Quantcast Interlace, how "fields" are retained through editing - digitalFAQ Forum
Go Back    Forum > Digital Video > Video Project Help > Encode, Convert for discs

Reply
 
LinkBack Thread Tools
  #1  
02-16-2011, 09:29 AM
magillagorilla magillagorilla is offline
Free Member
 
Join Date: Jan 2011
Posts: 17
Thanked 0 Times in 0 Posts
Interlace, let's talk about it.......

I know what interlace is and why it exists but I'm confused about how it operates between different hardware and software.

I'm working on my never ending home movies restoration job. All my VHS tapes are caped in HUFFYUV 720x480i. So the files look more or less identical to the original VHS except the rescale. Now when I play the HUFFY files back in, say, VLC and choose the de-interlace option, it does a fairly good job on playback. Also AVISynth does a good job of de-interlaceing.

But... if I want to leave the video interlaced, how does software and hardware understand how to de-interlace video? I derailed my logic when I realized that 720 is a higher resolution than the original VHS frames, therefore I have effectively doubled up on some pixels. How in the world does my playback system know which pixels belong to which fields? If I place a black mat over my frame or resize the footage and encode is to MPEG2 and burn it to DVD, do I get some weird multiple interlace? How does anything in the encode/playback chain keep track of "fields" when footage has been re-scaled?
Reply With Quote
Someday, 12:01 PM
admin's Avatar
Ads / Sponsors
 
Join Date: ∞
Posts: 42
Thanks: ∞
Thanked 42 Times in 42 Posts
  #2  
02-16-2011, 11:50 AM
NJRoadfan NJRoadfan is offline
Premium Member
 
Join Date: Sep 2010
Posts: 1,134
Thanked 350 Times in 287 Posts
Keep in mind that interlacing applies only to the vertical resolution (the 480 part). Every other horizontal line in your video is part of a field. Editing software is made aware of interlacing by you telling it or if the file itself is flagged as interlaced.

De-interlacing is far from a perfect science. Different methods have been developed through the years and some work better then others depending on content. Thats why programs like VLC give you multiple options to deinterlace your video.
Reply With Quote
  #3  
02-16-2011, 10:56 PM
admin's Avatar
admin admin is offline
Site Staff | Web Development
 
Join Date: Jul 2003
Posts: 4,333
Thanked 635 Times in 452 Posts
There's also variations in hardware vs software algorithms, and then the past couple of years have seen some impressive software processing from the command-line video tools like Avisynth and mencoder. Yadif, YadifMod, and the NNEDI family, for example. There's a few more, too. Speed and quality varies highly. There's even been some decent repair tools created, that can fix deinterlacing damage.

- Did this site help you? Then upgrade to Premium Member and show your support!
- Also: Like Us on Facebook for special DVD/Blu-ray news and deals!
Reply With Quote
Reply




Similar Threads
Thread Thread Starter Forum Replies Last Post
Video capture with horrible color noise bands? lzrplayr Capture, Record, Transfer 23 02-07-2021 04:34 PM
Fixing JVC DVD recorder "LOADING" / JVC will not recognize blank DVDs via Email or PM Video Hardware Repair 14 09-24-2020 07:35 AM
Recommendations to transfer video from capture PC to main PC? GroverXpup Project Planning, Workflows 3 11-24-2017 05:13 PM
Add HTML option to vBulletin 3.x "Send Email to Users" admincp admin Website and Server Troubleshooting 0 04-28-2010 08:29 AM

Thread Tools



 
All times are GMT -5. The time now is 06:01 PM