IMX50 "Combing" issue

Former user wrote on 7/29/2017, 3:39 PM

Using IMX50 as archive, combing issues ...

The source material is mpeg in .avi wrapper, uncompressed, 720x576 25fps progressive.  PAL region.

I intended to use Sony IMX50 as archive when the project was completed and delete the AVI'S, but I noticed "combing" in just a few places with rapid movement, after rendering out, the original was better at these spots.  

If I output to say an .mp4, not to archive, just to compare, the .mp4 (progressive) doesn't have the combing issue, it's similar to the source material.

If I output to DV25 and make sure to select progressive in the render template it also is better at the problem points, as good as source or .mp4, for this issue.

The IMX50 has no progressive option in the template, only upper field.

I compared in Vegas and also playback with vlc, similar results.  Within Vegas, for it not to look terrible, even more combing, it's essential to set project properties to progressive, not interlaced, so no matching to the mxf media here!

The IMX50 render template only outputs to interlaced, upper field first, sounds ok for PAL, thats default for PAL, except for DV, as best I understand it.

Am I missing something here?

Comments

Musicvid wrote on 7/29/2017, 9:37 PM

Sounds like it may be related in some way to this discussion:

https://www.vegascreativesoftware.info/us/forum/another-nasty-latent-vegas-rendering-bug--100192/

Former user wrote on 7/30/2017, 3:51 AM

Thanks Musicvid. Before posting I had come across this, did a re-read, good stuff, may be related.

The 1st. frame example posted by johnmeyer, of extreme jaggies on verticals is what I got before setting program properties to progressive, which fixes that issue while my new .mxf archive is loaded on the timeline.

But it still has spots with fast movement thats worse than a .mp4 or DV25 test sample. I already tried all different interpolate options, no change. I guess the IMX50 is just not suitable for what i'm trying to use it for, given the issue. Better to know about it now anyway than just assume it was doing a good job and maybe only discover the issue much later when its too late.

Maybe it would be ok if my source material was interpolated, either pal or ntsc, but my source is what it is, old vhs, capture device, usb, Nero captures to .avi progressive, no compression.

Its a pity, because as an archive option, for my needs it looked like a good comprise option.