Send SDL frame to another process and display it - ffmpeg

Question

I am trying to send a frame to another process in order to display it. I'm using dranger tutorial02.
I was thinking to serialize the SDL_Overlay struct to bytes after the call to sws_scale, send it to the other process, deserialize it and call SDL_DisplayYUVOverlay to display it.
Do you think this is my best choice?
If so, I'm having hard time serializing this struct.. here's the code:
size_t size_of_Overlay(SDL_Overlay *bmp) {
/*
* typedef struct {
*
* Uint32 format;
* int w, h;
* int planes;
* Uint16 *pitches;
* Uint8 **pixels;
* Uint32 hw_overlay:1; <- can I ignore it? cant point to a bit-field..
*
* } SDL_Overlay;
*/
// w,h,planes format pitches pixels
return sizeof(int)*3 + sizeof(Uint32) + sizeof(Uint16)*bmp->w + sizeof(Uint8)*bmp->h*3;
}
void overlay_to_buf(SDL_Overlay* bmp, char* buf) {
if(!bmp || !buf) {
perror("overlay_to_buf");
exit(1);
}
memcpy(buf, &bmp->format, sizeof(Uint32));
buf += sizeof(Uint32);
memcpy(buf, &bmp->w, sizeof(int));
buf += sizeof(int);
memcpy(buf, &bmp->h, sizeof(int));
buf += sizeof(int);
memcpy(buf, &bmp->planes, sizeof(int));
buf += sizeof(int);
memcpy(buf, bmp->pitches, sizeof(Uint16)*bmp->w);
buf += sizeof(Uint16)*bmp->w;
memcpy(buf, bmp->pixels[0], sizeof(Uint8)*bmp->h);
buf += sizeof(Uint8)*bmp->h;
memcpy(buf, bmp->pixels[1], sizeof(Uint8)*bmp->h);
buf += sizeof(Uint8)*bmp->h;
memcpy(buf, bmp->pixels[2], sizeof(Uint8)*bmp->h);
buf += sizeof(Uint8)*bmp->h;
}
void buf_to_overlay(SDL_Overlay *bmp, char* buf) {
if(!bmp || !buf) {
perror("buf_to_overlay");
exit(1);
}
memcpy(&bmp->format, buf, sizeof(Uint32));
buf += sizeof(Uint32);
memcpy(&bmp->w, buf, sizeof(int));
buf += sizeof(int);
memcpy(&bmp->h, buf, sizeof(int));
buf += sizeof(int);
memcpy(&bmp->planes, buf, sizeof(int));
buf += sizeof(int);
bmp->pitches = (Uint16*)malloc(sizeof(Uint16)*bmp->w);
memcpy(bmp->pitches, buf, sizeof(Uint16)*bmp->w);
buf += sizeof(Uint16)*bmp->w;
bmp->pixels[0] = (Uint8*)malloc(sizeof(Uint8)*bmp->h);
memcpy(bmp->pixels[0], buf, sizeof(Uint8)*bmp->h);
buf += sizeof(Uint8)*bmp->h;
bmp->pixels[1] = (Uint8*)malloc(sizeof(Uint8)*bmp->h);
memcpy(bmp->pixels[1], buf, sizeof(Uint8)*bmp->h);
buf += sizeof(Uint8)*bmp->h;
bmp->pixels[2] = (Uint8*)malloc(sizeof(Uint8)*bmp->h);
memcpy(bmp->pixels[2], buf, sizeof(Uint8)*bmp->h);
buf += sizeof(Uint8)*bmp->h;
}

Answer 1

I've succeeded to serialize it and display on the other process..
The way of serialization was wrong, here's the correct code:
size_t size_of_Overlay(SDL_Overlay *bmp) {
/*
* typedef struct {
*
* Uint32 format;
* int w, h;
* int planes;
* Uint16 *pitches;
* Uint8 **pixels;
* Uint32 hw_overlay:1; <- doesn't being accounted
*
* } SDL_Overlay;
*/
return sizeof(int)*3 + sizeof(Uint32) + sizeof(Uint16)*3 + sizeof(Uint8)*bmp->h*bmp->w*3;
}
void overlay_to_buf(SDL_Overlay* bmp, char* buf) {
if(!bmp || !buf) {
perror("overlay_to_buf");
exit(-1);
}
memcpy(buf, &bmp->format, sizeof(Uint32));
buf += sizeof(Uint32);
memcpy(buf, &bmp->w, sizeof(int));
buf += sizeof(int);
memcpy(buf, &bmp->h, sizeof(int));
buf += sizeof(int);
memcpy(buf, &bmp->planes, sizeof(int));
buf += sizeof(int);
memcpy(buf, &bmp->pitches[0], sizeof(Uint16));
buf += sizeof(Uint16);
memcpy(buf, &bmp->pitches[1], sizeof(Uint16));
buf += sizeof(Uint16);
memcpy(buf, &bmp->pitches[2], sizeof(Uint16));
buf += sizeof(Uint16);
memcpy(buf, bmp->pixels[0], sizeof(Uint8)*bmp->h*bmp->w);
buf += sizeof(Uint8)*bmp->h*bmp->w;
memcpy(buf, bmp->pixels[1], sizeof(Uint8)*bmp->h*bmp->w);
buf += sizeof(Uint8)*bmp->h*bmp->w;
memcpy(buf, bmp->pixels[2], sizeof(Uint8)*bmp->h*bmp->w);
}
void buf_to_overlay(SDL_Overlay *bmp, char* buf) {
if(!bmp || !buf) {
perror("to_message");
exit(-1);
}
memcpy(&bmp->format, buf, sizeof(Uint32));
buf += sizeof(Uint32);
memcpy(&bmp->w, buf, sizeof(int));
buf += sizeof(int);
memcpy(&bmp->h, buf, sizeof(int));
buf += sizeof(int);
memcpy(&bmp->planes, buf, sizeof(int));
buf += sizeof(int);
memcpy(&bmp->pitches[0], buf, sizeof(Uint16));
buf += sizeof(Uint16);
memcpy(&bmp->pitches[1], buf, sizeof(Uint16));
buf += sizeof(Uint16);
memcpy(&bmp->pitches[2], buf, sizeof(Uint16));
buf += sizeof(Uint16);
/* pixels are allocated outside the function,
* just one allocation during the whole video since
* the screen size doesn't change.
*/
memcpy(bmp->pixels[0], buf, sizeof(Uint8)*bmp->h*bmp->w);
buf += sizeof(Uint8)*bmp->h*bmp->w;
memcpy(bmp->pixels[1], buf, sizeof(Uint8)*bmp->h*bmp->w);
buf += sizeof(Uint8)*bmp->h*bmp->w;
memcpy(bmp->pixels[2], buf, sizeof(Uint8)*bmp->h*bmp->w);
}