audio.c

AAC编解码源码

/*
** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
** Copyright (C) 2003-2004 M. Bakker, Ahead Software AG, http://www.nero.com
**
** This program 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 of the License, or
** (at your option) any later version.
**
** This program 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 this program; if not, write to the Free Software
** Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
**
** Any non-GPL usage of this software or parts of this software is strictly
** forbidden.
**
** Commercial non-GPL licensing of this software is possible.
** For more info contact Ahead Software through [e-mail].
**
** $Id: audio.c,v 1.11 2004/02/06 10:23:27 menno Exp $
**/

#ifdef _WIN32
#include <io.h>
#endif
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <math.h>
#include <faad.h>
#include "audio.h"


audio_file *open_audio_file(char *infile, int samplerate, int channels,
                            int outputFormat, int fileType, long channelMask)
{
    audio_file *aufile = malloc(sizeof(audio_file));

    aufile->outputFormat = outputFormat;

    aufile->samplerate = samplerate;
    aufile->channels = channels;
    aufile->total_samples = 0;
    aufile->fileType = fileType;
    aufile->channelMask = channelMask;

    switch (outputFormat)
    {
    case FAAD_FMT_16BIT:
        aufile->bits_per_sample = 16;
        break;
    case FAAD_FMT_24BIT:
        aufile->bits_per_sample = 24;
        break;
    case FAAD_FMT_32BIT:
    case FAAD_FMT_FLOAT:
        aufile->bits_per_sample = 32;
        break;
    default:
        if (aufile) free(aufile);
        return NULL;
    }

    if(infile[0] == '-')
    {
#ifdef _WIN32
        setmode(fileno(stdout), O_BINARY);
#endif
        aufile->sndfile = stdout;
    } else {
        aufile->sndfile = fopen(infile, "wb");
    }

    if (aufile->sndfile == NULL)
    {
        if (aufile) free(aufile);
        return NULL;
    }

    if (aufile->fileType == OUTPUT_WAV)
    {
        if (aufile->channelMask)
            write_wav_extensible_header(aufile, aufile->channelMask);
        else
            write_wav_header(aufile);
    }

    return aufile;
}

int write_audio_file(audio_file *aufile, void *sample_buffer, int samples, int offset)
{
    char *buf = (char *)sample_buffer;
    switch (aufile->outputFormat)
    {
    case FAAD_FMT_16BIT:
        return write_audio_16bit(aufile, buf + offset*2, samples);
    case FAAD_FMT_24BIT:
        return write_audio_24bit(aufile, buf + offset*4, samples);
    case FAAD_FMT_32BIT:
        return write_audio_32bit(aufile, buf + offset*4, samples);
    case FAAD_FMT_FLOAT:
        return write_audio_float(aufile, buf + offset*4, samples);
    default:
        return 0;
    }

    return 0;
}

void close_audio_file(audio_file *aufile)
{
    if (aufile->fileType == OUTPUT_WAV)
    {
        fseek(aufile->sndfile, 0, SEEK_SET);

        if (aufile->channelMask)
            write_wav_extensible_header(aufile, aufile->channelMask);
        else
            write_wav_header(aufile);
    }

    fclose(aufile->sndfile);

    if (aufile) free(aufile);
}

static int write_wav_header(audio_file *aufile)
{
    unsigned char header[44];
    unsigned char* p = header;
    unsigned int bytes = (aufile->bits_per_sample + 7) / 8;
    float data_size = (float)bytes * aufile->total_samples;
    unsigned long word32;

    *p++ = 'R'; *p++ = 'I'; *p++ = 'F'; *p++ = 'F';

    word32 = (data_size + (44 - 8) < (float)MAXWAVESIZE) ?
        (unsigned long)data_size + (44 - 8)  :  (unsigned long)MAXWAVESIZE;
    *p++ = (unsigned char)(word32 >>  0);
    *p++ = (unsigned char)(word32 >>  8);
    *p++ = (unsigned char)(word32 >> 16);
    *p++ = (unsigned char)(word32 >> 24);

    *p++ = 'W'; *p++ = 'A'; *p++ = 'V'; *p++ = 'E';

    *p++ = 'f'; *p++ = 'm'; *p++ = 't'; *p++ = ' ';

    *p++ = 0x10; *p++ = 0x00; *p++ = 0x00; *p++ = 0x00;

    if (aufile->outputFormat == FAAD_FMT_FLOAT)
    {
        *p++ = 0x03; *p++ = 0x00;
    } else {
        *p++ = 0x01; *p++ = 0x00;
    }

    *p++ = (unsigned char)(aufile->channels >> 0);
    *p++ = (unsigned char)(aufile->channels >> 8);

    word32 = (unsigned long)(aufile->samplerate + 0.5);
    *p++ = (unsigned char)(word32 >>  0);
    *p++ = (unsigned char)(word32 >>  8);
    *p++ = (unsigned char)(word32 >> 16);
    *p++ = (unsigned char)(word32 >> 24);

    word32 = aufile->samplerate * bytes * aufile->channels;
    *p++ = (unsigned char)(word32 >>  0);
    *p++ = (unsigned char)(word32 >>  8);
    *p++ = (unsigned char)(word32 >> 16);
    *p++ = (unsigned char)(word32 >> 24);

    word32 = bytes * aufile->channels;
    *p++ = (unsigned char)(word32 >>  0);
    *p++ = (unsigned char)(word32 >>  8);

    *p++ = (unsigned char)(aufile->bits_per_sample >> 0);
    *p++ = (unsigned char)(aufile->bits_per_sample >> 8);

    *p++ = 'd'; *p++ = 'a'; *p++ = 't'; *p++ = 'a';

    word32 = data_size < MAXWAVESIZE ?
        (unsigned long)data_size : (unsigned long)MAXWAVESIZE;
    *p++ = (unsigned char)(word32 >>  0);
    *p++ = (unsigned char)(word32 >>  8);
    *p++ = (unsigned char)(word32 >> 16);
    *p++ = (unsigned char)(word32 >> 24);

    return fwrite(header, sizeof(header), 1, aufile->sndfile);
}

static int write_wav_extensible_header(audio_file *aufile, long channelMask)
{
    unsigned char header[68];
    unsigned char* p = header;
    unsigned int bytes = (aufile->bits_per_sample + 7) / 8;
    float data_size = (float)bytes * aufile->total_samples;
    unsigned long word32;

    *p++ = 'R'; *p++ = 'I'; *p++ = 'F'; *p++ = 'F';

    word32 = (data_size + (68 - 8) < (float)MAXWAVESIZE) ?
        (unsigned long)data_size + (68 - 8)  :  (unsigned long)MAXWAVESIZE;
    *p++ = (unsigned char)(word32 >>  0);
    *p++ = (unsigned char)(word32 >>  8);
    *p++ = (unsigned char)(word32 >> 16);
    *p++ = (unsigned char)(word32 >> 24);

    *p++ = 'W'; *p++ = 'A'; *p++ = 'V'; *p++ = 'E';

    *p++ = 'f'; *p++ = 'm'; *p++ = 't'; *p++ = ' ';

    *p++ = /*0x10*/0x28; *p++ = 0x00; *p++ = 0x00; *p++ = 0x00;

    /* WAVE_FORMAT_EXTENSIBLE */
    *p++ = 0xFE; *p++ = 0xFF;

    *p++ = (unsigned char)(aufile->channels >> 0);
    *p++ = (unsigned char)(aufile->channels >> 8);

    word32 = (unsigned long)(aufile->samplerate + 0.5);
    *p++ = (unsigned char)(word32 >>  0);
    *p++ = (unsigned char)(word32 >>  8);
    *p++ = (unsigned char)(word32 >> 16);
    *p++ = (unsigned char)(word32 >> 24);

    word32 = aufile->samplerate * bytes * aufile->channels;
    *p++ = (unsigned char)(word32 >>  0);
    *p++ = (unsigned char)(word32 >>  8);
    *p++ = (unsigned char)(word32 >> 16);
    *p++ = (unsigned char)(word32 >> 24);

    word32 = bytes * aufile->channels;
    *p++ = (unsigned char)(word32 >>  0);
    *p++ = (unsigned char)(word32 >>  8);

    *p++ = (unsigned char)(aufile->bits_per_sample >> 0);
    *p++ = (unsigned char)(aufile->bits_per_sample >> 8);

    /* cbSize */
    *p++ = (unsigned char)(22);
    *p++ = (unsigned char)(0);