/* * *  output_wav.c *     *	Copyright (C) Aaron Holtzman - May 1999 * *  This file is part of ac3dec, a free Dolby AC-3 stream decoder. *	 *  ac3dec is free software; you can redistribute it and/or modify *  it under the terms of the GNU General Public License as published by *  the Free Software Foundation; either version 2, or (at your option) *  any later version. *    *  ac3dec is distributed in the hope that it will be useful, *  but WITHOUT ANY WARRANTY; without even the implied warranty of *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the *  GNU General Public License for more details. *    *  You should have received a copy of the GNU General Public License *  along with GNU Make; see the file COPYING.  If not, write to *  the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  * *  This file is based on output_linux.c by Aaron Holtzman. *  All .wav modifications were done by Jorgen Lundman <lundman@lundman.net> *  Any .wav bugs and errors should be reported to him. * * */#ifdef HAVE_CONFIG_H#  include <config.h>#endif#include <stdio.h>#include <errno.h>#include <string.h>#include <unistd.h>#include <fcntl.h>#include "ac3.h"#include "decode.h"#include "debug.h"#include "output.h"#include "downmix.h"#include "ring_buffer.h"#include "wav.h"#define BUFFER_SIZE 1024 static char output_file[] = "output.wav";static int fd;static struct wave_header wave;/* * open the file for writing to */int output_open(int bits, int rate, int channels){  /*  int tmp;*/    /*   * Open the output file   */  fd=open(output_file,O_WRONLY | O_TRUNC | O_CREAT, 0644);   if(fd < 0)     {      dprintf("%s: Opening audio output %s\n",	      strerror(errno), output_file);      goto ERR;    }  dprintf("Opened audio output \"%s\"\n",output_file);  /* Write out a ZEROD wave header first */  memset(&wave, 0, sizeof(wave));  /* Store information */  wave.common.wChannels = channels;  wave.common.wBitsPerSample = bits;  wave.common.dwSamplesPerSec = rate;  if (write(fd, &wave, sizeof(wave)) != sizeof(wave)) {    dprintf("failed to write wav-header: %s\n", strerror(errno));    goto ERR;  }  return 1;   ERR:  if(fd >= 0) { close(fd); }  return 0;}/* * play the sample to the already opened file descriptor */void output_play(bsi_t *bsi,stream_samples_t *samples){  int i;	float *left,*right;	float norm = 1.0;	float left_tmp = 0.0;	float right_tmp = 0.0;	sint_16 *out_buf;    if(fd < 0)    return;  	//Downmix if necessary 	downmix(bsi,samples);	//Determine a normalization constant if the signal exceeds 	//100% digital [-1.0,1.0]	//	//perhaps use the dynamic range info to do this instead	for(i=0; i< 256;i++)	{    left_tmp = samples->channel[0][i];    right_tmp = samples->channel[1][i];		if(left_tmp > norm)			norm = left_tmp;		if(left_tmp < -norm)			norm = -left_tmp;		if(right_tmp > norm)			norm = right_tmp;		if(right_tmp < -norm)			norm = -right_tmp; 	}	norm = 32000.0/norm;	/* Take the floating point audio data and convert it into	 * 16 bit signed PCM data */	left = samples->channel[0];	right = samples->channel[1];	for(i=0; i < 256; i++)	{		out_buf[i * 2 ]    = (sint_16) (*left++  * norm);		out_buf[i * 2 + 1] = (sint_16) (*right++ * norm);	}	write(fd, out_buf,BUFFER_SIZE);}voidoutput_close(void){  off_t offset;  /* Find how long our file is in total, including header */  offset = lseek(fd, 0, SEEK_CUR);  if (offset < 0) 	{    dprintf("lseek failed - wav-header is corrupt\n");    goto ERR;  }  /* Rewind file */  if (lseek(fd, 0, SEEK_SET) < 0) 	{    dprintf("rewind failed - wav-header is corrupt\n");    goto ERR;  }  /* Fill out our wav-header with some information. */  offset -= 8;  strcpy(wave.riff.id, "RIFF");  wave.riff.len = offset + 24;  strcpy(wave.riff.wave_id, "WAVE");  offset -= 4;  offset -= 8;  strcpy(wave.format.id, "fmt ");  wave.format.len = sizeof(struct common_struct);  wave.common.wFormatTag = WAVE_FORMAT_PCM;  wave.common.dwAvgBytesPerSec =     wave.common.wChannels * wave.common.dwSamplesPerSec *    (wave.common.wBitsPerSample >> 4);  wave.common.wBlockAlign = wave.common.wChannels *     (wave.common.wBitsPerSample >> 4);  strcpy(wave.data.id, "data");  offset -= sizeof(struct common_struct);  wave.data.len = offset;  offset -= 8;  strcpy(wave.riffdata.id, "RIFF");  wave.riffdata.len = offset;  strcpy(wave.riffdata.wave_id, "WAVE");  offset -= 4;  offset -= 8;  strcpy(wave.dataformat.id, "DATA");  wave.dataformat.len = offset;  if (write(fd, &wave, sizeof(wave)) < sizeof(wave)) 	{    dprintf("wav-header write failed -- file is corrupt\n");    goto ERR;  } ERR:  close(fd);}