Free online video downloader for YouTube, Instagram, Facebook, Twitter and
many other sites
For HD Videos >= 1080p:
Directly save videos in 4K/HD quality online is hard, but you can free use VideoProc to save video/playlist from 1000+ sites in batch and original quality. Convert, edit, record and more.
Merge video and audio formats together, some websites like YouTube provide high quality videos as separate video and audio files, now you can merge these files together and save a high quality (1080p Full HD) video
Cut the video or audio file online by choosing the start and end time
Save video and audio files using an alternative download method if the original download links are not working for some reason
Download video subtitles and closed captions when they are available