shithub: sox

ref: 9d742e2840dacfffe8ecda3ef25ed6aa7974ac6b
dir: /src/sox.c/

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/*
 * Sox - The Swiss Army Knife of Audio Manipulation.
 *
 * This is the main function for the command line sox program.
 *
 * July 5, 1991
 * Copyright 1991 Lance Norskog And Sundry Contributors
 * This source code is freely redistributable and may be used for
 * any purpose.  This copyright notice must be maintained. 
 * Lance Norskog And Sundry Contributors are not responsible for 
 * the consequences of using this software.
 *
 * Change History:
 *
 * June 1, 1998 - Chris Bagwell (cbagwell@sprynet.com)
 *   Added patch to get volume working again.  Based on patch sent from
 *   Matija Nalis <mnalis@public.srce.hr>.
 *   Added command line switches to force format to ADPCM or GSM.
 *
 * September 12, 1998 - Chris Bagwell (cbagwell@sprynet.com)
 *   Reworked code that handled effects.  Wasn't correctly draining
 *   stereo effects and a few other problems.
 *   Made command usage (-h) show supported effects and file formats.
 *   (this is partially from a patch by Leigh Smith
 *    leigh@psychokiller.dialix.oz.au).
 *
 */ 

#include "st.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>		/* for malloc() */
#include <errno.h>
#include <sys/types.h>		/* for fstat() */
#include <sys/stat.h>		/* for fstat() */

#ifdef HAVE_UNISTD_H
#include <unistd.h>		/* for unlink() */
#endif

#ifdef HAVE_GETOPT_H
#include <getopt.h>
#else
#ifndef HAVE_GETOPT
int getopt(int,char **,char *);
extern char *optarg;
extern int optind;
#endif
#endif

/*
 * SOX main program.
 *
 * Rewrite for new nicer option syntax.  July 13, 1991.
 * Rewrite for separate effects library.  Sep. 15, 1991.
 * Incorporate Jimen Ching's fixes for real library operation: Aug 3, 1994.
 * Rewrite for multiple effects: Aug 24, 1994.
 */

static int dovolume = 0;        /* User wants volume change */
static double volume = 1.0;     /* Linear volume change */
static int clipped = 0;		/* Volume change clipping errors */
static int writing = 0;	        /* are we writing to a file? */
static int soxpreview = 0;	/* preview mode */

static LONG ibufl[BUFSIZ/2];	/* Left/right interleave buffers */
static LONG ibufr[BUFSIZ/2];	
static LONG obufl[BUFSIZ/2];
static LONG obufr[BUFSIZ/2];

/* local forward declarations */
static void doopts(ft_t, int, char **);
static void copy_input(ft_t);
static void open_input(ft_t);
static void copy_output(ft_t);
static void open_output(ft_t);
static void usage(char *) NORET;
static int filetype(int);
static void process(void);
static void statistics(void);
static LONG volumechange(LONG *buf, LONG ct, double vol);
static void checkeffect(void);
static int flow_effect_out(void);
static int flow_effect(int);
static int drain_effect(int);

#ifdef SOXMIX
#define MAX_INPUT_FILES 2
#define REQUIRED_INPUT_FILES 2
#else
#define MAX_INPUT_FILES 1
#define REQUIRED_INPUT_FILES 1
#endif

static ft_t informat[MAX_INPUT_FILES] = { 0 };
static int input_count = 0;

static ft_t outformat = 0;
static int output_count = 0;

/* We parse effects into a temporary effects table and then place into
 * the real effects table.  This makes it easier to reorder some effects
 * as needed.  For instance, we can run a resampling effect before
 * converting a mono file to stereo.  This allows the resample to work
 * on half the data.
 *
 * Real effects table only needs to be 2 entries bigger then the user
 * specified table.  This is because at most we will need to add
 * a resample effect and an channel averaging effect.
 */
#define MAX_EFF 16 
#define MAX_USER_EFF 14

/* 
 * In efftab's, location 0 is always the input stream.
 *
 * If one was to support effects for quad-channel files, there would 
 * need to be an effect tabel for each channel.
 */

static struct st_effect efftab[MAX_EFF]; /* left/mono channel effects */
static struct st_effect efftabR[MAX_EFF];/* right channel effects */
static int neffects;			 /* # of effects to run on data */

static struct st_effect user_efftab[MAX_USER_EFF];
static int nuser_effects;

int main(argc, argv)
int argc;
char **argv;
{
        int argc_effect;
	ft_t ft;
	int parsing_output = 0;

	myname = argv[0];

	/* Loop over arguments and filenames, stop when an effect name is found */
	while (optind < argc && output_count < 1 &&
	       st_checkeffect(argv[optind]) != ST_SUCCESS)
	{
	
	    /* 
	     * Its possible to not specify the output filename by using 
	     * "-e" option. This allows effects to be ran on data but 
	     * no output file to be written.
	     */
	    if (strcmp(argv[optind], "-e"))
	    {
		/* No -e option appears to be set.  Attempt to see if
		 * this is the last filename or not.  If we see no more
		 * options or an effect name then we assume this is
		 * the last filename.
		 */
		if (input_count >= REQUIRED_INPUT_FILES &&
		    (optind == (argc-1) || 
		     st_checkeffect(argv[optind+1]) == ST_SUCCESS ||
		     input_count >= MAX_INPUT_FILES))
		{
		    parsing_output = 1;
		}

		if (parsing_output)
		    writing = 1;
	    }
	    else 
	    {
		/* -e option found.  Make sure this was done on the
		 * output side.  Should be no more parameters or
		 * a valid effects name.
		 */
		if (input_count >= REQUIRED_INPUT_FILES &&
		    (optind == (argc-1) || 
		     st_checkeffect(argv[optind+1]) == ST_SUCCESS ||
		     input_count >= MAX_INPUT_FILES))
		{
		    parsing_output = 1;
		}

		if (parsing_output)
		{
		    writing = 0;
		    optind++;  /* Move passed -e */
		}
		else
		{
		    usage("Can only specify \"-e\" for output filenames");
		}
	    }

	    ft = (ft_t)malloc(sizeof(struct st_soundstream));
	    st_initformat(ft);

	    doopts(ft, argc, argv);

	    /* See if we have all the input filenames we need.  
	     * If not, then parse this as input filenames.
	     *
	     * If we have enough but haven't reached the max #
	     * of inputs, then only treat this as an input filename
	     * if it looks like we have more filenames left.
	     */
	    if (!parsing_output)
	    {
		if (optind < argc)
		{
		    ft->filename = argv[optind];
		    optind++;

		    copy_input(ft);
		    open_input(ft);
		}
	    }
	    else
	    {
		if (optind < argc && writing)
		{
		    ft->filename = argv[optind];
		    optind++;
		}
		else
		{
		    ft->filename = 0;
		}

		copy_output(ft);
		/* Hold off on opening file until the very last minute.
		 * This allows us to verify header in input files are
		 * what they should be and parse effect command lines.
		 * That way if anything is found invalid, we will abort
		 * without truncating any existing file that has the same
		 * output filename.
		 */
	    }
	}

	/* Make sure we got at least the required # of input filename */
	if (input_count < REQUIRED_INPUT_FILES ||
	    !informat[REQUIRED_INPUT_FILES-1] || 
	    !informat[REQUIRED_INPUT_FILES-1]->filename)
	    usage("Not enough input files specified");

	if (!outformat || (!outformat->filename && writing))
	    usage("No output file?");

	/* Loop through the reset of the arguments looking for effects */
	nuser_effects = 0;

        while (optind < argc)
        {
	    if (nuser_effects >= MAX_USER_EFF)
	    {
	        st_fail("To many effects specified.\n");
	    }

	    argc_effect = st_geteffect_opt(&user_efftab[nuser_effects], 
		                           argc - optind, &argv[optind]);

	    if (argc_effect == ST_EOF)
	    {
	        int i1;
	        fprintf(stderr, "%s: Known effects: ",myname);
	        for (i1 = 1; st_effects[i1].name; i1++)
	            fprintf(stderr, "%s ", st_effects[i1].name);
	        fprintf(stderr, "\n\n");
	        st_fail("Effect '%s' is not known!", argv[optind]);
	    }


	    /* Skip past effect name */
	    optind++;

	    (*user_efftab[nuser_effects].h->getopts)(&user_efftab[nuser_effects], 
			                             argc_effect, 
						     &argv[optind]);

	    /* Skip past the effect arguments */
	    optind += argc_effect;
	    nuser_effects++;
	}

	if (dovolume)
	    st_report("Volume factor: %f\n", volume);

	if (dovolume && volume < 0.0)
	    st_report("Volume adjustment is negative.  This will result in a phase change\n");
 
	process();
	statistics();
	return(0);
}

static void copy_input(ft_t ft)
{
    informat[input_count] = ft;

    /* Let auto effect do the work if user is not overriding. */
    if (!ft->filetype)
	ft->filetype = "auto";

    if ( st_gettype(ft) )
	st_fail("Unknown input file format for '%s'.  Use -t option to override",ft->filename);

    /* Default the input comment to the filename if not set from
     * command line.
     * FIXME: Should be a memory copy, not a pointer asignment.
     */
    if (!ft->comment)
    	ft->comment = ft->filename;

    input_count++;
}

static void open_input(ft_t ft)
{
    /* Open file handler based on input name.  Used stdin file handler
     * if the filename is "="
     */
    if (! strcmp(ft->filename, "-"))
	ft->fp = stdin;
    else if ((ft->fp = fopen(ft->filename, READBINARY)) == NULL)
	st_fail("Can't open input file '%s': %s", ft->filename, 
		strerror(errno));

    /* See if this file is seekable or not */
#if	defined(DUMB_FILESYSTEM)
    ft->seekable = 0;
#else
    ft->seekable = (filetype(fileno(ft->fp)) == S_IFREG);
#endif
}

#if defined(DOS) || defined(WIN32)
#define LASTCHAR '\\'
#else
#define LASTCHAR '/'
#endif

static void copy_output(ft_t ft)
{
    outformat = ft;

    if (writing && !ft->filetype && ft->filename) {
 	/* Use filename extension to determine audio type. */

        /* First, chop off any path portions of filename.  This
         * prevents the next search from considering that part. */
        if ((ft->filetype = strrchr(ft->filename, LASTCHAR)) == NULL)
            ft->filetype = ft->filename;

        /* Now look for an filename extension */
        if ((ft->filetype = strrchr(ft->filetype, '.')) != NULL)
            ft->filetype++;
        else
            ft->filetype = NULL;
    }

    if (writing && ft->filename)
    {
	if ( st_gettype(ft) )
	    st_fail("Unknown output file format for '%s'.  Use -t option to override",ft->filename);

    }

    output_count++;
}

static void open_output(ft_t ft)
{
    if (writing) {
	/*
	 * There are two choices here:
	 *	1) stomp the old file - normal shell "> file" behavior
	 *	2) fail if the old file already exists - csh mode
	 */
	if (! strcmp(ft->filename, "-"))
	{
	    ft->fp = stdout;

	    /* stdout tends to be line-buffered.  Override this */
	    /* to be Full Buffering. */
	    if (setvbuf (ft->fp,NULL,_IOFBF,sizeof(char)*BUFSIZ))
	    {
		st_fail("Can't set write buffer");
	    }
	}
	else {

	    ft->fp = fopen(ft->filename, WRITEBINARY);

	    if (ft->fp == NULL)
		st_fail("Can't open output file '%s': %s", 
			ft->filename, strerror(errno));

	    /* stdout tends to be line-buffered.  Override this */
	    /* to be Full Buffering. */
	    if (setvbuf (ft->fp,NULL,_IOFBF,sizeof(char)*BUFSIZ))
	    {
		st_fail("Can't set write buffer");
	    }

	} /* end of else != stdout */
#if	defined(DUMB_FILESYSTEM)
	ft->seekable = 0;
#else
	ft->seekable  = (filetype(fileno(ft->fp)) == S_IFREG);
#endif
    }
}

#ifdef HAVE_GETOPT_H
static char *getoptstr = "+r:v:t:c:phsuUAaigbwlfdDxV";
#else
static char *getoptstr = "r:v:t:c:phsuUAaigbwlfdDxV";
#endif

static void doopts(ft_t ft, int argc, char **argv)
{
	int c;
	char *str;

	while ((c = getopt(argc, argv, getoptstr)) != -1) {
		switch(c) {
		case 'p':
			soxpreview++;
			break;

		case 'h':
			usage((char *)0);
			/* no return from above */

		case 't':
			if (! ft) usage("-t");
			ft->filetype = optarg;
			if (ft->filetype[0] == '.')
				ft->filetype++;
			break;

		case 'r':
			if (! ft) usage("-r");
			str = optarg;
#ifdef __alpha__
			if ((! sscanf(str, "%u", &ft->info.rate)) ||
					(ft->info.rate <= 0))
#else
			if ((! sscanf(str, "%lu", &ft->info.rate)) ||
					(ft->info.rate <= 0))
#endif
				st_fail("-r must be given a positive integer");
			break;
		case 'v':
			if (!ft || dovolume) usage("-v");
			str = optarg;
			if (! sscanf(str, "%lf", &volume))
			    st_fail("Volume value '%s' is not a number", 
				    optarg);
			dovolume = 1;
			break;

		case 'c':
			if (! ft) usage("-c");
			str = optarg;
			if (! sscanf(str, "%d", &ft->info.channels))
				st_fail("-c must be given a number");
			break;
		case 'b':
			if (! ft) usage("-b");
			ft->info.size = ST_SIZE_BYTE;
			break;
		case 'w':
			if (! ft) usage("-w");
			ft->info.size = ST_SIZE_WORD;
			break;
		case 'l':
			if (! ft) usage("-l");
			ft->info.size = ST_SIZE_DWORD;
			break;
		case 'f':
			if (! ft) usage("-f");
			ft->info.size = ST_SIZE_FLOAT;
			break;
		case 'd':
			if (! ft) usage("-d");
			ft->info.size = ST_SIZE_DOUBLE;
			break;
		case 'D':
			if (! ft) usage("-D");
			ft->info.size = ST_SIZE_IEEE;
			break;

		case 's':
			if (! ft) usage("-s");
			ft->info.encoding = ST_ENCODING_SIGN2;
			break;
		case 'u':
			if (! ft) usage("-u");
			ft->info.encoding = ST_ENCODING_UNSIGNED;
			break;
		case 'U':
			if (! ft) usage("-U");
			ft->info.encoding = ST_ENCODING_ULAW;
			break;
		case 'A':
			if (! ft) usage("-A");
			ft->info.encoding = ST_ENCODING_ALAW;
			break;
		case 'a':
			if (! ft) usage("-a");
			ft->info.encoding = ST_ENCODING_ADPCM;
			break;
		case 'i':
			if (! ft) usage("-i");
			ft->info.encoding = ST_ENCODING_IMA_ADPCM;
			break;
		case 'g':
			if (! ft) usage("-g");
			ft->info.encoding = ST_ENCODING_GSM;
			break;
		
		case 'x':
			if (! ft) usage("-x");
			ft->swap = 1;
			break;
		
		case 'V':
			verbose = 1;
			break;
		}
	}
}

#ifdef SOXMIX
static int compare_input(ft_t ft1, ft_t ft2)
{
    if (ft1->info.rate != ft2->info.rate)
	return ST_EOF;
    if (ft1->info.size != ft2->info.size)
	return ST_EOF;
    if (ft1->info.encoding != ft2->info.encoding)
	return ST_EOF;
    if (ft1->info.channels != ft2->info.channels)
	return ST_EOF;

    return ST_SUCCESS;
}
#endif

/* 
 * Process input file -> effect table -> output file
 *	one buffer at a time
 */

static void process(void) {
    int e, f, flowstatus;
#ifdef SOXMIX
    int s;
    ULONG ilen[MAX_INPUT_FILES];
    LONG *ibuf[MAX_INPUT_FILES];
#endif
  
    for (f = 0; f < input_count; f++)
    {
	/* Read and write starters can change their formats. */
	if ((* informat[f]->h->startread)(informat[f]) != ST_SUCCESS)
	{
	    st_fail("Failed reading %s: %s",informat[f]->filename,
		    informat[f]->st_errstr);
	}

	/* Go a head and assume 1 channel audio if nothing is detected. 
	 * This is because libst usually doesn't set this for mono file
	 * formats (for historical reasons).
	 */
	if (informat[f]->info.channels == -1)
	    informat[f]->info.channels = 1;

	if ( st_checkformat(informat[f]) )
	    st_fail("bad input format for file %s",informat[f]->filename);

	st_report("Input file %s: using sample rate %lu\n\tsize %s, encoding %s, %d %s",
		  informat[f]->filename, informat[f]->info.rate, 
		  st_sizes_str[informat[f]->info.size], 
		  st_encodings_str[informat[f]->info.encoding], 
		  informat[f]->info.channels, 
		  (informat[f]->info.channels > 1) ? "channels" : "channel");

	if (informat[f]->comment)
	    st_report("Input file %s: comment \"%s\"\n", 
		      informat[f]->filename, informat[f]->comment);
    }

#ifdef SOXMIX
    for (f = 1; f < input_count; f++)
    {
	if (compare_input(informat[0], informat[f]) != ST_SUCCESS)
	{
	    st_fail("Input files must have the same rate, channels, data size, and encoding");
	}
    }
#endif
   
    if (writing)
    {
	open_output(outformat);

	/* Always use first input file as a reference for output
	 * file format.
	 */
	st_copyformat(informat[0], outformat);

	if ((*outformat->h->startwrite)(outformat) == ST_EOF)
	{
	    st_fail(outformat->st_errstr);
	}

	if (st_checkformat(outformat))
		st_fail("bad output format");

	st_report("Output file %s: using sample rate %lu\n\tsize %s, encoding %s, %d %s",
	       outformat->filename, outformat->info.rate, 
	       st_sizes_str[outformat->info.size], 
	       st_encodings_str[outformat->info.encoding], 
	       outformat->info.channels, 
	       (outformat->info.channels > 1) ? "channels" : "channel");

	if (outformat->comment)
	    st_report("Output file: comment \"%s\"\n", outformat->comment);
    }

    /* build efftab */
    checkeffect();

    /* Start all effects */
    for(e = 1; e < neffects; e++) {
	(* efftab[e].h->start)(&efftab[e]);
	if (efftabR[e].name) 
	    (* efftabR[e].h->start)(&efftabR[e]);
    }

    /* Reserve an output buffer for all effects */
    for(e = 0; e < neffects; e++) 
    {
	efftab[e].obuf = (LONG *) malloc(BUFSIZ * sizeof(LONG));
	if (efftab[e].obuf == NULL)
	{
	    st_fail("could not allocate memory");
	}
	if (efftabR[e].name) 
	{
	    efftabR[e].obuf = (LONG *) malloc(BUFSIZ * sizeof(LONG));
	    if (efftabR[e].obuf == NULL)
	    {
		st_fail("could not allocate memory");
	    }
	}
    }

#ifdef SOXMIX
    for (f = 0; f < MAX_INPUT_FILES; f++)
    {
	ibuf[f] = (LONG *)malloc(BUFSIZ * sizeof(LONG));
	if (!ibuf[f])
	{
	    st_fail("could not allocate memory");
	}
    }
#endif

    /* 
     * Just like errno, we must set st_errno to known values before
     * calling I/O operations.
     */
    for (f = 0; f < input_count; f++)
	informat[f]->st_errno = 0;
    outformat->st_errno = 0;

    /* Run input data through effects and get more until olen == 0 */
    do {

#ifndef SOXMIX
        efftab[0].olen = (*informat[0]->h->read)(informat[0], 
                                              efftab[0].obuf, (LONG) BUFSIZ);

    	if (informat[0]->st_errno)
	{
	    st_warn("Error reading from %s: %s", informat[0]->filename,
		    informat[0]->st_errstr);
	    break;
	}
#else
	for (f = 0; f < input_count; f++)
	{
	    ilen[f] = (*informat[f]->h->read)(informat[f],
			                      ibuf[f], (LONG)BUFSIZ);
	    if (informat[f]->st_errno)
	    {
    		st_warn("Error reading from %s: %s", informat[f]->filename,
    			informat[0]->st_errstr);
    		break;
	    }
	}
	if (f < input_count && informat[f]->st_errno)
	    break;

	efftab[0].olen = 0;
	for (f = 0; f < input_count; f++)
	    if (ilen[f] > efftab[0].olen)
		efftab[0].olen = ilen[f];

	for (s = 0; s < efftab[0].olen; s++)
	{
	    /* Mix data together by dividing by the number
	     * of audio files and then summing up.  This prevents
	     * overflows.
	     */
	    for (f = 0; f < input_count; f++)
	    {
		if (f == 0)
		    efftab[0].obuf[s] = 
			(s<ilen[f]) ? (ibuf[f][s]/input_count) : 0;
		else
		    if (s < ilen[f])
			efftab[0].obuf[s] += ibuf[f][s]/input_count;
	    }
	}
#endif

        efftab[0].odone = 0;

        if (efftab[0].olen == 0)
	    break;

        /* Change the volume of this initial input data if needed. */
        if (dovolume)
	    clipped += volumechange(efftab[0].obuf, efftab[0].olen,
		                    volume);

	/* mark chain as empty */
	for(e = 1; e < neffects; e++)
	    efftab[e].odone = efftab[e].olen = 0;

	flowstatus = flow_effect_out();

	/* Negative flowstatus says no more output will ever be generated. */
	if (flowstatus < 0 || outformat->st_errno)
	    break;

    } while (1); /* break; efftab[0].olen == 0 */

    /* Drain the effects out first to last, 
     * pushing residue through subsequent effects */
    /* oh, what a tangled web we weave */
    for(f = 1; f < neffects; f++)
    {
	while (1) {

	    if (drain_effect(f) == 0)
		break;		/* out of while (1) */
	
	    if (writing&&efftab[neffects-1].olen > 0)
		(* outformat->h->write)(outformat, efftab[neffects-1].obuf,
				       (LONG) efftab[neffects-1].olen);

	    if (efftab[f].olen != BUFSIZ)
		break;
	}
    }
	

    /* Very Important: 
     * Effect stop is called BEFORE files close.
     * Effect may write out more data after. 
     */
    
    for (e = 1; e < neffects; e++) {
	(* efftab[e].h->stop)(&efftab[e]);
	if (efftabR[e].name)
	    (* efftabR[e].h->stop)(&efftabR[e]);
    }

    for (f = 0; f < input_count; f++)
    {
	/* If problems closing input file, just warn user since
	 * we are exiting anyways.
	 */
	if ((* informat[f]->h->stopread)(informat[f]) == ST_EOF)
	    st_warn(informat[f]->st_errstr);
	fclose(informat[f]->fp);
    }

    if (writing)
    {
	/* problem closing output file, just warn user since we
	 * are exiting anyways.
	 */
        if ((* outformat->h->stopwrite)(outformat) == ST_EOF)
	    st_warn(outformat->st_errstr);
    }
    if (writing)
        fclose(outformat->fp);
}

static int flow_effect_out(void)
{
    int e, havedata, flowstatus = 0;

    do {
      /* run entire chain BACKWARDS: pull, don't push.*/
      /* this is because buffering system isn't a nice queueing system */
      for(e = neffects - 1; e > 0; e--) 
      {
	  flowstatus = flow_effect(e);
	  if (flowstatus)
              break;
      }
      
      /* If outputing and output data was generated then write it */
      if (writing&&(efftab[neffects-1].olen>efftab[neffects-1].odone)) 
      {
          (* outformat->h->write)(outformat, 
                                     efftab[neffects-1].obuf, 
                                     (LONG) efftab[neffects-1].olen);
          efftab[neffects-1].odone = efftab[neffects-1].olen;
      }
      
      if (outformat->st_errno)
      {
          st_warn("Error writing: %s",outformat->st_errstr);
	  break;
      }

      /* If any effect will never again produce data, give up.  This
       * works because of the pull status: the effect won't be able to
       * shut us down until all downstream buffers have been emptied.
       */
      if (flowstatus < 0)
	  break;
      
      /* if stuff still in pipeline, set up to flow effects again */
      havedata = 0;
      for(e = 0; e < neffects - 1; e++)
          if (efftab[e].odone < efftab[e].olen) {
              havedata = 1;
              break;
          }
    } while (havedata);

    return flowstatus;
}

static int flow_effect(e)
int e;
{
    LONG i, done, idone, odone, idonel, odonel, idoner, odoner;
    LONG *ibuf, *obuf;
    int effstatus;

    /* I have no input data ? */
    if (efftab[e-1].odone == efftab[e-1].olen)
	return 0;

    if (! efftabR[e].name) {
	/* No stereo data, or effect can handle stereo data so
	 * run effect over entire buffer.
	 */
	idone = efftab[e-1].olen - efftab[e-1].odone;
	odone = BUFSIZ;
	effstatus = (* efftab[e].h->flow)(&efftab[e], 
			      &efftab[e-1].obuf[efftab[e-1].odone], 
			      efftab[e].obuf, &idone, &odone);
	efftab[e-1].odone += idone;
	efftab[e].odone = 0;
	efftab[e].olen = odone;
	done = idone + odone;
    } else {
	
	/* Put stereo data in two seperate buffers and run effect
	 * on each of them.
	 */
	idone = efftab[e-1].olen - efftab[e-1].odone;
	odone = BUFSIZ;
	ibuf = &efftab[e-1].obuf[efftab[e-1].odone];
	for(i = 0; i < idone; i += 2) {
	    ibufl[i/2] = *ibuf++;
	    ibufr[i/2] = *ibuf++;
	}
	
	/* left */
	idonel = (idone + 1)/2;		/* odd-length logic */
	odonel = odone/2;
	effstatus = (* efftab[e].h->flow)(&efftab[e],
					  ibufl, obufl, &idonel, &odonel);
	
	/* right */
	idoner = idone/2;		/* odd-length logic */
	odoner = odone/2;
	effstatus = (* efftabR[e].h->flow)(&efftabR[e],
					   ibufr, obufr, &idoner, &odoner);

	obuf = efftab[e].obuf;
	 /* This loop implies left and right effect will always output
	  * the same amount of data.
	  */
	for(i = 0; i < odoner; i++) {
	    *obuf++ = obufl[i];
	    *obuf++ = obufr[i];
	}
	efftab[e-1].odone += idonel + idoner;
	efftab[e].odone = 0;
	efftab[e].olen = odonel + odoner;
	done = idonel + idoner + odonel + odoner;
    } 
    if (done == 0) 
	st_fail("Effect took & gave no samples!");
    if (effstatus == ST_EOF)
	return -1;
    return 1;
}

static int drain_effect(e)
int e;
{
    LONG i, olen, olenl, olenr;
    LONG *obuf;

    if (! efftabR[e].name) {
	efftab[e].olen = BUFSIZ;
	(* efftab[e].h->drain)(&efftab[e],efftab[e].obuf,
			       &efftab[e].olen);
    }
    else {
	olen = BUFSIZ;
		
	/* left */
	olenl = olen/2;
	(* efftab[e].h->drain)(&efftab[e], obufl, &olenl);
	
	/* right */
	olenr = olen/2;
	(* efftab[e].h->drain)(&efftabR[e], obufr, &olenr);
	
	obuf = efftab[e].obuf;
	/* This loop implies left and right effect will always output
	 * the same amount of data.
	 */
	for(i = 0; i < olenr; i++) {
	    *obuf++ = obufl[i];
	    *obuf++ = obufr[i];
	}
	efftab[e].olen = olenl + olenr;
    }
    return(efftab[e].olen);
}

/*
 * If no effect given, decide what it should be.
 * Smart ruleset for multiple effects in sequence.
 * 	Puts user-specified effect in right place.
 */
static void
checkeffect()
{
	int i;
	int needchan = 0, needrate = 0, haschan = 0, hasrate = 0;
	int effects_mask = 0;

	needrate = (informat[0]->info.rate != outformat->info.rate);
	needchan = (informat[0]->info.channels != outformat->info.channels);

	for (i = 0; i < nuser_effects; i++)
	{
	    if (user_efftab[i].h->flags & ST_EFF_CHAN)
	    {
		haschan++;
	    }
	    if (user_efftab[i].h->flags & ST_EFF_RATE)
	    {
		hasrate++;
	    }
	}

	if (haschan > 1)
	    st_fail("Can not specify multiple effects that modify channel #");
	if (hasrate > 1)
	    st_fail("Can not specify multiple effects that change sample rate");
	if (haschan && !needchan)
	    st_fail("Can not specify channel effects when input and output channel # are equal");
	if (hasrate && !needrate)
	    st_fail("Can not specify sample rate effects when input and output rate are equal");

	/* If not writing output then do not worry about adding
	 * channel and rate effects.  This is just to speed things
	 * up.
	 */
	if (!writing)
	{
	    needchan = 0;
	    needrate = 0;
	}

	/* --------- add the effects ------------------------ */

	/* efftab[0] is always the input stream and always exists */
	neffects = 1;

	/* If reducing channels then its faster to run all effects
	 * after the avg effect.
	 */
        if (needchan && !(haschan) &&
	    (informat[0]->info.channels > outformat->info.channels))
        {
	    /* Find effect and update initial pointers */
	    st_geteffect(&efftab[neffects], "avg");

	    /* give default opts for added effects */
	    (* efftab[neffects].h->getopts)(&efftab[neffects],(int)0,
					    (char **)0);

	    /* Copy format info to effect table */
	    effects_mask = st_updateeffect(&efftab[neffects], informat[0], 
		                           outformat, effects_mask);

	    neffects++;
	}

	/* If reducing the number of samples, its faster to run all effects
	 * after the resample effect.
	 */
	if (needrate && !(hasrate) &&
	    (informat[0]->info.rate > outformat->info.rate))
	{
	    if (soxpreview)
	        st_geteffect(&efftab[neffects], "rate");
	    else
	        st_geteffect(&efftab[neffects], "resample");

	    /* set up & give default opts for added effects */
	    (* efftab[neffects].h->getopts)(&efftab[neffects],(int)0,
					    (char **)0);

	    /* Copy format info to effect table */
	    effects_mask = st_updateeffect(&efftab[neffects], informat[0], 
		                           outformat, effects_mask);

	    /* Rate can't handle multiple channels so be sure and
	     * account for that.
	     */
	    if (efftab[neffects].ininfo.channels > 1)
	    {
	        memcpy(&efftabR[neffects], &efftab[neffects], 
		       sizeof(struct st_effect));
	    }

	    neffects++;
        }

	/* Copy over user specified effects into real efftab */
	for(i = 0; i < nuser_effects; i++) 
	{
	    memcpy(&efftab[neffects], &user_efftab[i], 
		   sizeof(struct st_effect));

	    /* Copy format info to effect table */
	    effects_mask = st_updateeffect(&efftab[neffects], informat[0], 
		                           outformat, effects_mask);

	    /* If this effect can't handle multiple channels then
	     * account for this.
	     */
	    if ((efftab[neffects].ininfo.channels > 1) &&
		!(efftab[neffects].h->flags & ST_EFF_MCHAN))
	    {
	        memcpy(&efftabR[neffects], &efftab[neffects], 
		       sizeof(struct st_effect));
	    }

	    neffects++;
	}

	/* If rate effect hasn't been added by now then add it here.
	 * Check adding rate before avg because its faster to run
	 * rate on less channels then more.
	 */
	if (needrate && !(effects_mask & ST_EFF_RATE))
	{
	    if (soxpreview)
	        st_geteffect(&efftab[neffects], "rate");
	    else
	        st_geteffect(&efftab[neffects], "resample");

	    /* set up & give default opts for added effects */
	    (* efftab[neffects].h->getopts)(&efftab[neffects],(int)0,
					    (char **)0);

	    /* Copy format info to effect table */
	    effects_mask = st_updateeffect(&efftab[neffects], informat[0], 
		                           outformat, effects_mask);

	    /* Rate can't handle multiple channels so be sure and
	     * account for that.
	     */
	    if (efftab[neffects].ininfo.channels > 1)
	    {
	        memcpy(&efftabR[neffects], &efftab[neffects], 
		       sizeof(struct st_effect));
	    }

	    neffects++;
        }

	/* If code up until now still hasn't added avg effect then
	 * do it now.
	 */
	if (needchan && !(effects_mask & ST_EFF_CHAN))
        {
	    st_geteffect(&efftab[neffects], "avg");

	    /* set up & give default opts for added effects */
	    (* efftab[neffects].h->getopts)(&efftab[neffects],(int)0,
					    (char **)0);

	    /* Copy format info to effect table */
	    effects_mask = st_updateeffect(&efftab[neffects], informat[0], 
		                           outformat, effects_mask);

	    neffects++;
	}
}

static void statistics(void) {
	if (dovolume && clipped > 0)
		st_report("Volume change clipped %d samples", clipped);
}

static LONG volumechange(buf, ct, vol)
LONG *buf;
LONG ct;
double vol;
{
	double y;
	LONG *p,*top;
	LONG clips=0;

	p = buf;
	top = buf+ct;
	while (p < top) {
	    y = vol * *p;
	    if (y < -2147483647.0) {
		y = -2147483647.0;
		clips++;
	    }
	    else if (y > 2147483647.0) {
		y = 2147483647.0;
		clips++;
	    }
	    *p++ = y + 0.5;
	}
	return clips;
}

static int filetype(fd)
int fd;
{
	struct stat st;

	fstat(fd, &st);

	return st.st_mode & S_IFMT;
}

static char *usagestr = 
"[ gopts ] [ fopts ] ifile [ fopts ] ofile [ effect [ effopts ] ]";

static void usage(opt)
char *opt;
{
    int i;
    
	fprintf(stderr, "%s: ", myname);
	if (verbose || !opt)
		fprintf(stderr, "%s\n\n", st_version());
	fprintf(stderr, "Usage: %s\n\n", usagestr);
	if (opt)
		fprintf(stderr, "Failed: %s\n", opt);
	else {
	    fprintf(stderr,"gopts: -e -h -p -v volume -V\n\n");
	    fprintf(stderr,"fopts: -r rate -c channels -s/-u/-U/-A/-a/-i/-g -b/-w/-l/-f/-d/-D -x\n\n");
	    fprintf(stderr, "effect: ");
	    for (i = 1; st_effects[i].name != NULL; i++) {
		fprintf(stderr, "%s ", st_effects[i].name);
	    }
	    fprintf(stderr, "\n\neffopts: depends on effect\n\n");
	    fprintf(stderr, "Supported file formats: ");
	    for (i = 0; st_formats[i].names != NULL; i++) {
		/* only print the first name */
		fprintf(stderr, "%s ", st_formats[i].names[0]);
	    }
	    fputc('\n', stderr);
	}
	exit(1);
}


/* called from util.c:fail */
void cleanup(void) {
	/* Close the input file and outputfile before exiting*/
	if (informat[0] && informat[0]->fp)
		fclose(informat[0]->fp);
	if (outformat && outformat->fp) {
		fclose(outformat->fp);
		/* remove the output file because we failed, if it's ours. */
		/* Don't if its not a regular file. */
		if (filetype(fileno(outformat->fp)) == S_IFREG)
		    REMOVE(outformat->filename);
	}
}