Undocumented 24F takes advantage of the various features in the camera. Magic Bullet claims to "unique combination of field based pattern matching and motion compensated deinterlacing techniques delivering the sharpest results on the market".

Which is better?

In the European Broadcasting Union they've had a long debate of the HD standards, and the question of compensating deinterlacing is one of the issues. Technical people do seem to agree that none of the deinterlacing compensation techniques are fully satisfactory.

As a rule of thumb one could argue that the best choice is a progressive CCD, then the second best alternative is a solution embedded in the camera such as Canon's 24F, and the post processing strategy is the one thereafter. This argumentation relies on the assumption/fact the there is more information available in the camera than what one can gain from the image produced by the camera.

Although, pre-compression, the camera has more information, it is also processing in real-time and would be dependent on the algorithm. I thought for the Sony's, post-processing was preferred. In the Canon, the CCD has higher resolution, however the 24F reduces the resolution significantly. Is there a clear answer for this camera?

No it is not reduced "significantly." Have you looked at any of the sample clips provided here on an HDTV?

I believe the reviews have indicated it is about 540 line resolution, vs 1080 interfaced and 700 or so for the HD100. The 540 lines I believe was similar to the HVX200.

I thought the BBC always used software for a 24p conversion, and the Cineform site references Magic Bullet and DVFilm Maker several times. Has someone done tests with post-processing software vs the Canon 24F mode?

Have you looked at any of the sample clips provided here on an HDTV?

I've looked at the sames in the two shootouts on my 1600x1200 monitors. With a lot of those images, it was hard to tell from the review whether it was 60i or 24f, and whether it was from the HDV tape of HD-SDI output.

Do you know of some definitive images for comparison? What are we looking at in this-- http://i.cmpnet.com/dv/magazine/2006/June/TX-64-XLH1.jpg -- 1920x1080 image?

that is a 60i image. You can see the interlacing in the girls hair.

The only problem with deinterlacing 60i in post in the fact that 1080i video is filtered to about 810 lines. I do not mean there is a 1920x810 image but the amount of detail is equal to that of 810 lines. If you deinterlace this each field actually only has 405 lines of detail compared to 540 from Cineframe and the any where between 540 and 810 lines for 24F. Unless you use a tool that is very very slow to try and rebuild the detail you are only getting 405 lines of detail per field. This isn't really such a bad thing but it does show that even if 24F or 30F is only getting 540 lines (which I think it is getting more depending on the color of the scene) it is still better than 405 so maybe it isn't such a bad thing.

The other thing you have to think about is aliasing artifacts. With a normal deinterlacer you will end up with odd edge artifacts, shimmering details and thin lines that flash on and off. 24F and 30F seem to not have these issues. While the resolution may be lower it doesn't look like deinterlaced video. There are no thin object artifacts because any of those problems are not captured in the first place in the camera. You will end up with a very clean overall pleasant image no matter what level of detail or motion is in the scene.

Something else to think about is the fact that 24F and 30F use a true progressive mpeg2 encoding with a chroma pixel block of 2x2 pixels. Interlaced mpeg2 has a really messed up form of 4:2:0 where each field has a chroma with a kind of a 2x4 pixel block. The chroma samples alternate on the fields which can make a huge mess. When you discard a field with interlaced mpeg2 video the chroma really suffers. Using 24F and 30F will give you a much more natural form of 4:2:0. Since 4:2:0 duplicates the chroma every other line 24F HDV doesn't really loose any chroma detail compared to 60i anyways. Both formats would loose the same amount of chroma. The only thing you really gain with 60i HDV is luma detail.

Was the image captured from HDV tape or directly with HD-SDI?

I thought that Canon stored the image with a 2:3:3:2 pulldown. Doesn't that waste a lot of the bandwidth?

Magic Bullet and DVFilm Maker both claim to have algorithms that look at all of the lines to synthesize the missing information. Howerver, I don't have any experience with them.

That image shows much more detail than the 1280x720 HD100 image in the attached blowup. If vertical resolution is only 810 lines, and the HD100 is around 700 lines, why is the difference so large? Was it HD-SDI vs analog component HD? Was it compression algorithms to tape? Was it a different focus (the HD100 image seemed to have leaves behind the subject in focus, that were out of focus on the H1)?

Was the image captured from HDV tape or directly with HD-SDI?

I thought that Canon stored the image with a 2:3:3:2 pulldown. Doesn't that waste a lot of the bandwidth?

Magic Bullet and DVFilm Maker both claim to have algorithms that look at all of the lines to synthesize the missing information. Howerver, I don't have any experience with them.

That image shows much more detail than the 1280x720 HD100 image in the attached blowup. If vertical resolution is only 810 lines, and the HD100 is around 700 lines, why is the difference so large? Was it HD-SDI vs analog component HD? Was it compression algorithms to tape? Was it a different focus (the HD100 image seemed to have leaves behind the subject in focus, that were out of focus on the H1)?


No the pulldown doesn't waste bandwidth at all. In fact it is the only 1080i HDV format that saves bandwidth. The pulldown is added during output. On the tape it is a true 24 fps mpeg2 video. That is why so many NLE's have problems with the format. Canon went with the method of mpeg2 that gives the highest quality but is a very special form of mpeg2. The pulldown is just duplicate flags that do not take any bits. Therefore you have that many more bits per frame. SONY wastes bandwidth by putting their 24 fps format with the pulldown built in into a 60i video. Even though many fields are duplicates the encoder and decoder treat them as whole new fields wasting bits to encode the same thing twice. Since the 60i encoder doesn't even know some of the fields are duplicated it treats everything as a whole new frame and encodes it like that.

A very good (but slow) method such as DVFilm Maker can do a fairly good job at trying to make up the missing detail but it isn't perfect. Even if it does a very good job it is very slow. It is much easier and faster to just deal with the 24F and edit in a 24p project and be able to output right to your final format as 24p.

One other advantage to using 24F is the fact that you are shooting in a 24fps and can tell if a shot is working while you are shooting. If you shoot at 60i a shot may seem to work but when you convert it to 24p it may not work exactly the way you wanted it to. By shooting with 24F you know exactly how the motion will turn out and get the exact look you are looking for ir terms of pacing and motion smoothness.

About the 810 vs 700 lines. The reason is because you are looking at objects of two different sizes. You have to either scale up the 720p video to match or scale down the 1080i to match. You will see that they are fairly close when you do this. While there are only 810 lines of detail it is still sitting inside of 1080 lines so it can look like there is more detail there because the lines get blended together. Resolution isn't everything either. There are a lot of other facets that make up video quality. Take the sample images that you are looking at. Every image in those tests except for the JVC images are from a 1080i camera. While those images all share 1920x1080 pixels you can tell that some have more detail than others. A resolution test isn't going to test how many vertical pixels are in a image but the amount of detail it can resolve. How small can an object be before it starts to get blended into a blob of pixels. HDV cameras have many issues that lower the true level of detail. That is why for the most part video from the JVC camera can hold up to the level of detail from a 1080i camera. The JVC may use less pixels but it makes better use of a higher percentage of those pixels. 1080i on the other hand may waste a lot of those pixels. I say may because it is a lot more complicated than that. While 1080i may not show 1920x1080 unique pixels it does show a blended version of ????x???? which may make up a smooth image that can give the illusion of having a lot of detail. For example on a 720p image a tree turnk may be 4 pixels wide. on a 1080i image that same tree trunk may be 6 pixels wide. While those 6 pixels may be a blended version of the 4 pixels it still looks like the tree has more pixels. the 720 blown up to 1080 depends on math to interpolate the in between pixels. The 1080 uses physics and laws of nature to come up with the in between detail which to some people may give a more natural realistic look even though it may not have more detail.

Those images were different sizes because the they had different numbers of pixels. The detail in the black strip and the shades in the lavender strip are clearly present in the H1 image and not in the HD100.

What was unclear was if the image was recorded to tape, and which lens was used.

Does the Canon actually use that bandwidth when it marks the frames duplicates? How is that done...or is that subject for a different forum?

I image this would affect the XH-A1/G1 and HDV10 also.

Does the Canon actually use that bandwidth when it marks the frames duplicates?

The duplicates are not recorded to tape.

How is that done.

If two frames are identical, omit one and mark the other.

Best,
Christopher

I probably didn't ask the question well. Does it change the compression algorithm to use the extra bandwidth? In order to use the bandwidth, wouldn't the image have to be stored differently?

Are there screen shots on line of 24F saved to tape and 60i saved to tape? With an HD100 for reference?

Thanks,

David

For those outdoor shots, all of that was recorded to tape.

The HD100 was not a "reference" camera; it was one of several HD camcorders that we were comparing in side-by-side tests for the Texas HD Shootout back in April. Our reference camera was a Panasonic AG-HDC27H VariCam, but we did not take it to the river that day for these particular frame grabs that you're referring to above. Cameras present for that sequence of shots were the Canon XL H1 with 20x HD lens, Panasonic AG-HVX200, JVC GY-HD100A, Sony HVR-Z1U, and Sony PDW-F350 with a Fujinon 2/3rd-inch adapter and lens.

Are any of the Canon images 24F?

Are any of the Canon images 24F?At the moment, I don't have time to dig up and consult my copy of the shot list. Suffice to say that we did a little bit of everything with all of these cameras including 24F on the Canon. We're currently working on the assembly of a set of DVD data discs which will include .m2t files that you can view on an HDTV. We haven't fixed a delivery date or a price yet, but it'll be soon and affordable.

Meanwhile you can download and view a variety of 24F HD video clips from our XL H1 Sample Clips forum (http://www.dvinfo.net/conf/forumdisplay.php?f=126).

How about this for 24F resolution? Right click and save. View in QT player at actual image size (1920x1080)

Thanks, Barlow.

Do you have a 1080i version of the same image.

Chris, all of the stuff I saw on the clips had been reduced to a lower resolution.

What would be really nice is setting up an H1 and taking 1080i and 24F to tape, HD-SDI, and HD component out of the same image. And comparing them side by side.

At the Texas shootout we did this, recording 60i and 24F from the Canon XL H1 to tape and out SDI to a Mac capture station at the same time. Some cameras such as the JVC GY-HD100 do not have SDI so we captured their analog component output also while recording to tape. All of that will make it into the Texas HD Shootout data DVD set that I mentioned earlier in this thread. We'll make a pretty big announcement when it's available for sale.

Thanks, Barlow.

Do you have a 1080i version of the same image.

Here's a 1080i--Same shoot, different image:

In the real world, still pictures are not accurate to what the eye sees in motion video. Both the HVX and XLH TECHNICALLY have 540 lines of resolution by harsh analysis under a microscope. In reality, they look much sharper. Does 60i look sharper than 24F? YES, does it look dramatically sharper? Absolutely not... I would not use an external program to deinterlace, IMHO you would be losing a lot by not letting the camera do it.




ash =o)

Not to mention the fact that I've never seen 60i converted to 24p 100% flawlessly. There are usually some double frames and slight funkiness in every render no matter how short or long.

The theory is that 24F is a real-time smart deinterlace of 48i (interlace CCD's reclocked to 48HZ)--and the lack of any kind of deinterlace artifacts leads me to believe that something else might be going on. I think it's too sharp to simply be a field doubling, yet it shows no side-effects of deinterlacing.

Any alternate theories out there?

A very good (but slow) method such as DVFilm Maker can do a fairly good job at trying to make up the missing detail but it isn't perfect.

Yes, I second this. I've deinterlaced some DV footages with DVFilm and it works pretty well if the object has moved in one direction and not too much between the fields of a frame. But, for example, if there is a bird jumping from left to right and simultaneously moving its tail up and down, the output of DVFilm is quite far from perfect.

The techinical difficulty is, in 1/48 (or as in my case in 1/50) second a bird is able to move quite a lot. When there is any kind of back and forth motion between the fields while something else is moving in one direction, designing a deinterlacing algorithm is about next to impossible.

At the Texas shootout we did this, recording 60i and 24F from the Canon XL H1 to tape and out SDI to a Mac capture station at the same time. Some cameras such as the JVC GY-HD100 do not have SDI so we captured their analog component output also while recording to tape. All of that will make it into the Texas HD Shootout data DVD set that I mentioned earlier in this thread. We'll make a pretty big announcement when it's available for sale.

Did you do both HD-SDI and analog component from from the H1? A feature of the H1, G1, and HD250 is the availablity of HD-SDI. However, it seems to come with a $3k price tag. One question is: is the difference from analog worth $3k, or 75% more than the same camera/lens with just analog component out?

Output capture on the Texas HD Shootout was managed by Mike Curtis. If I recall correctly, I don't think we bothered with component output from the H1. David, if you find the $3K pricetag of SDI intimidating, then let me suggest that it is definitely not for you. SDI was put on this camera and on the XH G1 primarily to benefit small studios and production facilities that are already set up for SDI. The price difference is not just $3K, as you'll also need an SDI input on your NLE capture station plus all of the storage that uncompressed or low compressed video requires. What the difference between Serial Digital Interface and component analog is "worth," is a highly relative question that only you can answer. If the $3K difference in price concerns you, then by all means disregard it. Establish what your budget really is (for not only the camera but also its associated support, plus your editing system requirements) and work within that budget.

In other words... the cost to go SDI is not $3K but more like $5K or perhaps higher, because you've got to account for the extra cost on the capture side, not just the camera side. Plus all the extra drive space needed for video storage, which is an order of magnitude higher than what it would be for 25mbps HDV.

The cost of acquisition is about the same. Current plan would be to use Cineform ProspectHD with the AJA Xena LHe card, which takes both HD-SDI and analog component.

As a hobbiest my budget is not that fixed. Somewhat surprisingly, the early reviews of the HVX200 seemed to show that that is DVCProHD 4:2:2, as part of the overall system, didn't give it a decisive edge over the H1 or HD100. With both the H1, G1, and HD250 providing a choice, the quality is the main determinent.

How HD-SDI compares to analog component compares to HDV on the same camera is probably a key factor in my purchase decision.

But there's no advantage to analog component capture on playback... the only advantage is if you're capturing live while shooting. You're going to lug a capture station around with the camera whenever you want to shoot video? You can't do it with a laptop either. Perhaps portability and computer power availability is not a concern in your specific situation?

And yet, camera ergonomics, form factor and handling will carry a much greater impact on the quality of your video than whatever output you choose to capture from. The right camera for you is the one which feels best in your hands... that alone is far, far more important than any differences in numbers or technical specifications. Try the cameras out for yourself, instead of counting pixels on a screen.

Virtually never off the tripod. Rarely (never follow focus). The camera (to me) is all about image and to a (much) lesser extent sound. It seems that all of these cameras have similar audio recording, other than the HVX200.

Form factor is a little issue. An H1 or HD100 is more likely to get a request for a permit. With an A1 or HVX200 you could be a tourist. The A1/G1 comes either way. As does the the HD100.

The smaller size is easier to carry. However on the road the camera is way small compared to lights, C-stands, flags, etc.

Lugging around a capture station everywhere you go and finding power for it is an interesting way to shoot video. Best of luck to you.

What do you use to power your lights? The tape is the alternative when the capture station isn't available.

As far as the capture station is concerned, the Antec LanBoy case will make a nice, compact unit. Designed to be carried (to LAN parties). Even comes with a carrying strap. 16.5" x 17.5" x 8.2"...not that much bigger than a camera bag.

Image from Newegg site
http://images10.newegg.com/NeweggImage/productimage/11-129-145-04.JPG