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View Full Version : What causes this horizontal "lag" i video? W/PIC



brendanryder
Mar 12, 2009, 07:09 PM
so i was watching a video and noticed that whe ever there was motion going on there would be parts that looked like they suffer from lag.
from what i can see form the screen grab it looks really bad. Is this from a shooting in like 60i and then converting to 24P because it almost looks like its missing part of the image?

http://img21.imageshack.us/img21/2204/picture3hpv.png

I would of googled this but im not sure what it is haha

Thanks


suburbiton
Mar 12, 2009, 07:11 PM
Look up tearing.
brendanryder
Mar 12, 2009, 07:14 PM
ok so its my computer and not the way the video was recorded then right?
suburbiton
Mar 12, 2009, 07:18 PM
Could be the video - depends where you're watching it (if it's on YouTube, for example, it could have been uploaded like that).
brendanryder
Mar 12, 2009, 07:22 PM
Could be the video - depends where you're watching it (if it's on YouTube, for example, it could have been uploaded like that).

http://www.skateperception.com/viewvideo/17739/
suburbiton
Mar 12, 2009, 07:25 PM
Ah - that's an interlacing artefact. That's cos it was recorded on a rubbish camcorder, edited on a ***** computer, ripped onto a DVD, uploaded to a website etc. etc. and each time its being converted and reconverted from different formats and some things think it's interlaced, others progressive and it all gets messed up.

It's not your display.
brendanryder
Mar 12, 2009, 07:27 PM
haha ok thanks.
So moral of the story is dont compress and recompress and export and import a bunch of times at different points?
LethalWolfe
Mar 12, 2009, 07:44 PM
Ah - that's an interlacing artefact. That's cos it was recorded on a rubbish camcorder, edited on a ***** computer, ripped onto a DVD, uploaded to a website etc. etc. and each time its being converted and reconverted from different formats and some things think it's interlaced, others progressive and it all gets messed up.

It's not your display.
Playback interlaced footage on a progressive monitor (like a computer monitor) and you will always see the individual fields. It doesn't matter if you are using a $50 camera off eBay or a $50,000 camera new off the shelf. Interlaced footage is designed to be viewed on an interlaced display and, w/o de-interlacing at some point, will not playback properly on a progressive display.


Lethal
bimmzy
Mar 13, 2009, 06:24 AM
haha ok thanks.
So moral of the story is dont compress and recompress and export and import a bunch of times at different points?

The moral of the story is that interlace video look great on an interlaced display, and progressive video looks great on a progressive display.

If, as most indi videos are, viewed on peoples computers (which have progressive displays) your interlaced material will show all its nasty artefacts. It's best to covert to progressive by de-interlacing for this purpose.

The up side is that scenes with masses of action will be artefact free.
The down side is that the resolution of you video will be trounced.

Advise: use a smart de-interlacer to preserve vertical resolution. :D