The phrase "grainy quality" refers to a visual or audio characteristic that appears rough, textured, or pixelated, usually due to small particles or noise. Full definition
While large (I measured it at four and a half inches wide by three and a half deep) the texture has an unpleasant grainy quality. (digitaltrends.com)
In a 2003 interview with Hans Ulrich Obrist, reprinted in the Tate exhibition's catalog (which also reprints an interview that I did with Jonas last year), she recalls how «that grainy quality of early video was so strange, even otherworldly. (thenation.com)
It may sound flighty, but maybe there is a aesthetic feeling to such grainy quality, that this is the best that money can get, this is as far as material can go on such a cheaply made film. (cinema-scene.com)