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MIDI vs Audio features

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Market DJ
Posts: 7
Joined: Sat May 17, 2014 11:35 am

MIDI vs Audio features

Post by Market DJ »

Hi Eric,

As I'm not an expert on this, I was wondering why there are many more features to steer the visuals from MIDI inputs than from audio files? In other words, why is there no possibility to extract more from audio than its volume, freq.range, best pitch and tone?

A related question: is there a way to translate audio back into MIDI so one can create/access the broader range of characteristics?

Thx.
Magic
Site Admin
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Joined: Wed Apr 09, 2014 9:28 pm

Re: MIDI vs Audio features

Post by Magic »

Good question!

So, the short answer is that MIDI is control data which is already in a numerical form, whereas audio is a representation of a sound wave and needs to be analyzed further in order to extract relevant data.

It's therefore pretty easy to just use MIDI as it is; MIDI is all numbers, and those numbers can be directly applied to module parameters in Magic. We've tried to provide all the possible ways that MIDI control data is represented, which is why there are a lot of MIDI features.

By contrast though, we have to use algorithms to analyze audio. Some of the algorithms are simple, like Volume, but some are more complex, like Best Pitch. But even more important than that, there are only a few ways to analyze audio which we decided were actually relevant to controlling visuals. In other words, you could do some forms of analysis that are pretty complex, but they don't cause the visuals to change in a very interesting way.

Of course, if you have any suggestions for new things we should experiment with, definitely let me know. Beat detection is probably the most common thing people suggest, so we're already looking into that one.

In order to get MIDI from audio, you have to do the same kind of analysis. This is true for whatever program you use. I'm pretty sure there are already a lot of programs out there that do audio-to-MIDI, but I'm not sure what the best ones are. If anyone knows, feel free to post! :)

Eric
Market DJ
Posts: 7
Joined: Sat May 17, 2014 11:35 am

Re: MIDI vs Audio features

Post by Market DJ »

Another question for you.

Suppose one uses a DAW and created a multi-track/channel/etc. composition, each produced by a separate VST, etc. Say you have > 20 tracks making up the composite composition or master song (you actually may have many more tracks, some managing volume, BPM, balance, etc. via controllers within the DAW.) The goal is to have the master be played as the sound to the eventual video to be rendered within Magic. However, you want the visuals to respond to individual characteristics of the individual tracks. Again, we know that, in principle, MIDI exposes many more of those characteristics compared to audio.

Now, let's ignore for the moment the need to do real-time audiovisuals and instead assume, as stated, that the goal is to create a video. If you use audio-files, you can simply export each track separately, as well as the master, to individual WAV-files and import those into Magic. However, although MIDI allows you access to many more characteristics, the problem is that if you use MIDI to transfer the audio, e.g. via LoopBE1, you are limited to 16 channels. Does this mean that you somehow have to have another MIDI-connection to add extra channels to cover all 20 tracks?

In short, if there is no need for real-time performance, and if the individual tracks that make up the master song exceed 16, is audio the way to go?

Thx for any advice.
Magic
Site Admin
Posts: 3440
Joined: Wed Apr 09, 2014 9:28 pm

Re: MIDI vs Audio features

Post by Magic »

Another good question. So, just as one really quick answer, there is a version of LoopBe (http://www.nerds.de/en/loopbe30.html) which provides 30 "cables", each with 16 channels. That's an easy solution but it's $20 or €17.

Alternatively, keep in mind that each MIDI channel has lots of individual commands, so you could use the same channel more than once, as long as you use different commands on each one. For example, you could use different controller messages, or different note velocities.

One important thing to keep in mind though is that currently you can't use MIDI when you're exporting a movie. We're hoping to allow MIDI files be loaded into Magic so you can "play" them just like audio files, but that won't be available in the near future. For now, MIDI is limited to real-time use, and exporting a movie can only use audio files.
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