codec.software by Cole Williams Software

Encoder

CW-Opus

Opus encoder and decoder

WAV ↔ Ogg Opus

A Windows command-line Opus encoder and decoder with VBR, constrained VBR, CBR and Cole Williams pVBR, plus high-quality 44.1 kHz resampling, extensive OpusTags support and a self-contained Ogg Opus path.

Quality scale CW-Opus does not use q values. Use bitrate (-b) and mode selection; complexity 0–10 controls encoder effort, not a quality rank.
Download x64 Version 1.6.1.0 Download x86 Version 1.6.1.0
Overview Features How it differs Commands Downloads Verification

Overview

CW-Opus

A Windows command-line Opus encoder and decoder with VBR, constrained VBR, CBR and Cole Williams pVBR, plus high-quality 44.1 kHz resampling, extensive OpusTags support and a self-contained Ogg Opus path.

Features

  • Ogg Opus encoding from mono or stereo WAV
  • Ogg Opus decoding to 48 kHz PCM16 WAV
  • VBR, constrained VBR and constant-bitrate modes
  • Cole Williams pVBR when -cvbr is combined with an explicit -b value
  • Explicit -b value becomes the protective minimum in pVBR mode
  • High-quality 44.1 kHz to 48 kHz frontend resampling
  • Native Opus rates bypass frontend resampling
  • 8, 12, 16, 24, 44.1 and 48 kHz WAV input support
  • 16-bit, 24-bit and 32-bit integer PCM input
  • 32-bit floating-point WAV input
  • RIFF/WAVE and compatible WAVE_FORMAT_EXTENSIBLE PCM/float input
  • Encoder complexity from 0 to 10
  • Selectable 2.5, 5, 10, 20, 40 or 60 ms frame duration
  • Extensive OpusTags metadata support
  • Arbitrary Vorbis/Opus comments with --tag
  • Self-contained Ogg Opus writing without a libogg dependency
  • Encoding output can be written to stdout
  • Windows x64 and x86 release builds

Practical comparison

How CW-Opus differs

CW-Opus is a focused Windows Opus tool rather than a general multimedia framework. Its main differentiators are the Cole Williams pVBR bitrate-floor mode, a dedicated high-quality path for CD-rate 44.1 kHz input, and a self-contained Ogg Opus implementation with extensive metadata support.

pVBR: protected variable bitrate

Using -cvbr together with an explicit -b value activates the Cole Williams protective mode. The selected bitrate acts as a minimum floor while the encoder remains free to use more data when the material benefits from it.

Standard constrained VBR

Using -cvbr without an explicit bitrate retains conventional constrained-VBR behaviour. This keeps bitrate variation more controlled without applying the CW minimum-bitrate floor.

44.1 kHz handled directly

CD-rate 44.1 kHz WAV input is automatically converted to 48 kHz by the frontend before reaching libopus, so users do not need to resample CD material separately.

Native-rate bypass

WAV input already using a native Opus API rate is passed directly to the encoder without the 44.1-to-48 kHz frontend resampling stage.

High-resolution PCM input

The CLI accepts 16-, 24- and 32-bit integer PCM plus 32-bit floating-point WAV input and normalises it into the encoder’s internal 24-bit processing domain.

Self-contained Ogg path

CW-Opus writes and reads its Ogg Opus container path directly rather than requiring a separate libogg runtime dependency.

Command line

Command examples

Default VBR encode

Encode using the default 128000 bit/s target, complexity 10 and 20 ms frame duration.

Command Prompt
C:\> cw-opus.exe input.wav -o output.opus

Standard constrained VBR

Enable conventional constrained-VBR operation.

Command Prompt
C:\> cw-opus.exe -cvbr input.wav -o output.opus

pVBR with 192 kbit/s minimum

Enable the Cole Williams protective mode with 192000 bit/s as the minimum bitrate floor.

Command Prompt
C:\> cw-opus.exe -cvbr -b 192000 input.wav -o output.opus

High-quality pVBR

Use a 256000 bit/s minimum with maximum encoder complexity.

Command Prompt
C:\> cw-opus.exe -cvbr -b 256000 --complexity 10 input.wav -o output.opus

Constant bitrate

Encode using constant-bitrate operation at 192000 bit/s.

Command Prompt
C:\> cw-opus.exe -cbr -b 192000 input.wav -o output.opus

10 ms frames

Select a 10 ms Opus frame duration.

Command Prompt
C:\> cw-opus.exe -framesize 10 input.wav -o output.opus

Metadata

Encode in pVBR mode while writing common OpusTags metadata.

Command Prompt
C:\> cw-opus.exe -cvbr -b 192000 --title "Track" --artist "Artist" --album "Album" input.wav -o output.opus

Custom OpusTag

Add an arbitrary Vorbis/Opus comment.

Command Prompt
C:\> cw-opus.exe input.wav --tag "SOURCE=Studio Master" -o output.opus

Encode to stdout

Write the encoded Ogg Opus stream to standard output.

Command Prompt
C:\> cw-opus.exe input.wav -o -

Decode Opus to WAV

Decode supported Ogg Opus input to 48 kHz PCM16 WAV.

Command Prompt
C:\> cw-opus.exe -d input.opus -o output.wav

Project notes

CW-Opus does not use a q quality scale. Quality/bitrate behaviour is controlled with -b together with VBR, constrained VBR, pVBR or CBR, while --complexity controls encoder effort rather than a quality ranking.

The source internally describes -cvbr plus an explicit -b value as “CW protective cVBR”; codec.software uses pVBR as the public-facing name for that bitrate-floor behaviour.

The encoder currently accepts mono/stereo WAV input at 8, 12, 16, 24, 44.1 and 48 kHz.

Only 44.1 kHz input uses the dedicated frontend resampler; native Opus API rates bypass it.

The decoder currently supports mono/stereo Ogg Opus using channel mapping family 0 and writes 48 kHz PCM16 WAV.

SIMD optimisation remains described conservatively elsewhere; this CLI source does not itself define a public SSE/AVX dispatch contract.

Downloads

Download x64 Version 1.6.1.0 View download → Download x86 Version 1.6.1.0 View download →

Verification

Release downloads can be verified independently using the published SHA-256 checksum and Windows digital signature.

Publisher & digital signature Cole Williams Software Limited