platform/common/mp3_helix.c

   1 /*
   2  * Some mp3 related code for Sega/Mega CD.
   3  * Uses the Helix Fixed-point MP3 decoder
   4  * (C) notaz, 2007-2009
   5  *
   6  * This work is licensed under the terms of MAME license.
   7  * See COPYING file in the top-level directory.
   8  */
   9
  10 #include <stdio.h>
  11 #include <string.h>
  12 #include <dlfcn.h>
  13
  14 #include <pico/pico_int.h>
  15 /*#include "helix/pub/mp3dec.h"*/
  16 #include "mp3.h"
  17
  18 #ifndef _MP3DEC_H
  19 typedef void *HMP3Decoder;
  20 #define ERR_MP3_INDATA_UNDERFLOW -1
  21 #define ERR_MP3_MAINDATA_UNDERFLOW -2
  22 #endif
  23
  24 static void *mp3dec;
  25 static unsigned char mp3_input_buffer[2 * 1024];
  26
  27 #ifdef __GP2X__
  28 #define mp3dec_decode _mp3dec_decode
  29 #define mp3dec_start _mp3dec_start
  30 #endif
  31
  32 static void *libhelix;
  33 HMP3Decoder (*p_MP3InitDecoder)(void);
  34 void (*p_MP3FreeDecoder)(HMP3Decoder);
  35 int (*p_MP3Decode)(HMP3Decoder, unsigned char **, int *, short *, int);
  36
  37 int mp3dec_decode(FILE *f, int *file_pos, int file_len)
  38 {
  39         unsigned char *readPtr;
  40         int bytesLeft;
  41         int offset; // mp3 frame offset from readPtr
  42         int had_err;
  43         int err = 0;
  44         int retry = 3;
  45
  46         do
  47         {
  48                 if (*file_pos >= file_len)
  49                         return 1; /* EOF, nothing to do */
  50
  51                 fseek(f, *file_pos, SEEK_SET);
  52                 bytesLeft = fread(mp3_input_buffer, 1, sizeof(mp3_input_buffer), f);
  53
  54                 offset = mp3_find_sync_word(mp3_input_buffer, bytesLeft);
  55                 if (offset < 0) {
  56                         lprintf("find_sync_word (%i/%i) err %i\n",
  57                                 *file_pos, file_len, offset);
  58                         *file_pos = file_len;
  59                         return 1; // EOF
  60                 }
  61                 readPtr = mp3_input_buffer + offset;
  62                 bytesLeft -= offset;
  63
  64                 had_err = err;
  65                 err = p_MP3Decode(mp3dec, &readPtr, &bytesLeft, cdda_out_buffer, 0);
  66                 if (err) {
  67                         if (err == ERR_MP3_MAINDATA_UNDERFLOW && !had_err) {
  68                                 // just need another frame
  69                                 *file_pos += readPtr - mp3_input_buffer;
  70                                 continue;
  71                         }
  72                         if (err == ERR_MP3_INDATA_UNDERFLOW && !had_err) {
  73                                 if (offset == 0)
  74                                         // something's really wrong here, frame had to fit
  75                                         *file_pos = file_len;
  76                                 else
  77                                         *file_pos += offset;
  78                                 continue;
  79                         }
  80                         if (-12 <= err && err <= -6) {
  81                                 // ERR_MP3_INVALID_FRAMEHEADER, ERR_MP3_INVALID_*
  82                                 // just try to skip the offending frame..
  83                                 *file_pos += offset + 1;
  84                                 continue;
  85                         }
  86                         lprintf("MP3Decode err (%i/%i) %i\n",
  87                                 *file_pos, file_len, err);
  88                         *file_pos = file_len;
  89                         return 1;
  90                 }
  91                 *file_pos += readPtr - mp3_input_buffer;
  92         }
  93         while (err && --retry > 0);
  94
  95         return !!err;
  96 }
  97
  98 int mp3dec_start(FILE *f, int fpos_start)
  99 {
 100         if (libhelix == NULL) {
 101                 libhelix = dlopen("./libhelix.so", RTLD_NOW);
 102                 if (libhelix == NULL) {
 103                         lprintf("mp3dec: load libhelix.so: %s\n", dlerror());
 104                         return -1;
 105                 }
 106
 107                 p_MP3InitDecoder = dlsym(libhelix, "MP3InitDecoder");
 108                 p_MP3FreeDecoder = dlsym(libhelix, "MP3FreeDecoder");
 109                 p_MP3Decode = dlsym(libhelix, "MP3Decode");
 110
 111                 if (p_MP3InitDecoder == NULL || p_MP3FreeDecoder == NULL
 112                     || p_MP3Decode == NULL)
 113                 {
 114                         lprintf("mp3dec: missing symbol(s) in libhelix.so\n");
 115                         dlclose(libhelix);
 116                         libhelix = NULL;
 117                         return -1;
 118                 }
 119         }
 120
 121         // must re-init decoder for new track
 122         if (mp3dec)
 123                 p_MP3FreeDecoder(mp3dec);
 124         mp3dec = p_MP3InitDecoder();
 125
 126         return (mp3dec == 0) ? -1 : 0;
 127 }