>I shoot mostly in low light, so for me progressive is useless due to it's inferior light gathering ability on most cameras as compared to interlaced. I shoot 60i.

John, bear with me because I'm trying to better understand all this. Are you saying that 60i gives better light gathering ability than 60p? As far as I know, light gathering for a given camera is mostly a function of shutter speed and aperture. So wouldn't 720p60 do as well as 1080i60 from a lighting perspective?

EDIT: I removed this misstatement: "So certainly 60i would do better in low light than 30p."

/jerry

> "What is your preferred approach for high motion video DVD's? I ask because in the dvxuser forum for my HMC150 cam, one of the most experienced videographers recommends shooting 720p60 rather than 1080i60, and then rendering the 720p60 using the DVDA widescreen template which puts it into a 60i stream (ie, one progressive frame per field). My instincts (rather than hard evidence) have told me this would be preferable for putting fast action HD on DVD. Your thoughts?"

My instincts tell me the same thing. The problem with interlacing and fast motion is that quite often the motion is so fast that there is no way to blend the interlaced fields back together again because too much motion has occurred between fields. This is why Vegas has the Deinterlace Mode of Interpolate Fields. What it does is effectively throw half of the fields away and build the frame from the same moment in time from one set of fields. The suggestion of shooting 60p and turning it into 60i is along the same lines, i.e., each frame would composed of fields from the same moment in time. This makes sense to me.

~jr

Jerry read the bit at the end of Philip Hodgetts article i posted above this may explain why some folks say you get more light from interlaced footage.

>The suggestion of shooting 60p and turning it into 60i is along the same lines, i.e., each frame would composed of fields from the same moment in time.

JR, looks like I am missing something fundamental here. Why wouldn't each frame be composed of fields from two moments (aka progressive frames) in time, 1/60th of a second apart, just like interlaced?

/jerry

>Jerry read the bit at the end of Philip Hodgetts article i posted above this may explain why some folks say you get more light from interlaced footage.

Rory, I looked but couldn't find the referenced info in your links. Can you enlighten me?

/jerry

> "JR, looks like I am missing something fundamental here. Why wouldn't each frame be composed of fields from two moments (aka progressive frames) in time, 1/60th of a second apart, just like interlaced?"

I assumed DVD Architect is just throwing half of the frames away and only using 30. I was going to say that if the camera shoots 30p this would be the same thing. Perhaps the camera they were talking about could only shoot 60i or 60p? I don't know. You are correct that encoding 60p as 60i doesn't solve the problem because the motion difference is still there. You need to encode 30p as 60i.

~jr

> I assumed DVD Architect is just throwing half of the frames away and only using 30

JR, I think you are right. I just rendered some 720p60 to DVDA widescreen and viewed it in Vegas. Only every other frame advances. I don't have any more time to play with it today but if I learn anything else I'll post it here.

/jerry

Lots of good theory and numbers here.

In practice, however: how many non professional users have got equipment to show their works at 60p (or 50p PAL land).
Just got a new camera yesterday doing 1920x1080 50 progressive at 28 Mbps.
Fine - but not even my new 58 inch Dlna plasma can show it (at movements it mixes up to 1-2 seconds of frames).
Also not the PC connected to the Plasma via HDMI or DVI can do it(converts to 25p on-the-fly - need new graphics card).

So I can chose between 25p or 50i. 25i is hack-hack-hack at movements while 50i does movements smoothly and at resulting resolution on the screen nearly undistinguishable to the 25p (for the naked eye - ah: for my naked eye, at least).
So I have increased the bit rate for the mpeg-2 delivery format to the Dlna plasma from 25 to 30 Mbps - and for the time beeing this gives the best result for my equipment (actually a quite extrordinary resulting quality btw., I dare say)

Ritsmer what cam did you get?..50p very nice.

You said it simply and straight “ for my eye” that is the bottom line of everything in filming and editing, motion graphics. if it looks good its good.
To dissect an atom to see the gamut and artifacts of an electron is vanity. afforded only those who are retired and have nothing to do with their spare time


Jerry I don’t understand the technical jargon.it was simplified by technical folks that produce/work feature films
Simplified this is how I understood it, interlacing loses detail and the beam becomes thicker thereby giving the manifestation of being a stop brighter.
“For the atom splitters,to repeat this is how I understood it.”

Current video cameras and displays don't exactly scan like the old tube based cameras and CRTs.

Still the point is correct, interlaced video is lower vertical resolution than progressive by design. You might benefit from reading this.
In part:

"Kell factor is sometimes incorrectly stated to exist to account for the effects of interlacing. Interlacing itself does not affect Kell factor, but because interlaced video must be low-pass filtered (i.e., blurred) in the vertical dimension to avoid spatio-temporal aliasing (i.e., flickering effects), the Kell factor of interlaced video is said to be about 70% that of progressive video with the same scan line resolution."

There is a side effect to the low pass filter used in interlaced cameras, it improves the S/N ratio or at least it should. It certainly works well in the EX1.

Bob.

@Rory: you will laugh - but it is a Sony DSC-TX100V.
Bought it for inconspicuous recordings.
Had/have the TX7 and the TX9 (1080 50i at 17 Mbps), and thought TX100V might "just" be another update - but: The sensor is far more sensitive giving substantially less noise and less softness. The lens system is 100% new giving next to no barrel distortion and better stabilization. The white balance is much better. You even have tracking focus when recording video (just point out the focus point on the 3 1/2 inch oled touch screen) ... and several other astonishing goodies.

I will use it in 50p 28Mbps mode to get the best basic material for editing and to avoid some of the theoretical 2 x 0.7 reduction on the way from camera lens to the Plasma screen (1 time in Vegas and 1 more time encoding in the plasma TV)

Not at all I am looking for something that is small and can give me 50p to lock next to my one cam, I don’t want to outlay big bucks but I need the 50f nothing fancy just 50p at 720 …this looks like what I need

At a guess what would the lens compare to 50mm, 35mm?

Thanks Bob

I had to go and read the Kel Factor in simple terms at the bottom. :-)

Lens? zooms 25-100 mm in 35 mm terms.

It is not yet on Sony US but check the specs here:
http://www.sony.co.nz/product/dsc-tx100v

(don't faint when you see it - you can also get it in black :-))