PC-based controllers - bad and ugly, but do they have to be?

[Brian]

...and transmitting them 44 times a second, you are going to get aliasing at higher 'chase' speeds, as well as jitter in things like automatic movement generation.

And there is a very good chance that your 'cost effective' fixtures won't cope with that refresh rate. It might say DMX on the box but it doesn't mean it's really DMX compliant.

[jfitzpat]

How would linear/exponential/ease-in/ease-out/etc CC curves for pan/tilt/fades/etc stay timed using a MIDI-triggered DMX desk or Bluelite? Everything is perfectly compensated for now the way I'm doing it now. Would a DMX desk or DMX software speed up or slow down internal curves depending on an incoming MIDI tempo?

 

You could still trigger from MIDI, since you do everthing else in a 'jam' sequencer, just instead of 1:1 on channels you would be doing 1->many and have access to all DMX values.

 

-jjf

[Hambone]

That still does't answer my question. All of my lighting is sequenced in beats and bars, not seconds. If If I trigger a 4-beat pan, it tempo-compensates itself. 4 beats needs to be 4 beats, irrespective of tempo. If the tempo is 60 BPM, the 4-beat pan will take 4 seconds. At 120 BPM, it takes 2 seconds. And if the clip is quantized, it stays in perfect sync. Does Bluelite or a DMX desk do this?

 

Using Live's scenes and Follow Actions, I'm able to transmit DMX on 100+ channels at once without a problem, all from a sequence or from a single button.

[jfitzpat]

That still does't answer my question. All of my lighting is sequenced in beats and bars, not seconds. If If I trigger a 4-beat pan, it tempo-compensates itself. 4 beats needs to be 4 beats, irrespective of tempo. If the tempo is 60 BPM, the 4-beat pan will take 4 seconds. At 120 BPM, it takes 2 seconds. And if the clip is quantized, it stays in perfect sync. Does Bluelite or a DMX desk do this?

 

Using Live's scenes and Follow Actions, I'm able to transmit DMX on 100+ channels at once without a problem, all from a sequence or from a single button.

 

Yes, a BlueLite system can do this. For example, if you pre program a show to a SMPTE source, then slow the source down 3%, everything slows down proportionally. Events don't just trigger at different intervals, fades, movement generation, everthing proportionally changes. You could use a MIDI clock the same way (BPM based).

 

The difference is that when you pre-record your sequences in raw MIDI, they are a certain granularity. That is, the updates are recorded level changes. As you slow down, transitions get courser. Lighting systems generally (and the BlueLite system in particular) calculate the 'in between' values on the fly, so fades and transitions remain at max resolution, regardless of how much you adjust from your original timebase.

 

As for how much you can transmit or not, it is basic math, nothing more. 31250 baud is roughly 3125 characters per second (I can't recall stop bit count for MIDI off the top of my head). Every CC change is 3 bytes, so you can send about 1000 of them in 1 second. So, if you fade 100 channels (stage fade to black), your update rate is about 10 Hz, right at the bottom of acceptable speeds for an acceptable theatrical fade. If you primarily bump and flash, 100+ is believable, but right at the limit of the technology.

 

Compare this to a BlueLite rig I just saw running in San Francisco on vacation this week. Two ArKaos systems (16 layers total) is 672 channels. Another 500 or so channels for intelligents, 96 for dimmers, and 64 for lasers, all updating at 30 Hz (so movement generation on the video layers is smooth). The point is not that your approach is bad, just that it technologically does not scale well if you want to use the same approach with larger rigs. 30 Hz updating would be 33 channels per MIDI stream, or 40 MIDI outputs. Some features would remain un reachable (since CC channels are 0-127, not 0-255 like DMX), and you would be programming features from the manual (no abstraction layer for the devices being controlled).

 

-jjf

[Tomo]

Using Live's scenes and Follow Actions, I'm able to transmit DMX on 100+ channels at once without a problem, all from a sequence or from a single button.

Comparing that to modern 'real' lighting consoles, many of which can happily do 12 universes (or 6144 channels) of DMX at full-speed simultaneously all from a sequence or single button...

 

The processing and transmission capabilities are irrelevant - any modern PC has enough processing power to create and manipulate massive amounts of level and attribute data.

 

The problem with PC-based systems is, and always will be, the User Interface.

 

That User Interface is why people buy lighting consoles - both the Eos and Congo OLEs run on a standard PC.

But controlling a show using the OLE (if this was possible) would be incredibly difficult, because the keyboard UI is so poor!

 

For some applications, a perfectly good UI can be created on a PC - but for others, it cannot be done simply due to the physical limitations of a keyboard and pointing device.

 

This, and ONLY this, is the limitation of PC-based control.

[Hambone]

Yes, a BlueLite system can do this. For example, if you pre program a show to a SMPTE source, then slow the source down 3%, everything slows down proportionally. Events don't just trigger at different intervals, fades, movement generation, everthing proportionally changes. You could use a MIDI clock the same way (BPM based).

Now THAT sounds useful. If I can send MIDI clock from Ableton Live on the Mac to a PC running Bluelite to keep everything in sync, it sounds like a winner. I can still use Live's Follow Actions, MIDI effects, etc, but to generate MIDI note-ons to trigger BlueLite events.

 

Will I be limited to the 128 MIDI notes from one MIDI channel, or can I transmit multiple MIDI channels to BlueLite? And what about CCs to trigger BlueLite events?

 

Sorry for getting off-topic, but maybe this info will be relevant to others.

[jfitzpat]

Sorry for getting off-topic, but maybe this info will be relevant to others.

 

Back in '05 I wrote a white paper on MIDI->DMX which can still be found here. Since then, I've written a number of additional samples. Also, the Live Panel has been updated to accept BPM and location plug-ins.

 

It sounds like what you want to do is trigger live panel sequences via MIDI (there are three built in maps for that) and use the MIDI clock beat plug-in, though you could use some of the other schemes covered.

 

Personally, I thought that the big advantages of using a lighting system in-between your MIDI sequencer and your lights would be capacity, ease of programming (it seems tedious to adjust values from the manual), no granularity change with tempo change in updates, and access to all features on the fixtures. These advantages would not be BlueLite specific, but could be provided by many different DMX systems.

 

-jjf

[Hambone]

It sounds like what you want to do is trigger live panel sequences via MIDI (there are three built in maps for that) and use the MIDI clock beat plug-in, though you could use some of the other schemes covered

-jjf

Yep!

 

Can you confirm that I can trigger Live Panel sequences via MIDI notes and/or CCs on all 16 MIDI channels? And how many Live Panel sequences are there? And will it work with the BlueLite software minimized on the PC? The VISCA camera control software I use needs to have the focus.

 

Mods - if this info is irrelevant to others, please tell me, and I'll us PMs.

[jfitzpat]

Can you confirm that I can trigger Live Panel sequences via MIDI notes and/or CCs on all 16 MIDI channels? And how many Live Panel sequences are there? And will it work with the BlueLite software minimized on the PC? The VISCA camera control software I use needs to have the focus.

 

Midi: No, by default the LivePanel maps all look at one channel. However, if you look at the three maps you will see that you have over 1100 recalls (each of unlimited length), as well as direct speed, level, direction, etc. control.

 

Background: Yes, the application works minimized, etc. in response to external inputs.

 

-jjf

[Hambone]

Midi: No, by default the LivePanel maps all look at one channel. However, if you look at the three maps you will see that you have over 1100 recalls (each of unlimited length), as well as direct speed, level, direction, etc. control.

-jjf

How can I map 1100 recalls with only 128 MIDI notes to choose from? I'll want to use MIDI sequences to trigger those recalls.

[jfitzpat]

Midi: No, by default the LivePanel maps all look at one channel. However, if you look at the three maps you will see that you have over 1100 recalls (each of unlimited length), as well as direct speed, level, direction, etc. control.

-jjf

How can I map 1100 recalls with only 128 MIDI notes to choose from? I'll want to use MIDI sequences to trigger those recalls.

 

Page/Recall (24 x 48). If you use CC values (one of the maps), it is easier still, since the note does not just have to be on/off trigger like a NoteOn message.

 

-jjf

[Hambone]

Page/Recall (24 x 48). If you use CC values (one of the maps), it is easier still, since the note does not just have to be on/off trigger like a NoteOn message.

-jjf

So various CC values within a given CC can recall various parameters, not unlike DMX values on a given DMX channel?

[jfitzpat]

Page/Recall (24 x 48). If you use CC values (one of the maps), it is easier still, since the note does not just have to be on/off trigger like a NoteOn message.

-jjf

So various CC values within a given CC can recall various parameters, not unlike DMX values on a given DMX channel?

 

There is a built in map geared towards notes (best for an actual keyboard dedicated to lighting), a map geared towards CC messages (probably better for a sequencer), and a map geared towards program changes (intended for self operating live musicisions).

 

The nice thing about CC messages is that they carry a specific value of 0-127 (a NoteOn is a specific note with the velocity the key was struck, with a value of 0 reserved for special meaning (equiv to NoteOff)). So while it takes 72 'notes' (24+48) to access 1100+ (24x48) recalls, the same thing can be done with two CC controllers (page and recall directly expressed).

 

However, either way, you should be editing/generating a lot less MIDI traffic than a 1:1 relationship with individual DMX channels.

 

-jjf