The free version works fine for simple MP4 downloads. However, if you want to download an entire playlist, convert to MP3, or use the accelerator, you have to pay $30 a year. That is expensive compared to lifetime licenses from competitors.
For complex streaming protocols (like HLS or MPEG-DASH), AVD often requires a Native App (companion software) to merge video and audio segments that browsers cannot handle alone. Core Features & Benefits The Best Firefox Addons - MakeUseOf ant video downloader