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Old May 11th, 2006, 08:05 AM   #1
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Deinterlacing,but not better quality.pls help!

Hello,this will be my first post and unfortunately a quite negative one.I am writing here,because I know I can find many specialists here who will be willing to share their ideas of the problems I might have.
I made a wedding DVD for my clients two days ago.All the previous projects I made were viewed on TV and nobody had complained.This client watched it on PC and told me there are lines throughout the whole video.I immediately figured out that deinterlacing were needed for whole video.I did it and gave it to him,and then he said that the video became a lil shaky (or out of shrpness) while watching on TV.
And I know I can't deinterlace properly since when I do it in AP thru "field options",then "always deinterlace" function,the video always becomes just a lilttle bit shaky,not exactly how it was before when it was interlaced and watched on TV.So now,it is ok to watch on PC,but it is bad for TV.I use PAL,Sony vx2100,AP 2.0,I burn it directly to DVD through Premiere.So,I wonder how to properly deinterlace the video for perfect watching both on computer and TV set.Thank you!
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Old May 11th, 2006, 08:33 AM   #2
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shaky?? it eems to me that ur not deinterlacing at all, but your switching field orders... which is something u DONT want to do...

as for the combing effect your client saw, thats what happens with interlaced footage thrown on a progressive panel... this is due to either latency or display resolutions which are higher then the source material.
U can deinterlace it with about a 15% or so loss in NOTABLE sharpness, however u should remember that deinterlacing in post not only softens the image, but brings along its own problems, such as motion choppiness.. Some people say that deinterlacing brings ur sharpness down to 50... this is innacurate and your 2 fields are interpolated into single frames, in trun ur not Losing anythign, ur just seening a different image... the image u see is a blended or interpolated single frame from 2 different fields.. theres nothign wrong with deinterlacing in post... its been done many many MANY times...

as for the solution, i say go grab a copy or demo of Vegas 6 and throw ur project on there. select a progressive scan option (pal or ntsc) then render out. this is your easiest and most hassle free solution to your conundrumpremiere has never been good with progressive scan (be it sourced material or conversion) even to this day with the RTx2, it still wont do a full res Pal progressive... be it on its ow or through the RT.. 24p yes, 25p no
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Old May 11th, 2006, 08:50 AM   #3
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thank you,peter.
I deinterlaced the whole video with "always deinterlace" function in "field options" in premiere 2.0
I don't really mean the picture is shaky,but it is somehow not that sharp as it was when interlaced and watched on TV.It is kind of strobing,but to very very small extent.And of course,this effect comes when the picture is moving.
I cannot get Vegas 6 now as I need to give the copy in about 30 hours.I just wonder is AP so bad in deinterlacing??Or should I set other setting while exporting to DVD?The settings are PAL,prog,2 pass,etc
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Old May 11th, 2006, 11:25 AM   #4
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trust me the download alone will save u a hassle.. even if all ur using vegas for is to render to progressive

that strobing your seeing is interlace flicker... which is MUCH more noticable on slowmotion
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Old May 11th, 2006, 11:27 AM   #5
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Like Peter said, you're going to lose sharpness if you deinterlace. That's what happens when you take 60 fields and combine them to make 30 frames. What happens if you don't tell it to "always deinterlace" but just render it to a progressive MPEG-2 file? That may work better, not sure though. Could be a little nicer as it would add 3:2 pulldown for interlaced display but keep the source as progressive, so that it would look better on a progressive display like a computer monitor. This is relatively easy to do in Vegas, but I've not used Premiere Pro 2.0 yet, so I'm not sure what encoding options you have.
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Old May 11th, 2006, 01:14 PM   #6
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Peter,

Premiere has a history of very poor deinterlacing quality. I had hoped this was improved in 2.0, but it sounds like it hasn't, especially if it was noticed by your client (a non-professional). Perhaps other 2.0 users could chime in on their perception of the deinterlace quality of 1.5 vs. 2.0?

How about providing two versions? A version for TV, interlaced, and a version for computer viewing, deinterlaced?

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Old May 12th, 2006, 02:24 AM   #7
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joshua,this can be a very good idea and I think I will give him two copies in couple of hours.thanx!
what exactly does Vegas do?is it editing software or for dvd authoring?should I switch to it instead of Premiere?
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Old May 12th, 2006, 10:53 AM   #8
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youve never heard of Vegas?? wow dude.. where u been.. ?? :p

Vegas is an NLE not unlike Premier... however its a PURELY software based NLE and will virtually run on any configuration and almost any medium to high end spec.. with premiere though, it has Matrox HW available for it, however with this "realtime" performance, u still have to prerender... and being HW based, u are restricted to what u can and cant do... for me and what i do, HW based editing is too restrictive..
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Old May 12th, 2006, 12:07 PM   #9
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Peter,

I've been using Premiere for years with no hardware, and without pre-rendering. It supports realtime, and realtimes effects, only limited to the speed or your CPU and amount of memory. I can usually run two effects simultaneously on a P4 2.8 GHz w/ 1 GB memory.

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Old May 12th, 2006, 12:16 PM   #10
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Quote:
Originally Posted by Joshua Provost
Peter,

I've been using Premiere for years with no hardware, and without pre-rendering. It supports realtime, and realtimes effects, only limited to the speed or your CPU and amount of memory. I can usually run two effects simultaneously on a P4 2.8 GHz w/ 1 GB memory.

Josh
Ditto.

Also, while exporting in PRemiere Pro, disable the 'Always De-Interlace' option in the timeline.

Go to File > Export > Movie.
Click on 'Settings'
Go down to Keyframe and Rendering
Select Deinterlace Video Footage.
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Old May 15th, 2006, 01:13 AM   #11
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Quote:
Originally Posted by Aanarav Sareen
Ditto.

Also, while exporting in PRemiere Pro, disable the 'Always De-Interlace' option in the timeline.

Go to File > Export > Movie.
Click on 'Settings'
Go down to Keyframe and Rendering
Select Deinterlace Video Footage.
So,the video will be deinterlaced anyway?
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Old May 15th, 2006, 05:30 AM   #12
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the real question is: what make you think that deinterlacing would give you a better picture ?
there is to way to shoot, interlaced 1080i and 720p, each one having their own asset.
if you deinterlace a 1080i, it means you recompress the picture to another format. recompressing is always the first source of loss, especially on mpeg2-ts.
then , to make a deinterlaced picture out of two frames, you need to trade off something. either you drop a frame and resize to lower resolution (1080i60 to 720p30), or just lower resolution (1080i60 to 720p60), or blend two frames (make them a bit fuzzi on fast movement) to make 1080i60 to 720p30, or use a deinterlace process that can remove some part of picture (introducing artifact most of time).
So , to make it short, no deinterlace process would really improve image quality.
it si just a mean to go to another format when required (to transfer to film for example, on play on devices not supporting interlaced video).
Not a way to make picture better.

If yoiu really want to improve picture quality while going to deinterlaced, i would propose such workflow.
uprez your 1440x1080i to 1920x1080i.
then deinterlace using a soft that can interpret moving part of pictures.
then resize to 1280x720p
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Old June 30th, 2006, 08:54 AM   #13
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hi there,been away for some time.
I use deninterlacing to give me a little more "film" look when watching on TV.
If I don't deinterlace, the picture is fine on TV,but it is very amateur of "home video-ish", how to say it....Possibly on NTSC it's another story, but we use PAL and I do not want to have the same picture on DVD as on my camera.Without deinterlacing, I have exactly the same picture as on my cam, its like if I connected my camera straight to TV and watched the movie from camera.Can't stand that "home video" quality.
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Old June 30th, 2006, 09:16 AM   #14
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"If yoiu really want to improve picture quality while going to deinterlaced, i would propose such workflow.
uprez your 1440x1080i to 1920x1080i.
then deinterlace using a soft that can interpret moving part of pictures.
then resize to 1280x720p"

Interesting, however the generation loss your looking at here will compromise image quality, (interpolation up, then deinterlacing (further interpolation) then back down to 720p (3rd gen of interpolation)
Irrepsective of the fact that your attempt to scale to footage up to 1920, the generational loss, in addition with the interpolation generations is compromising your image.

IMO, a clean down conversion from 1080i to 720p should suffice and save u time,however, your STILL compromising quality as your interpolating up to 720p, from a temporal 540 fields.

As for PC's running interlaced...
here are afew things to consider.. most LCD panels and Plasma displays have inbuilt deinterlacing. This is why u dont notice the combing effect on most standalone commercial screens. However, run teh same footag through a PC and u WILL notice this combing. This is due to the excessivly high resolutions of PC's coupled with the lack of deinterlacing devices in the playback SW, the panel itself or PC CRT monitors.
In addition, the refresh rate of PC screens is usually higher than 50/60hz as found in our standard TV's. This again all contributes to the playback image qualty
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