1080p and i converting and using with 720p footage mix question

[time2clmb]

Hey, I shoot with my gopro on 720p to be able to get the 60 frames per second to make smoother slow motion. I have some 1080i footage rendered to 720 with a friends cam, but have had some interlace flicker piss off although I had the reduce option checked. I have a new camcorder that I would like to use together with the gopro for edits and will be rendering to 720p. For the camcorder I have the choice of shooting in 1080p, or 1080i. Obviously I can't make the 720p better if shooting in 720p, so when using the camcorder will I get better results by redering out the 1080p down to 720p...better match P for P right?? Or is there much difference if shooting 1080I and then converting that to 720p?? It came with a program to convert my 1080p files to AVCHD.

I'm mostly asking because I will be mixing the footage and i'm pretty set on shooting gopro in 720 for the faster frame rate. I am trying to avoid any interlacing issues...I hate footage that has the interlace flicker. I use Vegas pro 10. Can't render out to 1080p anyways...just 1080i. Personally I can't tell the diff between 1080 and 720 which is another reason why as the rendered files don't take up as much space so.... Any insight appreciated in simple video jong terms.

[Atrain505]

Convert the 1080i to 720p. When converting deinterlace. Mpeg streamclip is a free program that does a decent job.
Convert both the go pro and the other cam to the same codec for ease of editing. Prores in final cut land not sure what works best with vegas.

[time2clmb]

Awesome, thanks for answering that. Is the 1080i over 1080p preference due to file size or editing ease or is it just due to no point since converting anyways....?

[systemoverblow'd]

He's telling you what todo with the footage you already have. From this point forward shoot 1080p if you can help it. That way it is just a scale issue and not a frame rate issue.

[time2clmb]

^ not how I read it, sounds like you are disagreeing with his post where he is saying shoot in "i" you are saying shoot in "p".... both options frame rate is the same exept for the gopro. There's nothing in his post that mentions only doing that to the footage I already have if i'm reading it right.

[kidwoo]

I think Atrain only addressed the conversion once you have 60i footage. If he's saying shoot from now on in 60i he's fuggin nuts Or maybe he just knows something I don't.

You probably know this but interlaced footage is not whole frames but fields consisting of alternating lines. In 60i that's 60 interlaced fields or two pairs of alternating lines at 30fps each. When you convert interlaced to progressive footage most programs are throwing out half the fields and interpolating the empty lines left by the missing set to complete whole progressive frames. So you lose half the info anyway. This is what 'deinterlacing' is. Those interlaced comb lines on the outside of anything moving is the difference in time between the two pairs of fields. To get rid of that, you either have to just ditch half of them or average them........either of which gives you compromised images. If you shoot in progressive modes, all the program is doing is scaling, not filling in blank spaces AND scaling. Plus you have FULL progressive frames which is most likely your end product anyway.

That camera has 1080/60p right? If so there's no reason to shoot in 60i....at all.


Your camera probably records even 1080/60p in a 60i storage format but that's a whole other conversation

[systemoverblow'd]

^ not how I read it, sounds like you are disagreeing with his post where he is saying shoot in "i" you are saying shoot in "p".... both options frame rate is the same exept for the gopro. There's nothing in his post that mentions only doing that to the footage I already have if i'm reading it right.

Do what you want, but you came here for advice. Mine is correct as kidwoo explains.

[kidwoo]

I stand tall with anyone who's avatar recognizes josh brolin's greatest roll of his career.

[Tippster]

When you convert interlaced to progressive footage most programs are throwing out half the fields and interpolating the empty lines left by the missing set to complete whole progressive frames. So you lose half the info anyway. This is what 'deinterlacing' is. Those interlaced comb lines on the outside of anything moving is the difference in time between the two pairs of fields. To get rid of that, you either have to just ditch half of them or average them........either of which gives you compromised images.

Like you said, depends on the program. Professional de-interlacing programs do not simply line double one field vs another, but merge the two. Yes there is a bit of interpolation used to do so since the two fields were recorded at separate moments in time, but the time to scan two fields is the same as scanning one progressive frame in 1080i vs 1080p. Many assume each frame in a Progressive recording is captured instantly and that is simply not the case - it's basically (very oversimplified) two fields captured at 1/60th of a second each vs 1 full frame captured at 1/30. The latter has some motion smear, which is why sports are still shot mainly in 1080i.

1080p60 is a different matter. It is def. the best format to shoot anything in, but the file sizes are so big that it's not very practical without huge compression algorithms (mainly AVCHD), which bring in their own problems.

Then again it all depends what you're gonna display your footy on anyway.

[kidwoo]

Yeah I was assuming he's not using the 1500 dollar program realm.

I tried doing the old school 60i to 60p conversion so I could get 1080/60p out of my HPX once. On a cable cam I use a stabilization plug in that crops and the 720/60p stuff suffers obviously. I could never get it to look as good. And I'm pretty sure current premiere pro offerings do the melding, not the tossing and filling in method. Still wasn't too stoked on the result.

[time2clmb]

Do what you want, but you came here for advice. Mine is correct as kidwoo explains.

All good, was just trying to clarify. Appreciate the advice for sure.

That camera has 1080/60p right? If so there's no reason to shoot in 60i....at all.

Yeah can record in either one and it comes with a program to convert the 1080p to AVCHD.

Your camera probably records even 1080/60p in a 60i storage format but that's a whole other conversation

I'm not even going to ask lol

[Atrain505]

Ya I was just referring to the footage you already have which sounded like 1080i. From now on when shooting keep everything progressive. 1080p or 720p. For editing better to downscale than to upscale in most cases. Especially for web. So all files should be 720 same codec for editing. If you were going to big screen maybe discuss other options.