DV Info Net

DV Info Net (https://www.dvinfo.net/forum/)
-   Canon XH Series HDV Camcorders (https://www.dvinfo.net/forum/canon-xh-series-hdv-camcorders/)
-   -   Canon A1 - Need answer ASAP Please! (https://www.dvinfo.net/forum/canon-xh-series-hdv-camcorders/77659-canon-a1-need-answer-asap-please.html)

Tyler Graas October 17th, 2006 12:12 PM

Canon A1 - Need answer ASAP Please!
 
I convinced the powers that be to buy the new XH A1. I have two questions i need quickly answered please.

1. Can the camera shoot in 4x3 standard mode? If yes, does it do it in the correct aspect ratio or does it letter box it because of the 16:9 chips?

2. Is the A1 capable of recording to hard disk?

thanks guys. I love this forum.

Tyler Graas October 17th, 2006 12:16 PM

one more sorry.

Can this camera record to regular old Mini DV? I understand the compression issues.

Chris Hurd October 17th, 2006 12:21 PM

Howdy from Texas,

Can this camera record to regular old Mini DV? Yes it can record to regular old Mini DV.

Is the A1 capable of recording to hard disk? Yes it can record via FireWire output to any of a variety of hard disk recorders such as the Focus Enhancements FireStore FS-C for example.

Can the camera shoot in 4x3 standard mode? Yes it can shoot in 4x3 standard mode. The 16x9 display shows a 4x3 image with black masks on the unused left and right hand portions of the widescreen LCD panel.

Hope this helps,

Pete Bauer October 17th, 2006 12:24 PM

HD, including HDV is inherently 16:9. But yes, you can shoot DV in 4:3 or 16:9 to tape or via 1394 (Firewire) to an external device such as a Firestore or a computer's hard disk. Enjoy!

See also (and note both the HDV and miniDV logos):
http://www.dvinfo.net/canonxh/watchdog.php

Tyler Graas October 17th, 2006 12:42 PM

THANKS!

You guys rock.

Barlow Elton October 17th, 2006 01:03 PM

Be aware, however, that shooting 4x3 with one of these cameras will *feel* much more confined, especially in wide angle shots. Essentially, the camera will crop the image to 4x3 just like you will see it in the VF, and your wide angles will simply not be as wide as 16x9. In all likelihood, you will have to back up more often to get a shot composed the way you want.

Consider getting a wide angle adapter if you are going to work in 4x3 DV.

Thomas Smet October 17th, 2006 01:34 PM

If you plan on shooting 4x3 DV then why may I ask are you buying a HDV camera of this high of quality? You could pretty much almost do the same with any level of DV camera out there right now. Unless you plan on shooting HDV but sometimes may need 4x3 video. If that is the case it is very easy and will usually look better to shoot HDV and downscale and crop to create a 4x3 DV file.

Bill Pryor October 17th, 2006 02:14 PM

I use a 16:9 chip camera (DSR500) and often have to shoot in 4:3. It's no problem at all. However, the downside is that when it crops in from left and right, you are, in effect, using slightly smaller chips. This means your lens will not be as wide as it is in 16:9 mode. Instead of about 32mm (in "real" lens terms) at the wide angle, it's probably going to be closer to 40mm (again "real" lens terms). Probably more like shooting with the Sony V1 or the XL2, both of which have lenses that really aren't quite wide enough for many things. It's something that will probably be a minor annoyance if you shoot in any cramped offices, but a wide angle adapter will make you a happy camper.

I had to shoot 4:3 for about 2 years after having a 16:9 camera, and it often made me scream obscenities. Not because of the wide angle thing, but because the world looks so much better in 16:9. Once you've been there, it's difficult to go back.

Todd Siechen October 17th, 2006 02:25 PM

When you record to a hard drive via the firewire, is the compression the same as if recoding to MiniDV tape? Is this compression quality adjustable at all? Thanx

Pete Bauer October 17th, 2006 08:17 PM

Firestore saves to a variety of formats, but HDV to a computer hard drive is a set data rate (about the same as miniDV's 13GB/hour) and is not user-adjustable.

Chris Hurd October 17th, 2006 09:08 PM

Quote:

Originally Posted by Todd Siechen
Is this compression quality adjustable at all?

It's crucial to understand that compression does *not* affect quality. You can have high compression and excellent quality, just as you can have very little compression and horrible quality. Quality is a function of the efficiency of the particular codec. Bitrate has nothing to do with it. Hope this helps,

Todd Siechen October 18th, 2006 01:50 AM

Quote:

Originally Posted by Chris Hurd
It's crucial to understand that compression does *not* affect quality. You can have high compression and excellent quality, just as you can have very little compression and horrible quality. Quality is a function of the efficiency of the particular codec. Bitrate has nothing to do with it. Hope this helps,

Actually no Chris - you have now totally confused me and everything I thought I knew about compression and how I thought it affected the quality of my images and video. You state that compression does not affect quality. Now in a lossless compression codec, this makes sense to me, but as far as I understand it, MPEG like JPEG is not lossless. All the MPEG2 compression work I have ever done for DVD always has the classic trade off.. more quality at the expense of more space used and vice versa. Higher compression yields more noticeable artifacts etc etc. If compression didn't affect quality of video then why would anyone ever need to use uncompressed video for *ANY* reason? Also the bitrate statement - again I completely don't understand your statement that bitrate has nothing to do with compression. Isn't a highly compressed (lower quality) video stream delivering a lower bitrate and vice versa?

So what am I missing?

Chris Hurd October 18th, 2006 08:31 AM

Quote:

Originally Posted by Todd Siechen
So what am I missing?

What you're missing is the fact that not all codecs are created equal, but more on that in a moment.

Quote:

I completely don't understand your statement that bitrate has nothing to do with compression.
I made no such statement! Bitrate has *everything* to do with compression. Please re-read my post. What I said was that "quality is a function of the efficiency of the particular codec. Bitrate has nothing to do with it." Meaning, bitrate has nothing to do with quality. I never said it has nothing to do with compression. You're making the mistake of assuming that compression governs image quality. It does not. The efficiency of the codec, that is, the technology behind a given codec and how it is implemented, is what ultimately governs quality, and it does so to a much greater extent than compression.

Quote:

All the MPEG2 compression work I have ever done for DVD always has the classic trade off.. more quality at the expense of more space used and vice versa.
When you're creating a DVD, you're limited to working within one particular MPEG2 codec... only one set of operational rules. The only available variation is bitrate. With only one variable at play -- only one axis of adjustment -- of course that's going to affect quality, depending on how you choose to trade space for it using the bitrate.

You don't have the freedom to switch between various MPEG2 encoders when you're in the middle of burning that DVD, but if you step back and compare all of the different MPEG2 encoding schemes in all markets at all levels of cost, you'll see that these new axes of adjustment -- the quality of the encoding algorithm, the cost to obtain it, the hardware and software systems required to support it -- these factors have a much greater overall effect on "quality" than bitrate ever did. For example, check out any recent big name Hollywood movie on DVD. It's MPEG2 but it sure wasn't burned with Roxio. Plus, consider that there's at least 90 minutes worth of feature film as well as whatever extras and trailers are thrown in for good measure. It's going to look *better* than 60 minutes of the same material burned with software costing $70 at Comp USA. Higher compression, lower bitrate, and yet *better* quality... because not all MPEG2 is created equal. Quality is ultimately determined by the make and model of the particular codec.

Here's another way to look at it: examine the difference in quality between two identical images, each compressed the exact same amount, but with different encoders (link -- JPEG vs. JPEG2000: An Objective Comparison of Image Encoding Quality). If compression was the only thing governing image quality, then there should be no difference between the two images. Obviously the difference in quality is the result of the difference between two encoding processes. You could go a step further and compress one of them even more, but still produce a *better* image relative to the less compressed version. If bitrate determined quality, then we shouldn't see any difference between two identical video clips, compressed equally in Apple QuickTime and Microsoft Windows Media... and yet the reality is that people will still argue about which is better because one will look blocky and the other will look blurry (link -- QT vs. WMV: An Objective Comparison of Video Encoding Quality).

Going back to quality differences between *identical* compression schemes, consider the variation in quality between DV codec suppliers. All are 25mbps yet not all are created equal. For years the ones to beat were the Apple and Canopus DV codecs... there are many others, all 25mbps DV, but Apple and Canopus were highly regarded as the best. In fact, Avid was so impressed with the Canopus DV codec that they used it in their own NLE product line throughout the late 1990's. Throughout the realm of DV codecs, the bitrate has always been the same, but there have been wide variations in quality. Why? Because so many complicated and incredibly complex methods are involved in creating efficient video compression schemes... motion compensation, subsampling, block differencing, frame segmentation, search threshold, distortion measure, prediction error, motion vector correction, yada yada, it goes on and on. And some companies, like Apple and Canopus, do it better than others.

With a hard disk recording device like the FireStore FS-C, the compression is fixed at 25mbps -- it has to be, or it wouldn't be DV and HDV compliant. What's adjustable is the type of editing format, or wrapper, that you choose to assign to the recorded video. If you're editing on Final Cut Pro, then you'll assign the FireStore to write a QuickTime file extension. If you're using Avid, it'll write an OMF extension. If you have a Canopus system then you'll pick AVI Type II C, which is specific for Canopus as opposed to plain 'ol AVI Type II or Type I, which the FireStore can write as well. The primary advantage here is the *convenience* factor. You're creating an edit-ready file that doesn't have to be captured. That's the appeal of the FireStore.

Convenience is also the primary appeal of HDV. It doesn't *need* to be any less compressed than 25mbps. The quality of HDV is already more than adequate for the triple conveniences it provides of low cost, maximum recording time relative to other HD formats, and backward compatability with DV. If you change the bitrate and compression ratio, then you'd have to give up all three of those conveniences, which were the primary appeal of HDV in the first place. At that point it's not HDV anymore, but some other HD format. Fortunately there are a variety of other HD formats from which to choose. It's up to you to decide if it's worth giving up those particular conveniences that HDV offers... for some folks it's well worth it, for some folks it's not. Thankfully we all have a wide variety of HD format options readily available to us.... there's something for everyone.

The primary goal of video compression technology has always been to achieve higher image quality with *higher* compression ratios and *lower* bitrates. Take for example the forthcoming RED telecine software, which will offer the capability of shooting 4K images with REDCODE Raw, using VBR wavelet compression at a mere 27 MB/s. You don't need a super-computer for that, nor do you need multiple terrabytes of storage space. That's the beauty of it.

I couldn't believe my eyes when I saw AVC encoded video (also known as H.264) for the first time, during the Apple press conference at NAB2005, projected on a thirty-foot screen at a mere 8mbps. Just eight megabits per second, and it blew me away. It's all about the *efficiency* of the codec, and the advanced video encoding technology that goes into it... and that's how we get *superior* image quality from *higher* compression ratios and *lower* bitrates. Hope this helps,

Todd Siechen October 18th, 2006 11:37 AM

Well of course a high cost hardware codec is going to be much better quality than a low cost software codec. No surprise there. But that wasn't what I was responding to or refuting. But no matter - at least now I know what you were trying to say. While your lengthy response was largely unnecessary, it is appreciated. 8)

Robert Sanders October 18th, 2006 12:31 PM

Quote:

Originally Posted by Chris Hurd
What you're missing is the fact that not all codecs are created equal, ... BIG SNIP...

I couldn't believe my eyes when I saw AVC encoded video (also known as H.264) for the first time, during the Apple press conference at NAB2005, projected on a thirty-foot screen at a mere 8mbps.

Well said, Chris.


All times are GMT -6. The time now is 04:28 PM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2024 The Digital Video Information Network