View Full Version : Canon Rebel T2i - Live Webcast HDMI Capture


Brandon Drury
January 30th, 2011, 12:47 PM
Hello,

I'm hoping to purchase a Canon T2i today. I just have one specific question that I didn't see answered in the manual.

I'm putting together live tutorials of audio mixing in Cubase 5 (that's my real job). My goal is to send the HDMI output of my recording computer's video card AND the HDMI output of the Rebel T2i to an HDMI switch which would then flow into an HDMI capture card like the Black Magic Shuttle.

It's very important that no editing is done after the fact. Either I get it right or I do it again. I'm cool with that and would even prefer it for these low-budget kind of productions.

The Canon T2i manual does say that you can HDMI to a TV in full 1080p in playback mode, but it's not clear what happens when simply selecting record mode without actually pushing the record button.

Does anyone know?

Thanks,
Brandon

David A. Ludwig
January 30th, 2011, 02:37 PM
the T2i dumbs down the output to SD during recording.

alex is working on the hdmi output in Magic Lantern, i haven't had a chance to test it yet, not sure what the status is, search this forum.

you might also consider using camtasia and/or xsplit broadcaster...

Brandon Drury
January 30th, 2011, 02:47 PM
Well, because of my live switching thing (between the camera and the screen capture on my recording computer), I'll never actually push the "record" button on the Ti2. It'll just be in "live stream" mode or whatever. That (hopefully) 1080p live stream will flow into my switcher and that will flow into a Blackmagic HDMI capture card (or equivalent).

It's clear that my current way of doing this is quite odd ball as pretty everyone is recording to their flash cards or whatever.

I don't want to back down from my live-on-the-floor switching/editing because I'll be able to crank out WAY more videos in the same amount of time. The how-to nature of the videos doesn't require a full-blown, scripted production. In fact, I'm positive for what I'm doing, the production will suffer.

When it comes to webcasts, which I'll definitely be doing, the live setup is absolutely required.

---

Camtasia is out. They can't share audio with my ASIO audio interface. That's not an option since I'll be using my audio mixing console during the recording and need 32 channels of audio output.


I'll check out xsplit broadcast.

Brandon

Steve Oakley
January 30th, 2011, 06:19 PM
you can't do what you are planning with an HDMI switch.

1. HDMI talks from the sender to the reciever and back to set up resolution, frame rate, audio and copy protection bits. if you break the connection, the negotiation takes place again.

2. you would drop out of capture due to the break in data as soon as you did switch

3. the 550D does not have a clean output. even if all the display stuff is turned off, it still may have some overlay on it. if when and until ML has clean output, you can plan doing real work like this until its shipping.

in order to do what you want, you should get a camcorder with HDMI output like a canon HV series. you will find that holding focus will be a problem with the 550D if you can't get to about F4. been there done that. use the cheap HD camcorder.

as for changing video sources, you need a real video switcher. some have HDMI ins, but most are SDI. that means you'll need 2 HDMI->SDI converters to feed the switcher. most modern switchers have frame syncs so you can get away with not having to lock cameras / sources with sync. if you could switch video with a passive switch, or even a simple active dumb switch, we'd all be doing it. to switch video the way you picture, you need a real video switcher and there is no way around that as a fact.

I think your plan of not editing and just redoing will in the end be as much work if not more. No matter what there are always bits to clean up. there's a reason why you need crew to do live switches like this... because its not anywhere near as simple as you think. if it was, no one would hire the people typically involved for a multi camera shoot the way they do.

Brandon Drury
January 30th, 2011, 08:24 PM
Thanks for the info, Steve.

I had a gut feeling that there would be issues with the syncing in the same way that my analog to digital audio converters always need a clock. That makes sense.

I still think the style of production I have in mind would work if I can get the technical details down. I don't deny that a full crew is needed for an elaborate "real" production. However, mine is going to be a very "duct tape" affair. Real video guys would laugh at it. The switching is there really just so I don't have 8 hours of DVDs that are nothing but screen capture. Anytime a "concept" pops up, I'll push the switch button and talk to the camera for a minute or two. It's certainly "editing" by any stretch of the imagination. It's just an improvement on the current "Youtube standard" or lack there of.

I was planning on 3 seconds of black space in between each "cut". I'm cool with that. If I screw up, I either start all over or keep it. In my experience as a pro audio engineer/producer, I'm POSITIVE that shooting this the non-live way would take 10x as long, but my standards are quite amateur. It's the info that sells itself and I'm not a "video guy". My customers know that.

I already do my ultra-lo-fi talks live in front of my camera and do just fine. The only different with this setup, in concept, is the ability to immediately switch to a screen capture. For the kind of content I'm creating, the live rambling would be even more valuable to my demographic than a scripted, rehearsed, and well-edited piece. My tests have shown this.

This guy here is doing what I want to do, more or less: YouTube - TF19 - Wirecast 4, Epiphan VGA2USB LR and an iPad (http://www.youtube.com/watch?v=mOjnIcNlv18)

I'll do my homework on 550d vs Canon HV series.

Thanks for the help, Steve.

Brandon

Brandon Drury
February 1st, 2011, 11:56 AM
While the switching would have to be software based to pull off the live idea (and I'd need a capture card for each HDMI input), this guy has nailed what I want to do more so than anyone else I've seen.

HDMI Showcase - Colours of England on Vimeo

The fact that it looks OUT STANDING (at least to my layman eyes) is a good sign.

Brandon

Steve Oakley
February 2nd, 2011, 06:34 PM
maybe you posted the wrong link, but there is nothing live about that clip... completely edited.

actually decklink might have an app to do what you want if you put 2 intensity cards into the machine.