Motion interpolation

Mock-up of a motion interpolation of a horse and rider galloping. Each two original frames on the top have an interpolated frame between them on the bottom.

Motion interpolation is a form of video processing in which intermediate animation frames are generated between existing ones, in an attempt to make animation more fluid.

Applications

HDTV

Motion interpolation is used in various display devices such as HDTVs and video players, aimed at alleviating the video artifacts introduced by framerate conversions in fixed-framerate displays such as LCD TVs. Films are recorded at a frame rate of 24 frames per second (frame/s) and television is typically filmed at 25, 50, 30 or 60 frames per second (the first two being PAL, the other two from NTSC). Normally, when a fixed framerate display such as an LCD screen is used to display a video source whose framerate is less than that of the screen, frames are often simply duplicated as necessary until the timing of the video is matched to that of the screen, which introduces a visual artifact known as judder, perceived as "jumpiness" in the picture. Motion interpolation intends to remedy this by generating intermediate frames that make animation more fluid. This feature has received many criticisms from many consumers because it made special effects in movies appearing less realistic, and decreasing the quality of the cinematography of the film.^[1]

It should be noted that, while common, not all 120 Hz HDTVs include a motion interpolation feature. Also, anti judder technology is not the same as motion blur reducing technology, but is frequently lumped together with it.^[2]

The commercial name given to motion interpolation technology varies across manufacturers, as does its implementation.

• Hitachi - Reel120^[3]
• Insigna - DCM Plus, for Digital Clear Motion 120Hz
• LG - TruMotion 120Hz, 240Hz
• Panasonic - Intelligent Frame Creation (IFC)
• Philips - HD Digital Natural Motion^[4]
• Samsung - Auto Motion Plus 120 Hz^[5], 240 Hz
• Sharp - Fine Motion Enhanced^[6]
• Sony - MotionFlow 100Hz, 100Hz PRO (XBR series, Australia), 120Hz, 200Hz, 240Hz.^[7][8]
• Vizio - MEMC (Motion Estimation, Motion Compensation)^[9]

Side Effects

Several Side effects can be introduced by the use of the technology.

• Stable Image (Positive)

According to CNET.com executive editor David Carnoy, with Sony's MotionFlow motion interpolation objects look more stable when the feature is turned on. This is sometimes accompanied by a glitch in the picture.^[2] Not everyone likes the effect and some complain that it gives film a "video" look.^[9]

• Artificial look (Negative)

The "video" look side effect is also commonly referred to as "Soap Opera Effect" after the way those shows looked, having been shot on cheaper 30Hz video instead of regular broadcast equipment or film. ^[10]

• Artifacts

Some implementations can result in added image artifacts such as "underwater" blurring.

PC video players

WinDVD uses Philips' TrimensionDNM for frame interpolation.^[11]

CrystalPlayer uses Motion Morphing MultiSampling for frame interpolation.^[12]

PowerDVD uses TruTheater Motion for interpolation of DVD and video files to up to 72 FPS.^[13]

See also

• HDTV blur
• Television standards conversion
• VidFIRE
• Motion Compensation

References

1. ^ http://shepherdsons.wordpress.com/2008/01/27/hd-ruins-movies-120hz-1080p-fake/
2. ^ ^{a b} Carnoy, David (October 25, 2007). "Six things you need to know about 120 Hz LCD TVs". CNET.com. http://reviews.cnet.com/4520-6449_7-6792632-1.html. Retrieved 2008-02-02. 
3. ^ Hitachi to Unveil New Line of Ultra Thin LCDs at CES
4. ^ Trimension
5. ^ Samsung LN-T4071F
6. ^ Sharp intros slate of new AQUOS LCD HDTVs
7. ^ SONY UNVEILS FIRST BRAVIA FLAT-PANEL LCD HDTVs WITH INTERNET VIDEO LINK COMPATIBILITY
8. ^ Sony's site for explaining Motionflow 200Hz using the world's largest zoetrope and Kaká
9. ^ ^{a b} Moskovciak, Matthew (January 8, 2008). "Vizio adds 120 Hz LCDs to its lineup". CNET.com. http://ces.cnet.com/8301-13855_1-9845306-67.html. Retrieved 2008-02-01. 
10. ^ Biggs, John (August 12, 2009). "Help Key: Why 120Hz looks “weird”". crunchgear.com. http://www.crunchgear.com/2009/08/12/help-key-why-hd-video-looks-weird. Retrieved 2009-11-13. 
11. ^ Intervideo WinDVD 8 Platinum
12. ^ Crystal Reality - ultimate video and multimedia solutions for PC, Symbian and PocketPC platforms
13. ^ "Video Enhancement - TrueTheater Technology". CyberLink. http://www.cyberlink.com/stat/technology/enu/true-theater-solution.jsp. Retrieved 2009-08-24.