NTSC Timeline + HD 24P Clip + Effect = Resolution Drop

[Earl Thurston]

Hi folks. I believe I've discovered a bug in Premiere Pro CS3.

Last year, I created a series of recycling PSAs using 720p24 source material scaled down on a NTSC-DV timeline in PPro 1.5.1. Everything used to look great in that version.

The client recently asked for some updates, so I opened the project in the latest version, CS3, and discovered that several of the clips had a terrible resolution drop.

I did some testing today to find the root of the problem. I wanted to determine if perhaps it was Premiere or CineForm, but the problem occurs even with uncompressed HD material.

Here is the recipe to create the problem:

• Premiere Pro CS3 (up to and including 3.1.1)
• NTSC-DV timeline (in my case, 4:3 ratio)
• HD 720p24 source clips scaled down 67% to fit vertically (originally from JVC HD100; CineForm AVI or uncompressed AVI both affected)
• ANY effect applied (sample below used Gamma Correction with no adjustments; Frame Blending off)

The result is the vertical resolution drops by about half, as if Premiere is treating the progressive scan footage as interlaced and attempting to de-interlace it.

Clips with no effects and Frame Blending turned off turn out okay. (Frame Blending is on by default in PPro CS3, so the resolution drop occurs immediately unless Frame Blending is turned off manually for each clip.)

I should also mention some other strange quirks I encountered while analyzing the problem:

• The Monitor window always shows the resolution drop -- even with unaffected clips -- when it's set to any zoom percentage other than 100% (e.g. 200%, Fit, etc). The only time the unaffected clips look correct is when the Monitor window is set to 100%.
• Stills exported directly from the timeline will always look correct (no resolution drop) even if the timeline is rendered first. You need to export the timeline to another AVI or MPEG-2 file first and then capture your stills from that.