Is this possible? I'm trying to blow up the subtitles of some anime to watch on my PSP. Thanks in advance.
No different from blowing up any image or video. You just zoom in. Just like zooming in on any image though it is going to become blocky. I guess if I were doing it I would use AVISynth. Crop to seperate main video and subs. Zoom the subs. Crop/resize them back and then use stackvertical() to join it all back together. My advice though would be to get some glasses. Does the PSP support ttxt subs (official mp4 subs) or Nero's vobsubs? If it does and you could find external subs you could just crop the old ones off.