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* published by the Free Software Foundation. Oracle designates this
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*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
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package com.sun.media.sound;
import javax.sound.midi.*;
import java.util.ArrayList;
// TODO:
// - define and use a global symbolic constant for 60000000 (see convertTempo)
/**
* Some utilities for MIDI (some stuff is used from javax.sound.midi)
*
* @author Florian Bomers
*/
public class MidiUtils {
public final static int DEFAULT_TEMPO_MPQ = 500000; // 120bpm
public final static int META_END_OF_TRACK_TYPE = 0x2F;
public final static int META_TEMPO_TYPE = 0x51;
/** return true if the passed message is Meta End Of Track */
public static boolean isMetaEndOfTrack(MidiMessage midiMsg) {
// first check if it is a META message at all
if (midiMsg.getLength() != 3
|| midiMsg.getStatus() != MetaMessage.META) {
return false;
}
// now get message and check for end of track
byte[] msg = midiMsg.getMessage();
return ((msg[1] & 0xFF) == META_END_OF_TRACK_TYPE) && (msg[2] == 0);
}
/** return if the given message is a meta tempo message */
public static boolean isMetaTempo(MidiMessage midiMsg) {
// first check if it is a META message at all
if (midiMsg.getLength() != 6
|| midiMsg.getStatus() != MetaMessage.META) {
return false;
}
// now get message and check for tempo
byte[] msg = midiMsg.getMessage();
// meta type must be 0x51, and data length must be 3
return ((msg[1] & 0xFF) == META_TEMPO_TYPE) && (msg[2] == 3);
}
/** parses this message for a META tempo message and returns
* the tempo in MPQ, or -1 if this isn't a tempo message
*/
public static int getTempoMPQ(MidiMessage midiMsg) {
// first check if it is a META message at all
if (midiMsg.getLength() != 6
|| midiMsg.getStatus() != MetaMessage.META) {
return -1;
}
byte[] msg = midiMsg.getMessage();
if (((msg[1] & 0xFF) != META_TEMPO_TYPE) || (msg[2] != 3)) {
return -1;
}
int tempo = (msg[5] & 0xFF)
| ((msg[4] & 0xFF) << 8)
| ((msg[3] & 0xFF) << 16);
return tempo;
}
/**
* converts<br>
* 1 - MPQ-Tempo to BPM tempo<br>
* 2 - BPM tempo to MPQ tempo<br>
*/
public static double convertTempo(double tempo) {
if (tempo <= 0) {
tempo = 1;
}
return ((double) 60000000l) / tempo;
}
/**
* convert tick to microsecond with given tempo.
* Does not take tempo changes into account.
* Does not work for SMPTE timing!
*/
public static long ticks2microsec(long tick, double tempoMPQ, int resolution) {
return (long) (((double) tick) * tempoMPQ / resolution);
}
/**
* convert tempo to microsecond with given tempo
* Does not take tempo changes into account.
* Does not work for SMPTE timing!
*/
public static long microsec2ticks(long us, double tempoMPQ, int resolution) {
// do not round to nearest tick
//return (long) Math.round((((double)us) * resolution) / tempoMPQ);
return (long) ((((double)us) * resolution) / tempoMPQ);
}
/**
* Given a tick, convert to microsecond
* @param cache tempo info and current tempo
*/
public static long tick2microsecond(Sequence seq, long tick, TempoCache cache) {
if (seq.getDivisionType() != Sequence.PPQ ) {
double seconds = ((double)tick / (double)(seq.getDivisionType() * seq.getResolution()));
return (long) (1000000 * seconds);
}
if (cache == null) {
cache = new TempoCache(seq);
}
int resolution = seq.getResolution();
long[] ticks = cache.ticks;
int[] tempos = cache.tempos; // in MPQ
int cacheCount = tempos.length;
// optimization to not always go through entire list of tempo events
int snapshotIndex = cache.snapshotIndex;
int snapshotMicro = cache.snapshotMicro;
// walk through all tempo changes and add time for the respective blocks
long us = 0; // microsecond
if (snapshotIndex <= 0
|| snapshotIndex >= cacheCount
|| ticks[snapshotIndex] > tick) {
snapshotMicro = 0;
snapshotIndex = 0;
}
if (cacheCount > 0) {
// this implementation needs a tempo event at tick 0!
int i = snapshotIndex + 1;
while (i < cacheCount && ticks[i] <= tick) {
snapshotMicro += ticks2microsec(ticks[i] - ticks[i - 1], tempos[i - 1], resolution);
snapshotIndex = i;
i++;
}
us = snapshotMicro
+ ticks2microsec(tick - ticks[snapshotIndex],
tempos[snapshotIndex],
resolution);
}
cache.snapshotIndex = snapshotIndex;
cache.snapshotMicro = snapshotMicro;
return us;
}
/**
* Given a microsecond time, convert to tick.
* returns tempo at the given time in cache.getCurrTempoMPQ
*/
public static long microsecond2tick(Sequence seq, long micros, TempoCache cache) {
if (seq.getDivisionType() != Sequence.PPQ ) {
double dTick = ( ((double) micros)
* ((double) seq.getDivisionType())
* ((double) seq.getResolution()))
/ ((double) 1000000);
long tick = (long) dTick;
if (cache != null) {
cache.currTempo = (int) cache.getTempoMPQAt(tick);
}
return tick;
}
if (cache == null) {
cache = new TempoCache(seq);
}
long[] ticks = cache.ticks;
int[] tempos = cache.tempos; // in MPQ
int cacheCount = tempos.length;
int resolution = seq.getResolution();
long us = 0; long tick = 0; int newReadPos = 0; int i = 1;
// walk through all tempo changes and add time for the respective blocks
// to find the right tick
if (micros > 0 && cacheCount > 0) {
// this loop requires that the first tempo Event is at time 0
while (i < cacheCount) {
long nextTime = us + ticks2microsec(ticks[i] - ticks[i - 1],
tempos[i - 1], resolution);
if (nextTime > micros) {
break;
}
us = nextTime;
i++;
}
tick = ticks[i - 1] + microsec2ticks(micros - us, tempos[i - 1], resolution);
if (Printer.debug) Printer.debug("microsecond2tick(" + (micros / 1000)+") = "+tick+" ticks.");
//if (Printer.debug) Printer.debug(" -> convert back = " + (tick2microsecond(seq, tick, null) / 1000)+" microseconds");
}
cache.currTempo = tempos[i - 1];
return tick;
}
/**
* Binary search for the event indexes of the track
*
* @param tick - tick number of index to be found in array
* @return index in track which is on or after "tick".
* if no entries are found that follow after tick, track.size() is returned
*/
public static int tick2index(Track track, long tick) {
int ret = 0;
if (tick > 0) {
int low = 0;
int high = track.size() - 1;
while (low < high) {
// take the middle event as estimate
ret = (low + high) >> 1;
// tick of estimate
long t = track.get(ret).getTick();
if (t == tick) {
break;
} else if (t < tick) {
// estimate too low
if (low == high - 1) {
// "or after tick"
ret++;
break;
}
low = ret;
} else { // if (t>tick)
// estimate too high
high = ret;
}
}
}
return ret;
}
public static class TempoCache {
long[] ticks;
int[] tempos; // in MPQ
// index in ticks/tempos at the snapshot
int snapshotIndex = 0;
// microsecond at the snapshot
int snapshotMicro = 0;
int currTempo; // MPQ, used as return value for microsecond2tick
private boolean firstTempoIsFake = false;
public TempoCache() {
// just some defaults, to prevents weird stuff
ticks = new long[1];
tempos = new int[1];
tempos[0] = DEFAULT_TEMPO_MPQ;
snapshotIndex = 0;
snapshotMicro = 0;
}
public TempoCache(Sequence seq) {
this();
refresh(seq);
}
public synchronized void refresh(Sequence seq) {
ArrayList list = new ArrayList();
Track[] tracks = seq.getTracks();
if (tracks.length > 0) {
// tempo events only occur in track 0
Track track = tracks[0];
int c = track.size();
for (int i = 0; i < c; i++) {
MidiEvent ev = track.get(i);
MidiMessage msg = ev.getMessage();
if (isMetaTempo(msg)) {
// found a tempo event. Add it to the list
list.add(ev);
}
}
}
int size = list.size() + 1;
firstTempoIsFake = true;
if ((size > 1)
&& (((MidiEvent) list.get(0)).getTick() == 0)) {
// do not need to add an initial tempo event at the beginning
size--;
firstTempoIsFake = false;
}
ticks = new long[size];
tempos = new int[size];
int e = 0;
if (firstTempoIsFake) {
// add tempo 120 at beginning
ticks[0] = 0;
tempos[0] = DEFAULT_TEMPO_MPQ;
e++;
}
for (int i = 0; i < list.size(); i++, e++) {
MidiEvent evt = (MidiEvent) list.get(i);
ticks[e] = evt.getTick();
tempos[e] = getTempoMPQ(evt.getMessage());
}
snapshotIndex = 0;
snapshotMicro = 0;
}
public int getCurrTempoMPQ() {
return currTempo;
}
float getTempoMPQAt(long tick) {
return getTempoMPQAt(tick, -1.0f);
}
synchronized float getTempoMPQAt(long tick, float startTempoMPQ) {
for (int i = 0; i < ticks.length; i++) {
if (ticks[i] > tick) {
if (i > 0) i--;
if (startTempoMPQ > 0 && i == 0 && firstTempoIsFake) {
return startTempoMPQ;
}
return (float) tempos[i];
}
}
return tempos[tempos.length - 1];
}
}
}