Tips to make YouTube videos clear

By default, YouTube video resolution is only 320x240, so even a video that was originally clear will be heavily compressed and blurred when uploaded to YouTube. Due to the increasing speed of Internet access in foreign countries, YouTube confirmed in November last year that it will keep up with the trend and will provide users with clearer video playback. In December last year, we have already previewed a resolution of up to 960x540. YouTube video, the effect is quite good. Now, if you want to watch more clear YouTube videos, you can refer to the following.
First of all, these methods are only valid for a small number of existing YouTube videos in HD, not all. As for which videos are available in HD, it is only up to you to experiment. For example, the following example, the video of the popular puppy skateboarding on YouTube, the original version is this effect:

original effect

But if you add a video link &fmt=6 parameter, after the link becomes the following form, you will find that the video becomes a clearer version (the resolution is unknown, but definitely higher than the original 320x240):

http://Youtube.com/watch? v=CQzUsTFqtW0&fmt=6

Take a look at the comparison of the same scene (roughly), left for the original version, right for the clear version:

Picture comparison

Similarly, if you add the parameter &fmt=18 to the link, YouTube will turn the video into a clear version of 480x360, such as the following:

http://www.youtube.com/Watch? v=QAE2-FQHkok&fmt=18

Due to the clarity, the video will load longer than before under the same network conditions. But if your internet speed is fast enough and you don't want to manually experiment with parameters every time, you can install the FireFox script so that every time you open a YouTube video, it automatically adds parameters; if the video has a clear version, then You will see a clear version, and if you don't have it, it will return to the original version.