[grc] Converting file format question

[Brian Shiratsuki]

audacity 2.2.1 on ubuntu 18.04.1 opens my test .opus file.

if your workstation is linux, then you could install opus-tools, and
use opusdec to decode to a .wav file.

if it's a mac, then opus-tools is in macports and probably brew. if
you don't use either of those, then you could download a pre-built
ffmpeg and figure out how to use that. you would, however, be trusting
a party in the christmas islands for a faithful, untainted build:

<https://evermeet.cx/ffmpeg/>

it might be possible to use afconvert from a recent macos to decode
opus. unfortunately, the opus is probably in an ogg container, and it
could be that afconvert does not understand those. the Internet has
instructions for using afconvert to create caf opus, but not for how
to ingest ogg caf.

brian s

briChrome:~> file foo.opus
foo.opus: Ogg data, Opus audio,

briChrome:~> opusdec foo.opus foo.wav
Decoding to 44100 Hz (2 channels), Header v0
Encoded with libopus 0.9.9-21-g8770b07
artist=Ehren Starks
title=Paper Lights
album=Lines Build Walls
date=2005-09-05
copyright=Copyright 2005 Ehren Starks
license=http://creativecommons.org/licenses/by-nc-sa/1.0/
organization=magnatune.com
Decoding complete.

briChrome:~> file foo.wav
foo.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit,
stereo 44100 Hz

On Thu, Jan 24, 2019 at 10:13 PM Frieda Werden via grc
<grc at maillist.peak.org> wrote:
> I have received a batch of files in Opus format and have not been able to
> open them in Audacity.  I see a number of sites that offer online
> conversion of Opus to .wav and/or mp3.  But a few years ago I had an
> experience where an online file converter I used successfully was later
> hacked and downloaded a virus.  Does anyone have online or offline
> solutions for doing this conversion?