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Bad transcoding problem wit interlaced footage... ¿Any solution?

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Pau Luzón Herrera
Bad transcoding problem wit interlaced footage... ¿Any solution?
on Sep 10, 2015 at 11:28:11 am

Hi everyone!!

I'm Pau, film editor from Spain. A friend of mine asked me for advice with a problem he found editing a project and I couldn't find any solution, maybe you can help me.

The history goes like this:

He shot some scenes for a documentary with a CANON LEGRIA HF R306 camera at a 50i framerate. As he wanted to edit it in 25p he just transcoded the original footage (h264 1920x1080 50i) to a 25fps ProRes using standard Mpeg Streamclip settings.

This created some artefacts in the image when there is movement inside the frame, I think that it is due a bad deinterlacing transcode. He just ignored those artefacts and kept editing, and, here comes the biggest issue, he deleted the camera raw footage, so there is no way to just transcode it again.

Now he has a full length documentary with most of his footage with some weird frame fussion artifacts, I've tried every trick I know about deinterlacing transcoded footage, but it didn't worked as, in fact, it is not interlaced footage but progressive with blended frames.

This is how his footage looks:

He is editing in Final Cut Pro, but I also tried to solve the problem with Premiere Pro CC. None of my attempts came with a solution.

¿Some ideas about how to fix it? I don't think there is an easy solution since the original camera footage is gone, but maybe some of you have some useful trick that I don't know about :)

Thank you, guys. We'll truly appreciate any help on the subject.


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Shane Ross
Re: Bad transcoding problem wit interlaced footage... ¿Any solution?
on Sep 10, 2015 at 1:25:26 pm

Sorry, but if it was converted like this...if that is what a still frame looks like, there's no way to fix it. That look is "burned in" to the footage.

Why on earth did he delete the camera originals? You NEVER do that. Ever. Issues like this are one reason you don't, but there are a million more reasons...such as they take up less space than the converted files, so are easier to archive.

Tell your friend to never ever delete the camera originals. And sorry that there's nothing you can do about this footage.....but the damage is burned into the converted files.

Shane
Little Frog Post
Read my blog, Little Frog in High Def


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Pau Luzón Herrera
Re: Bad transcoding problem wit interlaced footage... ¿Any solution?
on Sep 10, 2015 at 1:44:19 pm
Last Edited By Pau Luzón Herrera on Sep 10, 2015 at 1:51:49 pm

Fist of all, thanks a lot for your answer, I'm a long time follower of Digital Frog, I feel kinda honoured getting an answer from you ;) .

Yeah, I knew that getting rid of the original files was going to make solving this issue almost impossible, but I wanted to ask around if there was some way so I could be 100% sure before telling him the bad news.

I'll tell him next time he better call me BEFORE transcoding anything.

Thanks again for your time and dedication!


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Mark Suszko
Re: Bad transcoding problem wit interlaced footage... ¿Any solution?
on Sep 10, 2015 at 7:49:04 pm

On the bright side... maybe he still has a good radio documentary in there somewhere.


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Nick Meyers
Re: Bad transcoding problem wit interlaced footage... ¿Any solution?
on Sep 10, 2015 at 1:27:48 pm

sorry, bad news:
there is no solution.
he's stuck with the blended frames.
cant believe he got rid of the camera original.
and the moral of the story is...


nick


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Pau Luzón Herrera
Re: Bad transcoding problem wit interlaced footage... ¿Any solution?
on Sep 10, 2015 at 1:36:27 pm
Last Edited By Pau Luzón Herrera on Sep 10, 2015 at 1:46:45 pm

and the moral of the story is...

...leave the editing to editors.

Thanks a lot for your time :)


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Pau Luzón Herrera
Re: Bad transcoding problem wit interlaced footage... ¿Any solution?
on Sep 10, 2015 at 2:16:17 pm

Before closing this thread, some additional info regarding this CANON LEGRIA HF R306 camera:

I've tried to transcode some original files recorded in 50i fps to 25fps, just to see if it can be done and how... And actually it is impossible to deinterlace the source material into 'clean' progressive video!! Every software, from Quicktime to Premiere, interprets the source material as progressive 25fps... but with this blended frame artefacts, so no way to deinterlace what is already deinterlaced.

This is weird... Am I missing something?

Anyway, at this moment my advise if someday you find yourself working with that camera, just shoot in progressive.

Cheers!


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Michael Gissing
Re: Bad transcoding problem wit interlaced footage... ¿Any solution?
on Sep 14, 2015 at 3:45:07 am

It looks like the field order is being interpreted back to front. All 25 fps codecs are upper field first except DV codec in standard def. All HD 25 fps codecs should be upper first. This looks like the transcode has either set the field order wrong or that camera shoots 50i with the wrong frame order.

Either way it was not properly deinterlaced in the transcode so the error is baked in.


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