audacity/lib-src/twolame/frontend/audioin_sndfile.c

/*
 *	TwoLAME: an optimized MPEG Audio Layer Two encoder
 *
 *	Copyright (C) 2004-2007 The TwoLAME Project
 *
 *	This library is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU Lesser General Public
 *	License as published by the Free Software Foundation; either
 *	version 2.1 of the License, or (at your option) any later version.
 *
 *	This library 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
 *	Lesser General Public License for more details.
 *
 *	You should have received a copy of the GNU Lesser General Public
 *	License along with this library; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *  $Id: frontend.h 156 2007-03-20 23:57:35Z nhumfrey $
 *
 */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <sndfile.h>
#include "frontend.h"



/* 
  format_duration_string() 
  Create human readable duration string from libsndfile info
*/
static char *format_duration_string(SF_INFO * sfinfo)
{
    float seconds = 0.0f;
    char *string = NULL;
    int minutes = 0;
    
    string = malloc(MAX_NAME_SIZE);
    if (!string) {
        return NULL;
    }

    if (sfinfo->frames == 0 || sfinfo->samplerate == 0) {
        snprintf(string, MAX_NAME_SIZE, "Unknown");
        return string;
    }

    // Calculate the number of minutes and seconds
    seconds = sfinfo->frames / sfinfo->samplerate;
    minutes = (seconds / 60);
    seconds -= (minutes * 60);

    // Create a string out of it
    snprintf(string, MAX_NAME_SIZE, "%imin %1.1fsec", minutes, seconds);

    return string;
}



/* 
  print_info_sndfile() 
  Display information about input file
*/
static void print_info_sndfile(struct audioin_s *audioin)
{
    SNDFILE *file = audioin->file;
    SF_FORMAT_INFO format_info;
    SF_FORMAT_INFO subformat_info;
    char sndlibver[128];
    char *duration = NULL;

    // Get the format
    format_info.format = audioin->sfinfo->format & SF_FORMAT_TYPEMASK;
    sf_command(file, SFC_GET_FORMAT_INFO, &format_info, sizeof(format_info));

    // Get the sub-format info
    subformat_info.format = audioin->sfinfo->format & SF_FORMAT_SUBMASK;
    sf_command(file, SFC_GET_FORMAT_INFO, &subformat_info, sizeof(subformat_info));

    // Get the version of libsndfile
    sf_command(file, SFC_GET_LIB_VERSION, sndlibver, sizeof(sndlibver));

    // Get human readable duration of the input file
    duration = format_duration_string(audioin->sfinfo);

    fprintf(stderr, "Input Format: %s, %s\n", format_info.name, subformat_info.name);
    fprintf(stderr, "Input Duration: %s\n", duration);
    fprintf(stderr, "Input Library: %s\n", sndlibver);

    free(duration);

}


/* Read in some audio samples into buffer */
static int read_sndfile(audioin_t * audioin, short *buffer, int samples)
{
    SNDFILE *file = audioin->file;
    return sf_read_short(file, buffer, samples);
}


/* Return error string (or NULL) */
static const char *error_str_sndfile(audioin_t * audioin)
{
    SNDFILE *file = audioin->file;

    if (sf_error(file) == SF_ERR_NO_ERROR) {
        // No error
        return NULL;
    } else {
        // Return error string
        return sf_strerror(file);
    }
}

static int close_sndfile(audioin_t * audioin)
{
    SNDFILE *file = audioin->file;

    free(audioin);

    return sf_close(file);
}

audioin_t *open_audioin_sndfile(char *filename, SF_INFO * sfinfo)
{
    audioin_t *audioin = NULL;

    // Allocate memory for structure
    audioin = malloc(sizeof(audioin_t));
    if (audioin == NULL) {
        fprintf(stderr, "Failed to allocate memory for audioin_t structure.\n");
        exit(ERR_MEM_ALLOC);
    }
    // Open the input file by filename
    audioin->file = sf_open(filename, SFM_READ, sfinfo);

    // Check for errors
    if (audioin->file == NULL) {
        fprintf(stderr, "Failed to open input file (%s):\n", filename);
        fprintf(stderr, "  %s\n", sf_strerror(NULL));
        exit(ERR_OPENING_INPUT);
    }
    // Fill-in data structure
    audioin->samplesize = 0;
    audioin->sfinfo = sfinfo;
    audioin->print_info = print_info_sndfile;
    audioin->read = read_sndfile;
    audioin->error_str = error_str_sndfile;
    audioin->close = close_sndfile;


    return audioin;
}