bass - MIDI tick to millisecond? -

-



i realize there many questions here concerning converting midi ticks milliseconds (ex: how convert midi timeline actual timeline should played, midi ticks actual playback seconds !!! ( midi music), midi timestamp in seconds) , have looked @ them all, tried implement suggestions, still not getting it.

(did mention little "math phobic")

can me work practical example? using bass lib un4seen. have data need - don't trust calculations.

bass methods

tick

// position of midi stream uint64_t tick = bass_channelgetposition(midifilestream, bass_pos_midi_tick)

ppqn

//the pulses per quarter note (or ticks per beat) value of midi stream. float ppqn; bass_channelgetattribute(handle, bass_attrib_midi_ppqn, &ppqn);

tempo

 //tempo in microseconds per quarter note.  uint32_t tempo = bass_midi_streamgetevent( midifilestream, -1, midi_event_tempo);

my attempt @ calculating ms value tick:

float currentmilliseconds = tick * tempo / (ppqn * 1000);

the value appears correct don't have confidence in since not quite understanding formula.

printf("tick %llu\n",tick); printf("ppqn %f\n",ppqn); printf("tempo %u\n",tempo); printf("currentmilliseconds %f \n", currentmilliseconds);

example output:

tick 479 ppqn 24.000000 tempo 599999 currentmilliseconds 11974.980469

update

my confusion continues based on blog post think have code right – @ least output seems accurate. conversely, answer provided @strikeskids below yields different results. maybe have order of operations problem in there?

float kmillisecondsperquarternote = tempo / 1000.0f; float kmillisecondspertick = kmillisecondsperquarternote / ppqn; float deltatimeinmilliseconds = tick * kmillisecondspertick; printf("deltatimeinmilliseconds %f \n", deltatimeinmilliseconds);

. 

float currentmillis = tick * 60000.0f / ppqn / tempo; printf("currentmillis %f \n", currentmillis);

output:

 deltatimeinmilliseconds 11049.982422   currentmillis 1.841670

tempo in beats per minute. because want getting time, should have in denominator of fraction.

currenttime = currenttick * (beats / tick) * (minutes / beat) * (millis / minute)

millis = tick * (1/ppqn) * (1/tempo) * (1000*60)

to use integer arithmetic efficiently do

currentmillis = tick * 60000 / ppqn / tempo





wiki

Comments

Post a Comment

Popular posts from this blog

Asterisk AGI Python Script to Dialplan does not work -

-
i'm stuck project have check database of sip extension incoming caller id , dial sip extension. below receive when run script on asterisk cli. -- registered sip '9125' @ 192.168.1.102:50142 > saved useragent "zoiper rv2.8.40" peer 9125 [2017-08-22 13:53:33] notice[5095]: chan_sip.c:24558 handle_response_peerpoke: peer '9125' reachable. (17ms / 2000ms) == using sip rtp tos bits 184 == using sip rtp cos mark 5 -- executing [0112617769@from-trunk:1] answer("sip/obitrunk1-0000000d", "") in new stack > 0x1ca50d0 -- probation passed - setting rtp source address 192.168.1.98:16834 -- executing [0112617769@from-trunk:2] agi("sip/obitrunk1-0000000d", "test.py") in new stack -- launched agi script /var/lib/asterisk/agi-bin/test.py args: ['/var/lib/asterisk/agi-bin/test.py'] env line: agi_request: test.py env line: agi_channel: sip/obitrunk1-0000000d env line: agi_language: en env line: a
Read more

python - Read npy file directly from S3 StreamingBody -

-
i have many .npy (numpy) , .json files saved in s3, need download , load these files. for json files downloading files , loading dictionary using following code: obj = s3.object(bucket, key) response = obj.get() body = response['body'].read().decode('utf-8') data = json.loads(body) that way avoid writing .json file disk , reading it. now want same .npy files, equivalent? currently downloading file, saving temp file on disk , loading np.load avoid if possible. following https://stackoverflow.com/a/28196540/3509999 : obj = s3.object(bucket, key) io.bytesio(obj.get()["body"].read()) f: # rewind file f.seek(0) arr = np.load(f) wiki
Read more

kotlin - Out-projected type in generic interface prohibits the use of metod with generic parameter -

-
i start using kotlin , defined interface this: interface aadapter<vh : recyclerview.viewholder> { fun oncreateaviewholder(parent: viewgroup): vh fun onbindaviewholder(v: vh, position: int) } and when try use on code: class klasa ( private val adapter: aadapter<*> ) { fun dosth(){ //... val vh = this.adapter.oncreateaviewholder(parent) //on below line error adapter.onbindaviewholder(v, position) //... } } i error out-projected type 'aadapter<*>' prohibits use of 'public abstract fun onbindaviewholder(v: t, position: int): unit i tied add "in" or "out" definition i'm confused. how allow it. replace aadapter<*> aadapter<recyclerview.viewholder> . class klasa ( private val adapter: aadapter<recyclerview.viewholder> ) { // ... because have declared aadapter has type parameter vh type subclass of recyclerview.
Read more