Forums > Jitter

Is there an easy way to capture oscilloscope feed into .mov?

July 25, 2009 | 10:51 am

Hi everyone,

I finally bought the Max bundle after 5 years of hesitation. So please have mercy on me if this question is outright silly RTFM-type of stuff, I am still a "Jitter virgin" Wink

We’re doing a TV show and there is need for a cutscene with music playing and an oscilloscope view of the track playing as image while it plays. I am trying to produce this cutscene with Max.

So with my tiny experience with max patching, I managed to create a patch that displays an oscilloscope in a way that I want (size on screen, colors etc.). I am using the oscilloscope object of course, at this stage I couldn’t hope to be able to do my own scope from scratch Smile

Is there an easy way to feed the oscilloscope image into a Jitter matrix? If I understood the basics correctly, I should be able to record a matrix into a MOV file using the basic matrix recorder object. I could mux the resulting video with the original audio to get the thing done.

Thanks in advance!

(Also, If you have any definite suggestions for easing the learning curve with max programming, please share them)



Jan
July 25, 2009 | 12:53 pm

Hello tetsuneko,

if you use the jit.poke~ object to write the sound-data into a matrix than you can output the generated video i.e. via firewire using the jit.dx.videoout (Windows)/ jit.qt.videooute (Mac) and record it with any device.

Examples how to use the jit.poke~ and the j.qt.videoout you will find in the help files and/or the tutorials.Tutorial 22 and 27.

Lot’s of fun with your projects.

Jan


July 25, 2009 | 5:11 pm

Thank you! I will get started on learning these objs.

Cheers

EDIT: Using this approach will result in an aliased image of the waveform?? I’d prefer antialiased, would look nicer.. O’well, I’ll see if I can do this at all first and worry about that later.. the tutorials make me feel like I have a lot to learn about jitter before I can do this – all this RGB stuff and hsync are most likely bread-n-butter jittery but it’s all new to me Smile


July 25, 2009 | 7:53 pm

I think I found an easier way to do this. I stumbled into the "Jitter recipes" set and found a very simple way to get an oscilloscope matrix by using jit.catch Wink

So now I have a matrix that I can dump into qt.rec or firewire video out. The only thing is, the resulting oscilloscope is heavily pixelated, but otherwise functions beautifully (really good response with a lot less CPU load than the scope obj uses)

Now if I can just figure out how to control the pixellation to get a smooth 16:9 DV PAL image, I’ll be happy as a cow Very Happy


July 25, 2009 | 11:26 pm

You might be interested in this thread where Graham Wakefield posted a nice jitter [scope~]-esque patch just a few moments ago.

lh


July 26, 2009 | 11:35 am

Thank you for the link!

I actually got my own ramblings to work last night, managed to get a mov out with decent quality. But these are really interesting, nice to see how people with real jitter talent are doing things!


July 26, 2009 | 11:37 pm

don’t know if it’s optimized enough for your needs, but jit.desktop can at least grab what you’re seeing on the screen. So setting the oscilliscope object’s size, the jit.desktop resolution, and the jit.qt.record that grabs the jit.desktop output correctly, should give you a movie of what’s happening. you can also use jit.vcr to grab the audio along with the oscilloscope and save it all together.

The only problem is possibly dropping some frames since jit.desktop isn’t as optimized as something like Camtasia which is designed just for screen grabbing, but running it on a fast comp should be OK, and you should get exactly what you see (no aliasing or pixelation), provided all the sizes and resolutions match up.


July 27, 2009 | 12:26 pm

jitter.vcr? That’s amazing, I was just trying to figure out how to record the audio into the same video (which will save lots of time as I don’t have to mux/demux the video to get the audio into it) Wink)

I’m using a 2007 model MBP, so I hope that’s fast enough.. the first few test runs I’ve made with jit.qt.rec don’t seem to skip too many frames, (except for the end, when I press stop, the last few seconds of the recorded video always give a "frozen" video) so I’m pretty confident that I can use it instead of dumping the output to FW.

I am really glad I bought Max.. And with your help it’s been a very pleasant ride so far! It’s a bit overwhelming in the beginning, your suggestions and tips are immensely appreciated.

Cheers


July 28, 2009 | 9:05 am

Ok, so I tried the jit.vcr module last night and couldn’t record anything useful with it.. Got like 0.1 FPS or similar..and audio dropouts as well.. so looks like I have to either go with the muxing way or output into FW and record the FW output with a DV recorder.

So it seems that jit.vcr consumes a lot more resources than jit.qt.rec?

EDIT:
I transferred my test patch onto a WinXP workstation (running the max demo) and this time jit.vcr produced a working mov! Must be the infamous laptop 5400 rpm internal drive that was causing my dropouts.. In any case, I now have a working patch that I can use to open a .wav and to export a (more or less stable) 25fps 1024×576 mov with sound and picture in "acceptable" sync.. the file even imported nicely into Avid Smile)

Once again, thanks for everyone who helped on this one.. I couldn’t have done it without your help!


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