#include <stdio.h>#include <stdlib.h>#include "config.h"#include "tmndec.h"#include "global.h"/* private prototypes */static void getpicturehdr _ANSI_ARGS_((void));/* * decode headers from one input stream * until an End of Sequence or picture start code * is found */int getheader(){  unsigned int code, gob;  /* look for startcode */  startcode();  code = getbits(PSC_LENGTH);  gob = getbits(5);  if (gob == SE_CODE)     return 0;  if (gob == 0) {    getpicturehdr();    if (syntax_arith_coding)        /* reset decoder after receiving */      decoder_reset();	        /* fixed length PSC string */  }  return gob + 1;}/* align to start of next startcode */void startcode(){  /* search for new picture start code */  while (showbits(PSC_LENGTH)!=1l)          flushbits(1);}/* decode picture header */static void getpicturehdr(){  int pos, pei, tmp;  pos = ld->bitcnt;  prev_temp_ref = temp_ref;  temp_ref = getbits(8);  trd = temp_ref - prev_temp_ref;  if (trd < 0)    trd += 256;  tmp = getbits(1); /* always "1" */  if (!tmp)    if (!quiet)      printf("warning: spare in picture header should be \"1\"\n");  tmp = getbits(1); /* always "0" */  if (tmp)    if (!quiet)      printf("warning: H.261 distinction bit should be \"0\"\n");  tmp = getbits(1); /* split_screen_indicator */  if (tmp) {    if (!quiet)      printf("error: split-screen not supported in this version\n");    exit (-1);  }  tmp = getbits(1); /* document_camera_indicator */  if (tmp)    if (!quiet)      printf("warning: document camera indicator not supported in this version\n");  tmp = getbits(1); /* freeze_picture_release */  if (tmp)    if (!quiet)      printf("warning: frozen picture not supported in this version\n");  source_format = getbits(3);  pict_type = getbits(1);  mv_outside_frame = getbits(1);  long_vectors = (mv_outside_frame ? 1 : 0);  syntax_arith_coding = getbits(1);  adv_pred_mode = getbits(1);  mv_outside_frame = (adv_pred_mode ? 1 : mv_outside_frame);  pb_frame = getbits(1);  quant = getbits(5);  tmp = getbits(1);  if (tmp) {    if (!quiet)      printf("error: CPM not supported in this version\n");    exit(-1);  }  if (pb_frame) {    trb = getbits(3);    bquant = getbits(2);  }  else {    trb = 0;  }#ifdef USE_TIME  if (framerate > 0 && trd > 0)    doframerate(0);#endif	  pei = getbits(1);pspare:  if (pei) {     /* extra info for possible future backward compatible additions */    getbits(8);  /* not used */    pei = getbits(1);    if (pei) goto pspare; /* keep on reading pspare until pei=0 */  }  if (verbose>0) {    /*$printf("picture header (byte %d)\n",(pos>>3)-4);$*/    if (verbose>1) {      printf("  temp_ref=%d\n",temp_ref);      /*$printf("  pict_type=%d\n",pict_type);      printf("  source_format=%d\n", source_format);      printf("  quant=%d\n",quant);      if (syntax_arith_coding)         printf("  SAC coding mode used \n");      if (mv_outside_frame)        printf("  unrestricted motion vector mode used\n");      if (adv_pred_mode)        printf("  advanced prediction mode used\n");$*/      if (pb_frame) {        /*$printf("  pb-frames mode used\n");$*/        printf("  trb=%d\n",trb);        /*$printf("  bquant=%d\n", bquant);$*/      }    }  }}