DMX patching bug?

[Arjan]

Hi,

After experimenting with the software over the last few weeks I picked up an Xpress 512 today. When I try to this this with my DMX equipment I run into the following problem when I try to use the DMX patching feature.

If I use this DMX patching arrrangement in ShowXpress:

Universe_____Channel______DMX outputs
1___________13___________17
1___________14___________18
1___________15___________19
1___________16___________20
1___________17___________21

then fader 17 becomes non-functional as shown by the ShowXpress DMX Levels screen and the fact that my scanner won't respond to this fader/channel. If I remove the patch from 17->21 I can again use fader 21 so I know there's no problem with the scanner hardware.

Apparently the patch combination 13->17 and 17->21 creates some sort of internal loop in the software, preventing it from using this kind of patching where some target channels overlap with an actually used source channel.

The above scenario does not seem out of the ordinary to me. Is this something you could fix, hopefully short term?

Other than this little problem I'm having a blast with your software and interface

[support]

Yes, our software is not able to manage "multi-levels" dmx patching.
Universe_____Channel______DMX outputs
1___________13___________17
1___________17___________21
Gives channel 13 moves dmx output 21, and channel 17 does nothing.

[Arjan]

Hi,

From my point of view as a user this isn't multi-level patching; at least that's not what I'm trying to accomplish. I'm simply trying to patch fader 13 to DMX channel 17 and fader 17 to DMX channel 21.

As a programmer I wonder how come that the software doesn't allow this type of input/output mapping. I have no idea of the internal architecture of the software but I suppose there is such a concept as a 'DMX frame buffer' that holds all the DMX channel values for one update iteration to be sent to the actual interface (or 3d visualizer or whatever). The mapping could then be implemented by creating a copy of that frame buffer and then applying the mapping using one buffer as the source and the other as the destination. The destination one then gets send to the rest of the world. Of course you'll run into trouble if you only have on buffer and then try to do the mapping by copying the data for channel 13 to channel 17 and then copy this overwritten channel 17 data to channel 21. That would effectively create multi-level mapping (although not in a reliable fashion since the order in which you iterate through the channels to copy or map them would affect the result).

Anyway it's not such a big deal for me right now, I can handle re-assigning DMX addresses on my actual fixtures. But it sure would be useful to have a mapping that does not have this limitation.

Still liking the software a lot, although I have experienced a few crashes in ControlBoard while simply triggering buttons in Live through MIDI, nothing else going one. I had the 3d visualizer on, no DMX output. Previously you told me you can't use stackdump files but I'll see if I can somehow reproduce this using a MIDI file that you can simply playback to the software to make it crash. Or do you have a build of the software along that has debug info and a .pdb file? Then I could tell you what source file and line the crash occurs on, I have Visual Studio 2008 Profesional installed on my system so I can jump into the debugger any time it crashes.

I don't know what programming language you use but you might want to look into minidumps and how to use them for debugging. We started using them about a year ago and it's turned out to be the most effective way ever to diagnose and fix crashes that occur on a customer's computer. If you like I can give you some pointers where to start, although I only have experience with this in native C++.

Thanks,
Arjan

[support]

The crash happen certainely in the "Midi in" procedure.
The cause is certainely too many incoming midi data (although our code includes a protection against too many incoming midi data).
We will try to reproduce this.