amiga_mpega.c

Go to the documentation of this file.

/* MPGLIB replacement using mpega.library (AmigaOS)
 * Written by Thomas Wenzel and Sigbjrn (CISC) Skj�et.
 *
 * Big thanks to St�hane Tavernard for mpega.library.
 *
 */

/* $Id: amiga_mpega.c,v 1.3 2005/11/01 13:01:56 robert Exp $ */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef AMIGA_MPEGA

#define __USE_SYSBASE
#include "lame.h"
#include <stdio.h>
#include <stdlib.h>

/* We need a small workaround here so GCC doesn't fail upon redefinition. :P */
#define FLOAT _FLOAT
#include <proto/exec.h>
#include <proto/mpega.h>
#undef _FLOAT

#ifndef __GNUC__
#include <dos.h>
#endif

struct Library *MPEGABase = NULL;
MPEGA_STREAM *mstream = NULL;
MPEGA_CTRL mctrl;

static const int smpls[2][4] = {
/* Layer x  I   II   III */
    {0, 384, 1152, 1152}, /* MPEG-1     */
    {0, 384, 1152, 576} /* MPEG-2(.5) */
};


#ifndef __GNUC__
static int
break_cleanup(void)
{
    /* Dummy break function to make atexit() work. :P */
    return 1;
}
#endif

static void
exit_cleanup(void)
{
    if (mstream) {
        MPEGA_close(mstream);
        mstream = NULL;
    }
    if (MPEGABase) {
        CloseLibrary(MPEGABase);
        MPEGABase = NULL;
    }
}


int
lame_decode_initfile(const char *fullname, mp3data_struct * mp3data)
{
    mctrl.bs_access = NULL;

    mctrl.layer_1_2.mono.quality = 2;
    mctrl.layer_1_2.stereo.quality = 2;
    mctrl.layer_1_2.mono.freq_div = 1;
    mctrl.layer_1_2.stereo.freq_div = 1;
    mctrl.layer_1_2.mono.freq_max = 48000;
    mctrl.layer_1_2.stereo.freq_max = 48000;
    mctrl.layer_3.mono.quality = 2;
    mctrl.layer_3.stereo.quality = 2;
    mctrl.layer_3.mono.freq_div = 1;
    mctrl.layer_3.stereo.freq_div = 1;
    mctrl.layer_3.mono.freq_max = 48000;
    mctrl.layer_3.stereo.freq_max = 48000;
    mctrl.layer_1_2.force_mono = 0;
    mctrl.layer_3.force_mono = 0;

    MPEGABase = OpenLibrary("mpega.library", 2);
    if (!MPEGABase) {
        error_printf("Unable to open mpega.library v2\n");
        exit(1);
    }
#ifndef __GNUC__
    onbreak(break_cleanup);
#endif
    atexit(exit_cleanup);

    mp3data->header_parsed = 0;
    mstream = MPEGA_open((char *) fullname, &mctrl);
    if (!mstream)
        return (-1);

    mp3data->header_parsed = 1;
    mp3data->stereo = mstream->dec_channels;
    mp3data->samplerate = mstream->dec_frequency;
    mp3data->bitrate = mstream->bitrate;
    mp3data->nsamp = (float) mstream->ms_duration / 1000 * mstream->dec_frequency;
    mp3data->mode = mstream->mode;
    mp3data->mode_ext = 0; /* mpega.library doesn't supply this info! :( */
    mp3data->framesize = smpls[mstream->norm - 1][mstream->layer];

    return 0;
}

int
lame_decode_fromfile(FILE * fd, short pcm_l[], short pcm_r[], mp3data_struct * mp3data)
{
    int     outsize = 0;
    WORD   *b[MPEGA_MAX_CHANNELS];

    b[0] = pcm_l;
    b[1] = pcm_r;

    mp3data->header_parsed = 0;
    while ((outsize == 0) || (outsize == MPEGA_ERR_BADFRAME)) /* Skip bad frames */
        outsize = MPEGA_decode_frame(mstream, b);

    if (outsize < 0)
        return (-1);

    mp3data->header_parsed = 1;
    mp3data->stereo = mstream->dec_channels;
    mp3data->samplerate = mstream->dec_frequency;
    mp3data->bitrate = mstream->bitrate;
    mp3data->mode = mstream->mode;
    mp3data->mode_ext = 0; /* mpega.library doesn't supply this info! :( */
    mp3data->framesize = smpls[mstream->norm - 1][mstream->layer];

    return outsize;
}

#endif /* AMIGA_MPEGA */

---