/*===========================================================================*
 * jpeg.c								     *
 *									     *
 *	procedures to deal with JPEG files				     *
 *									     *
 * EXPORTED PROCEDURES:							     *
 *	JMovie2JPEG							     *
 *      ReadJPEG							     *
 *									     *
 *===========================================================================*/

/*
 * Copyright (c) 1995 The Regents of the University of California.
 * All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose, without fee, and without written agreement is
 * hereby granted, provided that the above copyright notice and the following
 * two paragraphs appear in all copies of this software.
 *
 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
 * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
 * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
 * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO
 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
 */

/*  
 *  $Header: /u/smoot/md/mpeg_encode/RCS/jpeg.c,v 1.7 1995/09/09 01:10:28 smoot Exp $
 *  $Log: jpeg.c,v $
 *  Revision 1.7  1995/09/09 01:10:28  smoot
 *  added greyscale, and fixed odd-sized images
 *
 * Revision 1.6  1995/06/08  20:36:00  smoot
 * added "b"'s to fopen()s for MSDOS
 *
 * Revision 1.5  1995/02/02  21:24:02  eyhung
 * slight cleanup of unused variables
 *
 * Revision 1.4  1995/01/19  23:08:33  eyhung
 * Changed copyrights
 *
 * Revision 1.3  1995/01/19  22:58:34  smoot
 * fixes (I dont know what)
 *
 * Revision 1.2  1994/11/12  02:11:50  keving
 * nothing
 *
 * Revision 1.1  1994/03/15  00:27:11  keving
 * nothing
 *
 * Revision 1.2  1993/12/22  19:19:01  keving
 * nothing
 *
 * Revision 1.1  1993/07/22  22:23:43  keving
 * nothing
 *
 */


/*==============*
 * HEADER FILES *
 *==============*/

#include <stdio.h>
#ifndef WIN32
#include <unistd.h> /* lseek */
#endif
#include "all.h"
#include "mtypes.h"
#include "frames.h"
#include "prototypes.h"
#include "param.h"
#include "readframe.h"
#include "fsize.h"
#include "rgbtoycc.h"
#include "jpeg.h"

/* make it happier.... */
#undef DCTSIZE2
#include "jpeglib.h"

#define HEADER_SIZE 607   /*JFIF header size used on output images*/

void safe_jcopy_sample_rows _ANSI_ARGS_ ((JSAMPARRAY input_array, int source_row, JSAMPARRAY output_array, int dest_row, int num_rows, JDIMENSION num_cols, JDIMENSION max_cols, boolean resample));


/*=======================================================================*
 *                                                                       *
 * JMovie2JPEG                                                           *
 *                                                                       *
 *      Splits up a Parallax J_Movie into a set of JFIF image files      *
 *                                                                       *
 * RETURNS:     nothing                                                  *
 *                                                                       *
 * SIDE EFFECTS:    none                                                 *
 *                                                                       *
 *   Contributed By James Boucher(jboucher@flash.bu.edu)                 *
 *               Boston University Multimedia Communications Lab         *
 * This code was adapted from the Berkeley Playone.c and Brian Smith's   *
 * JGetFrame code after being modified on 10-7-93 by Dinesh Venkatesh    *
 * of BU.                                                                *
 *       This code converts a version 2 Parallax J_Movie into a          *
 * set of JFIF compatible JPEG images. It works for all image            *
 * sizes and qualities.                                                  *
 ************************************************************************/
void
  JMovie2JPEG(infilename,obase,start,end)
char *infilename;       /* input filename string */
char *obase;            /* output filename base string=>obase##.jpg */ 
int start;              /* first frame to be extracted */
int end;                /* last frame to be extracted */
{
  FILE *inFile;			/* Jmovie file pointer */
  FILE *outFile;		/* JPEG file pointer for output file */
  int fd, i;			/* input file descriptor and a counting variable*/
  char ofname[256];		/* output filename string */
  int Temp = 0, temp = 0;	/* dummy variables */
  int image_offset = 0;		/* counting variable */
  /* J_Movie header infomation */
  int ver_no;			/* version number - expected to be 2 */
  int fps;			/* frame rate - frames per second */
  int no_frames;		/* total number of frames in jmovie */
  int bandwidth;		/* bandwidth required for normal playback*/
  int qfactor;			/* quality factor used to scale Q matrix */
  int mapsize;			/* number of color map entries - 2^24 */
  int audio_tracks;		/* number of audio tracks ==1    */
  int audiosize;		/*number of bytes in audio tracks */
  int *inoffsets;		/* input frame offsets from start of jmovie*/
  int width;			/* image width */
  int height;			/* image height */
  int size;			/* total image size in bytes */
  char op_code;			/* jmovie op_code */
  char jpeg_size[4];		/* jpeg data size */
  static char junk[1000];	/* data sink for audio data */

  /* The next array represents the default JFIF header for
     quality = 100 and size = 320x240. The values are
     adjusted as the J_Movie header is read.  The default
     size of this array is set large so as to make room
     for the appending of the jpeg bitstream. It can be
     made smaller if you have a better idea of its expected size*/
  static char inbuffer[300000] = {    
    0xFF, 0xD8, 0xFF, 0xE0, 0x00, 0x10, 0x4A, 0x46,  
    0x49, 0x46, 0x00, 0x01, 0x01, 0x00, 0x00, 0x01,
    0x00, 0x01, 0x00, 0x00, 0xFF, 0xC0, 0x00, 0x11,  
    0x08, 0x00, 0xF0, 0x01, 0x40, 0x03, 0x01, 0x21,
    0x00, 0x02, 0x11, 0x01, 0x03, 0x11, 0x01, 0xFF,  
    0xDB, 0x00, 0x84, 0x00, 0x10, 0x0B, 0x0C, 0x0E,
    0x0C, 0x0A, 0x10, 0x0E, 0x0D, 0x0E, 0x12,  
    0x11, 0x10, 0x13, 0x18, 0x28, 0x1A, 0x18, 0x16,
    0x16, 0x18, 0x31, 0x23, 0x25, 0x1D, 0x28, 0x3A,  
    0x33, 0x3D, 0x3C, 0x39, 0x33, 0x38, 0x37, 0x40,
    0x48, 0x5C, 0x4E, 0x40, 0x44, 0x57, 0x45, 0x37,  
    0x38, 0x50, 0x6D, 0x51, 0x57, 0x5F, 0x62, 0x67,
    0x68, 0x67, 0x3E, 0x4D, 0x71, 0x79, 0x70, 0x64,  
    0x78, 0x5C, 0x65, 0x67, 0x63, 0x01, 0x11, 0x12,
    0x12, 0x18, 0x15, 0x18, 0x2F, 0x1A, 0x1A, 0x2F,  
    0x63, 0x42, 0x38, 0x42, 0x63, 0x63, 0x63, 0x63,
    0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,  
    0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,  
    0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,  
    0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,  
    0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,  
    0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0xFF, 0xC4,
    0x01, 0xA2, 0x00, 0x00, 0x01, 0x05, 0x01, 0x01,  
    0x01, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03, 0x04,  
    0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B,
    0x10, 0x00, 0x02, 0x01, 0x03, 0x03, 0x02, 0x04,  
    0x03, 0x05, 0x05, 0x04, 0x04, 0x00, 0x00, 0x01,
    0x7D, 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05,  
    0x12, 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61,
    0x07, 0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xA1,  
    0x08, 0x23, 0x42, 0xB1, 0xC1, 0x15, 0x52, 0xD1,
    0xF0, 0x24, 0x33, 0x62, 0x72, 0x82, 0x09,   
    0x0A, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x25, 0x26,
    0x27, 0x28, 0x29, 0x2A, 0x34, 0x35, 0x36, 0x37,  
    0x38, 0x39, 0x3A, 0x43, 0x44, 0x45, 0x46, 0x47,
    0x48, 0x49, 0x4A, 0x53, 0x54, 0x55, 0x56, 0x57,  
    0x58, 0x59, 0x5A, 0x63, 0x64, 0x65, 0x66, 0x67,
    0x68, 0x69, 0x6A, 0x73, 0x74, 0x75, 0x76, 0x77,  
    0x78, 0x79, 0x7A, 0x83, 0x84, 0x85, 0x86, 0x87,
    0x88, 0x89, 0x8A, 0x92, 0x93, 0x94, 0x95, 0x96,  
    0x97, 0x98, 0x99, 0x9A, 0xA2, 0xA3, 0xA4, 0xA5,
    0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xB2, 0xB3, 0xB4,  
    0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xC2, 0xC3,
    0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, 0xCA, 0xD2,  
    0xD3, 0xD4, 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA,
    0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8,  
    0xE9, 0xEA, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6,
    0xF7, 0xF8, 0xF9, 0xFA, 0x01, 0x00, 0x03, 0x01,  
    0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02,  
    0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 
    0x0A, 0x0B, 0x11, 0x00, 0x02, 0x01, 0x02, 0x04,  
    0x04, 0x03, 0x04, 0x07, 0x05, 0x04, 0x04, 0x00,
    0x01, 0x02, 0x77, 0x00, 0x01, 0x02, 0x03, 0x11,  
    0x04, 0x05, 0x21, 0x31, 0x06, 0x12, 0x41, 0x51,
    0x07, 0x61, 0x71, 0x13, 0x22, 0x32, 0x81, 0x08,  
    0x14, 0x42, 0x91, 0xA1, 0xB1, 0xC1, 0x09, 0x23,
    0x33, 0x52, 0xF0, 0x15, 0x62, 0x72, 0xD1,   
    0x0A, 0x16, 0x24, 0x34, 0xE1, 0x25, 0xF1, 0x17,
    0x18, 0x19, 0x1A, 0x26, 0x27, 0x28, 0x29, 0x2A,  
    0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x43, 0x44,
    0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x53, 0x54,  
    0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x63, 0x64,
    0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x73, 0x74,  
    0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x82, 0x83,
    0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A, 0x92,  
    0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A,
    0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, 0xA9,  
    0xAA, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8,
    0xB9, 0xBA, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7,  
    0xC8, 0xC9, 0xCA, 0xD2, 0xD3, 0xD4, 0xD5, 0xD6,
    0xD7, 0xD8, 0xD9, 0xDA, 0xE2, 0xE3, 0xE4, 0xE5,  
    0xE6, 0xE7, 0xE8, 0xE9, 0xEA, 0xF2, 0xF3, 0xF4,
    0xF5, 0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFF, 0xDA,  
    0x00, 0x0C, 0x03, 0x01, 0x00, 0x02, 0x11, 0x03,
    0x11, 0x00, 0x3F, 0x00  

    };
    
  if(start > end)
    {
      fprintf(stderr,"bad frame numbers\n");
      exit(1);
    }
    
  /* open J_Movie */
  inFile = fopen(infilename, "rb");
  if (inFile == NULL) 
    {
      perror (infilename);
      exit (1);
    }
    
  /* get file descriptor */    
  fd = fileno(inFile);
    
  /* The following lines parse the jpeg_movie header and recover the */
  /* relavant information */

  fseek (inFile, (8*sizeof(char)),0);
    
  if (fread (&ver_no,sizeof(int),1,inFile) != 1)
    {
      perror("Error in reading version");
      exit(1);
    }  
  if(ver_no != 2){
    perror("Unrecognized version - Quantization tables may be wrong\n");
  }
  if (fread (&(fps),sizeof(int),1,inFile) != 1)
    {
      perror("Error in reading fps");
      exit(1);
    }  
  if (fread (&(no_frames),sizeof(int),1,inFile) != 1)
    {
      perror("Error in reading no_frames");
      exit(1);
    }  

  inoffsets = (int *)malloc(no_frames*sizeof(int));
    
  if (fread (&(width),sizeof(int),1,inFile) != 1)
    {
      perror("Error in reading width");
      exit(1);
    }  
  /* set image width in JFIF header */
  inbuffer[27] = (char)(0xFF & (width >> 8));
  inbuffer[28] = (char)(0xFF & width);
 
  if (fread (&(height),sizeof(int), 1,inFile) != 1)
    {
      perror("Error in reading height");
      exit(1);
    }  
  /* set image height in JFIF header */
  inbuffer[25] = (char)(0xFF & (height >> 8));
  inbuffer[26] = (char)(0xFF & height);
    
  if (fread (&(bandwidth),sizeof(int),1,inFile) != 1)
    {
      perror("Error in reading bandwidth");
      exit(1);
    }  
    
  if (fread (&(qfactor),sizeof(int),1,inFile) != 1)
    {
      perror("Error in reading qfactor");
      exit(1);
    }  
  /* The default quality factor = 100, therefore, if
     our quality factor does not equal 100 we must
     scale the quantization matrices in the JFIF header*/    
  /* Note values are clipped to a max of 255 */
  if(qfactor != 100){
    for(Temp=44;Temp<108;Temp++){
      temp= (inbuffer[Temp]*qfactor)/100;
      inbuffer[Temp] = (char)((temp<255) ? temp : 255);
    }
    for(Temp=109;Temp<173;Temp++){
      temp = (inbuffer[Temp]*qfactor)/100;
      inbuffer[Temp] = (char)((temp<255) ? temp : 255);
    }    
  }
  
  if (fread (&(mapsize),sizeof(int),1,inFile) != 1)
    {
      perror("Error in reading mapsize");
      exit(1);
    }  
  if (fread (&(image_offset),sizeof(int),1,inFile) != 1)
    {
      perror("Error in reading image offset");
      exit(1);
    }
  if (fread (&(audio_tracks),sizeof(int),1,inFile) != 1)
    {
      perror("Error in reading audio tracks");
      exit(1);
    }
    
  fread(junk,sizeof(int),1,inFile);
    
  if (fread (&(audiosize),sizeof(int),1,inFile) != 1)
    {
      perror("Error in reading audiosize");
      exit(1);
    }
    
  fseek (inFile,(image_offset),0);
    

  if(no_frames <= end)
    {
      end = no_frames - 1;
    }
    

  for(i=0;i<no_frames;i++) 
    {
      fread(&(inoffsets[i]),sizeof(int),1,inFile);
    } /* Reads in the frame sizes into the array */
    
  rewind(inFile);

  /* Extract JFIF files from J_Movie */    
  for (i=start; i<=end ; i++) 
    {
      size = inoffsets[i]- inoffsets[i-1]- 5;
      lseek(fd, inoffsets[i-1],0); 
      read(fd, &(op_code), 1);
      while( op_code !=  0xffffffec)
	{
	  read(fd,junk,audiosize);
	  read(fd, &(op_code), 1);  
	  size = size - audiosize ;
	} /* To skip the audio bytes in each frame */
      read(fd,jpeg_size,4);
      read(fd,&(inbuffer[607]),(size));
      sprintf(ofname,"%s%d.jpg",obase,i);
      outFile = fopen(ofname, "wb");
      fwrite(inbuffer,(size+607),sizeof(char),outFile);
      fclose(outFile);        
    }
  free(inoffsets);
  fclose(inFile);
}




/*===========================================================================*
 *
 * ReadJPEG  contributed by James Arthur Boucher of Boston University's
 *                                Multimedia Communications Lab
 *
 *      read a JPEG file and copy data into frame original data arrays
 *
 * RETURNS:     mf modified
 *
 * SIDE EFFECTS:    none
 *
 *===========================================================================*/
/*************************JPEG LIBRARY INTERFACE*********************/
/*
 * THE BIG PICTURE:
 *
 * The rough outline this JPEG decompression operation is:
 *
 *      allocate and initialize JPEG decompression object
 *      specify data source (eg, a file)
 *      jpeg_read_header();     // obtain image dimensions and other parameters
 *      set parameters for decompression
 *      jpeg_start_decompress();
 *      while (scan lines remain to be read)
 *              jpeg_read_scanlines(...);
 *      jpeg_finish_decompress();
 *      release JPEG decompression object
 *
 */
void
ReadJPEG(mf, fp)
    MpegFrame *mf;
    FILE *fp;
{

  /* This struct contains the JPEG decompression parameters and pointers to
   * working data (which is allocated as needed by the JPEG library).
   */
  static struct jpeg_decompress_struct cinfo;
  static struct jpeg_error_mgr jerr;
  /* More stuff */
  JSAMPARRAY scanarray[3];
  int ci, cp;
  JDIMENSION ncols[3], nrows[3], maxcols[3];
  jpeg_component_info *compptr;
  JDIMENSION buffer_height;
  int current_row[3];
  int h_samp[3],v_samp[3];
  static boolean first=TRUE;
  uint8 **orig[3];
  boolean resample = FALSE;

  if (first) {
    first = FALSE;
    /* Allocate and initialize JPEG decompression object */
    cinfo.err = jpeg_std_error(&jerr);
  }
  
  if (fp == stdin) {
    static boolean first_stdin = TRUE;
    /*
     ** If we're reading from stdin we want to create the cinfo struct
     ** ONCE (during the first read).  This is because when reading jpeg
     ** from stdin we will not release the cinfo struct, because doing
     ** so would totally screw up the read buffer and make it impossible
     ** to read jpegs from stdin.
     ** Dave Scott (dhs), UofO, 7/19/95
     */
    if (first_stdin) {
      first_stdin = FALSE;
      /* Now we can initialize the JPEG decompression object. */
      jpeg_create_decompress(&cinfo);
      /* specify data source (eg, a file) */
      jpeg_stdio_src(&cinfo, fp);
    } /* else do nothing */
  } else {
    /* Now we can initialize the JPEG decompression object. */
    jpeg_create_decompress(&cinfo);
    /* specify data source (eg, a file) */
    /* Normal case, use the file! */
    jpeg_stdio_src(&cinfo, fp);
  }
  
  /* read file parameters with jpeg_read_header() */
  
  (void) jpeg_read_header(&cinfo, TRUE);
  /* We can ignore the return value from jpeg_read_header since
   *   (a) suspension is not possible with the stdio data source, and
   *   (b) we passed TRUE to reject a tables-only JPEG file as an error.
   */
  
  /* read out sampling factors */
  for(cp=0, compptr = cinfo.comp_info;
      cp < cinfo.num_components;
      cp++, compptr++) {
    h_samp[cp] = compptr->h_samp_factor;
    v_samp[cp] = compptr->v_samp_factor;
  }
  
  
  /* So we can do the more efficient raw reading */
  /* set parameters for decompression */
  cinfo.raw_data_out = TRUE;
  if (cinfo.jpeg_color_space == JCS_YCbCr) {
    /* Nothing, this is what we want */
  } else if (cinfo.jpeg_color_space == JCS_GRAYSCALE) {
    /* deal with it later */
  } else {
    /* who knows, let jpeg handle it */
      fprintf(stderr, "Not a supported colorspace (%d)\n",cinfo.jpeg_color_space);
      fprintf(stderr, "Try\tBASE_FILE_FORMAT PNM\n\tINPUT_CONVERT djpeg *\n");
      exit(1);
    }

  jpeg_calc_output_dimensions(&cinfo);
  
  /* tell mpeg_encode the size of the JPEG Image*/
  Fsize_Note(mf->id, (int)(cinfo.image_width), (int)(cinfo.image_height));
  
  /* Allocate memory for the raw YCbCr data to occupy*/
  Frame_AllocYCC(mf);		/*allocate space for mpeg frame*/
  
  /* copy pointers to array structure- this make the following
     code more compact  */
  orig[0] = mf->orig_y;
  orig[1] = mf->orig_cb;
  orig[2] = mf->orig_cr;

  jpeg_start_decompress(&cinfo);
  
  buffer_height = cinfo.max_v_samp_factor * cinfo.min_DCT_scaled_size;
  
  if ((cinfo.jpeg_color_space != JCS_GRAYSCALE)) {
    if ((h_samp[0] == 2) && (h_samp[1] == 1) && (h_samp[2] == 1) &&
	(v_samp[0] == 1) && (v_samp[1] == 1) && (v_samp[2] == 1)) {
      static boolean printed = FALSE;
      
      resample = TRUE;
      if (!printed) {
	fprintf(stderr, "mpeg_encode will resample this JPEG for you.\n");
	fprintf(stderr, "you may wish to compare the quality against doing:\n");
	fprintf(stderr, "\tBASE_FILE_FORMAT PNM\n\tINPUT_CONVERT djpeg *\n");
	fprintf(stderr, "which will take longer, but may look better\n");
	printed = TRUE;
      }
    } else if ((h_samp[0] == 2)  && (h_samp[1] == 1) && (h_samp[2] == 1) &&
	       (v_samp[0] == 2)  && (v_samp[1] == 1) && (v_samp[2] == 1)){
      /* we are 4:1:1 as expected by the encoder*/
    } else {
      fprintf(stderr, "Not a supported subsampling ratio\n");
      fprintf(stderr, "Try\tBASE_FILE_FORMAT PNM\n\tINPUT_CONVERT djpeg *\n");
      exit(1);
    }}
  
  for (cp = 0, compptr = cinfo.comp_info;
       cp < cinfo.num_components;
       cp++, compptr++) {
    /* larger than needed, but who cares, seems to work better */
    ncols[cp] = (JDIMENSION)(buffer_height * (1 + cinfo.image_width/buffer_height));
    maxcols[cp] = (cp==0) ? Fsize_x : Fsize_x>>1;
    nrows[cp] = (JDIMENSION)((buffer_height*compptr->v_samp_factor) /
			     cinfo.max_v_samp_factor);
    scanarray[cp] = (*cinfo.mem->alloc_sarray)
      ((j_common_ptr) &cinfo, JPOOL_IMAGE, ncols[cp], nrows[cp]);
  }
  
  while (cinfo.output_scanline < cinfo.output_height) {
    (void) jpeg_read_raw_data(&cinfo, scanarray, buffer_height);
    if (cinfo.output_scanline > Fsize_y) continue;

    /* transfer data from jpeg buffer to MPEG frame */
    /* calculate the row we wish to output into */
    for (ci = 0, compptr = cinfo.comp_info;
	ci < cinfo.num_components;
	ci++, compptr++){
      if (resample) {
	if (ci == 0) {
	  current_row[ci] = cinfo.output_scanline-buffer_height;
	} else {
	  current_row[ci] = (cinfo.output_scanline-buffer_height)/2;
	}
      } else {
	current_row[ci] = ((cinfo.output_scanline - buffer_height)*
			  (v_samp[ci])/cinfo.max_v_samp_factor);  
      }
      safe_jcopy_sample_rows(scanarray[ci], 0, (JSAMPARRAY)(orig[ci]),
			     current_row[ci], nrows[ci], ncols[ci], 
			     maxcols[ci], (boolean)((ci==0) ? FALSE : resample));
    }
  }
  
  /* If we have greyscale, clear out Cr and Cb */
  if (cinfo.jpeg_color_space == JCS_GRAYSCALE) {
   for (ci = 1;  ci < 3;  ci++) {
     for (cp = 0; cp < Fsize_y;  cp++) {
      memset(orig[ci][cp], 128, (Fsize_x>>1));
      memset(orig[ci][cp], 128, (Fsize_x>>1));
    }}}

  /* Step 7: Finish decompression */
  
  (void) jpeg_finish_decompress(&cinfo);
  /* We can ignore the return value since suspension is not possible
   * with the stdio data source.
   */
  
  /* Step 8: Release JPEG decompression object */
  
  /*
   ** DO NOT release the cinfo struct if we are reading from stdin, this
   ** is because the cinfo struct contains the read buffer, and the read
   ** buffer may (and almost always does) contain the end of one image and
   ** the beginning of another.  If we throw away the read buffer then
   ** we loose the beginning of the next image, and we're screwed.
  ** Dave Scott (dhs), UofO, 7/19/95
  */
  if (fp == stdin) {
    static int no_from_stdin = 0;
    no_from_stdin++;
    /* fprintf( stderr, "%d jpeg images read from stdin\n", no_from_stdin); */
  }
  else {
    /* This is an important step since it will release a good deal of memory. */
    jpeg_destroy_decompress(&cinfo);
  }

  /* After finish_decompress, we can close the input file.
   * Here we postpone it until after no more JPEG errors are possible,
   * so as to simplify the setjmp error logic above.  (Actually, I don't
   * think that jpeg_destroy can do an error exit, but why assume anything...)
   */
  
  
  /* At this point you may want to check to see whether any corrupt-data
   * warnings occurred (test whether jerr.pub.num_warnings is nonzero).
   * If you prefer to treat corrupt data as a fatal error, override the
   * error handler's emit_message method to call error_exit on a warning.
   */

  /* And we're done! */
  
}



void
safe_jcopy_sample_rows (input_array, source_row, output_array, dest_row,
			num_rows,  num_cols, max_cols, resample)
JSAMPARRAY input_array, output_array;
int source_row, dest_row, num_rows;
JDIMENSION num_cols, max_cols;
boolean resample;
/* Copy some rows of samples from one place to another.
 * num_rows rows are copied from input_array[source_row++]
 * to output_array[dest_row++]; these areas may overlap for duplication.
 * The source and destination arrays must be at least as wide as num_cols.
 */
{
  register uint8 *inptr, *outptr;
  register size_t count = (size_t) (num_cols * sizeof(JSAMPLE));
  register int row;
  
  input_array += source_row;
  output_array += dest_row;
  if (count > max_cols) {count = max_cols;}

  for (row = num_rows-resample; row > 0; row -= (1 + resample)) {
    inptr = *input_array++;
    outptr = *output_array++;
    memcpy(outptr, inptr, count);
  }
}
