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david van brink // Sat 2012.01.7 18:22 // {after effects}

AE: A Silly MIDI Trick

For amusement purposes only… after importing a MIDI file as keyframes (see earlier post), I rendered it back out using After Effects as a synthesizer, with the provided Tone audio effect.


click for

This was done by setting the Tone frequency expressions to reconstruct the appropriate musical pitch:

on = effect("ch_1_vel")("Slider").value ? 1 : 0;
note = effect("ch_1_pitch")("Slider");
on * 440 * Math.pow(2, (note-57)/12)

You could change 12 to something else, to hear it performed in some alternate equal-tempered scale. 8 and 17 sound kind-of interesting…


click for

And here’s the self-contained CS5 project to download.

Ariel // Mon 2012.04.16 23:5611:56 pm

Hi, I was wondering if there’s a way of processing an Image (in a layer) in after effects.
reading pixel by pixel color value. can u’r python script provide answer? thanks

oh, i dont know. what do you think?

david van brink // Mon 2011.12.26 13:56 // {after effects}

AE: Hello again, & MIDI

Edit: See note at end of article for warnings about this script AE CS 5.5 on Mac

Hello, pixel pushers and vert herders! Ah, it’s great to be back in After Effects land. Alas in this last year, the day job (got hired by Skype, acquired by Microsoft) and life in general (after throwing elaborate theme-parties for decades, planning a wedding wasn’t actually that hard, but still) got a little busy, but thankfully again have a little bit of time for my favorite things. That is, pixels.

Omino Python Since I released it this year, it’s been downloaded several thousand times, and about a dozen enthusiastic folks have licensed it. Alas, I don’t really have the time to either properly promote or properly support this as a paid product… so I’ll make it completely free soon.

Ok! So, MIDI!

What is MIDI

MIDI is a control protocol and file format invented 20-odd years ago for music playback on synthesizers. It records all the notes. A .mid file is typically quite small, since it has no sound data in it.

Into After Effects?

Yes! The attached script lets you read a MIDI file into After Effects, and provides keyframes with all the notes.


1. Download this file.
2. Put the file in /Applications/Adobe After Effects CS5/Scripts/ScriptUI Panels/
3. Run AE, and under window, choose om_midi.jsx, and dock the panel where you like.

Om midi panel


Here’s one way you could use this script. In the om_midi panel, click the little dot button, and choose a MIDI file. I used one from Wikipedia, BWV 772, one of JS Bach’s 2-part inventions.

Then, with a Comp selected, click Apply.

This creates a Null layer named “midi” with several Slider effects full of keyframes.

This particular MIDI file kept the left and right hands in separate channels, which is nice! The “pitch” effect has keyframes at the beginning of each note with a value of 60 for middle C, 61 for C-sharp, and so on. Here we can see the left and right hands’ keyframes.

A fun way to use these keyframes is to drive the Position property of another layer. I took a photo of my hand, and set the Position expression and Opacity expressions:

 transform.position + 5*(0,thisComp.layer("midi").effect("ch_0_pitch")("Slider")-60)

  transform.opacity * thisComp.layer("midi").effect("ch_0_vel")("Slider")

So the hand will move 5 pixels for each semitone, centered on Middle-C (60).
Then I rendered the audio as AIFF and added it to the comp. (I used Propellerheads Reason. Yeah… if you’re using MIDI you need yet another set of software to manipulate it.)

And here is the result animation:


click for

More Notes

This is just the simplest usage. A more elaborate deployment might be to export just 1 part of a complex sound-track work as MIDI, to get some of the cues into your AE timeline. With more complex scripts or expressions, you could to much more than just move the hands around.

The script will put multiple keyframes with the same time-value! In the example above, you can see the hands flicker slightly as the final chord begins. Most of the the part invention has just 1 note per hand, which was nice for the demo.

Also, inside the script is a general-purpose MIDI file reader, which you could use for other purposes. I’ve generated Illustrator pictures from scores, for example, full of circles and triangles. Drop me an email or comment if you want help using it! It’s pretty fun.

Update 2012.01.08 Warning about AE CS 5.5 on Mac

Under Mac OS X AE CS 5.5, when you choose the file, it deletes it! This is a CS5.5 bug. (Works fine in CS5.)

Best workaround is to use AE CS 5 or AE CS 4.
Another workaround is:

  • make a copy of the file, like myfile_copy.mid
  • Select it in the script UI
  • recopy the file (selecting it deleted it)
  • click apply and all is well.
Mylenium's Blog » Saved! // Sat 2011.12.31 03:203:20 am

[…] That has been true for the previously mentioned unwrapping cylinder thing and now it seems you can work with MIDI files in After Effects, after all. Not in the way that that person imagined (by tying them live to […]

hyp // Sun 2012.01.1 17:535:53 pm

any chance you can update this to work with CS 5.5? such an awesome script, but it doesnʻt work unfortunately. thanks for your hard work.

nathan // Tue 2012.01.3 15:133:13 pm

this is the coolest thing ever

arto // Wed 2012.01.4 14:352:35 pm

^hyp: Did you make a new comp & load a real .mid file? It works fine in my 5.5.

Thank you for a great script I’ve been searching for a long time! Gotta start learning those expressions now.. :)

david van brink // Sat 2012.01.7 13:501:50 pm

^arto I hope it’s useful for you.

^hyp — I tried AECS5.5 on Mac… and yes it’s broken. It deletes the file. This is a CS5.5 bug. Adding workarounds to the article…

lotzio // Tue 2012.01.10 18:366:36 pm


音のデータとAfter Effects その2 | AEP Project // Sat 2012.01.14 08:018:01 am

[…] 楽譜のデータから作る さて、少しだけ変わった方向からAEと音のデータについて考えます。動画だけでなく、音楽を制作される方なら、オーディオよりも楽譜としてデータを持って行けたら、嬉しいと思います。 MIDI、というファイル形式があります。昔のHPで流れてる音楽によく使われたり、カラオケでも使われている形式です。 MIDIとは「ある楽器をこの強さ、この音階で鳴らす」という楽譜の情報です。 もし、オーディオのデータのほかに、この楽譜のデータを持っていたら、より繊細な映像を作ることも可能です。 このMIDIには一曲分の情報を持つことができるので、例えばピアノとボーカルのバラード曲があった場合、オーディオデータだと一緒の波形になるか、個別に用意しないといけませんが、MIDIだとピアノとボーカル、それぞれの値を1つのファイルできちんと取得することができます。 このom_midiは、MIDIのデータをAEにキーフレームの情報として読みこむスクリプトです。 http://omino.com/pixelblog/2011/12/26/ae-hello-again-midi/ヌルレイヤーにスライダー制御エフェクトとして情報が入っています。 このスクリプトも、その1で紹介した「AudioToMarkers」と同様にAEの言語に合わせて中身を書き換える必要があるので注意してください。 また、注意する点として、修正の内容がバージョンによって違います。CS5以上では「スライダー制御」、CS4以前では「スライダ制御」ですので注意してください。 ちなみに、その1と同様でスクリプトの書き換えではExtendScript Toolkitを使用しています。 […]

cheerbot // Mon 2012.01.16 17:035:03 pm

Hey, I was really happy to find this as I’m trying to sync sequences of frames to execute on specific keyframed values of imported midi notes.

Through asking some questions (I’m new to AE), I started a discussion at forums.adobe.com/message/4142986 to get insight.

You may want to take a look, one suggestion is utilizing markers instead of key frames. I would love to see an easier way to automate and include midi values for dynamics and so would like to see this script expanded a little bit, and I would love to get you included as this script seems the easiest way at the moment to get midi data in beyond simple rhythmic uses. Also, on 5.5, deleting original file but easy to work around with a copy of course.

StoryBoy // Tue 2012.01.24 15:353:35 pm

Hi David,

Firstly, this works great!

Is there any chance of getting the JS Script to import CC midi values as well? I’ve got a MIDI file with a PITCHBEND envelope which would be awesome to have in after-effects.

Thanks again!

david van brink // Tue 2012.01.24 16:544:54 pm

SB — Excellent Idea. I’ll add that to the next rev. (Though if you’re inspired and know the MIDI bytes a little, you might be able to add it yourself…)

But yes, PitchBend and Control tracks… Oh the fun!

cheerbot // Tue 2012.01.24 22:4610:46 pm

Hey I just wanted to say thanks again, I’m going to be using this script a lot! I just finished this little thing which was pretty easy to make using the script and expressions your provided.


I’d also like to point out to others that if you’re going to be doing marker-based animation timemapping off of midi data, these two scripts are incredibly useful paired with David’s script:

Keyframes to Markers:

Copy markers:

oh, i dont know. what do you think?


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