JVC 720p30 downconversion to D1/BetaSP workflow

[Chris Poisson]

George,

I downloaded those and put them in a 29.97 DV NTSC timeline. I played them back to an NTSC monitor, they looked fine. What are you seeing?

[George Strother]

Chris

The “interlace” artifacts work backwards from normal interlacing – which is smooth while playing on an interlaced monitor, but shows interlace ripping when paused.

These down conversions show interlace ripping when playing, and it is much stronger or coarser than normal interlace should be, even when a normal file is paused. These down converted clips get smooth when paused.

One file is a JVC KY-HD100U 720p30 clip captured by component in AJA Kona LH: 720p59.95 8bit and placed it in a matching sequence, AJA Kona LH: 720p59.95 8bit.

Also an animation on the same timeline using only FCP Text and DVE (Basic Motion).

The clip workflow in this case was realtime component down conversion to BetaCamSP tape, then to BetaSP tape by component to Kona LH, captured as NTSC DV/ DVCam. Saved DV clips as reference movie from FCP timeline.

This gets a clip small enough to fit the 15MB file limit on the site I’m using, but preserves the details of the problem. These DV clips look exactly as the output to BetaSP looks.

I get the same results with every workflow I have tried.

George
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[Tom Brooks]

I see exactly what you’re talking about. When objects are moving there is a jagged or comb-like edge which disappears when you pause the timeline.

Isn’t this normal and predictable? Progressive 30P material will always look this way on an interlaced display, won’t it? Barry Green explains it in “The HVX Book” about the Panasonic HVX-200 camera. Look on page 51 of that book if you can get it. I’ll email the page to you if you can’t.

Thing is, I don’t see how you can fix the live shots for NTSC. The 30P is what it is. The animations could be done in the NTSC format instead of the 720P format.

I hope somebody like Gary Adcock jumps in here to explain this. It could help a lot of people understand which recording format to choose in a case like this.

[George Strother]

Sorry I’m late responding here.

Apple Support and AJA Support feel the files should have been converted to interlaced in the downconversion processes I have tried.

FCS2 makes reference to this in the online User Guide –

page III 688

“Progressive clips added to an interlaced sequence are interlaced during export or output.”

This works with 720pXX shot in DVCProHD format, but not when shot in HDV 720pXX format.

The animation is shown beacause it was created on an HDV 720p timeline and now the artifacts don’t go away when downconverted. The animation artifacts will go away when created on and downconverted from a DVCProHD timeline.

I’m just looking for a work around while the support teams are sorting it out.

George
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[Tom Brooks]

[George] “The animation artifacts will go away when created on and downconverted from a DVCProHD timeline.”

George,
I’m very interested to hear the resolution if you get it from the hardware folks. Question: Was the animation in DVCProHD created in 60P or 30P? I’m absolutely sure that 60P is downcoverted correctly, with each frame corresponding to a field in 60i. Not so sure what happens with 30P.
Thanks.
Tom