have the outside remember, if it is the first frame

1 files changed, 14 insertions, 14 deletions

diff --git a/timestretch.c b/timestretch.c
index b15bfe7..1f94837 100644
--- a/timestretch.c
+++ b/timestretch.c
@@ -17,7 +17,9 @@ static size_t  g_corr_length;
 
 static size_t  g_skip;          // Per frame skip
 static size_t  g_offset;        // Offset into stream, lower bits
-static size_t  g_firstframe;    // If this is set, the caller should provide initial data in g_overlap_buffer
+
+#define FRAME_FIRST 0x01
+#define FRAME_LAST  0x02
 
 /* some good default for mixing voice, values in micro seconds */
 #define OVERLAP            10   // overlapping length (music default = 12 ms)
@@ -33,7 +35,6 @@ static size_t calc_convert_values( int sample_rate, float tempo ) {
 
     free( g_overlap_buffer );
     g_overlap_buffer = malloc( sizeof(short) * g_overlap );
-    g_firstframe = 1;
     g_offset = 0;
 
     g_output_length = (sample_rate * OUTPUT_LEN ) / 1000;
@@ -47,7 +48,7 @@ static size_t calc_convert_values( int sample_rate, float tempo ) {
     // boost middle of sequence by top of a flat parabola
     // slope stolen from soundtouch, precalc table
     for( i = 0; i < g_corr_length; ++i )
-        g_overlap_heuristic[i] = (short)16384.0*(-(double)i*(double)i/((double)g_corr_length*(double)g_corr_length)+(double)i/(double)g_corr_length+0.75f);
+        g_overlap_heuristic[i] = (short)16384.0*(-(double)(i*i)/((double)(g_corr_length*g_corr_length))+(double)i/(double)g_corr_length+0.75f);
 
     g_skip = (size_t)( tempo * (float)g_output_length * 65536.0 );
     g_input_length = g_corr_length + g_output_length + g_overlap;
@@ -88,16 +89,15 @@ static unsigned int find_corr_max(const short *input, const short *mixbuf) {
 }
 
 // Returns the amount of samples that can be discarded from begin of the input buffer
-size_t process_frame( short *input, short *output, short *overlap, int lastframe ) {
+size_t process_frame( short *input, short *output, short *overlap, int frame_flag ) {
     int i, i_ = (int)g_overlap;
     unsigned int offset = 0;
 
     // The first frame needs to be copied verbatim,
     // we do not have anything to mix, yet.
-    if( g_firstframe ) {
+    if( frame_flag & FRAME_FIRST )
         sampcpy( output, input, g_output_length );
-        g_firstframe = 0;
-    } else {
+    else {
         offset = find_corr_max( input, overlap );
 
         // Cross fade end of last frame with begin of this frame
@@ -109,7 +109,7 @@ size_t process_frame( short *input, short *output, short *overlap, int lastframe
     }
 
     // On the last frame help connect the next frame from input seamlessly
-    if( lastframe )
+    if( frame_flag & FRAME_LAST )
         return offset + g_output_length;
 
     // Remember end of this frame for next frame
@@ -126,14 +126,13 @@ int main( int args, char **argv ) {
   size_t    in_fill = 0;
   short     outbuf[ g_output_length ];
   short     inbuf [ g_input_length  ];
+  int       fd_in  = open( "in.raw", O_RDONLY );
+  int       fd_out = open( "out.raw", O_CREAT | O_WRONLY | O_TRUNC );
+  int       first_frame = FRAME_FIRST;
+  (void)args; (void)argv; (void)out_chunk_size;
 
 //  printf( "DEBUG: OL: %zd SWL: %zd SL: %zd SK: %zd ICM: %zd\n", g_overlap, g_output_length, g_corr_length, g_skip / 65536, g_input_length );
 
-  int fd_in  = open( "in.raw", O_RDONLY );
-  int fd_out = open( "out.raw", O_CREAT | O_WRONLY | O_TRUNC );
-
-  (void)args; (void)argv; (void)out_chunk_size;
-
   while( 1 ) {
     size_t processed;
     size_t missing = g_input_length - in_fill;
@@ -148,7 +147,8 @@ int main( int args, char **argv ) {
     }
 
     // Do one cycle of processing and outputting
-    processed = process_frame( inbuf, outbuf, g_overlap_buffer, 0 );
+    processed = process_frame( inbuf, outbuf, g_overlap_buffer, first_frame );
+    first_frame = 0;
     write( fd_out, outbuf, g_output_length * sizeof(short) );
 
     memmove( inbuf, inbuf + processed, ( in_fill - processed ) * sizeof(short) );