can you pull 4:4:4 from an hmc150?

J

jonnyracket

Member
i was just wondering if there was a way to get a non comressed 4:4:4 signal from my hmc150. HDMI isn't capable of that, is it?
 
No, HDMI cannot transport 4:4:4. And no, you can't get 4:4:4 from any video camera today, except something like an HPX3700 or F35.
 
not counting the Red cameras, right?
i saw on jvc's site that they have "uncompressed" outputs on their GY-HD series cams and their new GY-HM100U...
is that still 4:2:2? what's the point of uncompressed then?...
thanks for the info though
 
Counting the Red cameras. They cannot deliver 4:4:4 at their stated resolutions. According to Graeme, it's more like 3.2:2:2. Yes I know Red's marketing confuses the issue, but the absolute fact of the matter is that you cannot get 4K 4:4:4 out of a Red One. The RedCode recording format is capable of recording 4:4:4, but the camera cannot deliver a stated-res 4:4:4 signal to the recording format.

Yes the JVC is still 4:2:2.

"Uncompressed" means it hasn't been run through MPEG-2 or H.264 or HDCAM or any other compression system. And there's not an HD camera available that doesn't offer uncompressed, every one of them does (either analog uncompressed, via the component output port, or digital uncompressed via the HD-SDI or HDMI ports). Getting uncompressed HD is no big deal, they all do it, even a little HV20 does it.
 
i thought the compression was directly related to the color space... hmmm something to think about;
you may have shattered my dreams for getting a Red camera. thanks...

so, then, what's the benefit of an uncompressed signal then? i mean, does it help with chroma keying? if the color space stays the same, i don't see the advantage of getting into capturing uncompressed. i was thinking it's be great for green screen work, but, apparently i'm out of luck there...
thanks again
 
You're on the right track. All video cameras process their signals internally at either 4:2:2 or 4:4:4. Then when they're done processing the signal, it's going to go somewhere -- either to a recorded media, or output on the digital outputs.

The recording format can have a mild to unnoticeable impact on your footage (AVC-Intra) or it can screw your footage six ways from Sunday (bad HDV recordings, etc). Usually the minimum that will happen is that the color will be chopped in half again, down to 4:2:0 (DVCPRO-HD and AVC-Intra will keep the 4:2:2 intact, but pretty much all the other HD formats are going to cut that color down in half again, to 4:2:0). On top of that, compression can wipe out fine detail, it can introduce artifacts, it can degrade the footage noticeably.

The digital output, however, will be the closest you can get to the best signal the camera is capable of delivering. It will have avoided all the degradation that happens during compression. But, it will be converted to 4:2:2 because that's what video *is*. There's pretty much no such thing as 4:4:4 video, 4:4:4 basically exists only in computer files, not in video footage. You can spend a fortune and get dual-link HD-SDI to record 4:4:4, but frankly -- you're not gonna. That's for Hollywood, not DVXUsers.

So uncompressed 4:2:2 is the best you're going to get. Is it worth it? Most of us don't bother. A few diehards might cable their HD-SDI or HDMI ports to their computers and capture uncompressed, and yes, it'll be better for greenscreening (especially if your camera records to 4:2:0!) But it's usually not a night and day difference.
 
well, it's something to think about...
i'm guessing the uncompressed formats are also gonna be a standard format (avi, mov, or the like) just an uncompressed codec?
i'd like to be able to get the most out of chroma keying, i don't use it much because i hate my footage looking lke a bad local tv commercial shot in the '80's. it'd be nice to be able to dabble a bit more...
 
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