fix some misaligned charts by making it ignore time signatures before notes.

for full explanation see the diff.

src/NoteDataUtil.cpp

@@ -564,18 +564,19 @@ void NoteDataUtil::LoadTransformedSlidingWindow( const NoteData &in, NoteData &o
 void PlaceAutoKeysound( NoteData &out, int row, TapNote akTap )
 {
 	int iEmptyTrack = -1;
-	int iEmptyRow = row - 1;
+	int iEmptyRow = row;
 	int iNewNumTracks = out.GetNumTracks();
 	bool bFoundEmptyTrack = false;
-	if( iEmptyRow < 0 )
+	int iRowsToLook[3] = {0, -1, 1};
-	{
+	
-		iEmptyRow = 0;
+	for( int j = 0; j < 3; j ++ )
-	}
-	for( int r = iEmptyRow; r <= iEmptyRow + 2; r += 2 )
 	{
+		int r = iRowsToLook[j] + row;
+		if( r < 0 )
+			continue;
 		for( int i = 0; i < iNewNumTracks; ++i )
 		{
-			if ( out.GetTapNote(i, r) == TAP_EMPTY )
+			if ( out.GetTapNote(i, r) == TAP_EMPTY && !out.IsHoldNoteAtRow(i, r) )
 			{
 				iEmptyTrack = i;
 				iEmptyRow = r;

src/NotesLoaderBMS.cpp

@@ -405,8 +405,37 @@ static void SetTimeSigAdjustments( const MeasureToTimeSig_t &sigs, Song &out, Me
 
 static void ReadTimeSigs( const NameToData_t &mapNameToData, MeasureToTimeSig_t &out )
 {
+	// some convertors change some measure's time signature before any notes are there
+	// it is required because sometimes the BGA starts before the music and the measure size
+	// is the difference between the start of first bar and the BGA.
+	// something like #00002:1.55. that made all subsequent notes 192th.
+	// here, find the lowest measure for notes, and make this function skip the time signatures before it.
+	int iStartMeasureNo = 999;
 	NameToData_t::const_iterator it;
 	for( it = mapNameToData.lower_bound("#00000"); it != mapNameToData.end(); ++it )
+	{
+		const RString &sName = it->first;
+		if( sName.size() != 6 || sName[0] != '#' || !IsAnInt( sName.substr(1,5) ) )
+			continue;
+		// this is step or offset data.  Looks like "#00705"
+		int iMeasureNo	= atoi( sName.substr(1, 3).c_str() );
+		int iBMSTrackNo	= atoi( sName.substr(4, 2).c_str() );
+		RString nData = it->second;
+		int totalPairs = nData.size() / 2;
+		if( iBMSTrackNo != BMS_TRACK_TIME_SIG && iBMSTrackNo != 7 )
+		{
+			for( int i = 0; i < totalPairs; ++i )
+			{
+				RString sPair = nData.substr( i*2, 2 );
+				if (sPair == "00")
+				{
+					continue;
+				}
+				if( iMeasureNo < iStartMeasureNo ) iStartMeasureNo = iMeasureNo;
+			}
+		}
+	}
+	for( it = mapNameToData.lower_bound("#00000"); it != mapNameToData.end(); ++it )
 	{
 		const RString &sName = it->first;
 		if( sName.size() != 6 || sName[0] != '#' || !IsAnInt(sName.substr(1, 5)) )
@@ -415,6 +444,8 @@ static void ReadTimeSigs( const NameToData_t &mapNameToData, MeasureToTimeSig_t
 		// this is step or offset data.  Looks like "#00705"
 		const RString &sData = it->second;
 		int iMeasureNo	= atoi( sName.substr(1, 3).c_str() );
+		if( iMeasureNo < iStartMeasureNo )
+			continue;
 		int iBMSTrackNo	= atoi( sName.substr(4, 2).c_str() );
 		if( iBMSTrackNo == BMS_TRACK_TIME_SIG )
 			out[iMeasureNo] = StringToFloat( sData );