In the context of DVDs, "jitter" can cause the signal you're trying to record to be doubled-up or skipped entirely. As a result, during the writing process, a few bits of data either get written twice, or are omitted.  These glitches often sound like tiny repeating clicks during playback, or imperfections in the video quality (less noticable). An approach that has produced good results is to do jitter correction in software. This involves performing overlapping reads, and then sliding the data around to find overlaps at the edges. Most DVD and CD recording programs will handle this, but if the Blank DVD or CD media is of poor quality, these errors are tranferred to the disc more easily and can't be corrected as well.