HMC150 vs DVX100-Chroma Key

[cdub10]

I've had a DVX-100A for 5 years. I love it! Im ready to jump in to the HMC150 world. Has anyone done any green screen shoots with the HMC? How does the AVCHD compression compare to what is recorded to miniDV tapes?

Thanks

[Robert M Wright]

My eyes tell me the image quality of AVCHD for HD is typically in the realm of what the image quality of DV is for SD, at close to the same bitrates. AVCHD video compression has two advantages, compared to DV compression, that help to achieve reasonably close to the same image quality at much higher resolutions. First, H264 is significantly more efficient period (whether or not intraframe only or intraframe and interframe) - probably on the order of 2X more efficient if intraframe only compression is employed. Second, AVCHD employs both intraframe and interframe compression. The added increase in image quality, using interframe compression also (in addition to intraframe), is quite substantial, with typical footage - on the order of 3X typically. All in all, AVCHD is probably in the neighboorhood of 6X more efficient, image quality per bit wise, than DV (again, with most typical footage) which is roughly about the difference in number of pixels being recorded (between HD and SD).

[ATL Media Group]

I've had a DVX-100A for 5 years. I love it! Im ready to jump in to the HMC150 world. Has anyone done any green screen shoots with the HMC?

That really depends on what you use to edit with. If you capture with Edius (and probably others) in the Canopus codec the DV footage was automatically upsampled to 4:2:2 for better chromakey. I got really great keys with my DVX100 and Edius/StormEdit.

I believe you can get a good key with Prorez from an HMC150.

[Robert M Wright]

I'm not 100% sure (would have to check), but I believe Canopus HQ is 4:2:2 also.

Regardless of how intermediate codecs store chroma information, DV is recorded at 4:1:1 and AVCHD is recorded at 4:2:0 (by the cameras). Converting video originally recorded as 4:1:1, to a format that stores video in a 4:2:2 format, or converting video originally recorded as 4:2:0, to a format that stores the video in a 4:2:2 format, does not magically increase the actual amount of chroma information that's there.

[Barry_Green]

Well, one is HD and the other is SD, so... either way, the HMC150 wins big.

If you're going to be uprezzing the DVX to HD, you'll find the HMC150 picture looks a million times better.

If you're going to be downconverting the HMC150 to SD, you'll have effectively 4:4:4 color sampling, which will key a million times better than the DVX.

So either way, the HMC150 wins.

[Justyn]

DV is just horrible to chromakey with too... especially with moving objects and faces turning and that. If you've been happy with DV, then you'll be over the moon happy with almost any flavor of HD. The 150 keys pretty well, it's not as forgiving as the P2 cameras but it does a great job and having an onboard waveform monitor is huge deal....

[cdub10]

Thanks for the replies everybody.

I won't be using the DVX and HMC together, I just wanted to know roughly what the visual difference would be. Shooting chroma-key with SD DV is not my preferred method, but it is something I've done before.

Anybody have any still images that they could show of an HMC chroma-key?

Thanks again.

[Barry_Green]

You can download an HMC150 clip and try keying it yourself to see what you think.
http://www.dvxuser.com/V6/showthread.php?t=190061

[cdub10]

Thanks Barry!

Would you say that the HMC is pretty much the DVX minus the tape drive, plus HD, focus assist, and waveform monitor?

[Denwa]

Thanks Barry!

Would you say that the HMC is pretty much the DVX minus the tape drive, plus HD, focus assist, and waveform monitor?

Other than the housing being pretty much the same.. NO.

Different optics, chips (obviously), batteries, software, hardware etc.

Optics and chipset are identical to the HPX170.