Every now and then I get some video that come with subtitle files. Some by default looks good on VLC. In some cases some will look ugly/distorted like this:


Upon opening the subtitle file with Textedit, I found these two lines in the first few line of the subtitle file:
PlayResX: 640
PlayResY: 480

Which clearly it's not correct. The correct video size should be:
PlayResX: 738
PlayResY: 420

After saving the file and replay with VLC show me a nice rendering of the subtitle:


You can also change the font, and some font styling. This might or might not work depends on the type of subtitle file.

Does my guide works for you? do let me know