download : svn :: features :: sf.net project - bug tracker :: news archive

libmpg123 API :: testing :: benchmarking :: faq :: links :: contact

Note: This API doc is automatically generated from the current development version that you can get via Subversion or as a daily snapshot from http://mpg123.org/snapshot. There may be differences (additions) compared to the latest stable release. See NEWS.libmpg123 and the overall NEWS file on libmpg123 versions and important changes between them.
Let me emphasize that the policy for libmpg123 is to always stay backwards compatible -- only additions are planned (and it's not yet planned to change the plans;-).

mpg123_to_wav.c

Go to the documentation of this file.

/*
        mpg123_to_wav.c

        copyright 2007 by the mpg123 project - free software under the terms of the LGPL 2.1
        see COPYING and AUTHORS files in distribution or http://mpg123.org
        initially written by Nicholas Humfrey
*/

#include <stdio.h>
#include <strings.h>
#include <mpg123.h>
#include <sndfile.h>


void usage()
{
        printf("Usage: mpg123_to_wav <input> <output>\n");
        exit(99);
}

void cleanup(mpg123_handle *mh)
{
        /* It's really to late for error checks here;-) */
        mpg123_close(mh);
        mpg123_delete(mh);
        mpg123_exit();
}

int main(int argc, char *argv[])
{
        SNDFILE* sndfile = NULL;
        SF_INFO sfinfo;
        mpg123_handle *mh = NULL;
        unsigned char* buffer = NULL;
        size_t buffer_size = 0;
        size_t done = 0;
        int  channels = 0, encoding = 0;
        long rate = 0;
        int  err  = MPG123_OK;
        off_t samples = 0;

        if (argc!=3) usage();
        printf( "Input file: %s\n", argv[1]);
        printf( "Output file: %s\n", argv[2]);
        
        err = mpg123_init();
        if( err != MPG123_OK || (mh = mpg123_new(NULL, &err)) == NULL
            /* Let mpg123 work with the file, that excludes MPG123_NEED_MORE messages. */
            || mpg123_open(mh, argv[1]) != MPG123_OK
            /* Peek into track and get first output format. */
            || mpg123_getformat(mh, &rate, &channels, &encoding) != MPG123_OK )
        {
                fprintf( stderr, "Trouble with mpg123: %s\n",
                         mh==NULL ? mpg123_plain_strerror(err) : mpg123_strerror(mh) );
                cleanup(mh);
                return -1;
        }

        if(encoding != MPG123_ENC_SIGNED_16)
        { /* Signed 16 is the default output format anyways; it would actually by only different if we forced it.
             So this check is here just for this explanation. */
                cleanup(mh);
                fprintf(stderr, "Bad encoding: 0x%x!\n", encoding);
                return -2;
        }
        /* Ensure that this output format will not change (it could, when we allow it). */
        mpg123_format_none(mh);
        mpg123_format(mh, rate, channels, encoding);

        /* Buffer could be almost any size here, mpg123_outblock() is just some recommendation.
           Important, especially for sndfile writing, is that the size is a multiple of sample size. */
        buffer_size = mpg123_outblock( mh );
        buffer = malloc( buffer_size );

        bzero(&sfinfo, sizeof(sfinfo) );
        sfinfo.samplerate = rate;
        sfinfo.channels = channels;
        sfinfo.format = SF_FORMAT_WAV|SF_FORMAT_PCM_16;
        printf("Creating 16bit WAV with %i channels and %liHz.\n", channels, rate);

        sndfile = sf_open(argv[2], SFM_WRITE, &sfinfo);
        if(sndfile == NULL){ fprintf(stderr, "Cannot open output file!\n"); cleanup(mh); return -2; }

        do
        {
                err = mpg123_read( mh, buffer, buffer_size, &done );
                sf_write_short( sndfile, (short*)buffer, done/sizeof(short) );
                samples += done/sizeof(short);
                /* We are not in feeder mode, so MPG123_OK, MPG123_ERR and MPG123_NEW_FORMAT are the only possibilities.
                   We do not handle a new format, MPG123_DONE is the end... so abort on anything not MPG123_OK. */
        } while (err==MPG123_OK);

        if(err != MPG123_DONE)
        fprintf( stderr, "Warning: Decoding ended prematurely because: %s\n",
                 err == MPG123_ERR ? mpg123_strerror(mh) : mpg123_plain_strerror(err) );

        sf_close( sndfile );

        samples /= channels;
        printf("%li samples written.\n", (long)samples);
        cleanup(mh);
        return 0;
}

---