HDV vs. HD
 

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.

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.

Why connect HD instead of Vegas' functions
 

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.

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.

HDV vs HD
 

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?

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.

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

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?

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.)

Review at HD for Indies
 

Interesting conclusion by Mike Curtis in the following article:
Mike Gets Hands On: Sony HDR-FX1 (HDV) vs Sony F900 (HDCAM) Footage Comparison
Just to be clear, in the last sentence "it's" refers to HDV.

Remember that Varicam and HVX200 use the same codec: DVCProHD

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

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!

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...

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.

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.

Metaphorically speaking, "HDV is to HD what DV is to SD" is about right, but looking how close DV is to uncompressed SD, and how close HDV is to uncompressed HD, I'd say that HDCAM is to HD as DV is to SD, from a technical compression point of view. Actually, I'd say both HDCAM and DVCproHD are, when compared to uncompressed HD, worse than how DV compares to uncompressed SD. Which is a pity, really....

Graeme

Yikes... that should mess with a few newbee minds!!!

I know it's nice to split hairs, and atoms... but isn't it enough for the majority of people coming to HD/HDV to know that they don't have to obtain a "whizz-bang" over the top "George Lucas will accept nothing less", camera to obtain very acceptable results that will display no worse than what the viewing device they are most likely going to be watching it on can handle?

The similarities I'm seeing here; to the printing industries' inability to accept the realities of Digital image processing, is almost uncanny. I think of all those printers who used to say "you can't get a decent print on a quarto page from less than 1200dpi at 100%" or "flatbed scanners will never be good enough for decent print quality", and wonder how many of them are now dead.

They just refused to see that the average punter doesn't get to see the original... and if the images they do see are still damned fine - they'll be satisfied. Oh... no, these dudes had to have image quality that was suitable for billboard size, just to do some mambie pambie magazine - then they whinged when their Macs choked under the size of the RIP.

I'm sure we'd never see a Digital Video version of that though...

I know that my shooting style is changing: much less camera movement. Much less handheld stuff. More static tripod with fewer pans and zooms. I'll probably order one of those new Steadicam Merlins when they're available. Anything to cut down and smooth out movement so as not to stress the mpeg compression.

Heh heh... Boy is THAT the truth. At SIGGRAPH last year some guy walks up to me in a booth, working on a Prospect HD post system and he looks at it and is impressed...then he asks if it's compressed. I tell him yes, and he says there's "...no way I could work with compressed post." Then I asked him what he was shooting on...he says HCDAM. I pointed out that HDCAM was compressed and he got a little snooty "No, I don't think you UNDERSTAND...HDCAM is a BROADCAST format..." I told him that he was shooting video that was being subsampled to 1440 and THEN was only 3:1:1.

...you'd think I just threw his puppy down a well.

The one thing that HDV does have going for it is that it is still a move up from SD when shot skillfully...it will be around for a while and I suspect most of us will be watching it on television at some point no matter what anyone says.

With the Panasonic 200 camera...keep in mind that the Varicams that I've seen have optics on the front that cost as much as a cartload of these new DVX200 cameras... Thinking that the image quality will be equivalent is probably optimistic.

Interestingly, I see most users judging potential P2 capacity based on 100 Mbits/sec. It's important to note that when you're shooting 24p with the Varicam on tape that the camera still records 60p to the cassette, and you simply playout 24 frames...40% of 60 frames...therefore your net bitrate is actually 40 Mbits/sec. P2 cards will actually record using only active frames so your net bitrate on the card is actually 40 Mbits/sec...making about 2.5x the capacity on a P2 card that most are thinking they would have at 100 Mbits/sec.

A lot of "problems" with HD are hidden by it's higher resolution. You can get away with more artifacts as they're a quarter of the size on screen, and most screens can't show the ful detail anyway. That's how HDCAM got away with it - the CRTs people were viewing it with just don't show enough detail for you to easily make out it's issues. The same applies to all the HD formats.

That's not to say that moving to higher resolutions is bad. I just get frustrated that the move to higher resolutions means more and more visible compression than DV which was thought of to be strictly the lower limit of what is acceptable in SD terms.

That doesn't mean I won't like or use affordable HD formats, but I'm going to be writing a lot more de-artifacting code.....

Graeme

cheers to graham
 

and we thank you for it. Your filters have helped my workflow to DVD be faster and cleaner.

lewis

Tim, can you quickly explain what active frames are about?

Active Frames is what Panasonic calls the actual frames you are using when you play back. On a Varicam, you always shoot 60p. When you tell the camera you're shooting 24p, you play back 24 interpolated frames from the 60p stream.

The 100 Mbit/sec data rate for DVC ProHD is based on 60p, if you are only using 24 frames, you are using 40% of the 60 frames/sec you were shooting...those 24 frames are the "active" frames.

On P2, the nice thing is that the card is dynamic enough that it can restrict recording to the active frames only. If you are shooting 24p, this would mean that your effective data rate is actually more like 40 Mbits/sec, giving you 2.5 times the space on the P2 card when you compare it to 100 Mbits/sec.

I should've said "duration"...obviously the data space is the same, but the record length attainable is 2.5X vs 100 Mbits/sec

Tim: I can see how this would apply when shooting at 720p resolution, but what about at 1080p? If the normal frame rate for the HVX200 at 1080p is 30 fps, would the data rate at 24p be 24/30 * 100 Mbps = 80 Mbps?

The 1080p/i DVCproHD codec is different to the 720p one, and can't be fooled into doing the "active frames" trick, and always records at 100mbps, hence 1080p24 is recorded as 1080i60 with a pulldown pattern, which is a shame really....

Graeme

Bump.... Was that the sound of a P2 card suddenly bloating?!!

I agree. I think that mant users will end up working with 720p with the DVX200 camera as data space is (of course) pricey.

Or...there may be some Hard Disk acquisition solution soon that will be appropriate. Stay tuned...

Firestore has already announced that they'll offer a drive-based recording solution for the HVX200, but I don't think this will entirely solve the recording expense issue for this camera. Panasonic says to figure about 1 GB/minute for full-bandwidth HD recording, which means an 80GB Firestore with an expected retail price of $2000 would only hold 80 minutes of footage. Given that, the option to record at 720p/30 with a bandwidth of 50 Mbps or 720p/24 with a bandwidth of 40 Mbps would still be useful even with the hard drive option. Otherwise, you'd need a stack of Firestores to get through any long event, and that would cost more than the camera itself.

I suspect that FireStore won't be the only option out there for long...though I doubt that you'll find many less expensive options any time soon.

Yes that's true, and that is why I'm so thrilled with my HVR-A1. It looks just incredible on even the biggest home TVs, and yet cost me less than $3000! Yeah, I could get a better picture if I rented a varicam, but I'd be scared to do the things I do with my A1 like shooting from ultralights, powerboats and rollerblades! With an H1 mounted in a Fig Rig with a decent shotgun mic clamped onto the circle, you can get quality like this for under two grand! The high end HD cameras are fine and at a certain level of production you need this kind of tool, but for the regular TV set projection that most of us watch anyway, you can get most of the way there for a whole lot less!

There is also the 4:4:4 Uncompressed Andromeda mod for the older DVX100, whenever Reel Stream is ready to start taking orders.

HDV / HD resolution
 

Reading through this thread has been interesting, but I have a question relating to David Newman's post (page one, sixth post). I was unaware the the resolution is different for 720 HDV and 720 DVCPRO HD. He quoted it as 960x720 for the HVX-200 using DVCPRO HD, versus 1280x720 for HDV. Can someone expand upon this and its significance ?

Yes, DVCProHD uses non-square pixels to record and output a 16x9 image using 960x720 pixels for 720p and 1280x1080 pixels for 1080i/p. This means the pixels are "squished" horizontally for recording and then "stretched" to yield the proper display ratio at output, so the image ends up looking normal when it's displayed. This is similar to what happens if you use a widescreen project setting for an SD DVD, which has 720x480 pixels regardless of whether it's widescreen or not.

The point of doing this is to reduce the number of data points being recorded to help squeeze an HD image into the amount of available recording bandwidth, which is just a small fraction of full uncompressed HD. HDV uses compression between frames to cut the data rate still further, but in the process manages to reduce the need for the sort of horizontal compression used by DVCProHD. One consequence of this is that DVCProHD has a lower theoretical maximum horizontal resolution compared to HDV, which helps explain why the HVX200 is reportedly yielding less measured resolution in camera comparisons than the Canon XLH1. But there are a variety of complicating factors in all of this, so it's not a simple matter of counting pixels to determine resolution.

Its been awhile since this thread was posted to...

How does XDCAM compare to HDV? ie: Between the Sony EX1 (XDCAM HD) and the Z7 (HDV)?

Is there much difference, especially when using it for consumers Hi-Def TVs?

Could either be used for film?

Just wanted to add some links to this sticky--been researching HDV vs. DVCProHD the last few days and figure other folks could benefit from these articles I've been reading.

These two articles compare four prosumer cameras (two HDV, one DVCProHD, and one DVCAM) against each other and the more expensive CineAlta and Varicam cameras.
http://www.adamwilt.com/HD/4cams-part1.html
http://www.adamwilt.com/HD/4cams-part2.html

This article deals specifically with pixel shifting technology but has some good tables comparing the various different video formats.
http://www.martin-doppelbauer.de/video/indexEN.htm

This article is specifically related to DVCProHD and the HVX200A
http://www.dv.com/columns/columns_it...leId=193001363