Question about 1440 x 1080

[Bryan Daugherty]

Originally Posted by Gene Gajewski

Umm, I think some (all?) of the consumer AVCHD cameras use full 1920x1080 sensors. No?

It's just HDV that does 1440X1080.

No. This statement is not true at all, and even though many of the newer cameras (consumer AVCHD) talk about megapixel chipsets those are packed into tiny chips that get very poor amounts of light compared to 1/3", 1/2", and 2/3" chips. Here is an article on the Videomaker .com website that pertains to this issue but for most cameras you will have to search model by model to find specific sensor pixel counts.

State of Imaging - on Videomaker.com -article 13054

The output may be 1920x1080 but the imaging sensor often is not. Here is a quick excerpt from the article with a few examples:

"...The Canon XL H1 has three 1440x1080-pixel sensors, the Sony HVR-Z1 has three 960x1080-pixel native sensors and the Panasonic AG-HVX200 has three 960x540-pixel sensors, yet they are all capable of reproducing 1080i (1920x1080-pixel) video. Each camcorder is capable of doing this by a measure of multiple technologies and algorithms that include pixel shifting and pixel interpolation..."

[Robert M Wright]

It should be noted that just because a camera records 1080 lines of video, that doesn't mean that the realistic resolution is that high. HD cameras vary considerably on realistic resolution (in the neighborhood of 600-800 lines is pretty common). It's pretty well known that 1080i out of an XL-H1 is sharper than 1080i out of an HVR-Z1U or HVX200, for example.

[Brian Boyko]

Originally Posted by Sean Lee

Thanks so much brian. It makes sense now.
So, if I shot 16:9 on SD miniDV, for the Setting on Final Cut, I should choose "DV-NTSC Anamorphic" instead of "DV-NTSC" or "DV-NTSC Firewire Basic"?

And, can 1440 x 1080 mix up with 1920 x 1080 on a same timeline?

I may have gotten the technical details wrong, but I think that explains it.

I'm not as good with final cut, but I'd try DV-NTSC Anamorphic, or a pixel ratio of 1.2. Usually I just capture as 4:3 and use the Motion tab to stretch out the video to the full 16:9 when rendering.

1440x1080 can, indeed, mix up with 1920x1080 on the same timeline so long as they are the same framerate.

[Bryan Daugherty]

Originally Posted by Robert M Wright

It should be noted that just because a camera records 1080 lines of video, that doesn't mean that the realistic resolution is that high. HD cameras vary considerably on realistic resolution...

Robert, that is a great way to sum it up. I could not think of the words to say it so succinctly. The vid clip (I linked earlier) from Vortex Media is very interesting, and goes into good detail in comparing HD, HDV, and XDCAM but it is also over an hour long...

Additional thought... It is similar to taking a wallet sized image in photoshop and blowing it up to an 8x10. The results will vary depending on the subject you are shooting. Low detailed moderate contract images will probably print out fine but the interpolation algorithms will have a harder time making the enlargement of more detailed, higher contrast images, resulting in softening as the contrast lines get muddied...

[David Heath]

Originally Posted by Gene Gajewski

Umm, I think some (all?) of the consumer AVCHD cameras use full 1920x1080 sensors. No?

It's just HDV that does 1440X1080.

Whilst AVC-HD may enable the recording of a 1920x1080 signal, virtually none of the cameras that use it are capable of doing justice to the recording format.

At the more expensive end, the HMC150, the sensors are 960x540 like the HVX200, so even after pixel shifting it's resolution is only about 1200x650. You're actually better off recording in 720p mode - it maintains the front end resolution, and does a better job of compression.

At the cheaper end, single sensors may indeed have many million of pixels, but simple numbers don't always tell the full story. Take account of de-Bayering and downconversion and you're likely to not have the reolution first hoped for, and a lot of nasty aliasing as well.

At least with 3 1440x1080 sensors, recording to HDV, you know where you stand.......

[David Heath]

Originally Posted by Bryan Daugherty

The output may be 1920x1080 but the imaging sensor often is not. Here is a quick excerpt from the article with a few examples:

"...The Canon XL H1 has three 1440x1080-pixel sensors, the Sony HVR-Z1 has three 960x1080-pixel native sensors and the Panasonic AG-HVX200 has three 960x540-pixel sensors, yet they are all capable of reproducing 1080i (1920x1080-pixel) video. Each camcorder is capable of doing this by a measure of multiple technologies and algorithms that include pixel shifting and pixel interpolation..."

And that is a very misleading statement, if not downright untrue. None of them even make a 1920x1080 recording.

What is true is that those three examples of camera may well give recordings of pixel dimensions 1440x1080 (1280x1080 for the HVX200) but what the actual sharpness of the image is is totally unrelated. Just as Super8 film blown up to 35mm won't look as sharp as if it was originally shot on 35mm.

Pixel shift is generally reckoned to give a resolution enhancement of about 1.5x for luminance. So if used horizontally, can indeed give 1440x1080 from 960x1080 chips. But if used horizontally AND VERTICALLY (as with the HVX200), the improvement is spread between the two axes, so about sq rt 1.5X (about 1.2x) on each axis. Hence you can expect performance relating to about 1200x650 from the 960x540 chips referred to.

[Bryan Daugherty]

The three examples of camera given are an excerpt from the article linked in that post. I never said they make a 1920x1080 recording in fact if you read the thread you will see that was precisely my point. The output resolution in the NLE is 1920x1080, but the recording is smaller and the chips are even smaller than that. If it came off differently than I am sorry for the confusion but you and I were saying similar things...

[Gene Gajewski]

Originally Posted by Bryan Daugherty

No. This statement is not true at all, and even though many of the newer cameras (consumer AVCHD) talk about megapixel chipsets those are packed into tiny chips that get very poor amounts of light compared to 1/3", 1/2", and 2/3" chips. Here is an article on the Videomaker .com website that pertains to this issue but for most cameras you will have to search model by model to find specific sensor pixel counts. ]

We *are* talking AVCHD cameras here, aren't we. There's little reason for them not to - withing reason of course - depending on the class of camera and it's intended market/usuage. DOF is a issue - but then you'd be better off buying a canera with a removable lens.

The output may be 1920x1080 but the imaging sensor often is not. Here is a quick excerpt from the article with a few examples:

"...The Canon XL H1 has three 1440x1080-pixel sensors, the Sony HVR-Z1 has three 960x1080-pixel native sensors and the Panasonic AG-HVX200 has three 960x540-pixel sensors, yet they are all capable of reproducing 1080i (1920x1080-pixel) video. Each camcorder is capable of doing this by a measure of multiple technologies and algorithms that include pixel shifting and pixel interpolation..."

And these are HDV camera's.

[Robert M Wright]

Even a camera like the EX1 (with three 1/2" 1920x1080 pixel sensors) doesn't resolve 1080 lines (but it is dang sharp). Hopefully, in the reasonably near future, we'll see a camera on par with the EX1, that records AVCHD (on cheap cards).

[David Heath]

Originally Posted by Bryan Daugherty

If it came off differently than I am sorry for the confusion but you and I were saying similar things...

Any criticism wasn't directed at you, but rather the article, sorry.

Originally Posted by Robert M Wright

Hopefully, in the reasonably near future, we'll see a camera on par with the EX1, that records AVCHD (on cheap cards).

But why should we want it? Use MxR adaptors and the EX can use exactly the same SDHC cards that you refer to for recording AVC-HD. My own experiences are that 35 Mbs MPEG2 is better quality than 21Mbs AVC-HD, whilst being far easier to edit. OK, up the AVC-HD bitrate and quality might achieve parity with the EX codec, but the effective need to transcode to edit remains. So why not just say stick with MPEG2 for a number of years, until processing power is more able to cope with AVC-HD.

The initial impetus behind AVC-HD was indeed given as "it's the only way we can record decent quality to cheap cards". Those people who so cleverly found out how to use SDHC cards reliably in an EX seem to have whipped the carpet out from under that argument......

[Robert M Wright]

The main reason I'd like to see an AVCHD camera, with comparable imaging to an EX1, is the considerably smaller size files needed to archive original footage. I'd also rather use recording media that the camera was designed to use, rather than hacking the hardware (that could easily be disabled by a firmware "upgrade" from Sony). It's not likely we will see such a camera real soon. By the time we do, editing AVCHD should be as smooth as editing MPEG-2 is today (probably smoother).

Octa-or-more-core processors, that are even more efficient per core than an i7, are not very far off really. We're also on the verge of seeing 64bit computing, as well as the power of massively parallel processing GPUs, finally being effectively unleashed for video editing and encoding purposes. More than an order of magnitude leap in performance seems pretty likely in the next 2-3 years.

AVCHD at 24mbps is certainly potentially capable of image quality performance that's at least on par with 35mbps MPEG-2. I was just looking at some footage out of a TM300, with a lot of motion, the other day. The image compression quality is pretty dang good (way better than HDV). Real-time AVCHD encoder chips are are coming along nicely (and will get better), while MPEG-2 encoding technology has pretty much peaked.

[Bryan Daugherty]

Gene- I quoted from the article linked and yes those are HDV which is where the 1440x1080 format comes from which is the topic of the OP, so i was trying to come back around.

David- Didn't take it personal, just hoping I didn't muddy the water with my statements.

I am with you David, on the XDCAM EX format. Lots of improvements over anything else out there at this time. From what I understand the new JVC XDCAM's come with SDHC slots already and the SxS slots are an add-on, though I am a fan of SONY it is an interesting development especially in tapeless acquisition.

[Gene Gajewski]

I don't think MPEG-2 is going away anytime soon. For one, it's a broadcast standard that's going to be with us for many years.

Secondly, AVCHD is great, but not *that* great - it's needs to be a couple of orders of magnitude better than MPEG-2. In the consumer market - it makes sernse in some areas - but why bother in the professional market. The space savings is good, but not so much that you'd trade everything for it, and you're probably going to go for something easier to work with on ingest.

Of course, increased processing power allows us to do things we couldn't efficently do before - and we can expect AVCHD to be easier to work with. But with storage getting ever cheaper - why waste the cycles - which could be put to better use.

2 cents, etc....

[David Heath]

Originally Posted by Robert M Wright

The main reason I'd like to see an AVCHD camera, with comparable imaging to an EX1, is the considerably smaller size files needed to archive original footage.

I just don't see the file size as that much of a problem. I'll agree that very roughly 25Mbs AVC-HD may correspond to 35Mbs XDCAM-EX for quality, but that only equates to corresponding file sizes of 50MB v 70MB. Given the far greater difficulty of editing AVC-HD, the file size gain just doesn't seem worth it. If AVC-HD really had meant you could use SDHC, stick to MPEG2 and you can't, it would be a different story, but recording XDCAM-EX to SDHC has totally blown that argument.

And yes, the JVC cameras shoot 35Mbs MPEG2 to SDHC natively, as they are designed to do. I don't feel too worried about future disabling of EX cameras regarding SDHC use. Sony haven't said much about how they feel about the situation, but a UK magazine recently published an interview on the subject where they did comment publicly. They didn't endorse the use of SDHC cards as such, but the interview was as interesting as much for what they didn't say as what they did. Most people have come away with the impression that they are far from antagonistic to the use of SDHC cards. Even if they DID block the use of MxR adaptors by disabling the USB bus, there seems nothing to stop a future adaptor making use of the PCIExpress interface to feed a SDHC card. Quite simply, the genie's out of the bottle.

OK, never say never, and in years to come then maybe AVC-HD will be as easy to edit as MPEG2 is now, but maybe by then we'll be looking towards some even newer and better codec, maybe wavelet based. In the meantime, the bitrate savings of MPEG4 may be well worthwhile for transmission, but much less so for acquisition.

[Robert M Wright]

Cineform proved the advantages and commercial viability of a wavelet codec, at least for intraframe only compression, a few years ago now. I'm a little surprised at Panasonic, for introducing AVC Intra, well after that, as their codec of the future. I would think a Cineform like codec would be a vastly superior choice. At similar bitrates to AVC-I, the image quality is excellent (dang near lossless, for practical purposes) and it takes far less CPU power to encode (and decode). That should translate into encoding chips (for in-camera video compression) that use less power and generate less heat. Add to that faster performance on editing machines, and it sure sounds like a real winner all the way around, that might have moved Panasonic well to the front of the pack.

AVCHD may only be lighter than XDCAM-EX by about 30% (as far as file sizes), but that's not a small issue, in my mind. When I go tapeless I expect I will probably wind up generating a lot more footage than I do now, and I just can't bring myself to throw away any footage I shoot of my parents, kids, grandkids, or even my dog (who is perhaps the most entertaining member of the family!), as well as of friends, etc. I look forward to not having the expense of tapes, but I'm likely to wind up buying a heck of a lot of Blu-Ray disks.