View Full Version : HDV vs HD


Hugh Mobley
May 7th, 2008, 03:34 PM
Question if anyone knows, I am considering a citidisk HD recorder, focus is also a consideration, however I am planning to use with my Sony HVR V1 which shoots HDV tape, but the chip is HD 1920x1080, Has anyone combined the two, the tape running HDV and also the HD recording at HD.

Noah Yuan-Vogel
May 7th, 2008, 03:56 PM
my understanding is that the citidisk HD is not compatible with HDV camcorders such as the V1. you'd need to use the citidisk HDV. all of these recorders simply record the same HDV or DVCPROHD or DV etc stream that would otherwise be recorded onto tape. the only difference is the recording media size and type. its great if you want to record for a long time without changing tapes and prefer copying files over capturing tape (copying files is probably up to 10x faster). but these hard drive recording solutions are somewhat less stable than tape or solid state recording media.

Craig Irving
May 8th, 2008, 09:29 AM
Hugh,

If your goal is to bypass HDV compression by using HDMI, there are a couple of products coming out that may interest you. One is the Cineform HDMI Recorder, and the other is the Convergent-Design nanoFlash XDR. They both allow HDMI input, both bypass HDV compression and allow you to record 4:2:2 at a higher quality.

The Cineform recorder obviously records into the high quality Cineform codec, which is wavelet. This will require using Cineform's plugin for your NLE in order to work with it.

The Convergent-Design nanoFlash XDR is going to allow recording into MPEG-2 (still using long-GOP <---not bad thing) yet allow you to record at 50mbps and even up to 100mbps.

As for the 1920 vs 1440 thing. Again, it's no big deal. Even though the chips in your V1U are processing at 1920, your HDMI recording device will still be capturing 1440. Again, this isn't a bad thing. It's the other compelling features I mentioned above that make these products attractive. I, for one, can't wait.

Chris Hurd
May 8th, 2008, 09:57 AM
Once again: HDV *is* HD. We don't debate that here.

See http://www.dvinfo.net/conf/showthread.php?t=121145

John Richard
May 10th, 2008, 07:54 AM
"The Convergent-Design nanoFlash XDR is going to allow recording into MPEG-2 (still using long-GOP <---not bad thing) yet allow you to record at 50mbps and even up to 100mbps."

The XDR will also have the option to record in I-frame (Intra-frame) as well which would be useful in certain situations.

Noah Yuan-Vogel
May 10th, 2008, 10:14 AM
Hugh,
Just to be clear, the citidisk HD should probably be called the citidisk DVCPROHD as it is only compatible with DVCPROHD cameras, in the same way that the citidisk HDV is only compatible with HDV cameras. It's just two different products for two different recording formats.

Craig,
Are you referring to the V1 specifically when you say HDMI recording would be 1440x1080? I'm fairly sure most cameras output 1920x1080 over HDMI and that is what would be recorded as it is the most widely supported frame size over HDMI.

Hugh Mobley
May 11th, 2008, 09:44 PM
How about Blackmagic Intensity via hdmi into Cineform neo hd, (I use Neo HDV now)wonder if that would work, I know Patrick Chan at Citidisk and going over there with a friend next week on another matter, going to take my V1 and run a few tests. HDMI will be the only way to get 1920x1080 if at all possible, firewire won't support it.And yes I know I don't necessarily need 1920x1080, 1440x 1080 is fine, even 1280x720, but when I put my cam to my hd tv thru a hdmi cable and play the tape, the difference is a big difference. the problem with citidisk it connects with a firewire, so will not really work,

Noah Yuan-Vogel
May 11th, 2008, 10:28 PM
what do you mean there is a big difference when you play a tape through hdmi on your hdtv? playing tape is always going to be 1440x1080 since that is what is on the tape, even though hdmi scales that up to 1920x1080 when you output it to the hdtv. there shouldnt be any noticeable difference in image quality between playing hdv on your computer and playing the tape over hdmi, either way you are playing the same hdv video stream.

yeah blackmagic intensity capturing to cineform through neo hd would give you 1920x1080 4:2:2, but its only useful if you capture live to your computer... meaning wherever you shoot video youll have to bring the computer and be tethered to it by hdmi cable while shooting. this isnt that convenient for a lot of types of shooting. it might be ok if you are in a studio. doing this to capture from tape isnt particularly useful since you wont get better image quality than HDV if you are just capturing from HDV and upconverting to cineform on capture.

camera->hdv->hdmi->intensity->cineformhd gives you the same quality as
camera->hdv->firewire->cineformhd since it can just upconvert in software and probably wont give you better image quality than camera->hdv->firewire->computer since the weak link in all these chains is HDV recorded to tape.

Craig Irving
May 12th, 2008, 07:30 AM
Craig,
Are you referring to the V1 specifically when you say HDMI recording would be 1440x1080? I'm fairly sure most cameras output 1920x1080 over HDMI and that is what would be recorded as it is the most widely supported frame size over HDMI.

I'm referring specifically to the V1U, yes. I am uncertain about other camcorders that feature HDMI.

Here are a few quotes from a Digital Content Producer article on the HVR-V1U:

"ClearVid technology is tightly integrated with Sony’s Enhanced Imaging Processor (EIP). The reality is that the HVR-V1’s “image” is being formed in and by the EIP. The CMOS chips are only "collectors" of information the EIP needs to both create and manipulate an image.

Image creation is the EIP’s most fundamental task because, according to Sony, the EIP works at “1920x1080/60p at 4:2:2.” This specification implies both that the created image is 1920x1080 and that it is created from 60p scanning of the ClearVid chips. Thus, the EIP has a 2 million-pixel buffer for each of the three primary colors."

"When the camera is operating, the EIP outputs uncompressed 1440x1080 in 4:2:2 color space. The digital data are output via the HDMI port."

David Newman from Cineform has also confirmed that the V1U's HDMI is outputting 1440x1080. I'll re-iterate that this is not necessarily a drawback. I'm just saying effectively you will be capturing 1440x1080 when using HDMI capture cards/recorders.

The advantages you're getting have more to do with color space and compression.

Hugh Mobley
May 15th, 2008, 07:44 AM
But cineform says if you use Cineform with Blackmagic Intensity on the V1, with Prospect HD, Aspect HD, you can live record, bypassing the camera's internal HDV signal, for an umcompressed HD signal. Only problem is its live into a recorder, not feasible at times, and I don't know whether Sony Vegas can use Prospect or Aspect HD, says Prospect HD will be 1920x1080 YUV 4.2.2 10 bit. By the time all this is done probably its time for an EX1

Jeff Mack
May 29th, 2008, 10:35 PM
Guys, I am getting into this late but I have a great solution that has worked for me with my Z-1. I bought the Miranda AD/DA converter. http://www.miranda.com/product.php?i=337&l=1

I go from the z-1 pre compression to the converter then to my IOHD via HD SDI. Then the IOHD to a MBP via 800 firewire while capturing Pro Res HQ to a 4 drive esata raid zero. Works great for me and no long gop! And has an HD SDI monitor feed.

Jeff