[FFmpeg-user] Question about libopus encoding.

Ferdi Scholten ferdi at sttc-nlp.nl
Mon Dec 4 18:57:28 EET 2023

*cap_soundcommand* "ffmpeg -f s16le -ar %s -ac 2 -i - -c:a libopus -vbr on
> -compression_level 0 -application lowdelay -b:a 128k -y temp_a.nut"
> Is this VBR encoding, is `-b:a 128k` the average bitrate or maximum/minimum
> allowed bitrate ?
> _______________________________________________
It is vbr recording with an average bitrate of 128k

Also you specify the lowest possible quality settings (compression_level 
0 eliminates the highest quality encoding modes as a trade off to 
encoding speed), so I wonder why you use 128k vbr, (assuming stereo input)

You further restrict the encoder optimizations (with -application 
lowdelay, which tries to eliminate the lowest quality encoding modes) 
which might (or not) also lead to lesser quality and almost certainly to 
bigger then needed encodes. (The opus api documentation specifically 
states to use it with caution...)

You can omit -vbr on as it is the default setting

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