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Old Nov 13, 2012, 01:09 AM
guyg is offline
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Sony action cam - slow motion 720x120 ??

HI
I did some AV at this mode with the sony actioncam
720 res on 120 fps
As i open the video in my editor.."normal speed x1 looks very slow
So to view at "normal" speed i need to X2 the speed on my editor.
slowing down the speed to 1/2 or 1/4 speed.. came out very slow but great video
Can someone explain why to see at normal speed i need to set the video peed up by X2
Tx
Guy
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Old Nov 13, 2012, 07:25 AM
Patrick Vos is offline
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I think it is because you were filming interlaced.
When filiming "Progressive" you make 25 images per second (aka 25fps). When making "Interlaced" footage you use a upper and lower field. This means you kinda split 1 frame into 2 frames. So to get a smooth film you need 50 (or in USA 60) frames per second.

120 / 2 = 60 frames (most likely interlaced)

There are techniques out there to "blend" frames etc. and "de-interlace" but it will never be the same as a progressive image.

Hopefully this helps
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Old Nov 13, 2012, 02:22 PM
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Patric
Tx for the info
Is there a way to evoid this interlaced during video
AS i just select the FPS at the camera and fly out there.
Is it in my edit software?

Thank you
GUY
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Old Nov 13, 2012, 02:27 PM
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HI
Got this from the web:
----------------------------------
Interlaced Footage:

All editing software is designed to edit interlaced footage. It's already in a correct format specification (i.e. NTSC video @ 29.97fps) and it means you can just edit the footage "as-is".


This is fine. You'll need to keep an eye on the field order, but you should know the field order of your source now. The main caveat with interlaced footage, in terms of editing, is that whenever you slow it down, or move it around, or apply certain effects, you need to deinterlace it. Deinterlacing can be good or bad depending on the method and, unfortunately, the method used by one of the most popular programs - Premiere - is pretty ugly. In fact, most stock deinterlacing features in editing programs are pretty crap so, during these parts, your video will look sub-standard. Also, if you need to edit a still in photoshop or use a mouth section for lip-synch you need to get sections that aren't interlaced otherwise things can get really messy.

The secondary issue with interlaced footage arises when you want to distribute your video for playback on a pc. Monitors are progressive devices and interlacing looks ugly, so you need to remove it somehow. The best way of removing interlacing from NTSC video is to recover the original film frames using a process called Inverse Telecine or IVTC. This works best when done before you edit - it is very difficult to successfully IVTC after you have edited the source.


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Old Nov 14, 2012, 06:12 AM
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Quote:
Originally Posted by guyg View Post
HI
I did some AV at this mode with the sony actioncam
720 res on 120 fps
As i open the video in my editor.."normal speed x1 looks very slow
So to view at "normal" speed i need to X2 the speed on my editor.
slowing down the speed to 1/2 or 1/4 speed.. came out very slow but great video
Can someone explain why to see at normal speed i need to set the video peed up by X2
Tx
Guy
Because its a slow motion capture, there is no interlacing, there is just 120 frames of video per second that is set to play at 60 frames per second. So 1 second of video recorded will take 2 seconds to play, which also makes for a nice cinematic aerial video.

Thats why you need to view it at twice the speed to look normal, there really isnt much to gain by playing 120fps video at 120fps unless the video was really jumpy.. Go here to see the differences/examples between the two.

http://boallen.com/fps-compare.html

http://frames-per-second.appspot.com/
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Old Nov 14, 2012, 02:04 PM
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Tx allot pach for the info
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Old Feb 28, 2015, 03:39 AM
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Sony Action Cam HDR AS20 SSlow Motion (GoPro Comp…:
Sony Action Cam HDR AS20 SSlow Motion (GoPro Competitor) Sand, Surf, Underwater and Snow Footage (16 min 26 sec)
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