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desbma / r128gain

Fast audio loudness scanner & tagger (ReplayGain v2 / R128)
GNU Lesser General Public License v2.1
171 stars 9 forks source link

opus: sample peak only diplays a minus sign #34

Closed MrGeorgen closed 3 years ago

MrGeorgen commented 3 years ago

When tagging an opus audo file( ogg container) the sample peak only shows a minus. The tag is fine however.

[mrgeorgen@mrgPC ~/Downloads]$ r128gain The_Weeknd-Save_Your_Tears.opus 
Analyzing loudness of file 'The_Weeknd-Save_Your_Tears.opus'... 
File 'The_Weeknd-Save_Your_Tears.opus': loudness = -7.9 LUFS, sample peak = - 
Tagging file 'The_Weeknd-Save_Your_Tears.opus'

I can upload the file, if you like

desbma commented 3 years ago

The - sign means the peak has not been calculated. This is done on purpose to respect the Opus standard for the R128 tags which does not define a format for peak tags, and calls them unreliable.

Peak normalizations are difficult to calculate reliably for lossy codecs because of variation in excursion heights due to decoder differences. In the authors' investigations, they were not applied consistently or broadly enough to merit inclusion here.

https://datatracker.ietf.org/doc/html/rfc7845#section-5.2.1

Don't ask me why they are calculated for other formats, as per the RGv2 specification, I am not a standard author.

MrGeorgen commented 3 years ago

ok, thanks for the info