mpeg2dec.c

linux下的一款mpeg播放器

/* mpeg2dec.c, main(), initialization, option processing                    */

/*
 * All modifications (mpeg2decode -> mpeg2play) are
 * Copyright (C) 1994, Stefan Eckart. All Rights Reserved.
 */

/* Copyright (C) 1994, MPEG Software Simulation Group. All Rights Reserved. */

/*
 * Disclaimer of Warranty
 *
 * These software programs are available to the user without any license fee or
 * royalty on an "as is" basis.  The MPEG Software Simulation Group disclaims
 * any and all warranties, whether express, implied, or statuary, including any
 * implied warranties or merchantability or of fitness for a particular
 * purpose.  In no event shall the copyright-holder be liable for any
 * incidental, punitive, or consequential damages of any kind whatsoever
 * arising from the use of these programs.
 *
 * This disclaimer of warranty extends to the user of these programs and user's
 * customers, employees, agents, transferees, successors, and assigns.
 *
 * The MPEG Software Simulation Group does not represent or warrant that the
 * programs furnished hereunder are free of infringement of any third-party
 * patents.
 *
 * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,
 * are subject to royalty fees to patent holders.  Many of these patents are
 * general enough such that they are unavoidable regardless of implementation
 * design.
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <fcntl.h>
#ifdef USE_TIME
#include <sys/time.h>
#endif

#define GLOBAL
#include "config.h"
#include "global.h"

/* private prototypes */
static void initdecoder _ANSI_ARGS_((void));
static void options _ANSI_ARGS_((int *argcp, char **argvp[]));
static int getval _ANSI_ARGS_((char *argv[]));

/* private data */
static int loopflag;

#ifdef USE_TIME
static void doframerate();
static int framerate;
static struct timeval tftarget;
#endif

int main(argc,argv)
int argc;
char *argv[];
{
  int first, framenum;
#ifdef USE_TIME
  int runtime;
  struct timeval tstart,tstop;
#endif

  options(&argc,&argv);

  ld = &base; /* select base layer context */

  /* open MPEG input file(s) */
  if (argv[1][0]=='-' || argv[1][1]=='\0')
  {
    base.infile = 0; /* stdin */
    loopflag = 0; /* can't rewind stdin */
  }
  else if ((base.infile=open(argv[1],O_RDONLY|O_BINARY))<0)
  {
    sprintf(errortext,"Input file %s not found\n",argv[1]);
    error(errortext);
  }

  if (base.infile != 0)
  {
    initbits();
    startcode();
    switch(showbits(32))
    {
    case SEQ_START_CODE:
      break;
    case PACK_START_CODE:
      sysstream = 1;
      break;
    default:
      error("This not a valid MPEG system or video stream\n");
      break;
    }
    lseek(base.infile,0l,0);
    initbits();
  }

  if (argc==4)
  {
    ld = &enhan; /* select enhancement layer context */

    if ((enhan.infile = open(argv[2],O_RDONLY|O_BINARY))<0)
    {
      sprintf(errortext,"Input file %s not found\n",argv[2]);
      error(errortext);
    }

    twostreams = 1;
    ld = &base;
  }

  first = 1;

  do
  {
    /* (re)set to begin of file */
    ld = &base;
    if (base.infile!=0)
      lseek(base.infile,0l,0);
    initbits();

    if (twostreams)
    {
      ld = &enhan;
      lseek(enhan.infile,0l,0);
      initbits();
      ld = &base;
    }

    framenum = 0;

    while (getheader())
    {
      if (first)
      {
        initdecoder();
#ifdef USE_TIME
        gettimeofday(&tstart,(struct timezone *)NULL);
	if (framerate > 0)
	  gettimeofday(&tftarget,(struct timezone *)NULL);
#endif
        first = 0;
      }

      getpicture(framenum);

      if (!secondfield)
      {
#ifdef USE_TIME
	if (framerate > 0)
	  doframerate();
#endif	
        framenum++;
      }
    }

    if (framenum!=0)
    {
      /* put last frame */
      putlast(framenum);
    }

  }
  while (loopflag);

  if (base.infile!=0)
    close(base.infile);

  if (twostreams)
    close(enhan.infile);

#ifdef USE_TIME
  gettimeofday(&tstop,(struct timezone *)NULL);
  runtime = 100*(tstop.tv_sec-tstart.tv_sec)
            + (tstop.tv_usec-tstart.tv_usec)/10000;
  if (!quiet && runtime!=0)
    printf("%d.%02d seconds, %d frames, %d.%02d fps\n",runtime/100, runtime%100,
      framenum, ((10000*framenum+runtime/2)/runtime)/100,
      ((10000*framenum+runtime/2)/runtime)%100);
#endif

  if (outtype==T_X11)
    exit_display();

  return 0;
}

static void initdecoder()
{
  int i, cc, size;
  static int blk_cnt_tab[3] = {6,8,12};

  /* check scalability mode of enhancement layer */
  if (twostreams && enhan.scalable_mode!=SC_SNR &&
     !(base.scalable_mode==SC_DP && base.scalable_mode==SC_DP))
    error("unsupported scalability mode\n");

  /* clip table */
  if (!(clp=(unsigned char *)malloc(1024)))
    error("malloc failed\n");

  clp += 384;

  for (i=-384; i<640; i++)
    clp[i] = (i<0) ? 0 : ((i>255) ? 255 : i);

  /* force MPEG-1 parameters */
  if (!base.mpeg2)
  {
    prog_seq = 1;
    prog_frame = 1;
    pict_struct = FRAME_PICTURE;
    frame_pred_dct = 1;
    chroma_format = CHROMA420;
    matrix_coefficients = 5;
  }

  /* round to nearest multiple of coded macroblocks */
  mb_width = (horizontal_size+15)/16;
  mb_height = (base.mpeg2 && !prog_seq) ? 2*((vertical_size+31)/32)
                                        : (vertical_size+15)/16;
  coded_picture_width = 16*mb_width;
  coded_picture_height = 16*mb_height;

  chrom_width = (chroma_format==CHROMA444) ? coded_picture_width
                                           : coded_picture_width>>1;
  chrom_height = (chroma_format!=CHROMA420) ? coded_picture_height
                                            : coded_picture_height>>1;
  blk_cnt = blk_cnt_tab[chroma_format-1];

  for (cc=0; cc<3; cc++)
  {
    if (cc==0)
      size = coded_picture_width*coded_picture_height;
    else
      size = chrom_width*chrom_height;

    if (!(refframe[cc] = (unsigned char *)malloc(size)))
      error("malloc failed\n");

    if (!(oldrefframe[cc] = (unsigned char *)malloc(size)))
      error("malloc failed\n");

    if (!(auxframe[cc] = (unsigned char *)malloc(size)))
      error("malloc failed\n");

    if (base.scalable_mode==SC_SPAT)
    {
      /* this assumes lower layer is 4:2:0 */
      if (!(llframe0[cc] = (unsigned char *)malloc((llw*llh)/(cc?4:1))))
        error("malloc failed\n");
      if (!(llframe1[cc] = (unsigned char *)malloc((llw*llh)/(cc?4:1))))
        error("malloc failed\n");
    }
  }

  if (base.scalable_mode==SC_SPAT)
  {
    if (!(lltmp = (short *)malloc(llw*((llh*vn)/vm)*sizeof(short))))
      error("malloc failed\n");
  }

  /* IDCT */
  init_idct();

  if (outtype==T_X11)
  {
    init_display("");
    init_dither();
  }
}

void error(text)
char *text;
{
  fprintf(stderr,text);
  exit(1);
}

/* compliance warning messages to user, but don't exit() */
void warning(text)
char *text;
{
  fprintf(stderr,"%s\n",text);
} 

#ifdef TRACE
/* trace output */
void printbits(code,bits,len)
int code,bits,len;
{
  int i;
  for (i=0; i<len; i++)
    printf("%d",(code>>(bits-1-i))&1);
}
#endif

/* option processing */
static void options(argcp,argvp)
int *argcp;
char **argvp[];
{
  outtype = T_X11;

  while (*argcp>1 && (*argvp)[1][0]=='-')
  {
    if ((*argvp)[1][1]=='\0') /* single '-' */
      break;

    while ((*argvp)[1][1])
    {
      switch (toupper((*argvp)[1][1]))
      {
#ifdef USE_TIME
      case 'F':
	framerate = getval(*argvp);
	break;
#endif
      case 'V':
        verbose = getval(*argvp);
        break;
      case 'O':
        outtype = getval(*argvp);
        break;
      case 'L':
        loopflag = 1;
        break;
      case 'S':
        sflag = 1;
        break;
#ifdef TRACE
      case 'T':
        trace = 1;
        break;
#endif
      case 'Q':
        quiet = 1;
        break;
      default:
        fprintf(stderr,"undefined option -%c ignored\n",(*argvp)[1][1]);
      }

      (*argvp)[1]++;
    }

    (*argvp)++;
    (*argcp)--;
  }

  if (sflag)
  {
    /* input file for spatial prediction */
    llinputname = (*argvp)[1];
    (*argvp)++;
    (*argcp)--;
  }

  if (*argcp!=2 && *argcp!=3)
  {
    printf("\n%s, %s\n",version,author);
    printf("Usage:   mpeg2play {options} input.m2v {upper.m2v}\n\
Options: -vn  verbose output (n: level)\n\
         -on  output format (0: X11 (default), 1: none)\n\
         -l   loop sequence\n\
         -q   quiet (no error output)\n\
         -s infile   spatial scalable sequence\n");
#ifdef USE_TIME
    printf("\
	 -fn  frame rate (default = as fast as possible)\n");
#endif    
    exit(0);
  }
}

static int getval(argv)
char *argv[];
{
  int val;

  if (sscanf(argv[1]+2,"%d",&val)!=1)
    return 0;

  while (isdigit(argv[1][2]))
    argv[1]++;

  return val;
}

#ifdef USE_TIME
static void doframerate()
{
  struct timeval tfdiff;

  /* Compute desired frame rate */
  if (framerate <= 0)
    return;
  tftarget.tv_usec += 1000000 / framerate;

  /* this is where we should be */
  if (tftarget.tv_usec >= 1000000)
  {
    tftarget.tv_usec -= 1000000;
    tftarget.tv_sec++;
  }

  /* this is where we are */
  gettimeofday(&tfdiff,(struct timezone *)NULL);

  tfdiff.tv_usec = tftarget.tv_usec - tfdiff.tv_usec;
  tfdiff.tv_sec  = tftarget.tv_sec  - tfdiff.tv_sec;
  if (tfdiff.tv_usec < 0)
  {
    tfdiff.tv_usec += 1000000;
    tfdiff.tv_sec--;
  }

  /* See if we are already lagging behind */
  if (tfdiff.tv_sec < 0 || (tfdiff.tv_sec == 0 && tfdiff.tv_usec <= 0))
    return;
  
  /* Spin for awhile */
  select(0,NULL,NULL,NULL,&tfdiff);
}
#endif