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Filed/interlace issue with Quicktime export
I am working with a 1920×1080 25 fps sequence. It all plays and looks fine in Final Cut but whenever I export as Quicktime I getting a terrible double image filed thing with bad interlacing artifacts. I’ve looked carefully at the output settings and they seem to match the sequence data – Apple ProRes 422 25 fps 1920 x 1080. I’m at a bit of a loss as to why this is happening. I’d be grateful for any guidance.
Here is a screen grab of the QT movie export:
Thank you.
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25 Replies
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I have now seen that these fault appears on the original footage although in not such an extreme way. I guess it’s a camera fault.
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no, it is not a fault, it is called ‘interlacing’.
This is what you have shot, and it is normal behaviour.If you want to output for broadcast / dvd / blueray, it is just fine.
Otherwise, de-interlace when transcoding to your output of choice.Bouke
https://www.videotoolshed.com/
smart tools for video pros -
Ya, ur viewing interlaced footage on a comp. screen.
Chris Tompkins
Video Atlanta LLC -
Thank you Bouke
Is this really just a problem of viewing interlaced footage on a computer monitor? It certainly looks fine on the rather small camera monitor. But as soon as I import it onto my Mac I get the artifacts – whether viewing the MTS files directly in VLC or after import into FCP. I have already tried a de-interlaced export as MPEG 4 but it was only partly successful, reducing the problem but not eliminating it. I’m now trying a Quicktime de-interlaced export from FCP.
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1) Stop calling this a ‘problem’. It is NOT a problem, it is the way it is intended to be.
2) Of course it looks fine in the camera. Do you think anyone would buy a camera that has a crappy viewfinder?
3) You can set up VLC to display interlaced material as fields, or de-interlace. Two menu items, one to turn it on/off, the second to choose the method.
A very extreme interlaced sample file is here:
https://www.editb.nl/fielddominancechange/
(Get the .mp4)This is one line black, one line white alternating.
This gives you a 50 Hz flicker if it is played one field after another, as it is on a normal TV.
(50 Hz as the file is 25 fps interlaced)
Toy with it, it shows a bit on how the different de-interlacers work.
Eg throwing away one field results in a pure black or white image, depending what field is trashed. Not suitable for SD de-interlacing, but can be good going from HD to small internet video.4) De-interlacing can be done in a huge amount of ways. FCP export uses QT, if you set de-interlacing there, you don’t get the best.
Compressor or any other encoding app. will give you better results.
Always, First de-interlace, then scale. If you first scale you introduce artefacts that cannot be repaired.
Note, the normal ‘ugly’ display of interlaced material does not contain artefacts, as it is NOT wrong!Bouke
https://www.videotoolshed.com/
smart tools for video pros -
You Shot HD Interlaced.
Edit HD Interlaced.
Export “Current Settings”Take that file into a compression program and create your deliverable such as Web, DVD, iPhone, whatever.
This is where you deinterlace in the process, when you are compressing to the deliverable.
Chris Tompkins
Video Atlanta LLC -
Thank you for your help Bouke and Chris. I guess I was figuring that this wasn’t a straightforward interlacing issue because I wasn’t getting good results when de-interlacing on export from FCP – the problem did not go away. Now I’m going to play with this after exporting and see how I can improve things.
All the best
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Further to my previous posting, here is a grab from de-interlaced Quicktime export from FCP.
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Don’t “de-interlace” when exporting from FCP.
Export “Current Settings”
See previous post.
Chris Tompkins
Video Atlanta LLC -
Thanks Chris – will work on this.
Best
Phil
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