HDV vs. HD

[Dwight Flynn]

Hi folks, I have a technical question about hdv and hd. Essentially what is the difference between the hdv and the hd standard. I use a P.C. and Vegas, and I was wondering if I should convert the HDV to HD. Also I read that there are cards out there for this type of conversion, what is the best one in terms of cost/quality, or should I be using a software solution (and which software)? I am trying to make my editing a bit easier, and need a bit of help and direction.

[David Newman]

A simple way to look at it. HDV is a subset of HD, just as DV is a subset SD. HDV is a tape format and a compression scheme for storing HD video on miniDV and DVHS. I do believe are good reasons to convert out of HDV format when editing on the PC, speed and flexibility are the main reasons, but in the end it is all HD. Our (CineForm) Connect HD product does export to an AVI format for smoother editing within Vegas and to enable compatibility with a wider range of video tools.

[Dwight Flynn]

I loaded a m2t file into Vegas and was able to render it into an avi file. I am interested in the Connect HD option but I need more information. Please explain, or point me to an explanation of what would be different in terms of conversion and ease of use in using connect HD versus simply converting to avi using Vegas' native functions? I do notice that the m2t files are jittery in Vegas but I had assumed that that would be straightened out when converted to avi no matter what the technique used to convert the file.

[David Newman]

Connect HD converts the M2T files into a high-performance AVI during capture -- saving a bunch of processing time and manual labor. The AVI compression used is CineForm's HD (CFHD) codec, which is optimized for HD post-production work. Using CFHD AVIs over any other compressed or uncompressed AVI, will be typically run 2 to 4 times faster for editing under Vegas. Transitions with color corrections will flow much smoother. As a Vegas user you should consider Connect HD if you intend to do a lot of HD work for the time savings alone. More info is on www.cineform.com.

[Pete Wilie]

I have searched DVInfo.net and the internet, and can not find a comprehensive comparison of HDV and HD (in particular DVCProHD). There are many specs thrown about in many posts, but it is difficult to know which are accurate.

In light of the Panasonic HVX200 which will record HD using DVCProHD codec at 100Mb/s, it would be very help to me, and I suspect to many, to have an unbiased comprehensive comparison. I should also note that the highly acclaimed Panasonic Varicam also uses the DVCProHD codec.

Does this comparison exist somewhere?
Can anyone provide it?

[David Newman]

There are good comparisons of codec solutions at http://codecs.onerivermedia.com/ -- the site many deals with Apple based codecs yet it does show some of the quality issues DVCPRO-HD (when used as a post-production format.) DVCPRO-HD is an OK aquistion but it has its limitations, just like HDV.

But HDV vs DVCPRO-HD (both are HD varients) here are the basics

Bitrate for 720p
HDV 19Mb/s (for all frame rates)
DVCPRO-HD 40/50/100Mb/s (for frame rates 24, 30 & 60p.)

Resolution at 720p
HDV 1280x720
DVCPRO-HD 960x720

Bitrate for 1080i/p
HDV 25Mb/s (for all frame rates)
DVCPRO-HD 100Mb/s for 60i -- (unsure how 24p is being encoded, likely only 80Mb/s will be used.)

Resolution at 1080i/p
HDV 1440x1080
DVCPRO-HD 1280x1080

Compression
Motion compensated MPEG2
I-Frames only DCT.

Conclusions:
Neither is superior to the other. MPEG2 is a more efficient compression so it compensates for its lower bit-rate. For moderate motion MPEG2 averages 2 to 3+ times more efficiency than I-frame DCTs (at the same PSNR quality -- PSNR explained here : http://www.cineform.com/technology/H...ology10bit.htm.) For 720p24 I believe HDV will have the superior quality, for 720p30 they are equivelent (although HDV as the edge in resolution) and for 720p60 DVCPRO-HD is the only player today (and would be a clear winner.) For 1080i60 DVCPRO-HD has the edge in quality, HDV higher resolution isn't quite enough to overcome DVCPRO-HDs bit-rate advantage at 1080i60. At 1080p24 (which doesn't truely exist today is either format) they will be much closer with the edge to DVCPRO-HD.

[Radek Svoboda]

David,

You said 2 to 3+ more efficient. I don't think it means 2x for 720p and 3.5x for 1080i because longer GOP, does it? How efficiency of the two formats compare?

Radek

[Radek Svoboda]

David, Please tell how Cineframe 25 fit into this. How close would be to HD100 in 24-25p? How close would best deinterlaced 1080-50i be. I have FX1E casmera. Radek

What is the range of I-frame size in CF25 and in 1080i HDV? How about in 720p HDV?

[David Newman]

Radek,

The 2 to 3 an average for MPEG2 in general, but not considering GOP length. True the longer GOP of the HD2 (1080) standard helps efficiency a little.

Cineframe 25's MPEG efficiency could be better if the compression is progressive, but the stream is flagged as interlaced. So I'm unsure whether the psuedo progressive mode have any bearing on compression efficiency, other than the slightly soften image (that helps a bit.)

[Pete Wilie]

Interesting conclusion by Mike Curtis in the following article:
Mike Gets Hands On: Sony HDR-FX1 (HDV) vs Sony F900 (HDCAM) Footage Comparison

-consider HDV a nice very high res consumer DV with this camera. I'd rank the HDR-FX1 about 1/2 of the way between a good DV camera (Canon XL1S or XL2, Sony VX2100) and the Panasonic Varicam. It's much better resolution than DV, but the clarity and color fidelity of the Varicam blows HDV away. But it's nowhere near the F900 in quality by any stretch.

Just to be clear, in the last sentence "it's" refers to HDV.

Remember that Varicam and HVX200 use the same codec: DVCProHD

[David Newman]

However that clarity has very little to do with compression, and for more to do with optics.

[Kevin Shaw]

Seems like most people expect the HVX200 to offer better image quality with more flexibility than today's HDV cameras, but that's not going to come cheap. The HVX200 itself is only $6K, but you'll probably end up spending that much or more again for the P2 memory cards plus some way to archive your HD footage. If you have that kind of money to spend you'll probably be happier with the Panasonic camera (assuming it works as well as predicted), but it's hard to beat the value which HDV offers. Note that someone's describing HDV quality as half way between that of an XL1 and a Varicam, for the price of the XL1. That's a heck of a deal!

[Steve Crisdale]

Originally Posted by Kevin Shaw

Seems like most people expect the HVX200 to offer better image quality with more flexibility than today's HDV cameras, but that's not going to come cheap. Note that someone's describing HDV quality as half way between that of an XL1 and a Varicam, for the price of the XL1. That's a heck of a deal!

And in the end... what are people going to be watching their stuff on? 35mm digital transfers on Movie screens?

I hate to pour cold water on their parades, but for the majority of people, HD stuff from these HD/HDV camcorders is gonna be watched on (at best) HDTV screens of 50" and less.

The best output that could be watched (freely available) on the vast majority of these sets will be MPEG2 1080i with bit-rates much less than 100/80Mbit. So; the output from a camera like the Varicam has to be re-encoded, downsampled and generally degraded from it's superior original quality to about the same as that from the cheaper HDV camcorders.

While doing so should provide excellent quality video, one has to wonder whether it's that much better than what the best of the HDV bunch of cameras offers.

I must admit to being tempted by very expensive and incredibly spec'd equipment. I hate to think of the computer power I'd need to invest in to work with these files however...

[Kevin Shaw]

Indeed, it's worth noting that what most people are going to end up watching on their expensive HDTVs is network broadcast HD signals, which happen to be the same format and bandwidth as HDV. And if/when HD DVD players finally start shipping in volume, the best quality playback format they'll support will be essentially the same as HDV. So although it always helps to have the highest possible quality source material, for many purposes HDV recording and delivery will look fine, and at a price point no other HD recording format can touch. (At least not in the near future.) As we get more and better HDV cameras, the practical effectiveness of this format should make it a big success with independent producers.

[Laurence Kingston]

I agree. HDV is to HD what DV is to SD. There will continue to be other more expensive formats, but in my world at least, HDV is the only one that will actually count.