It's linked above— https://people.xiph.org/~greg/opus-tools.zip
Are you using this one?
C:\opus-tools>opusenc.exe
Usage: opusenc [options] input_file output_file.opus
Encodes input_file using Opus. It can read the WAV, AIFF, or raw files.
General options:
-h, --help This help
-v, --version Version information
--quiet Quiet mode
input_file can be:
filename.wav file
- stdin
output_file can be:
filename.opus compressed file
- stdout
Encoding options:
--speech Optimize for speech
--music Optimize for music
--bitrate n.nnn Encoding bitrate in kbit/sec (6-256 per channel)
--vbr Use variable bitrate encoding (default)
--cvbr Use constrained variable bitrate encoding
--hard-cbr Use hard constant bitrate encoding
--comp n Encoding complexity (0-10, default: 10)
--framesize n Maximum frame size in milliseconds
(2.5, 5, 10, 20, 40, 60, default: 20)
--expect-loss Percentage packet loss to expect (default: 0)
--downmix-mono Downmix to mono
--downmix-stereo Downmix to stereo (if >2 channels)
--max-delay n Maximum container delay in milliseconds
(0-1000, default: 1000)
Diagnostic options:
--save-range file Saves check values for every frame to a file
--set-ctl-int x=y Pass the encoder control x with value y (advanced)
Preface with s: to direct the ctl to multistream s
This may be used multiple times
--uncoupled Use one mono stream per channel
Metadata options:
--comment Add the given string as an extra comment
This may be used multiple times
--artist Author of this track
--title Title for this track
Input options:
--raw Raw input
--raw-bits n Set bits/sample for raw input (default: 16)
--raw-rate n Set sampling rate for raw input (default: 48000)
--raw-chan n Set number of channels for raw input (default: 2)
--raw-endianness n 1 for bigendian, 0 for little (defaults to 0)