apps/codecs/ay.c

   1
   2 /* Ripped off from Game_Music_Emu 0.5.2. http://www.slack.net/~ant/ */
   3
   4 #include <codecs/lib/codeclib.h>
   5 #include "libgme/ay_emu.h"
   6
   7 CODEC_HEADER
   8
   9 /* Maximum number of bytes to process in one iteration */
  10 #define CHUNK_SIZE (1024*2)
  11
  12 static int16_t samples[CHUNK_SIZE] IBSS_ATTR;
  13 static struct Ay_Emu ay_emu;
  14
  15 /****************** rockbox interface ******************/
  16
  17 static void set_codec_track(int t, int multitrack) {
  18     Ay_start_track(&ay_emu, t);
  19
  20     /* for loop mode we disable track limits */
  21     if (!ci->loop_track()) {
  22         Track_set_fade(&ay_emu, Track_get_length( &ay_emu, t ) - 4000, 4000);
  23     }
  24     if (multitrack) ci->set_elapsed(t*1000); /* t is track no to display */
  25     else ci->set_elapsed(0);
  26 }
  27
  28 /* this is the codec entry point */
  29 enum codec_status codec_main(enum codec_entry_call_reason reason)
  30 {
  31     if (reason == CODEC_LOAD) {
  32         /* we only render 16 bits */
  33         ci->configure(DSP_SET_SAMPLE_DEPTH, 16);
  34
  35         /* 44 Khz, Interleaved stereo */
  36         ci->configure(DSP_SET_FREQUENCY, 44100);
  37         ci->configure(DSP_SET_STEREO_MODE, STEREO_INTERLEAVED);
  38
  39         Ay_init(&ay_emu);
  40         Ay_set_sample_rate(&ay_emu, 44100);
  41     }
  42
  43     return CODEC_OK;
  44 }
  45
  46 /* this is called for each file to process */
  47 enum codec_status codec_run(void)
  48 {
  49     blargg_err_t err;
  50     uint8_t *buf;
  51     size_t n;
  52     int track, is_multitrack;
  53     intptr_t param;
  54     uint32_t elapsed_time;
  55
  56     /* reset values */
  57     track = is_multitrack = 0;
  58     elapsed_time = 0;
  59
  60     DEBUGF("AY: next_track\n");
  61     if (codec_init()) {
  62         return CODEC_ERROR;
  63     }
  64
  65     codec_set_replaygain(ci->id3);
  66
  67     /* Read the entire file */
  68     DEBUGF("AY: request file\n");
  69     ci->seek_buffer(0);
  70     buf = ci->request_buffer(&n, ci->filesize);
  71     if (!buf || n < (size_t)ci->filesize) {
  72         DEBUGF("AY: file load failed\n");
  73         return CODEC_ERROR;
  74     }
  75
  76     if ((err = Ay_load_mem(&ay_emu, buf, ci->filesize))) {
  77         DEBUGF("AY: Ay_load_mem failed (%s)\n", err);
  78         return CODEC_ERROR;
  79     }
  80
  81     /* Update internal track count */
  82     if (ay_emu.m3u.size > 0)
  83         ay_emu.track_count = ay_emu.m3u.size;
  84
  85     /* Check if file has multiple tracks */
  86     if (ay_emu.track_count > 1) {
  87         is_multitrack = 1;
  88     }
  89
  90 next_track:
  91     set_codec_track(track, is_multitrack);
  92
  93     /* The main decoder loop */
  94     while (1) {
  95         enum codec_command_action action = ci->get_command(&param);
  96
  97         if (action == CODEC_ACTION_HALT)
  98             break;
  99
 100         if (action == CODEC_ACTION_SEEK_TIME) {
 101             if (is_multitrack) {
 102                 track = param/1000;
 103                 ci->seek_complete();
 104                 if (track >= ay_emu.track_count) break;
 105                 goto next_track;
 106             }
 107
 108             ci->set_elapsed(param);
 109             elapsed_time = param;
 110             Track_seek(&ay_emu, param);
 111             ci->seek_complete();
 112
 113             /* Set fade again */
 114             if (!ci->loop_track()) {
 115                 Track_set_fade(&ay_emu, Track_get_length( &ay_emu, track ) - 4000, 4000);
 116             }
 117         }
 118
 119         /* Generate audio buffer */
 120         err = Ay_play(&ay_emu, CHUNK_SIZE, samples);
 121         if (err || Track_ended(&ay_emu)) {
 122             track++;
 123             if (track >= ay_emu.track_count) break;
 124             goto next_track;
 125         }
 126
 127         ci->pcmbuf_insert(samples, NULL, CHUNK_SIZE >> 1);
 128
 129         /* Set elapsed time for one track files */
 130         if (!is_multitrack) {
 131             elapsed_time += (CHUNK_SIZE / 2) * 10 / 441;
 132             ci->set_elapsed(elapsed_time);
 133         }
 134     }
 135
 136     return CODEC_OK;
 137 }