There are several ways to improve the quality of a 720p video to HD. One way is to use a video converter software, such as AnyMP4, VideoProc, Aiseesoft, or EaseUS. These programs typically allow you to upload the 720p video, select an output format with a higher resolution (such as 1080p), and then convert the video. Some of these converters may also offer additional features, such as video editing or compression.
Another option for improving the quality of a 720p video is to use an online video converter, such as HDconvert or OnlineConvert. These websites typically allow you to upload the video, select an output format and resolution, and then convert the video. Some online converters may also offer additional features, such as video compression or the ability to convert the video to other devices or platforms.
It's important to note that while these methods can potentially improve the quality of a 720p video, the results may vary depending on the quality of the original video and the capabilities of the software or website being used. Additionally, converting a video to a higher resolution may increase the file size, so it's important to consider storage and bandwidth limitations when choosing a method to improve video quality.