Viarte / Legato Motion-compensated FRC for
Smooth - Sharp - Superior Image Quality
Accurate Simulated Motion-blur for Effective Judder Reduction

Practical Solutions for Judder Issues

Interlaced Material

Interlaced material is generally at a high field rate such as 50i or ntsc60i, so it has less judder issues than progressive material at 30p or below. Nevertheless, if judder is present in interlaced material for broadcast, then the only effective way it can be dealt with is to deinterlace first, then add simulated blur, and finally reinterlace, as blur processing is not practical in the interlaced domain.

Furthermore, if you are attempting to publish interlaced video on the Web, then for the very best results, you need to deinterlace it first using the best available deinterlacer, and then down-convert it to your target frame rate (usually 30p, 25p, or 24p), while adding an appropriate amount of blur. In either case, our Demeler deinterlacer (incorporated into our Viarte standards conversion server) provides the first stage in obtaining high quality progressive frame rates at 60p or 50p prior to frame rate conversion and adding blur, while also maintaining the original detail and without introducing additional motion artifacts.

Frame-rate Conversion and Adding Blur

With a clean progressive input at higher frame rates, you may want to convert down to lower frame rates such as 30p, 25p for publishing on the Web, or down to 24p for blu-ray discs. The motion blur in the original higher frame rate is usually insufficient to prevent judder if we simply discard alternate frames (e.g. 60p->30p or 50p->25p). At this stage, added blur obviously must be synthesized. Adding accurate simulated motion blur is a sophisticated process, which works best on higher input frame rates for pixel-accurate motion calculations. It therefore gives best results when adding blur as part of the frame-rate downconversion process.

Our Legato tool is designed specifically to do high quality frame rate conversion, with the capability to add accurate, adjustable motion-blur.

Viarte incorporates both Demeler and Legato to perform full standards conversion, and has recently been successfully used to convert from ntsc60i to ntsc24p with added blur in a major movie production.


The following examples illustrate various downconversions, with varying degrees of added blur expressed as a shutter angle in degrees. We recommend downloading from these links first as the files cannot be viewed in real time over the Web.

Crowd_run 1920x1080_50p to NTSC24p with added motion blur
Old_town_cross 1920x1080_50p to NTSC24p with added motion blur
"Finding The Gold Within" group_pan_excerpt 29.97p to 23.976p with added motion blur

See our Legato Examples page for more examples.