You can easily detect video noise by looking for a buzzing pattern that quickly changes from frame to frame. It’s best seen in real examples:

Noise usually appears in poor light conditions (night, dusk, indoor video, cloudy day…). Higher quality and more expensive cameras create better videos with less noise on average because they have larger sensors and bigger lenses that let more light in.

On the other hand, mobile devices have much smaller sensors (cheaper) but suffer from a lot more noise if the lightning is not perfect (think, sunny day and outside). Try to zoom into a picture you’ve taken indoors with your phone and you’ll what we’re talking about.

The easiest way to find this out is to open a video in your favorite video player and play it. If you see the tiny buzzing pattern, then we advise that you apply the noise reduction filter.

Noise and grain look very similar, but are caused by different things. Grain is typically found in older film tape formats like 32mm, 16mm, and 8mm. The grain is one of the things that give movies that unique 'film look', and it’s a good thing to have.

Noise is created when the camera signal is disturbed and it’s unwanted in videos/images. Noise can be in color, while grain is almost always without color.

Left side of the picture shows grain, while the digital noise is non the right. You can clearly see the noise has color, while grain has no color.