PDA

View Full Version : Content Problems



Woodj32177
28-09-2007, 11:03 PM
OK,
So I have some content from a client,
I had them encode it in the Photo jpeg codec at 70% quality.
but I am getting Jagged edges every time the video moves.
I understand this is Interlacing jaggedness,
but the person I am dealing with doesn't think photo-jpeg can be exported de-interlaced,

I believe he is using avid to export the content,
Any help would be appreciated, even if it is just instructions on how to export de-interlaced video from avid.

Would using the DV codec help, I was trying to use Photojpeg to get a bit more quality, but if I have to I will go back to DV.

Any help would be greatly appreciated!

Joshua Wood

samsc
28-09-2007, 11:16 PM
OK,
So I have some content from a client,
I had them encode it in the Photo jpeg codec at 70% quality.
but I am getting Jagged edges every time the video moves.
I understand this is Interlacing jaggedness,
but the person I am dealing with doesn't think photo-jpeg can be exported de-interlaced,

I believe he is using avid to export the content,
Any help would be appreciated, even if it is just instructions on how to export de-interlaced video from avid.

Would using the DV codec help, I was trying to use Photojpeg to get a bit more quality, but if I have to I will go back to DV.

Any help would be greatly appreciated!

Joshua Wood

interlacing or deinterlacing has nothing to do with the codec -

interlacing is an artifact of the way most video cameras work. If you shoot on film you dont get this - ( unless they do a 2:3 pulldown in telecine )
They dont work at 30FPS they split the image into two fields each 1/60s long - they then combine this into a single frame.
interlaced video looks like this: ( when displayed on any LCD or progressive scan monitor )
http://www.100fps.com/
http://en.wikipedia.org/wiki/Deinterlacing

---

Typically - Deinterlacing - is not part of an 'export' process - but part of the effects applied to a layer.
With live action footage - on any post-production software - irrespective of any subsequent use - it will need to be deinterlaced before zooming, scaling rotating, or even shifting..

In final cut - you apply the deinterlace filter to the layers and cliips.
i dont know anything about the avid workflow.

There are more complex software filters available from 3rd parties to do this -
deinterlacing accurately - is not easy or trivial.
3rd party plugins specialised to do this job:
For example the 'Fieldkit' from revision FX
http://www.revisionfx.com/products/fieldskit/

Richard

samsc
28-09-2007, 11:19 PM
Would using the DV codec help, I was trying to use Photojpeg to get a bit more quality, but if I have to I will go back to DV.
Joshua Wood

using dv wont help- footage will look the same.

dv doesnt deinterlace footage.

samsc
05-10-2007, 02:15 PM
The same problem will happen if content creators - turn on field rendering in after effects - or any other program.

this is a render setting in after effects.

you must insist that all content for media servers is rendered as FRAMES not fields.

basicmonkey
05-10-2007, 02:18 PM
I seem to get lots of Interlace artifacts (lines on motion) when playing back 1080i material through cat, i have tried a few formats in compressor, including AIC and PhotoJpeg, but it seems it's not so much the format but de-interlacing that matters.

In compressor I've tried de-interlacing the HD files and while taking a very long time does actually solve the problem.

I know this isn't a cat issue as QT seems to have trouble with 1080i HDV files, but is de-interlacing with compressor the only option?

Also I do love your new hidden feature, would a de-interlacing AIC option be possible in the future? tried the AIC one and still has those dam lines.

Thanks,

James

samsc
05-10-2007, 02:21 PM
you need to deinterlace the content, you need to work with either the content creator to ensure its frame rendered or you need to deinterlace yourself using whatever tools you have.

you will need to experiment.

there is not a single answer to the best way to deinterlace.

the interlacing is NOT a codec thing. its a content problem irrespective of codec. doesnt matter which codec you use.

samsc
05-10-2007, 05:24 PM
Also I do love your new hidden feature, would a de-interlacing AIC option be possible in the future?James

its possible to do simple deinterlacing by throwing away one half of the image- every other line.
but this isnt always acceptable-

this is what final cut does- in its simple deinterlace options.

samsc
06-10-2007, 08:58 PM
i have never tried this software - but it claims to do some of these things

jes-deinterlacer
http://www.macupdate.com/info.php/id/13069/jes-deinterlacer

there is also fields kit from revision fx

http://www.revisionfx.com/products/fieldskit/

and most editing and fx programs do deinterlacing as an fx on a layer.

roberto_novelli
07-10-2007, 07:50 PM
check

samsc
19-02-2008, 09:02 AM
I know this isn't a cat issue as QT seems to have trouble with 1080i HDV files, but is de-interlacing with compressor the only option?

James

HDV 1080i files - depends on the camera - and whether the camera shot interlaced or progressive.
My V1P makes progressive 1080i frames.
Most HDV cameras dont do this.

Suggest all HDV files are converted to apple intermediate codec.

SourceChild
19-02-2008, 07:03 PM
I cannot begin to tell you how many times I have had this problem. I have several church clients who all want "the outdoors" on their screen "indoors" (go figure).

Bottom line is they all tend to use camera footage which is interlaced. In addition to that, I also get tons of IMAG feeds which are also interlaced.

It's a nightmare:mad:

Here is the solution. Don't tell the content creator anything about the output file or the or the aspect ratio. Instead, have them export their files as close to uncompressed as possible in either a standard 3:4 size or a 9:16 size.

Just give them the crop specifications to create a window proportionate to the output screen.

What I mean by this is for example if you have 3 1024x768 projectors doing an edge blend of 25%, you'll end up with 2048x768. If you do the math, a scale conversion of that is 1920x720. This means that you tell your content creator to make an HD file at 1080p but you tell him the window frame is 1920x720 and the top and bottom strips 180 pixels are just dead space.

Once he outputs the file and sends it to you, you do the conversion, crop the file, and render it in the correct codec using one of the nicer programs like Richard mentioned for doing your interlaced to progressive conversions.

Incidentally, there is another thread that talks about i vs p and I would recommend you read it because there is a website link in there that shows just what kind of problems you'll run into converting from interlaced to progressive.

clyde
19-02-2008, 09:19 PM
A quick and dirty fix that works on any server when time is limited is eg.
One layer interlaced PAL rubbish
One layer PAL scan line png
multiply blend
a very very very little amount of blur
and wallah

of course goes for any res as long as the scan lines match the footage

samsc
19-02-2008, 09:47 PM
interlacing isnt just a problem for media servers- its a problem for everyone in post production...

you have to deinterlace anything whenever you move, shift, scale or rotate any image in any editing program