Update SMPTE millisecond code.

craigsapp · Apr 16, 2018 · ccb93a2 · ccb93a2
1 parent 880db73
commit ccb93a2
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Showing 2 changed files with 13 additions and 15 deletions.
diff --git a/src-library/Binasc.cpp b/src-library/Binasc.cpp
@@ -1042,12 +1042,12 @@ int Binasc::outputStyleMidi(ostream& out, istream& input) {
    input.read((char*)&byte2, 1);
    if (byte1 & 0x80) {
       // SMPTE divisions
-      tempout << "1'-" << 0xff - (ulong)byte1 + 1;
+      tempout << "'-" << 0xff - (ulong)byte1 + 1;
       if (commentsQ) {
          tempout << "\t\t\t; SMPTE frames/second";
       }
       tempout << endl;
-      tempout << "1'" << dec << (long)byte2;
+      tempout << "'" << dec << (long)byte2;
       if (commentsQ) {
          tempout << "\t\t\t; subframes per frame";
       }

diff --git a/src-library/MidiFile.cpp b/src-library/MidiFile.cpp
@@ -362,24 +362,22 @@ int MidiFile::read(istream& input) {
    // Header parameter #3: Ticks per quarter note
    shortdata = MidiFile::readLittleEndian2Bytes(input);
    if (shortdata >= 0x8000) {
-      int framespersecond = ((!(shortdata >> 8))+1) & 0x00ff;
-      int resolution      = shortdata & 0x00ff;
+      int framespersecond = 255 - ((shortdata >> 8) & 0x00ff) + 1;
+      int subframes       = shortdata & 0x00ff;
       switch (framespersecond) {
-         case 232:  framespersecond = 24; break;
-         case 231:  framespersecond = 25; break;
-         case 227:  framespersecond = 29; break;
-         case 226:  framespersecond = 30; break;
+         case 25:  framespersecond = 25; break;
+         case 24:  framespersecond = 24; break;
+         case 29:  framespersecond = 29; break;  // really 29.97 for color television
+         case 30:  framespersecond = 30; break;
          default:
                cerr << "Warning: unknown FPS: " << framespersecond << endl;
-               framespersecond = 255 - framespersecond + 1;
-               cerr << "Setting FPS to " << framespersecond << endl;
+               cerr << "Using non-standard FPS: " << framespersecond << endl;
       }
-      // actually ticks per second (except for frame=29 (drop frame)):
-      ticksPerQuarterNote = shortdata;
+      ticksPerQuarterNote = framespersecond * subframes;
 
-      cerr << "SMPTE ticks: " << ticksPerQuarterNote << " ticks/sec" << endl;
-      cerr << "SMPTE frames per second: " << framespersecond << endl;
-      cerr << "SMPTE frame resolution per frame: " << resolution << endl;
+      // cerr << "SMPTE ticks: " << ticksPerQuarterNote << " ticks/sec" << endl;
+      // cerr << "SMPTE frames per second: " << framespersecond << endl;
+      // cerr << "SMPTE subframes per frame: " << subframes << endl;
    }  else {
       ticksPerQuarterNote = shortdata;
    }