ref: e09adf59442cd36888eaea1d76e66ff3259d16b8
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 */