No, this is not a duplicate of this question.
I have been using youtube-dl to download some music videos from YouTube. I noted that left to its defaults, youtube-dl will use
bestvideo+bestaudio, and with recent videos, for
bestaudio it will nearly invariably download the Opus track.
I know that, encoded from source, Opus tracks usually have better quality than AAC tracks at the same bitrate.
However, I also know that Opus audio is not supported by the MP4 container, and since uploads to YouTube does not (yet) support MKV, the original upload would be using AAC. Which means the Opus audio track will be a lossy-transcode from AAC, potentially reducing quality.
(FI, I have no problem playing the remuxed video+audio using MPC-HC + K-Lite Mega Codecs, and I also have no problem extracting the audio using
ffmpeg -c:a copy and playing it using Foobar2000)
So, my question is: Do you think I should download the AAC track instead of the Opus track, or should I just let youtube-dl does its stuff? What benefit will I get downloading the Opus track compared to downloading the AAC track?