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Comment by lozf | Hacker News Reader

The only point in lossy encoding is to save space / bandwidth. Opus excels at getting good sound quality at lower bitrates.

If there's a talk or lecture on Youtube that you're about to grab, try the 50kbps Opus version and save your limited space for more important things, but you might need to remux from webm to an ogg container for compatibility.

    e.g. youtube-dl -f249 $URL  --exec 'ffmpeg -i {} -vn -c:a copy {}.ogg'

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You can DL and listen to a longish YT track without the video - in far less time and with (usually) better audio - by specifying format 251 (usually available).

For example, an hour-long performance video mp4 at 1280x720 gets you 96k audio and 280MB. 'youtube-dl -f 251 url' will get you a 160K Opus in 54 MB.

To my ears Opus sounds sweeter and fuller than mp3. At 64K and lower bit-rates, it's near the top.

You can replace the --exec 'ffmpeg ...' with just -x (or the long form --extract-audio).

Yes, but with opus, that only put's the audio in a .opus container, which isn't as widely compatible as the .ogg container.

It is literally the same bits. Feel free to change the extension if that helps (it does on some old Android versions, for sure).

Source: I am a co-author on RFC 6716 and RFC 7845.

Oh, good to know, thanks :)

I love youtube-dl, but I usually just download the lowest bitrate Opus stream with two taps on my phone using NewPipe[1].

[1] https://newpipe.schabi.org/

If you have youtube-dl and ffmpeg installed together on linux or both executables in the same directory on windows, youtube-dl automatically remuxes "incompatible" formats into an mkv file.

Yes, that's great for videos, but many audio players don't support matroska containers. Putting the opus audio in an ogg container seems to be most effective to get a playable file for most people, so that's my default suggestion.

Isn’t opus the default companion for both H.265 and AV1 in an MP4 container?

So why wouldn’t opus audio only in an MP4 container be playable everywhere those things are as well?

I really think we need to stop overloading the .MP4 file extension and standardize “.av1opusmp4” or “.h265opusmp4” or similar even though it is still an MP4 container. Even .webm is now overloaded with two codec generations.

We don’t get a “codecs” HTML attribute in a file system (at least not portably).

> e.g. youtube-dl -f249 $URL --exec 'ffmpeg -i {} -vn -c:a copy {}.ogg'

Why not just `youtube-dl -x` ?

See my reply above.

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