"Best Quality" detection is inaccurate

[Qazerowl]

When downloading a youtube video with a maximum resolution of 1080p or higher, youtube-dl will only download the 720p mp4 by default. I assume this is because it is detecting the quality of DASH videos incorrectly. While this can be worked-around by using -f 137/248/22/136/247/135/244/18/134/243/133/242/5/36/160 (which is, to the best of my knowledge, what the correct quality order should be), this is very inconvenient.

[phihag]

The DASH videos do not include audio.

You can use the experimental automatic merging with -f bestvideo+bestaudio. We're working on making that the default, but it must work for all users (even those without ffmpeg) before we enable it lest we break youtube-dl for inexperienced users.