On Thu, Jun 02, 2016 at 08:01:15PM +0800, Robert Storey wrote:
> Hi Adam, thanks for bringing Opus to my (our) attention. I looked it up and
> it does sound enticing
>
> However, looking at https://trac.ffmpeg.org/ there doesn't seem to be
> anything about converting files to Opus.

I've never used ffmpeg, but that page does talk about opus support. And
indeed, in Debian I see:
ffmpeg Depends: libavcodec57
libavcodec57 Depends: libopus0
so it's compiled in. And as ffmpeg boasts support for "the most obscure
ancient formats up to the cutting edge", I guess it has an interface to
select such formats... just don't ask me how.

I've always used opusenc directly.

> I do realize that converting an MPS to Opus isn't going to improve its
> sound quality, it's new encodings that should make the difference.

Yeah, you'll usually want to do this for new files. As most mp3 you get
come as 320k, you might still want to reencode them to opus at 96k
(transparent for most) or 128k (transparent for all known cases) to save
disk space -- it shouldn't perceptibly degrade quality further.

> However, I can see some benefit in knowing how to do the conversion so
> that all the sound files can be in the same format.

There's one caveat: ReplayGain. Because of mastering crimes (see
https://en.wikipedia.org/wiki/Loudness_war) I use ReplayGain religiously.
However opus is not supposed to support ReplayGain, having switched to newer
and better R128. Unfortunately, the target level of R128 is noticeably
quieter, meaning that in a mix of mp3/ogg/flac/opus files loudness levels
will vary, something ReplayGain/R128 is meant to prevent. Some players
(like Clementine which I use most) do support ReplayGain on opus files,
however I know of no tool to add ReplayGain tags to opus. Thus, I go
roundabout way by encoding source->flac->ReplayGain->opus (flac, unlike wav,
supports metadata).

> Just wondering if you have any useful links?

So you want some GUI tool? Sorry but I'm strictly a console monkey, doing
all my encoding using find, for, etc.


Meow!
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An imaginary friend squared is a real enemy.