Youtube is currently the most favorite video sharing site out there. But the default video quality in Youtube is not very good. This is to ensure smooth video playback for majority of internet users who has bandwidth of 512kbps or less.
Whenever a video is uploaded to Youtube (.wmv, .avi, .mov, .mpg), it is automatically converted to a flash file format with a resolution of 320×240 pixels. The default data rate is about 240kbps.
But in many countries (korea, US, UK) broadband users have high bandwidth up to 8mbps! YouTube is currently encoding the videos to higher resolution and higher quality for users from these countries. But you need to explicitly enable it! Here is how,
Consider the following YouTube URL – http://www.youtube.com/watch?v=QAE2-FQHkok . When you watch this video, there is a link on the bottom which says watch this video in higher quality. Another way to turn on high quality is by appending &fmt=6 to the URL. Hence http://www.youtube.com/watch?v=QAE2-FQHkok&fmt=6 will enable high quality video at 448×336 resolution and the audio quality is also improved. If you attach &fmt=18, the video resolution increases to 480×360 and the video is downloaded as an MP4 file!
If you are always logged into your YouTube account, you can enable high quality videos forever by selecting Account->Video Playback Quality->I have a fast connection. Always play higher-quality video when it’s available.
High resolution support is still in experimental stage and only a very small set of YouTube videos support this. Obviously for this to work, the uploaded file should be of higher quality!