MIDI Timing issue

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Darko
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Joined: 04/15/2013

Hi Matt!

Recently I have noticed something wierd with notes recorded in NanoStudio. It appears that there is a constant "drift" in recorded notes (timing oscillation). What made me discover this was that phrase I've played looked a bit different in sequencer (and maybe I was just imaganing it back then, but it sounded a bit different, too). I decided to closely inspect the issue and come up with and idea:

I have connected MIDI controller in arpeggiator mode to act as a constant clock device not synced to any particular bpm -- as seen on scrshots below, notes are not aligned with major thicks. Both FL Studio and NanoStudio were started and set to record input notes with Quantization OFF (obviously my first suspect). Then I've exported NS track to midi file and imported it back to FL Studio (it works either way). In FL there is a Timebase PPQ setting od 96 by default and up to 960 max, which effectively means MIDI resolution, but this setting did not affect this problem much even on the lowest 96 setting.

Now, NS MIDI track was transposed couple of notes down just to be able to see it better as a ghost channel (FL studio feature, same could be accomplished in NS by merging transposed notes on single track, but this was faster).

What I expected as a result was to get a perfect allignement of the events (notes), once I compensate for an initial delay due to manual record button activation in both apps. But, hold for a surprise:

and zoomed a random area to demonstrate jitter:

Now, I am aware of PPQ limitations and was wondering if this is the issue with NS? Is it on purpose limited in MIDI timing precision to save resources on the phone? I do not see any other valid explanation, but would like to know anyway.

Thanks,
Darko.

syrupcore
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Joined: 09/26/2010

How to ask a question right there!

Blip Interactive
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Joined: 04/05/2010

Hmm yeah, the problem is that the sequencer doesn't properly observe the time stamps on the incoming MIDI events, and instead bundles them into the sequence's 'current' position. On the Windows version, this realistically means a jitter of up to 3ms.

The sequencer was written before MIDI was available on iOS - it's more than good enough for touch screen input but it's a bit shabby these days. Next time I'd do it better ...!

Stiksi
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Joined: 11/21/2010

What Syrupcore said! We should really have a trophy to give to the best way to ask a question on the forum and this would be a prime candidate. Wow.

Blip Interactive
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Joined: 04/05/2010

Trophies only go out when the question is formatted in the style of a high school science experiment, with proper Aim, Method, Apparatus, Results and Conclusion sections :)

tom_tm
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Joined: 06/29/2011

Has anyone apart from me, tried to read the minuscule text then reply to this thread from an iPad? It doesn't work!!

No trophy from me. Instead I have to post this from my uninsulated loft while hot solar radiation caramelises any dandruff left on my burning scalp. :-/

syrupcore
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Joined: 09/26/2010

I replied on my iphone, actually.

Stiksi
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Joined: 11/21/2010

I replied from an iPad. There's zooming on the pad and landscape too. Double tap the text. I use the browser on 1password to read the forum.

tom_tm
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Joined: 06/29/2011

In Safari? Well I couldn't get it to work. :-/

Darko
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Joined: 04/15/2013

@ syrupcore, @ Stiksi
My english is not native, so I've read your post 3 times to understand it - I'll take that as a big compliment :)

@ Matt
Thanks for clarifying things. And about that trophy, NanoStudio is free for Windows, right? I think I've already got great one! :)