I’ve been experimenting with the query string parameters after the main Youtube address. Some people may refer to them as “Youtube codes”, but the easiest way to explain them is that they are the ampersands and snippet of text at the end of the web address. This string of of code, the Youtube query string parameters, adds functionality to what is presented. There is no real comprehensive guide on the Internet for this, but I’ve compiled a short list of the Youtube codes I could find here so that when you need them, you’ll be able to find the Youtube codes or “query string parameters” faster than I did.
Update: If you’re looking for query strings for Youtube or Google Maps, you might try Map Strings if the other link isn’t working.
|&hl=||hl stands for Host Language (thank you MapKi!) It is followed by “hl Parameter Values” which correspond to “Language/Locales” ex. en-US means English (United States and Canada).
It also can stand for hoc loco, which is Latin for “in this place” or hl stands for “human language”, but not in this case.
|&video_id=||Youtube video ID – used in conjunction with &get_video? to embed a Youtube video into another application. Not supported by Youtubes terms of service and may no longer work.|
|&t=||Youtube video tag – used in conjunction with Youtube video ID.|
|&fmt=||&fmt=6 is good quality, &fmt=18 is better, and &fmt=22 is the best. Video must originally be in high definition (HD) to work. May not work regardless as this feature is in beta and not available for all videos.|
|&rel=||Rel stands for related. In relation to youtube, rel=1 means show related feeds and rel=0 means don’t.|
|&fs=||Allows the fullscreen button to show up or not. 1 means it will show up, 0 means it is disabled.|
|&start=225||Starts the video 225 seconds into the video.|
I recommend this extensive post on Youtube plugins and tools for more information and for advanced users, check out the Youtube Reference Guide. Also, check out this Google Maps Parameters Guide from MapKi and Youtube Query String Arguments.