使用python-midi库从midi-events获取变量

Question

I use the python-midi library to read a midi file into a list.

variable = midi.read_midifile(source)

The entries look like those:

   midi.NoteOffEvent(tick=2, channel=10, data=[48, 98]),
   midi.NoteOnEvent(tick=46, channel=10, data=[48, 100]),
   midi.NoteOffEvent(tick=12, channel=10, data=[48, 100]),
   midi.NoteOnEvent(tick=36, channel=10, data=[48, 91]),
   midi.NoteOffEvent(tick=14, channel=10, data=[48, 91]),
   midi.NoteOnEvent(tick=34, channel=10, data=[48, 122]),

Now I'd like to get the parameters of those Events but I don't know how to do that. I want to count all ticks, get all different channels and also read the data (so the note and the velocity). I looked into the Github-Repository but I did not find the answer to my question. link to repository: https://github.com/vishnubob/python-midi

Could it be that pyhton-midi is not really made for reading and manipulating midi-files?

Answer 1

I don't know anything about the python-midi library but I'm guessing from the source code that read_midifile() method returns a Pattern object. The Pattern object contains a list of events.

Each event will contain a tick , channel and data property.

I'm guessing you can slice a Pattern object like a list, so you should be able to do this:

pattern = midi.read_midifile(source)
print pattern[0].tick

This will select the first event in the Pattern and print its tick property.

You could then count the ticks by doing something like:

pattern = midi.read_midifile(source)
tick_count = 0
# a unique list
channels = set()

for event in pattern:
    tick_count += event.tick
    channels.add(event.channel)

If you ever need to know what's in an object, you can always use the dir() function. Eg

print dir(event)

Good luck with your learning. Keep aiming high!