Why when i upload on youtube my video shows in low quality ?

OK, first of all what is your video resolution. if it's 320x240, YouTube is going to convert that to low quality. If it's 640x480, or 720x480, then YouTube is going to consider these medium quality.(HQ) You will get to choose from 240p,360p, and 480p resolutions in the bottom right corner of your video on YouTube with these 2 resolutions. And for high definition, you would need to upload your video as either 1280x720, or 1920x1080 resolution, for 720p, and 1080p performance. DVD quality is 720x480, while a Blue ray disk is 1920x1080. It's all about resolution. YouTube doesn't care about mp3 or video bit rates. It detects video quality by the resolution of your video that you are trying to upload.