Anyone shooting progressive, double fps?

ingvarai wrote on 7/17/2009, 1:52 PM
I am considering shooting progressive instead of interlaced. My camera allows 50p at 1280x720. Here are my assumptions:

- When rendering out to DVDA, Vegas will do the interlacing, so I will get no judder when watched on TV.
- I can also record using shutter speeds down to 1/1000 (maybe 1/2000). Already at 1/250 I expect images to be sharp, even when the camera is handheld / shooting from a moving vehicle. This leads me to think that applying a deshaker will certainly crop the image, but otherwise the usual image degradation would not happen. Also I think several effects "like" progressive material better than interlaced.
Any opinions?

ingvarai

Comments

farss wrote on 7/17/2009, 3:57 PM
I've shot 720p50 and output 50i on DVD.
Only problem I've had is Vegas getting the field order wrong which gives horrid motion. Always check on a CRT and fix as needed.

With such fast shutter speeds motion even with 50i can look a bit juddery. I'm now intending to shoot 720p50 with the shutter off to get enough MB to get smoother motion however this is the exact opposite of what you'd want for image stabilisation.

Be aware that if you're using the EX1 sensor readout time is 1/60th of a second regardless of shutter speed so with fast motion and fast shutter speed skew could be very apparent. How that might mess with image stabilisation in post I don't know.

Bob.
malowz wrote on 7/17/2009, 4:28 PM
im also recording 720p/60fps (ntsc land) and converting to dvd 30i.

converting from fullhd > dvd requires more procesing and filtering, 720p/60 is better and faster.

im using avisynth to downconvert the mp4 from ex3 to avi using canopus HQ codec.

1080i, using a quality and speed script, must do this:
resize > deinterlace > resize > separate fields > discard fields > reinterlace = 480i

720p/60, is this:
resize > separate fields > discard fields > reinterlace = 480i

farss wrote on 7/17/2009, 5:14 PM
That seem inordinately complex!

In Vegas:

720p50
resize>separate fields>576i

1080i
deinterlace>resize>reinterlace>576i

1080p
antialiasing(GB FX) > resize>separate fields>576i

Bob.
malowz wrote on 7/17/2009, 5:28 PM
"720p50 resize>separate fields>576i"
thats the "simple" way of saying, it in fact must be "resize > separate fields > discard fields > reinterlace" (as vegas do), or you will have a 240p/100fps jumpy video :)

"1080i deinterlace>resize>reinterlace>576i"
as i use a motion-compensated deinterlacer, process in full resolution is unecessary, so resize to 720x1080 before process speeds up without loosing visual quality. that's why the extra step.
farss wrote on 7/17/2009, 6:35 PM
""720p50 resize>separate fields>576i"

My head hurts :(

The process is (or should be) quite simple:

frame 1 read odd rows > field 1
frame 2 read even rows > field 2
etc.

If Vegas does separate fields the intermediate result of that would be 100i (technically 50PsF100) and would look much the same as 50p. There's no way to double temporal resolution and get 100fps without motion estimation.

Having said that the last time I shot 50p I was not entirely happy with what I ended up with. I've simply assumed that was due to using 1/100 sec effective shutter speed.

Bob.
ingvarai wrote on 7/18/2009, 7:21 AM
Bob:
With such fast shutter speeds motion even with 50i can look a bit juddery.

Very interesting. I will have to experiment and test, the only way to find out. BTW, I have a Paansonic HMC 151.

ingvarai