Compressing IplImage to JPEG using libjpeg in OpenCV
- by Petar
Hi everybody.
So I have this problem.
I have an IplImage that i want to compress to JPEG and do something with it. I use libjpeg.
I found a lot of answers "read through examples and docs" and such and did that. And successfully written a function for that.
FILE* convert2jpeg(IplImage* frame) {
FILE* outstream = NULL;
outstream=malloc(frame-imageSize*frame-nChannels*sizeof(char))
unsigned char *outdata = (uchar *) frame->imageData;
struct jpeg_error_mgr jerr;
struct jpeg_compress_struct cinfo;
int row_stride;
JSAMPROW row_ptr[1];
jpeg_create_compress(&cinfo);
jpeg_stdio_dest(&cinfo, outstream);
cinfo.image_width = frame->width;
cinfo.image_height = frame->height;
cinfo.input_components = frame->nChannels;
cinfo.in_color_space = JCS_RGB;
jpeg_set_defaults(&cinfo);
jpeg_start_compress(&cinfo, TRUE);
row_stride = frame->width * frame->nChannels;
while (cinfo.next_scanline < cinfo.image_height) {
row_ptr[0] = &outdata[cinfo.next_scanline * row_stride];
jpeg_write_scanlines(&cinfo, row_ptr, 1);
}
jpeg_finish_compress(&cinfo);
jpeg_destroy_compress(&cinfo);
return outstream;
}
Now this function is straight from the examples (except the part of allocating memory, but i need that since i'm not writnig to a file), but it still doesn't work.
It dies on jpeg_start_compress(&cinfo, TRUE); part?
Can anybody help?
