The PowerShot SX510 HS supports a maximum video resolution of 1920 x 1080 pixels. That's over six times the video resolution of a 640 x 480 pixels camera, which is the most common video resolution supported by digital cameras that are a similar age to the PowerShot SX510 HS. 640 x 480 pixels is also supported by this camera. In addition, this Canon camera support a video resolution of 320 x 240 pixels and 1280 x 720 pixels. A video resolution of 1920 x 1080 pixels is equivalent to Full HD video. You will require a Full HD TV or better to appreciate this level of detail.
This digital camera's video resolution (1920 x 1080 pixels) is in fact the best supported video resolution amongst all bridge camera digital cameras that have been available for around the same time as the PowerShot SX510 HS.
The worst supported video resolution across similar types of digital camera is 320 x 240 pixels.