iPad not playing compressed High Res videos?
Your suspicions on a 90mb file not being HD are correct. A 25 minute show that is HD would not be 90mb. Hell, that's even small for standard definition quality. Resolution and file size are very different. You can have a video file that is super compressed, but still runs in a higher resolution. The end-result will be a wide &amp; tall, but blurry, picture quality. 

As for why they are freezing on your iPad, it's possible that the conversion settings were a little off when someone created this file. I think this based on the small file size, mixed with high resolutions. It sounds like someone was trying very had to make a small file size and probably tweaked a bunch of settings on the export file to do so. It's possible the software you are trying to render it with (VLC, Infuse) are struggling to interpret the file. As you mentioned, the iPad can play other files fine.