Can Ecasound Read Opus Audio Files?

Ecasound cannot natively decode compressed Opus audio files directly, as it lacks built-in support or library bindings for the libopus codec. However, you can easily read, process, and route Opus audio in Ecasound by decoding the stream on the fly using external utilities such as opusdec or ffmpeg and piping the raw audio into Ecasound through standard input or named pipes.

Native Format Limitations

Ecasound relies on standard audio libraries such as libsndfile, libvorbis, and specific external helpers for formats like MP3 and FLAC. Because the Opus interactive audio codec was developed after Ecasound's core format engines were implemented, .opus files cannot be passed directly into the -i:filename.opus input argument without generating an unsupported format error.

How to Read Opus Files in Ecasound

To read audio from an Opus file, you must decode the compressed data to raw PCM or WAV in real time and deliver it to Ecasound's standard input.

Method 1: Using opusdec and Standard Input

The standard Opus tools package provides opusdec, which can decode .opus files to stdout:

opusdec --force-wav file.opus - | ecasound -i stdin -o alsa

In this command:

Method 2: Using FFmpeg

If opus-tools is not installed, ffmpeg can be used interchangeably to decode the file to standard input:

ffmpeg -i file.opus -f wav - | ecasound -i stdin -o default

Method 3: Using a Named Pipe (FIFO)

For multitrack sessions where you need multiple inputs simultaneously, standard input is not enough. You can create a Unix named pipe (FIFO) to serve the decoded Opus stream as a regular file input:

mkfifo /tmp/opus_stream.wav
ffmpeg -i file.opus -f wav -y /tmp/opus_stream.wav &
ecasound -i /tmp/opus_stream.wav -o default
rm /tmp/opus_stream.wav

While direct reading of Opus files is not supported out of the box, integrating external command-line decoders allows Ecasound to seamlessly process Opus audio without manual pre-conversion.