The subtitles for a movie I was watching were quite obscure. After only a few minutes, I had to move the subtitles forward by 10 seconds. The movie was 2 hours and 20 minutes long. Halfway through, the subtitles shifted by -200, which I realized was the limit; I couldn't adjust them any further. On an iPad, I could quickly input the desired subtitle timing, while on a phone, I could only manually adjust it by 0.25 seconds at a time.