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Why EVER use interlaced?
Can anyone cite ANY reason why you’d not choose to remove interlacing in an FCP project?
Yes, I understand the NTSC 60i format displays interlaced images – but my question is, “Why not remove interlacing from the original?”
This has got to sound like a dumb question – but, to me, everything looks so much better without interlacing – what’s the reason for ever retaining it in your footage that comes out of the camera?”
Thanks!
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28 Replies
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Sports, news…reality shows…some docs. People like smooth fluid motion for many things. If you don’t want it, if you want the progressive feel, then shoot progressive and work progressive. No one twisting your arm to work interlaced. But there are several shows that do want that, so they shoot and edit that way.
Shane
GETTING ORGANIZED WITH FINAL CUT PRO DVD…don’t miss it.
Read my blog, Little Frog in High Def -
Hi Shane – That’s interesting – I guess my question comes from the fact I shoot with a Sony HD camera that creates interlaced footage to tape – and then, when I look at individual frames, there’s very often some artifacts showing up along horizontal edges that makes the video look more like ‘video’ – and, as you suggest, that’s not my desired intent or style as I create what I WISH was shot on film – or that I had access to a nice progressive camera – so, you’ve answered my question – which I understand to be, “It’s only important if your customer cares” – which makes sense.
Thank you
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Tape based cameras…many of them…still shoot interlaced. That is the nature of tape. The only ones that don’t are the ones that shoot a true progressive format, 720p60…like the Panasonic Varicam. 1080 is an INTERLACED format by nature, so if you want to shoot progressive, say 24p, then it needs to shoot 24p over 30…and the tape is interlaced because, well, 1080i is an interlaced format. YOu can REMOVE the pulldown to get to 1080p 23.98…but with HDV, a GOP format, you can’t do that until you convert to a non-GOP format like ProREs…since GOP isn’t an actual frame format…it is 3 real frames and then a Group of Pictures in between.
Shane
GETTING ORGANIZED WITH FINAL CUT PRO DVD…don’t miss it.
Read my blog, Little Frog in High Def -
I can think of three good reasons to shoot and post produce interlaced.
Firstly smoother motion. 24 & 25 fps progressive places limitations on speed of pans and the capturing of fast moving images. A colleague who shoots underwater footage showed me some comparisons between 60i and 24psf on his HDCam and the 60i looked so much better. I work on docos and lots of editors like to speed manipulate to create slo mos. These are not scripted or shot at suitable frame rates or shutter speeds and slo mos from interlaced footage are smoother as a general rule.
Titles. Scrolling credits in interlace are much smoother and give much greater latitude for speed. These days we are being shoe-horned into lengths for credit rolls and the speed becomes determined by how many credits. I struggle to get progressive credit rolls to work unless I can control the speed which means losing control of the length. Clients don’t understand and the broadcasters think credit roll lengths are more important than the content.
Broadcast. All broadcasters world wide are still beaming out standard def interlaced pictures. 99% of my work is for international broadcasters so the final tape is always interlaced.
If you like the progressive look then shoot it in the camera and take the time and trouble to understanding shutter speeds. Plan and shoot slo mos at higher frame rates. From there you can edit in interlaced final timelines for broadcast delivery and get smooth credit rolls. Deinterlacing in post is losing resolution. Many people see deinterlacing as a way of fixing a field order problem. It might fix the problem but cost you resolution. There are better ways to fix interlace problems which are usually operator error.
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[Shane Ross] “1080 is an INTERLACED format by nature”
That’s not correct, we shoot 1080p30 (29.97psf) HDCam with our Sony F900s when called for. 1080p29.97 and 1080p30.00 are both part of the SMPTE HDTV standards.
The American LeMans Monterey “DocuRace”, airing this Sat on CBS at 1:30pm ET, has some 1080p30 in it. This show is a potpourri of every imaginable format – 1080i60, 1080p30, 1080p24/60, 720p60, even some PAL 25/24/60 widescreen SD.
Check it out or DVR it.
https://www.racer.com/cbs-takes-docudrama-approach-to-monterey-alms-broadcast/article/171221/John Heagy
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Thank you so much for taking the time to ad so much info to the discussion.
For me, the question of losing resolution is not an issue as it seems that VIDEO has TOO MUCH resolution – at least when subjectively compared against the creamy smooth look of film stock. For me, losing some resolution is a small price to pay for also losing the moving-edge artifacts that yell VID-EEE-OOO!
What I probably need to do is move into the 21st century and get a camera that shoots both progressive AND interlaced and saves the full res imagery to a card [and compress it into some MPEG space saver format].
The missing ingredient in my situation is money. But thanks for the insights of the people who are working at a level somewhat higher than I am.
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[John Heagy] “Shane Ross] “1080 is an INTERLACED format by nature”
That’s not correct, we shoot 1080p30 (29.97psf) HDCam with our Sony F900s when called for. 1080p29.97 and 1080p30.00 are both part of the SMPTE HDTV standards. “
That ‘s correct.
When you watch 1080p30 you are really watching 1080i60.
When you are shooting 1080p30 with the SONY, you are getting 1080i60 out of your HD/SD-SDI.
Is what is call Psf: Progressive segmented frame. The picture is fully progressive but is sent as Interlaced.
rafael -
[Rafael Amador] “When you watch 1080p30 you are really watching 1080i60.”
I knew that was coming…
FCP seqs/files and broadcast formats are handled differently. 1080i60 is a broadcast format, and a FCP seq setting, that can contain 30p. However, when talking about progressive camera files, they’re not segmented. When one shoots 1080p30 with a Canon 5D, or Pana 2700, it will be truly “p” at the file level. The F900 30p was a poor example on my part.
The whole interlace “issue” is so hard for people to understand… so I jump to “correction” when I see blanket statements that can be misinterpreted… sorry Shane.
We use 1080i FCP seqs even with 30p files because of the “truly” interlaced material we normally work with. Unfortunately it’s all too easy for an editor to mistakingly click “ok” when the seq setting mismatch pops up when a 30p file is the first onto a FCP 1080i60 timeline. This will set the Field Dominance to “None” any force any renders to 30p.
John Heagy
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John,
Cameras and NLEs are proprietary. The manufacturers can do whatever they want inside the machine or the application, as long as the output was standard.
Shane was refereeing to the “Standard VIDEO 1080”.
SRLs shoot progressive, but if they would be able to output an standard 1080 stream, this would be psf.
rafael -
[Lance Drake] “losing the moving-edge artifacts”
You still don’t get it.
These things are not artifacts. You won’t see them on an interlaced monitor.
Interlaced means two half resolution images in one.
We call them ‘fields’If you watch this on a proper interlaced monitor, only one of the two is displayed at a given time.
(For this you need an IO card.)Thus, Interlaced IS ‘reduced’ resolution.
On still images, you have full resolution. On motion, you have double the framerate at half the resolution.Now moving images shot interlaced look horrible on a progressive monitor, and especially when you freeze frame it.
This is why a decent NLE displays only one field when you pause it.If your output is for computer monitors, you can create a half resoltuion / double speed movie trough AE.
AE (if you interpret footage right) can render each field to a frame.
Thus, your 30i becomes 60p.(Of course you need a bit of horsepower to play back those files)
And then you enter a new problem. 60p is close to the refresh rate of a common flatscreen, but it isn’t locked. Thus every now and then a frame is updated half way the refresh of your screen, showing you two frames at the same time.
This gives a ‘jerkey’ look, and it aint pretty.
No real solutions for that at the moment…(at least not that i’m aware of)
Bouke
https://www.videotoolshed.com/
smart tools for video pros
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