Audio downloaded with conversion is capped at 160kbps bitrate

Version

6.2.4

Details

YouTube Video Link: https://www.youtube.com/watch?v=g6jK6blyPc4

I get an 237kbps webm audio stream but when I download it the file properties show it as 160kbps.

I guess this a limitation from YouTube but how do I even get this 237kbps stream in the first place?

Steps to reproduce

Get the stream: var audioStream = manifest.GetAudioOnlyStreams().First(x => (int)x.Bitrate.KiloBitsPerSecond == kbpsBitrate);

Download it (Tried saving as webm and mp3):

await Videos.DownloadAsync(fullStream, new ConversionRequestBuilder($"{filePathAndTitle}.{(onlyAudio ? ".mp3" : ".mp4")}")
                .SetFFmpegPath(FFmpegPath).SetPreset(ConversionPreset.UltraFast).SetContainer(onlyAudio ? "mp3" : "mp4").Build(),
                new Progress<double>(x => progress(x)), _cts.Token);

See in file properties only 160kbps bitrate

[BlyZeYT]

Interesting, maybe they raised it.

If you download the stream without conversion (i.e. not through YoutubeExplode.Converter), does the player still show 237kbps?

When I download only the audio stream without conversion the bitrate is the same

[Tyrrrz]

I think what might be happening is that FFmpeg converts the media from constant bitrate to variable bitrate, to reduce file size while keeping quality more or less lossless.

As for this:

When I do it like this I get 224kbps instead of 237kbps xD

It might be because FFmpegCore and YoutubeExplode counts units differently (1024 bytes in kilobyte vs 1000)?