Panasonic comparison

[Luis Caffesse]

"I think you at least agree that uncompressed 720p on Beta would looked better than 720p HDV"

I've been trying to stay out of this tangent...but I really feel someone should pipe up and state the obvious again, because it seems to be getting lost in the shuffle.

You can't record uncompressed 720P onto Beta.
Beta is an SD format.

So, you would downcovert the signal, add a pulldown, and record it onto Beta SP?



Sound like a big hassle for really no good reason.
If you're going to do something like go out of the uncompressed outputs, why not run it through an RGB - HDSDI converter and go into a DVCProHD deck?

Either way, seems like a lot of work for not much reward.

[Graeme Nattress]

I don't agree about betaSP being better for anything! Neither subjective or measured results show it has any use in a modern digital workflow. And as Luis points out, it doesn't do HD and it doesn't even do anamorphic widescreen. All it will do is take a lovely pristine digital image, add analogue noise and reduce it's resolution, and probably add some ringing artifacts on edges.

Graeme

[Michael Maier]

Ok, it all started as a joke I made to show how much I want a interchangeable HD camera, that I would record it to a beta sp deck. It was actually somebody else's idea I read on another board as I said.
But then people put Beta down because it's analog. I was trying to show that not because it's analog, it means it will always be worse than digital in every case scenario. I mentioned the Sony Hi-Def Center test between the BVW D600 and DVW700. It was ignored and then discredited as if I was lying. All I'm saying is, not because it's digital, it's better. When you say beta is not HD, then you can't record HD on it, you do realize DVDs are not HD and there are HD shot films available in DVDS, right? You say I can't record 720p to Beta because it's NTSC. Is 35mm film NTSC? We can watch them on a NTSC VHS can't we? The signal is digital, but if it's coming out as analog component , a conversion has been done already. You could lay it on anything you want, VHS, U-matic or DVCAM, DVCPRO, DVCPRO50 or whatever. As long as you have a deck with some sort of analog IN, you can record. It’s analog now.
I understand one saying it would look bad, that could be one’s opinion at least. But saying it's no possible to record it on Beta is just wrong.

But it doesn't matter. As I said I started it joking. I picked Beta because it's cheap. Somebody asked why not DVCPROHD. If one can afford a DVCPROHD deck, he can probably shoot Varicam, so what’s the point? I could have said dump the uncompressed component to DVCAM. It's also affordable. But it would compress it to 5.1. I picked Beta because it is "uncompressed". I wish I could do the test, because I could swear that this set up would get better results than HDV, specially for green screen. Beta keys very well and many think it keys better than DV.
Another point is, I just don't see why a DVD can keep all the detail and "resolution" from a 35mm print when you are watching a film DVD and Beta couldn't keep all the detail and "resolution" from the uncompressed 720p. I mean, when we watch a movie in DVD, it doesn't look like it was filmed in NTSC does it? But we are watching NTSC. That was the line of thinking I used about it looking good or not. Remember that many people have shot 16mm and transferred to Beta SP for editing back in the day. It still looked like film and would look better if blown up to 35mm than if it was originated on Beta in the first place. Same could be said about shooting uncompressed HD and transferring to Beta for editing. Just in this case, the transfer would be real time. I think it would look much better if you up-rez it to HD than it would if it was shoot in SD to begin with. It would transfer much better to film than it would if it was shot in SD or used the compressed HDV tapes. Specially if the uncompressed is 4:4:4 rather than 4:2:0. Is it that hard to see what I mean? If I'm missing something, please point it. Because till now, all that was said only makes me think that or you don't understand what I'm saying or I'm just getting picked at.

[Graeme Nattress]

Michael, the idea of recording the component out as high quality standard definition is not completely daft at all. The component out will, if an SD downconvert from the HD chips and DSP, be likely 4:2:2 of pretty high quality. It will most likely have a measured horizontal resolution of over 500 lines and look very nice.

Now, any recording of that analogue signal, should if you wish to do it justice, preserve that signal coming of the camera best, and be most accurate and faithful to that sourse. Ok so far?

Now we can look at which tape format will preserve that signal best. You have suggested BetaSP, and I have said it's not too good an idea. That is because, and we assume we're starting with a pristine analogue component signal here, BetaSP is a rather poor video format. I know it was the broadcast favourite for many a while, but we can measure how well it reproduces an analogue signal it is asked to record, and see how it does.

When we talk about component video, be it digital or analogue, we may say it's 4:2:2 or 4:4:4, or 4:1:1 or whatever. It's very easy to get these numbers for digital standard definition formats. Digital Betacam, which is arguably the best standard def tape format there is, is 4:2:2, which means it records luma at full rez and both chroma components at half horizontal rez. In this case, full rez is 720 horizontal pixels.

Now for analogue: you can't measure analogue in pixels, as it has none, but you can look at the frequency response of an analogue format, and directly convert that into a resolution in pixels figure so you can compare it directly with a digital format. If we were to do that, you'd measure your BetaSP and find that it's digital equivalent figure would be 3:1.5:1.5, so that's about 3/4 of the resolution of Digital Betacam in both luma and chroma. That means, any image it records will bel blurier.

Now, for noise levels. Digital video does not have noise as such, but it has quantisation errors as rounding errors as the video gets made into 8bits or 10bits. Again, you can mathematically equate noise levels to bits of digital video, and we find you can accurately represent a BetaSP noise level analogue signal with 8bits of digital video. 10bits, like Digital Betacam uses is nicer, but 8bits is just about good enough. If you look at lowly DV, it's noise levels are very similar to BetaSP in luma, and I think one of the chroma channels in BetaSP appears to be a bit noisier. There's not much in it though. Compression also comes into this too. Compression in digital is easy to think about, but you've got to remember that this too will act like noise, and look like noise in any measurement of the video. Digital Betacam is very lightly compressed, and indeed is visually lossless over many many generations.

Analogue video also suffers from artifacts, just as compressed digital video does too. BetaSP suffers from edge ringing, noise, and instability in the picture due to it being analogue. You can equate all of these to compression artifacts / noise levels too, and therefore you can see that BetaSP is most definately not 4:2:2 nor is it uncompressed.

If your goal is to preserve the analogue output of the camera in an SD format, record to these formats in order of quality:

Digital Betacam,
DVCPro50,
DVCpro/DVCAM/DV
MII,
BetaSP,
Hi8/S-VHS
VHS
Fisher Price Pixelvision ;-)

Graeme

[Michael Maier]

Fair enough. Now at least we are talking :)
But it is possible to record it to Beta, regardless of it being 720p, opposite to what somebody said.
But one thing you got me lost on. Whe you say:

<<<-- Originally posted by Graeme Nattress : The component out will, if an SD downconvert from the HD chips and DSP, be likely 4:2:2 of pretty high quality. It will most likely have a measured horizontal resolution of over 500 lines and look very nice. -->>>

I thought the uncompressed would be HD 720 lines, not SD 500 lines.

[Graeme Nattress]

If the camera outputs a downconverted, PAL in your case, standard definition component signal, then yes, you can record it to BetaSP.

As for lines of rez, you're getting horizontal and vertical mixed up. The pixel dimensions of the SD downconvert PAL would be 720x576, and after all the filtering that goes on, you can measure about >500 lines of horizontal resolution, and probably about 400 vertically because of the filtering to avoid interlaced twitter in the PAL (or NTSC for that matter) system. If you could output a progressive PAL signal from the camera without that filtering, you'd get >500 lines measured vertical resolution. The pixel resolution is like the theoretical max, and measured lines resolution is sort of a measured practical reality.

Graeme

[Ignacio Rodriguez]

> regardless of it being 720p, opposite to what somebody said.

Well you can sort of downsample it to NTSC or PAL, but as Graeme suggests: it will be nothing like 720p when it comes back off the tape. You cannot actually record 720p on anything but a digital medium.