Compress Bmp to Jpeg

Posted on 2009-04-09
Last Modified: 2012-05-06
Hi all,

I have a Application which does live Video Capturing , using Webcam, and show it to the user(every thing locally). still under stating :-)

Environment:- DirectShow, Win32api, C

Now, want to Compress and Decompress the video frames and show it .

In this regard, as my first step.....
--when ever a Button_click event is fired , i want to grab the image and save that image as JPEG.
--i could able to Grab the image (which is of DIB format).
--i even have the Library which compresses & De-Compresses BMP-JPEG -BMP where Input is .bmp file and Output is .Jpeg

-- When button clicked, i have the BitmapInfoheader & Image Bits.
can you please tell me how to Compress the .bmp(not from file) and save as .jpeg.

/////////////    code which captures Image on Button Clicked   /////////////

DWORD GrabFrame()


       BYTE *lpCurrImage = NULL;



        m_pImageBytes = pImage; // Copies the Image into m_pImageBytes		

        MakeBMPHeader();        // Header



void MakeBMPHeader()


	DWORD  dwBitmapInfoSize;

	dwBitmapInfoSize = sizeof(BITMAPINFO);

	m_pBmp   = (BITMAPINFO *)new BYTE [dwBitmapInfoSize];

	m_pBmp->bmiHeader.biSize = sizeof(BITMAPINFOHEADER);

    m_pBmp->bmiHeader.biWidth = m_un32ImageWidth;

    m_pBmp->bmiHeader.biHeight = m_un32ImageHeight*-1;	

    m_pBmp->bmiHeader.biPlanes = 1;

    m_pBmp->bmiHeader.biBitCount =(unsigned short) m_un32ImageBits; //CamBits i.e 24

    m_pBmp->bmiHeader.biCompression = BI_RGB;

    m_pBmp->bmiHeader.biSizeImage = 0;

    m_pBmp->bmiHeader.biXPelsPerMeter = 0;

    m_pBmp->bmiHeader.biYPelsPerMeter = 0;

    m_pBmp->bmiHeader.biClrUsed = 0;

    m_pBmp->bmiHeader.biClrImportant = 0;



//////////////////////////////////////   Compression Library   . /////////////////////////////

       /////  .... Where it takes commmand line parameters (i) .Bmp file (ii) .Jpeg(any name of the file


main (int argc, char **argv)


struct jpeg_compress_struct cinfo;

	struct jpeg_error_mgr jerr;

cjpeg_source_ptr src_mgr;

	FILE * input_file;

	FILE * output_file;



if ((input_file = fopen(argv[i], READ_BINARY)) == NULL) {

		fprintf(stderr, "can't open %s\n", argv[i]);



	else {

		fprintf(stderr, "Opened %s\n", argv[i]);



    if ((output_file = fopen(argv[i], WRITE_BINARY)) == NULL) {

		fprintf(stderr, "can't open %s\n", argv[i]);



	else {

		fprintf(stderr, "Opened %s\n", argv[i]);



src_mgr = jinit_read_bmp(&cinfo);

	src_mgr->input_file = input_file;

(*src_mgr->start_input) (&cinfo, src_mgr);


jpeg_stdio_dest(&cinfo, output_file);

jpeg_start_compress(&cinfo, TRUE);

	/* Process data */

while (cinfo.next_scanline < cinfo.image_height) {

		num_scanlines = (*src_mgr->get_pixel_rows) (&cinfo, src_mgr);

		(void) jpeg_write_scanlines(&cinfo, src_mgr->buffer, num_scanlines);


	/* Finish compression and release memory */

	(*src_mgr->finish_input) (&cinfo, src_mgr);



	/* Close files */



	return 0;			/* suppress no-return-value warnings */


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Question by:kishan66

Expert Comment

ID: 24109342

Accepted Solution

kishan66 earned 0 total points
ID: 24591793
i found solution myself.
anyways thank you.

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