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View Full Version : GH2 Best HACK for commercial green screen shoot



mr.coffee
12-14-2011, 12:36 PM
edit: Looks like my question was heard all the way over at personal view
http://personal-view.com/talks/discussion/1737/optimizing-your-greenscreen-shots-when-shooting-with-the-gh2

Totally new to the GH2-hack world.
I have a green screen shoot coming up.
The A camera will be the Alexa, and I was thinking of using my GH2 as B cam.

Now, I know the stock settings on firmware 1.1 aren't good enough, so I was thinking of going back to 1.0 and using one of the hacks.

The tests I've looked up on youtube were using Driftwood's 176mb GOP1.

With just a 64mb card, that hack blow though it pretty fast wouldn't it?
maybe I'm wrong?

Can you guys recommend something a little smaller mb-wise? Perhaps simpler to use for a noob?

Has anyone successfully shot a green screen with hack for commercial work?

Thanks
J-P

M. Gilden
12-14-2011, 03:04 PM
I'm interested in hearing this also.
But, I think pulling a good key has less to do with the bitrate than it does the color space. The bitrate will help ensure there aren't encoding artifacts (blurred/smoothed pixels), which is definitely helpful, but for the best possible key footage from a GH2, you might have to get an external recorder attached to the HDMI out (like the Atomos Ninja) and follow this to get 4:2:2 color and a solid bitrate:
http://marvelsfilm.wordpress.com/2011/04/19/panny-gh2-hdmi-recorder-bingo/

Again, that's for the *best* possible keying footage. You might not need all that. I've pulled keys with a T2i that looked good enough for what I was doing.

blazer003
12-14-2011, 05:20 PM
With my GH2 I can pull a nearly perfect key very easily from a mediocrely lit green screen with just the stock settings. I haven't tried the new high bit rate mode, but I'm sure it will be slightly better. I use Adobe Ultra plugin for Premiere CS5 though, and it's pretty amazing. But I think with good setup and lighting the new high bit rate mode will do you just fine. As always, doing a test is the only way to really know if it will work for you.

Kholi
12-14-2011, 06:22 PM
www.personal-view.com

I highly suggest signing up and asking the question, or doing a quick search, over there. They will be more informed.

mr.coffee
12-14-2011, 07:15 PM
With my GH2 I can pull a nearly perfect key very easily from a mediocrely lit green screen with just the stock settings. I haven't tried the new high bit rate mode, but I'm sure it will be slightly better. I use Adobe Ultra plugin for Premiere CS5 though, and it's pretty amazing. But I think with good setup and lighting the new high bit rate mode will do you just fine. As always, doing a test is the only way to really know if it will work for you.

If i understand you correctly, you're saying on the new 1.1 firmware using 1080p24 on highest setting....i will be fine. No need to hack?

M. Gilden
12-14-2011, 07:51 PM
I think he is referring to one of the hacks when he says "new high bit rate".

miseducation
12-14-2011, 10:30 PM
Actually there is a new 'high bit rate' mode in the 1.1 firmware and that's what he's referring to. It only outputs to 24mbps but supposedly its higher bitrate in some way (I'm fairly new to the GH2 as well.)

Also on the 4:2:2 space out of the HDMI, I'm fairly certain its only the AF100 that does HDMI 4:2:2 and not the GH2. Again, I've only been nerding out on GH2 stuff for a good week so please correct me if I'm wrong.

Hack-wise (and assuming you mean 64GB and not MB and assuming your card is Class 10 and of a decent brand) if I were in your position I'd consider:

- the oldest and most stable (one of the 44mbps ones)
- maybe (HUGE MAYBE without asking someone more knowledgeable than me) the Aquamotion V2. It's 100mbps, AVC Intra and and its the patch I use. My research showed it had the least amount of drawbacks with the highest bitrate (for my Sandisk Class 10 cards anyway.)
- SpanMyBitchUp, similarly high bitrate (I think in the 80-something mbps range), AVC Intra and longer recording times than Aquamotion.

(Personal note: I've pixel peeped only stock vs. Aquamotion v2 and for my eyes the difference is a pretty noticeable. I'm taking the internet's word on the hacks and haven't pitted them against each other whatsoever.)

Lastly, I'd take notice that you're only going to get 80 min or so on that 64GB with the hack (with Aquamotion anyway.) If you can afford an Alexa on the shoot, having only one memory card on set for your b-camera is just asking for something to go wrong.

M. Gilden
12-14-2011, 10:49 PM
Actually there is a new 'high bit rate' mode in the 1.1 firmware and that's what he's referring to. It only outputs to 24mbps but supposedly its higher bitrate in some way (I'm fairly new to the GH2 as well.)

Ah, I forgot about that.


Also on the 4:2:2 space out of the HDMI, I'm fairly certain its only the AF100 that does HDMI 4:2:2 and not the GH2. Again, I've only been nerding out on GH2 stuff for a good week so please correct me if I'm wrong.

This is one of those times you may be happy to be wrong. Did you bother following the link I posted along with that? It explains everything. Scroll back up and give it a click. Then thank me later. :)

miseducation
12-15-2011, 12:40 AM
Well holy crap, consider me corrected, sorry for glossing over the link. Is there really any reason to go AF100 at all at this point?

And to agree with you on another matter, I've also pulled some excellent keys out of a T2i/7D.

mr.coffee
12-15-2011, 05:17 AM
Thanks for the tip. Aquamotion v2. Ill try it.
The client pays for the Alexa. I'm bringing mine in as B cam more for testing. But I have a 64 and 2 -32s.