Movies and music fail when syncing to iPad from iTunes

Today I connected my iPad to my computer, and after adding, or attempting to add, movies to my iTunes, I synced the iPad to apply the changes. After I had synced these, it gave me more issues with movies; the new movies I had added to iTunes had not synced properly to my iPad, and hadn't appeared there. I tried deleting some of the movies I had on the iPad and resyncing them, and this didn't turn out well. The movies I deleted would not sync back to my iPad; they appeared there, but on iTunes had an exclamation mark ⚠ next to the name. On the iPad itself, it showed the movies, but wouldn't play them and said they had '0 bytes'. The movies I had originally added to my iTunes and tried to sync to my iPad turned out to be another issue and would not be added to my iTunes properly.

This is purely about the issue of the movies not syncing properly to my iPad. I recently tried ticking the 'Manually manage music and videos' button, and I checked 'Sync Music' and 'Sync Movies' in the tabs near, and when I did a message popped up saying that it needed to remove the music and movies on my iPad, then resync them. I tried this hoping it would attempt to fix the issue, but it turns out my music is having the same issue now as the movies, and they won't let me play them.

I have tried restarting iTunes, restarting my computer, reinstalling iTunes and many more, but nothing works. I'm sure it's not a file type issue, because I have tried in .mp4 and .m4v for the movies and the music is .mp3 I'm fairly sure. Help would be much appreciated.