when using "--audio-format vorbis", will a opus file be embedded in a ogg container or transcoded to vorbis?

[jjgh]

Since ogg is a container for both Vorbis and Opus, do you know what will happen when I download an audio only (DASH) .opus file together with the parameter --audio-format vorbis? I see that the resulting file extension is .ogg, but is the opus file being transcoded to Vorbis, or is it only being embedded in the resulting ogg container?

[dstftw]

> py -3.6 .\youtube_dl\__main__.py BaW_jenozKc -f 'bestaudio[acodec^=opus]' -x --audio-format vorbis
...
[download] Destination: youtube-dl test video ''_ä↭𝕐-BaW_jenozKc.webm
[download] 100% of 186.27KiB in 00:00
[ffmpeg] Destination: youtube-dl test video ''_ä↭𝕐-BaW_jenozKc.ogg
Deleting original file youtube-dl test video ''_ä↭𝕐-BaW_jenozKc.webm (pass -k to keep)
> ffmpeg.exe -i '.\youtube-dl test video ''''_ä↭𝕐-BaW_jenozKc.ogg'
...
Input #0, ogg, from '.\youtube-dl test video ''_├дтЖнЁЭХР-BaW_jenozKc.ogg':
  Duration: 00:00:09.85, start: 0.000000, bitrate: 94 kb/s
    Stream #0:0(eng): Audio: vorbis, 48000 Hz, stereo, fltp, 160 kb/s
    Metadata:
      LANGUAGE        : eng
      ENCODER         : Lavc57.93.100 libvorbis
At least one output file must be specified

 ENCODER         : Lavc57.93.100 libvorbis

[jjgh]

@dstftw ok, so it seems it's just being copied into the new container and no transcoding is happening, correct?