Will we ever see 4:2:2 HDV?

It is my understanding that the 4:2:0 color sampling of HDV is a limitation of the MPEG2 encoding process. Now, am I way off on that? I fail to get to excited about a 3 chip HDV camera if the color sampling doesn’t improve to 4:2:2 along with it. Is there any speculation out there of a 4:2:2 HD solution to be released in the future?

As usual, Thanks for the info.

-e trane

Your speculation raises an excellent question.

Sony called what they will do -- HDV2. Sony said it would have a higher data rate than 25Mbps.

These comments from Sony, lead me to speculate that "HDV2" might be 4:2:2.

And, that's because the additional bandwidth would allow greater chroma rez.


Best Regards,
Steve Mullen
Digital Video Consulting NYC
http://www.mindspring.com/~d-v-c
----------------------------
"GR-HD1 and JY-HD10 HDV Shooting Guide"
HDVcinema Partner -- Real-time HDV Editing in FCP in cooperation with the Heuris Indie HD Tool

Lorin,

Forgive me, but I find your facts somewhat questionable. I do not believe that any DV50 format utilizes MPEG2 as a compression scheme. If you have facts from a reliable source that proves otherwise, I would be interested in seeing them. Or if anyone else can correct me on this, I will retract that statement.

I also do not think that HDV is trying to specifically address the consumer market alone. It is trying to be a low-cost solution for HD, which hardly limits it to the consumer marketplace. JVC even considers the JY-HD10U a professional camcorder. (Though I’m sure their choice to consider it as such could be arguable). The speculated price tag of a 3 chip HDV camera will clearly place it out of the reach of the consumer market.

Color sampling is not my only measure of quality, but it is a very BIG one. My point was simply that the presumed price tag of the 3 chip HDV camera, with out an increase in color sampling quality, would not be worth my investment. This is because color sampling is so crucial to the overall quality of the image, more so even than lines of resolution. That is just my understanding and opinion however, and I’m sure others might feel differently. Again if proven otherwise I will gladly retract the statement.

For those using Standard DV (by that I assume you mean DV25), the current HDV offering is quite compelling. For those of us using higher quality DV50 cameras, it is not. Currently the extremely expensive “Pro” HD cameras are not an option for us either. We are talking about a price range around the $20k mark for the prosumer market. My question was specifically trying to deduce whether or not HDV was going to provide prosumer quality HD video at a prosumer price, or whether we would be waiting for some other technology. It is my opinion that 4:2:0 color sampling does not constitute “prosumer quality”.

If, as Steve suggests, the color sampling is a limit of bandwidth and not a natural limit to MPEG2 compression, then I have no doubts that the prosumer’s needs can be met by HDV in the future.

Steve,

Thank you for the information. I find these speculations to be quite encouraging!

-trane

Steve,

Thank you for the clarification. What you say makes sense to me, and I sign on to the speculation that this will be the way things go.

In rereading my post, I also want to apologize for my loose use of the term "prosumer". The reality is that this term is fairly relative and carries different weight for different people. As such it is not fair of me to base my arguments on my interpretation of the term.

The only point I really want to drive home, is my opinion that a speculated $20k price tag had better bring me 4:2:2. I simply won't pay $20 grand for 4:2:0 material. Oh, and that the prospect of HDV-Pro (a good name for it if it happens in the future) gives me goose bumps :)

-trane

SPECULATION

Sony and Panasonic are losing their ability to dominate the HD camera market. Their monopoly on camera recording is over. One TB hard drive costs nearly nothing and you can put 5 hrs of CinaAlta recording on it, at 24p. The blue laser burners will soon be available to every manufacturer. Signal processing is getting inexpensive, physically small and low power consuming. No one has monopoly on that. Sony and Panasonic no longer have CCD sensor monopoly. New CMOS is just as good. By NAB 2005 there will be megapixel CCDs available for still magapixel cameras that will also output 720/30p. So unless Sony comes out with some propriatery format that takes off soon, and which will become a standard, they will lose their competitive edge in this field. So will Matsushita.

I think that the majors are under a serious pressure to come out with quality affordable HD cameras soon. If they do not, Samsung will soon OEM to Sony not only flat panel displays but also lisense them their HD camera technology that I'm sure they are developing.

I think that Sony and Matsushita are seeing the writing on the wall and will act. I'm sure that XDCAM is made in such a manner, as to convert it to HD the easiest way. I'm sure that they can double the heads on HDV, double the tape speed, and get 50 Mbps stream on it. No big deal.

Will they offer 4:2:2 on HDV? I don't think so. Not even their CineAlta camcorder is 4:2:2. It's 3:1:1. That camera head's uncompressed output can now plug into the new SR VTR, via MPEG4 encoder, so it just moved into a different class.

So I think that Sony will spread itself in the following way by NAB 2006. How much of that will be available this year is to be seen:

- F1000, 4:4:4, with 35 mm CMOS chips, available at NAB 2006 $300K
- F950 camcorder, MPEG4, 4:4:4 available at NAB 2005, $200K
- F950 with SR VTR, MPEG4, 4:4:4 available now, approx. $200K now
- F900 with SR VTR, MPEG4, 4:2:2 available now, approx. $200K now
- F900 3:1:1 has been available for several years $100K
- 2/3" HXDCAM, 144 Mbps max, MPEG2 or 4, 4:2:2, available at NAB2005, $50K
- 1/2" HXDCAM, 72 Mbps max, MPEG2 or 4, 4:2:2, available at NAB2005, $25K
- 1/2" HDVCAM, 25 or 50 Mbps, 4:2:0, MPEG2, available at NAB 2004, $12K
- 1/3" HDVCAM, 25 or 50 Mbps, 4:2:0, MPEG2, available at NAB 2004, $6K
- 1/3" HDV, 25 Mbps, MPEG2, 4:2:0, available at 2004 Summer CES, $4K

These are just some very rough estimates. Of course there may be more varsions of HDCAM, etc.

With 50 Mbps and MPEG2 encoder you can make pretty decent low end indie digital cinema camera.

Steve,

I see. I think I understand now. Were you then speculating that the “HDV2” format will be a Sony proprietary HDV format, and that based on comments made by Sony (suggesting this format would have data rates higher than 25 Mbps) that it is a possibility this format maybe be a 4:2:2 format?

Should Sony deliver such a format, is it possible then that will that put a 3 chip, 16/9 HDV (HDV2 rather), 4:2:2 camera on the market for under $20 grand some time this year? Clearly, this is a speculative question.

-trane

Mr. E.T.:

I'm on your side! I do long for the better color resolution that we will eventually see out of variants from the HDV trend. At the moment I'm also sold on HDV being an excellent near-term solution, even though nobody is yet extending the spec to offer 4:2:2. That's the real message I was trying to convey in my post. HDV is great as-is for now, and due to get better over time. I wanted to bring to light the fact that MPEG2 can do 4:2:2, so we've got quite a future in this format.

[Mr. E. Trane] "I do not believe that any DV50 format utilizes MPEG2 as a compression scheme. If you have facts from a reliable source that proves otherwise, I would be interested in seeing them."

I apologize, I was wrong. In an article that I read it had compared these three 50Mbps formats as being recorded very similarly to a stream of MPEG2 I-Frames. I had remembered the codecs mentioned, and MPEG2, and had mentally associated them. Now that I've done more research, I wish to retract that statement. My fault.

Nonetheless, MPEG2 really does do 4:2:2. Here's a website which digs into more of the details, including color subsampling options:

http://wwwam.hhi.de/mpeg-video/papers/sikora/mpeg1_2/mpeg1_2.htm

I wish the rest of the information from my post had been more meaningful. We really are gaining quite a bit more color detail in HDV. Did the color resolution analysis make any sense at all? The main message there was that with 720p, basically you can scale down the image to get 640x360 at 4:4:4. In other words, use a good quality HDV camera as a high-quality source, and end up with fabulous widescreen NTSC. So the current JVC cams don't offer the best color... but with the (rumored) 3CCD camera that will show up at NAB this year, we've got a killer format we can use now to release high-quality material on standard DVDs, and capability to release the same material in the future on HD DVD.

[Mr. E. Trane] "I also do not think that HDV is trying to specifically address the consumer market alone. It is trying to be a low-cost solution for HD, which hardly limits it to the consumer marketplace."

True for now. The statement you are referring to is one I had made regarding the ultimate outcome of HDV -- "In the long run, HDV is really trying to address the consumer market, not the pros." As for near-term use, I had made the statement, "the thing that makes HDV compelling in the near term to users of low-end pro gear is resolution.". So yes, for now it's great for the pro-sumer. Groundbreaking even. And that's what I want to convey more than anything else. In the long run I expect we will enjoy a decade or more of utility out of this format, so in a few years it will end up being primarily a consumer-grade format, just like DV is today. At that point in time, I expect the pros to embrace better variants of HDV that use higher bitrates for 4:2:2 and 1080i recording. (1080i needs it more than 720p since it's more suceptible to macroblock artifacts in high-motion scenes.)

Who knows... Based on Steve Mullen's comments as of late, perhaps higher-end variants of HDV will be announced by Sony sooner rather than later! Would be nice to lay out the roadmap of HDV for people and show that it really has a strong future.

-Lorin

[Mr. E. Trane] "On the color resolution analysis, I think I understand what you are saying here, but I’m not sure I quite understand the math... if you downscale the HD image to SD, you’ll end up with a 4:4:4 image and that this is possible because HDV has more chroma detail than SD 4:2:2. Maybe you could clarify this for me a bit..."

Sure. You've got the idea. Start with 1280x720 and downsize by some whole number amount to achieve the least loss possible during the resize. I'm advocating dividing by exactly 2 here in each dimension. Now we aren't ending up with a full 720x480 resolution, so there still is a sacrifice in resolution compared with a true high-end NTSC cam. But overall you end up with some danged great 640x360 30 or 60fps progressive video. Better than DVD quality since after the resize it ends up being 4:4:4 sampling. It has still gone through the MPEG2 compression process, so you will have slight macroblock artifacts in high-motion scenes, but it's quite bearable. It could be stretched in width from 640 to 720 pixels to accomodate the NTSC aspect ratio, and put on a DVD with excellent results. When you divide both the vertical and horizontal resolution exactly in half, the result is that every 2x2 block of pixels from the original becomes one pixel in the result. Lots less luma noise since you're averaging four values together. And since color is sampled precisely once in every 2x2 block of pixels, each pixel in the result also ends up with its very own chroma info.

For a fun experiment, try doing this with today's GR-HD1 cam. You're averaging luma down 4:1 in the process, so much less of that camera's grain in those low-lit scenes. As well the camera already has somewhat washed out color, so it won't be outstanding, but still usable. You can start to appreciate where this format can take us with this kind of experiment. I imagine if you do that with a good 3CCD HDV cam then you should be able to get similar results to a high-end NTSC cam, but without spending that much money. Okay, you'd still lack a black balance adjustment, and some depth of field, and you're limited to letterboxed 640x360, but it's 4:4:4, and better than pro DV for the same price. Video you release now in high-quality NTSC can later be re-released in 720p.

For upcoming cams that do 60fps, you can use NTSC's interlacing to your advantage by taking out every even-numbered scan line on odd numbered frames, and vice-versa for even-numbered frames. Weave sequential frames of this "bob'd" video together, and you have true 60 field per second interlaced NTSC with great quality. All this pixel shifting madness is fairly easy to accomplish in the PC world using the freeware AVISynth program. To feed AVISynth, use the version of VirtualDub that reads MPEG2, and set it up as a frame server. The output then gets cranked through the AVISynth script, and finally put through a lossless compression like HuffYUV. Stellar NTSC results on a $10K budget, and HD leftovers for later. Now we just need someone to release a 720/60p 3CCD HDV camera!

-Lorin