ref: dab539cd14726de15932b0310532212f8da29bf7
dir: /sys/src/cmd/audio/mp3enc/mpglib_interface.c/
/* $Id: mpglib_interface.c,v 1.18 2001/01/06 01:00:33 markt Exp $ */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#ifdef HAVE_MPGLIB
#include <limits.h>
#include <stdlib.h>
#include <assert.h>
#include "interface.h"
#include "lame.h"
#ifdef WITH_DMALLOC
#include <dmalloc.h>
#endif
MPSTR mp;
plotting_data* mpg123_pinfo = NULL;
int lame_decode_init( void )
{
InitMP3 ( &mp );
return 0;
}
/*
* For lame_decode: return code
* -1 error
* 0 ok, but need more data before outputing any samples
* n number of samples output. either 576 or 1152 depending on MP3 file.
*/
int lame_decode1_headers(
unsigned char* buffer,
int len,
short pcm_l [],
short pcm_r [],
mp3data_struct* mp3data )
{
static const int smpls [2] [4] = {
/* Layer I II III */
{ 0, 384, 1152, 1152 }, /* MPEG-1 */
{ 0, 384, 1152, 576 } /* MPEG-2(.5) */
};
static char out [8192];
signed short int* p = (signed short int*) out;
int processed_bytes;
int processed_samples; // processed samples per channel
int ret;
int i;
mp3data->header_parsed = 0;
ret = decodeMP3 ( &mp, buffer, len, (char*)p, sizeof(out), &processed_bytes );
if ( mp.header_parsed ) {
mp3data->header_parsed = 1;
mp3data->stereo = mp.fr.stereo;
mp3data->samplerate = freqs [mp.fr.sampling_frequency];
mp3data->mode = mp.fr.mode;
mp3data->mode_ext = mp.fr.mode_ext;
mp3data->framesize = smpls [mp.fr.lsf] [mp.fr.lay];
if (mp.fsizeold > 0) /* works for free format and fixed, no overrun, temporal results are < 400.e6 */
mp3data->bitrate = 8 * (4 + mp.fsizeold) * mp3data->samplerate /
( 1.e3 * mp3data->framesize ) + 0.5;
else
mp3data->bitrate = tabsel_123 [mp.fr.lsf] [mp.fr.lay-1] [mp.fr.bitrate_index];
if (mp.num_frames>0) {
/* Xing VBR header found and num_frames was set */
mp3data->totalframes = mp.num_frames;
mp3data->nsamp=mp3data->framesize * mp.num_frames;
}
}
switch ( ret ) {
case MP3_OK:
switch ( mp.fr.stereo ) {
case 1:
processed_samples = processed_bytes >> 1;
for ( i = 0; i < processed_samples; i++ )
pcm_l [i] = *p++;
break;
case 2:
processed_samples = processed_bytes >> 2;
for ( i = 0; i < processed_samples; i++ ) {
pcm_l [i] = *p++;
pcm_r [i] = *p++;
}
break;
default:
processed_samples = -1;
assert (0);
break;
}
break;
case MP3_NEED_MORE:
processed_samples = 0;
break;
default:
assert (0);
case MP3_ERR:
processed_samples = -1;
break;
}
// printf ( "ok, more, err: %i %i %i\n", MP3_OK, MP3_NEED_MORE, MP3_ERR );
// printf ( "ret = %i out=%i\n", ret, totsize );
return processed_samples;
}
/*
* For lame_decode: return code
* -1 error
* 0 ok, but need more data before outputing any samples
* n number of samples output. Will be at most one frame of
* MPEG data.
*/
int lame_decode1(
unsigned char* buffer,
int len,
short pcm_l [],
short pcm_r [] )
{
mp3data_struct mp3data;
return lame_decode1_headers ( buffer, len, pcm_l, pcm_r, &mp3data );
}
/*
* For lame_decode: return code
* -1 error
* 0 ok, but need more data before outputing any samples
* n number of samples output. a multiple of 576 or 1152 depending on MP3 file.
*/
int lame_decode_headers(
unsigned char* buffer,
int len,
short pcm_l [],
short pcm_r [],
mp3data_struct* mp3data )
{
int ret;
int totsize = 0; // number of decoded samples per channel
while (1) {
switch ( ret = lame_decode1_headers ( buffer, len, pcm_l+totsize, pcm_r+totsize, mp3data ) ) {
case -1: return ret;
case 0: return totsize;
default: totsize += ret;
len = 0; /* future calls to decodeMP3 are just to flush buffers */
break;
}
}
}
int lame_decode(
unsigned char* buffer,
int len,
short pcm_l [],
short pcm_r [] )
{
mp3data_struct mp3data;
return lame_decode_headers ( buffer, len, pcm_l, pcm_r, &mp3data );
}
#endif
/* end of mpglib_interface.c */