rlm@0: /* Trims silence off beginning of SPC file.
rlm@0: Requires the accurate DSP; won't compile with the fast DSP.
rlm@0: Please note that the algorithm could be improved; this is just
rlm@0: a simple example showing the idea.
rlm@0: 
rlm@0: Usage: trim_spc [test.spc [trimmed.spc]]
rlm@0: */
rlm@0: 
rlm@0: #include "snes_spc/spc.h"
rlm@0: 
rlm@0: #include "demo_util.h" /* error(), load_file() */
rlm@0: 
rlm@0: /* Change to 1 to have it trim to next key on event rather than trim silence */
rlm@0: enum { use_kon_check = 0 };
rlm@0: 
rlm@0: /* True if all count samples from in are silent (or very close to it) */
rlm@0: int is_silent( short const* in, int count );
rlm@0: 
rlm@0: int main( int argc, char** argv )
rlm@0: {
rlm@0: 	/* Load file into memory */
rlm@0: 	long spc_size;
rlm@0: 	void* spc = load_file( (argc > 1) ? argv [1] : "test.spc", &spc_size );
rlm@0: 	
rlm@0: 	/* Load into emulator */
rlm@0: 	SNES_SPC* snes_spc = spc_new();
rlm@0: 	if ( !snes_spc ) error( "Out of memory" );
rlm@0: 	error( spc_load_spc( snes_spc, spc, spc_size ) );
rlm@0: 	
rlm@0: 	/* Expand SPC data so there's enough room for emulator to save to.
rlm@0: 	We simply overwrite the emulator data in the old SPC file rather
rlm@0: 	than creating new SPC data. This preserves the text tags from
rlm@0: 	the old file. */
rlm@0: 	if ( spc_size < spc_file_size )
rlm@0: 	{
rlm@0: 		spc_size = spc_file_size;
rlm@0: 		spc = realloc( spc, spc_size ); /* leaks memory if allocation fails */
rlm@0: 		if ( !spc ) error( "Out of memory" );
rlm@0: 	}
rlm@0: 	
rlm@0: 	/* Keep saving SPC, then playing a little more. Once SPC becomes non-silent,
rlm@0: 	write the SPC data saved just before this. */
rlm@0: 	{
rlm@0: 		long samples_trimmed = 0;
rlm@0: 		while ( 1 )
rlm@0: 		{
rlm@0: 			#define BUF_SIZE 1024
rlm@0: 			short buf [BUF_SIZE];
rlm@0: 			
rlm@0: 			if ( samples_trimmed > 10 * spc_sample_rate * 2 )
rlm@0: 				error( "Excess silence found" );
rlm@0: 			
rlm@0: 			spc_clear_echo( snes_spc );
rlm@0: 			spc_save_spc( snes_spc, spc );
rlm@0: 			
rlm@0: 			/* Fill buffer */
rlm@0: 			error( spc_play( snes_spc, BUF_SIZE, buf ) );
rlm@0: 			samples_trimmed += BUF_SIZE;
rlm@0: 			
rlm@0: 			/* See if SPC became non-silent */
rlm@0: 			if ( use_kon_check ? spc_check_kon( snes_spc ) : !is_silent( buf, BUF_SIZE ) )
rlm@0: 				break;
rlm@0: 		}
rlm@0: 		
rlm@0: 		printf( "Trimmed %.1f seconds\n", (double) samples_trimmed / spc_sample_rate / 2 );
rlm@0: 	}
rlm@0: 	
rlm@0: 	spc_delete( snes_spc );
rlm@0: 	write_file( (argc > 2) ? argv [2] : "trimmed.spc", spc, spc_size );
rlm@0: 	
rlm@0: 	return 0;
rlm@0: }
rlm@0: 
rlm@0: int is_silent( short const* in, int count )
rlm@0: {
rlm@0: 	unsigned const threshold = 0x10;
rlm@0: 	while ( count-- )
rlm@0: 	{
rlm@0: 		if ( (unsigned) (*in++ + threshold / 2) > threshold )
rlm@0: 			return 0;
rlm@0: 	}
rlm@0: 	return 1;
rlm@0: }