windows 7 - Why remote desktop (RDP) isn't fast enough for watching videos on a remote PC?

On my iPad, I tried to remote control a computer on my local network and open a video on it, but it wasn't fast enough (the video refresh rate was terrible). I've purposely tried to connect to the local area IP 192.168.0.xxx, my router touts 54Mb/s of transfer rate. What do I need to do to make my view of the video on the remote PC more fluid?

Added (after reading keen's answer): For example, if I want to stream from twitch.tv, that's hard because twitch.tv's ipad app doesn't work the majority of the time, so I can't really go directly to the "source". Other times when i'm browsing a site on the computer, and it streams a video. I want to sit on a sofa and watch it. It's inconvenient for me to type in the address on my ipad's browser again to go directly to the source. And this is a small website that hasn't created an app yet.

Answer

54Mbps (which is 6.75MBps) isn't great speed in front of local disk speed. Despite the number is bigger than Blu-ray's 30-40Mbps bitrate, don't forget its theoretical number and RDP transfers RAW frames which isn't compressed as in video formats. So, video of your question shouldn't be high quality.

Now, do these things before creating RDC: Click on arrow next to "Options" to reveal "Advanced Options". Go to "Display" tab and change all display settings to maximum (like Colors to 32-bit). Go to "Experience" tab and change "Connection Speed" to LAN. Also, set maximum settings of all experience options.
Use maximum experience settings in your iPad client (as you haven't provided details about it, I can't further help).

Update after Question Update:
You can't compare video streaming with RDP streaming. Video formats are compressed formats. It means when you stream videos, compressed data (no redundancy) flows from server to client. But, the scene of RDP is different. With RDP, a part of video file (which is compressed) doesn't flow from server to client. RDP draws frames after seeing the screen. More details on screen (like at the time of FullHD video play) means big sizes of raw frames. As raw frames aren't compressed like videos, its causing you problem on slow network.

However, you aren't out of luck. You can use a nice RDP compression and acceleration software.