My experience is the same as a reviewer below; the files aren't automatically merged, even if I point it to ffmpeg. But this is actually a plus! The DASH_A and DASH_V files are saved separately in my default download directory. So, if I want just audio or video, no need to do anything. And, the ffmpeg command to merge them is straightforward, and because it is a copy, fast and no loss of quality because of demuxing and muxing. e.g. ffmpeg -i file_DASH_A.mp4 -i file_DASH_V.mp4 -c:a copy -c:v copy file.mp4
Perfect!

Want to download 1080p and higher resolution videos? This is the only plugin does this with transparency.

Works like a charm!

unfortunately broken again. fix would be appreciated. thx

faltan opciones/links, menu innecesario; sorry

it worked like a charm for me. Thanks

Tut genau was es soll. Die unterschiedlichen Download-Methoden funktionieren. Bislang hatte ich keine schlechten Erfahrungen.
Wenn YD auch auf anderen Plattformen arbeiten würde währe es perfekt ;-)

Fonctionne avec les dernières MAJ FireFox

Wow, I'm so impressed I've actually registered to write this comment !

So I have been testing many ways to download the best audio quality from YT video. I've tried several online downloaders and apps and compared the output audio quality they offer.
But why there is such variety of audio formats and bitrates in audio files between many applications downloading from the same YT video ?
Because they all convert YT audio into another lossy format !

And then I found this extension ! When you download "audio only mp4" it doesn't convert anything, it lets you download audio file directly from google/YT servers and it's identical to origal audio you can hear while watching HD movie on YT (I've checked!) ! :)

So it's amazing extendion!
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My only suggestion would be to change extension of downloaded "audio only mp4" file to m4a or mp4a ,so it wouldn't look like real video file.

one addon to download them all

I highly suspect this add on of loading malware address which the antivirus catches. Many of the add ons on firefox are dangerous for security; the vpn misuses our facebook and so on.