverlay(cam4Overlay);
		SDL_DisplayYUVOverlay(cam4Overlay,&rect4);
}
....

I need to show the 4 cams in 4 SDL_Rect on the main screen.
I use thread to assolve this job.
The problems is:

My frame are showed correctly but each time i update one cam i can see
on the other a rect filled of blue color.

What i’m doing wrong? Anynone know where is my problem? I’m really nes
on the SDl lib. Please help me.

Thank’s in advance.

Carmelo Gallucci

2

int NumOverlay = 1;
SDL_Overlay *cam4Overlay[ NumOverlay ];
int flags = SDL_HWSURFACE|SDL_DOUBLEBUF; //SDL_SWSURFACE
| SDL_FULLSCREEN;
int nWidth = XWINDOWSIZE / cam4Struct->nRedim;
int nHeigth = YWINDOWSIZE / cam4Struct->nRedim;
int i = 0;

    SDL_Rect rect4;
    rect4.x = cam4Struct->nTopX;
    rect4.y = cam4Struct->nTopY;
    rect4.w = nWidth;
    rect4.h = nHeigth;

/* You may want to edit the nWidth and nHeight to fit every camra */
for( int yuv = 0; yuv < NumOverlay; yuv++ )
cam4Overlay[yuv] = SDL_CreateYUVOverlay(nWidth, nHeigth, SDL_YUY2_OVERLAY,
mainscreen);

while( !quit )
{
// …
for( int yuv = 0; yuv < NumOverlay; yuv++ )
{
SDL_LockYUVOverlay( cam4Overlay[ yuv ] );

memcpy(cam4Overlay->pixels[0],buffer.data,buffer.buffer_size);

SDL_UnLockYUVOverlay( cam4Overlay[ yuv ] );

SDL_Delay( 10 );

cam4Overlay->pitches[0] = 320;

SDL_DisplayYUVOverlay( cam4Overlay[ yuv ], rect4 ); // Obviously change the
rect4 to whereever
}

SDL_Flip( mainscreen );
SDL_Delay( 1 ); // Mmmmm…CPU conservation
}

I haven’t tested this code, but I think it should work.

Alex~ (not the other techie one…just a loser Alex)On 1/29/06, carmelo gallucci wrote:

Hi all. I need help after 3 night of work and no result.
I have for v4l cam (fedora 4 core) and i’m trying to build a GTK
interface to show all cam’s frames in the same winwows. I chose to
display YUV2 format. I i try one cam all seem to work correctly. The
code i’m using is the follow:

    SDL_Overlay *cam4Overlay;
    int flags       =  SDL_HWSURFACE|SDL_DOUBLEBUF; //SDL_SWSURFACE

| SDL_FULLSCREEN;
int nWidth = XWINDOWSIZE / cam4Struct->nRedim;
int nHeigth = YWINDOWSIZE / cam4Struct->nRedim;
int i = 0;

    SDL_Rect rect4;
    rect4.x = cam4Struct->nTopX;
    rect4.y = cam4Struct->nTopY;
    rect4.w = nWidth;
    rect4.h = nHeigth;

    cam4Overlay = SDL_CreateYUVOverlay(nWidth, nHeigth,

SDL_YUY2_OVERLAY, mainscreen);

    while( !quit )
    {
            ....
            .....

            SDL_LockYUVOverlay(cam4Overlay);

memcpy(cam4Overlay->pixels[0],buffer.data,buffer.buffer_size);

            cam4Overlay->pitches[0] = 320;

                    SDL_UnlockYUVOverlay(cam4Overlay);
                    SDL_DisplayYUVOverlay(cam4Overlay,&rect4);
    }
    ....

I need to show the 4 cams in 4 SDL_Rect on the main screen.
I use thread to assolve this job.
The problems is:

My frame are showed correctly but each time i update one cam i can see
on the other a rect filled of blue color.

What i’m doing wrong? Anynone know where is my problem? I’m really nes
on the SDl lib. Please help me.

Thank’s in advance.

Carmelo Gallucci

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