vertical grey lines over midi track, what are they?

Sorry if this is a n00b question, it’s my first here, and in fact I am pretty much a n00b, so it would figure.

I recorded a midi track (ardour 4.4 on Ubuntu studio). It is okay functionally, but the graphical display of the track is overlaid by a mass of vertical grey, single-pixel lines, each of which appears to have a yellow label at the top containing what seem to be maybe 6 numbers, some hex some decimal.

Can anyone enlighten me what these are?

They seem to be a problem because the graphical display is very slow to update as I scroll around, and I think it may be because the system is having to draw all these vertical markers, or whatever they are. Also I can hardly make out the midi notes to edit them, because of the mass of grey lines on top of them.

I suspect these may be something to do with the gadget I’m using to generate the midi data, which is a Yamaha EZAG guitar-shaped thingy that I just acquired. Because I’ve never seen these using my keyboard.

You’re apparently recording sysex data from your EZAG. To confirm, I suggest you zoom in a bit (to increase the spacing between the lines) and take a screenshot.

It’s like this…
I can make another shot if that isn’t clear enough.

Yes, I meant to zoom in far enough that you can see the text in the “flag” at the top of each line.

OK, is this better?
data label

Yep. Those are sysex messages sent by your controller. The EZAG sends out a sysex message for each fret that you press and release.

Thanks for your answer paul. I guess the EZAG has its reasons. And other than this annoyance it works fairly well. But it does raise a couple of further questions…
Are these sysex markers functional at all, I mean, can I do anything with them? Or do they just clutter the display and slow it to a crawl?
One for every note means there’s always going to be a lot of them.
Can the display of these perhaps be turned on/off? (ever hopeful)

Those sysex markers denote fret press/release, which on your EZAG are critical performance data, arguably at least as important as the note numbers. If you don’t want them, I suggest you use a keyboard, and file a feature request at to ignore incoming sysex when recording.

That’s good to know, I mean that the sysex markers are critical. That being so I certainly don’t want to lose that data. I didn’t really know what its role was.
However, what I would like to lose is the marker display, since it doesn’t appear to be any real use to me (I can’t do anything with it so far as I know), and the markers seem to significantly impede manual editing on my machine, because scrolling and zooming the display becomes very laggy - while it draws them all I suppose. Also it’s harder to make out what note data is under all those lines (which quite often fail to erase following view changes and threaten to cover the track entirely in time).
As you suggest, I will consider making feature request, but maybe just to toggle the marker display on and off, if that’s feasible, not to ignore the incoming data itself.
Thanks for Ardour, by the way, I’m loving it.