Audio bitrate in YouTube videos?

Question

This video clip: https://www.youtube.com/watch?v=wc0PB6Azwn0

What is the max audio bitrate and how to detect real audio bitrate? is it the same? Please no rumors and no guessing.

Does it depend on the video quality I am watching (1080p, 720p, etc)? If you say - yes, it makes no sense, because the clip was uploaded at one bitrate only.

Hope, someone who knows the subject can answer that questions. Is it possible to detect the audio bitrate from YouTube video at all? Stats for nerds is useless, it shows no audio bitrate. Taking consideration lossy (vs lossless) audio max is 320 Kbps, it cannot be higher than that by definition.

Anyone who knows?

Answer 1

You can use the command line tool youtube-dl to list all available transcodings for a given YouTube video by running youtube-dl -F <url-to-your-video>.

Example output using the URL mentioned in your question:

Studying the output we can see that the audio transcoding with the highest bitrate is "format 251" using the opus codec at an average bitrate of around 145k. Note that YouTube is not using a fixed bitrate but rather a variable bitrate with target of ~160k.

The opus codec is currently supported in most modern browsers (but not Safari). Browsers without support for opus will fallback to the m4a stream at a variable bitrate targeting ~128k.

If you want to make 100% sure which audio transcoding you're currently listening to, you can right click the YouTube video player and select "Stats for nerds" and look for the number mentioned in the codecs section and cross-reference that with the output given by youtube-dl: