//takes avi file (given on command line as only arg) and converts to pgms

int startframe,endframe;

#include <stdio.h>
#include <math.h>
#include "avitopgms.h"

// function prototypes

void usage(void);

unsigned int pixsz,frame;
unsigned char *lpColor,*clp;
 unsigned int palletized;
 unsigned int bpscanl, dib_offset,x,y;
 char basename[100],tailname[100],filename[100];
 FILE *fp;
 float R, G, B;
 unsigned char fr,fg,fb;
// globals

int main(int argc, char **argv)
{
	int i=0,j=0, err=0;
	char avifilename[100] = "";
        AVIFILEINFO thisPfi;
	float fps;
	int sys_bit_specd = 0, sys_byte_specd = 0;
        PAVISTREAM pVideoStream;

	time_t current_time, el_time;

      

	
	if(argc < 2)
	{
		usage();
	}




	// parse for paramters here

       strcpy(avifilename, argv[1]);
    // initialize AVI subsystem
	AVIFileInit();


    // open avi file and validate file parameters

	    hResult = AVIFileOpen(&pfile, avifilename, OF_READ, 0L);
	    if(hResult)
	    {
		    fprintf(stderr, "\ncould not open filename %s!\n", 
		    	avifilename);
		    exit(7);
	    }

	    // get info structure on file
	    hResult = AVIFileInfo(pfile, &thisPfi, sizeof(AVIFILEINFO));
	    if(hResult)
	    {
		    fprintf(stderr, "\n%s does not appear to be an AVI file!\n", 
		    	avifilename);
		    exit(8);
	    }

	    // open a stream
	    hResult = AVIFileGetStream(pfile, &pVideoStream, streamtypeVIDEO, 0);
	    if(hResult)
	    {
		    fprintf(stderr, "\ncould not retrieve video stream from %s!\n", 
			    avifilename);
		    exit(31);
	    }

	    // prepare to decompress frames
	    pget = AVIStreamGetFrameOpen(pVideoStream, NULL);

	    // print details on input file
	    fps = (float)thisPfi.dwRate/(float)thisPfi.dwScale;
	    fprintf(stderr, "%s file details:\nWidth = %u, Height = %u, FPS = %4.2f", 
		    avifilename, thisPfi.dwWidth, thisPfi.dwHeight, fps);

	    // now retrieve a video frame so we can identify details
	    // get pointer to bitmap
	    lpbi = AVIStreamGetFrame(pget, 0);
	    if(!lpbi)
	    {
		    fprintf(stderr, "\ncould not retrieve video details for %s!",avifilename);
		    fprintf(stderr, "\nyou probably do not have a codec for this compression scheme!");
		    fprintf(stderr, "\nor avi file may be corrupt!\n");
	    	exit(9);
	    }

	    // we only handle non-palletized video

	    pixsz = lpbi->biBitCount;
	    if(pixsz!=8)
	    {
		    fprintf(stderr, "\ncan only handle 8 bit video!,");
		    fprintf(stderr, "\nthis file is %i bits!\n", pixsz);
		    exit(10);
	    }

	    fprintf(stderr, ", Bits per pixel = %u", pixsz);

            if(thisPfi.dwWidth>4095)
	        {
		        fprintf(stderr, "\nHorizontal width must < 4096!");
	    	    err = 1;
	        }
	        if(thisPfi.dwHeight>4095)
	        {
		        fprintf(stderr, "\nVerical height must be < 4096!");
		        err = 1;
	        }

	    if(err)
		    exit(11);

	    fprintf(stderr, "\nTotal Video Frames = %u, ", thisPfi.dwLength);
	    fprintf(stderr, "Length = %u sec.", 
			    			(unsigned int)thisPfi.dwLength/(int)(fps+.5));



	    if (lpbi->biCompression != BI_RGB)
	    {
		    fprintf(stderr, "\ncan not handle compressed DIBs from codec!\n");
		    err = 1;
	    }

	// locate color table - should there be one???
	lpColor = (unsigned char *)lpbi + lpbi->biSize; 
    fprintf(stderr,"pixel size (bits) %d\n",pixsz);
	// next, actual DIB
	if(pixsz==8)

		palletized=1;

	else

		palletized=0;




	if(palletized)
		dib_offset = sizeof(BITMAPINFOHEADER) + lpbi->biClrUsed * 4;
	else
		dib_offset = sizeof(BITMAPINFOHEADER); // offset past bitmap header
	lpbitmp = (unsigned char *)lpbi + dib_offset; // pointer to actual bitmap
    fprintf(stderr,"dib offset %d\n",dib_offset);
	switch(pixsz)
	{
	case 8:
		bpscanl = (unsigned int)(((lpbi->biWidth + 3)>>2)<<2);
		break;
	default:
		fprintf(stderr, "\ninternal error: illegal pixsz value\n");
		exit(28); // should never occur
	}
	// convert RGB DIB to YUV (4:2:0)
//	lpframeY = (unsigned char *)frame[0];
//	lpframeU = (unsigned char *)frame[1];
//	lpframeV = (unsigned char *)frame[2];
        printf("basename - output will be in format basename.number.pgm\n");
	scanf("%s",basename);
	printf("startframe number? (numbering from 0)\n");
	scanf("%d",&startframe);
	printf("endframe number?\n");
	scanf("%d",&endframe);
        if ((startframe<0)||(endframe>thisPfi.dwLength)||(endframe<startframe))	
		 {
			 fprintf(stderr,"must have startframe and endframe in range %d %d\n",0,thisPfi.dwLength);
			 exit(3);
		 }
	sprintf(tailname,"%s",".pgm");
for (frame=startframe;frame< endframe;frame++)
 { //process frame
	sprintf(filename,"%s%d%s",basename,frame,tailname);
	fp = fopen(filename,"wb");
	fprintf(fp,"P5\n%d %d\n255\n",lpbi->biWidth,lpbi->biHeight);
	lpbi = AVIStreamGetFrame(pget, frame);
	for(y = 0; y < (lpbi->biHeight); y++)
		for(x = 0; x < (lpbi->biWidth); x++)

		{
			switch(pixsz)
			{
			case 8:
				lpcurpix = (unsigned char *)(lpbitmp + (lpbi->biHeight - 1 -y) * bpscanl+x) ;
				break;
			default:
				fprintf(stderr, "\ninternal error: illegal pixsz value\n");
				exit(29); // should never occur
			}//case
//			*lpframeY++ = (int)(RY*R + GY*G + BY*B);
//			Ubuffer[(hblank/2)+x + (topblank+y)*width] = (int)(RU*R + GU*G + BU*B + 128);
//			Vbuffer[(hblank/2)+x + (topblank+y)*width] = (int)(RV*R + GV*G + BV*B + 128);
		fwrite(lpcurpix,1,1,fp);
		
		}//for
	    //read in rest of frames
	   fclose(fp);
}//end frame loop


	    //clean up
		
	    AVIStreamGetFrameClose(pget);

	AVIFileRelease(pfile);
	AVIFileExit();

	return(0);
}


void usage()
{
	fprintf(stderr,"give avifilename on commandline\n");
	exit(0);
}



	// now do FIR chroma subsampling

	//conv444to422(Ubuffer, Ubuffer422);

	//conv444to422(Vbuffer, Vbuffer422);

	//conv422to420(Ubuffer422, frame[1]);

	//conv422to420(Vbuffer422, frame[2]);


// horizontal filter and 2:1 subsampling

static void conv444to422(src,dst)
unsigned char *src, *dst;
{
	int i, j, im5, im4, im3, im2, im1, ip1, ip2, ip3, ip4, ip5, ip6;

    for (j=0; j<height; j++)
	{
		for (i=0; i<width; i+=2)
		{
			im5 = (i<5) ? 0 : i-5;
			im4 = (i<4) ? 0 : i-4;
			im3 = (i<3) ? 0 : i-3;
			im2 = (i<2) ? 0 : i-2;
			im1 = (i<1) ? 0 : i-1;
			ip1 = (i<width-1) ? i+1 : width-1;
			ip2 = (i<width-2) ? i+2 : width-1;
			ip3 = (i<width-3) ? i+3 : width-1;
			ip4 = (i<width-4) ? i+4 : width-1;
			ip5 = (i<width-5) ? i+5 : width-1;
			ip6 = (i<width-5) ? i+6 : width-1;

			// FIR filter with 0.5 sample interval phase shift
				dst[i>>1] = clp[(int)(228*(src[i]+src[ip1])
                         +70*(src[im1]+src[ip2])
                         -37*(src[im2]+src[ip3])
                         -21*(src[im3]+src[ip4])
                         +11*(src[im4]+src[ip5])
                         + 5*(src[im5]+src[ip6])+256)>>9];
		}
		src+= width;
		dst+= width>>1;
	}
}



// vertical filter and 2:1 subsampling
static void conv422to420(src,dst)
unsigned char *src, *dst;
{
	int w, i, j, jm5, jm4, jm3, jm2, jm1;
	int jp1, jp2, jp3, jp4, jp5, jp6;

	w = width>>1;

    for (i=0; i<w; i++)
	{
		for (j=0; j<height; j+=2)
		{
			jm5 = (j<5) ? 0 : j-5;
			jm4 = (j<4) ? 0 : j-4;
			jm3 = (j<3) ? 0 : j-3;
			jm2 = (j<2) ? 0 : j-2;
			jm1 = (j<1) ? 0 : j-1;
			jp1 = (j<height-1) ? j+1 : height-1;
			jp2 = (j<height-2) ? j+2 : height-1;
			jp3 = (j<height-3) ? j+3 : height-1;
			jp4 = (j<height-4) ? j+4 : height-1;
			jp5 = (j<height-5) ? j+5 : height-1;
			jp6 = (j<height-5) ? j+6 : height-1;

			// FIR filter with 0.5 sample interval phase shift
			dst[w*(j>>1)] = clp[(int)(228*(src[w*j]+src[w*jp1])
                             +70*(src[w*jm1]+src[w*jp2])
                             -37*(src[w*jm2]+src[w*jp3])
                             -21*(src[w*jm3]+src[w*jp4])
                             +11*(src[w*jm4]+src[w*jp5])
                             + 5*(src[w*jm5]+src[w*jp6])+256)>>9];
		}
		src++;
		dst++;
    }
}