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1 /* Trims silence off beginning of SPC file.
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2 Requires the accurate DSP; won't compile with the fast DSP.
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3 Please note that the algorithm could be improved; this is just
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4 a simple example showing the idea.
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5
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6 Usage: trim_spc [test.spc [trimmed.spc]]
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7 */
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8
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9 #include "snes_spc/spc.h"
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10
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11 #include "demo_util.h" /* error(), load_file() */
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12
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13 /* Change to 1 to have it trim to next key on event rather than trim silence */
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14 enum { use_kon_check = 0 };
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15
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16 /* True if all count samples from in are silent (or very close to it) */
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17 int is_silent( short const* in, int count );
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18
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19 int main( int argc, char** argv )
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20 {
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21 /* Load file into memory */
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22 long spc_size;
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23 void* spc = load_file( (argc > 1) ? argv [1] : "test.spc", &spc_size );
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24
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25 /* Load into emulator */
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26 SNES_SPC* snes_spc = spc_new();
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27 if ( !snes_spc ) error( "Out of memory" );
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28 error( spc_load_spc( snes_spc, spc, spc_size ) );
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29
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30 /* Expand SPC data so there's enough room for emulator to save to.
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31 We simply overwrite the emulator data in the old SPC file rather
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32 than creating new SPC data. This preserves the text tags from
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33 the old file. */
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34 if ( spc_size < spc_file_size )
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35 {
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36 spc_size = spc_file_size;
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37 spc = realloc( spc, spc_size ); /* leaks memory if allocation fails */
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38 if ( !spc ) error( "Out of memory" );
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39 }
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40
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41 /* Keep saving SPC, then playing a little more. Once SPC becomes non-silent,
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42 write the SPC data saved just before this. */
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43 {
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44 long samples_trimmed = 0;
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45 while ( 1 )
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46 {
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47 #define BUF_SIZE 1024
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48 short buf [BUF_SIZE];
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49
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50 if ( samples_trimmed > 10 * spc_sample_rate * 2 )
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51 error( "Excess silence found" );
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52
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53 spc_clear_echo( snes_spc );
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54 spc_save_spc( snes_spc, spc );
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55
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56 /* Fill buffer */
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57 error( spc_play( snes_spc, BUF_SIZE, buf ) );
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58 samples_trimmed += BUF_SIZE;
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59
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60 /* See if SPC became non-silent */
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61 if ( use_kon_check ? spc_check_kon( snes_spc ) : !is_silent( buf, BUF_SIZE ) )
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62 break;
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63 }
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64
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65 printf( "Trimmed %.1f seconds\n", (double) samples_trimmed / spc_sample_rate / 2 );
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66 }
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67
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68 spc_delete( snes_spc );
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69 write_file( (argc > 2) ? argv [2] : "trimmed.spc", spc, spc_size );
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70
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71 return 0;
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72 }
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73
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74 int is_silent( short const* in, int count )
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75 {
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76 unsigned const threshold = 0x10;
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77 while ( count-- )
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78 {
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79 if ( (unsigned) (*in++ + threshold / 2) > threshold )
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80 return 0;
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81 }
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82 return 1;
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83 }
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