Using Opus codec for GCompris voice files

[Timothée Giet]

Le 23/01/2022 à 13:43, Karl Ove Hufthammer a écrit :
> Hi,
>
> I’m currently working on adding voice files for Norwegian Nynorsk to
> GCompris. The documentation
> (https://invent.kde.org/education/gcompris-data/-/blob/master/voices/HOWTO_ENCODE)
> says to encode them using Ogg Vorbis. But I’m wondering if it’s
> possible to use the Opus codec instead?
>
> Opus is the successor to Vorbis, developed by the same guy, and uses
> lower bitrate for the same quality. See
> https://opus-codec.org/comparison/ for a comparison. For my voice
> files, I can approximately *halve* the file size (compared to Vorbis,
> ‘oggenc -q0 --downmix’) with ~no perceptible loss in quality (compared
> to the *original* .wav file, and of course also to the Vorbis file).
>
>
Hi,

Sure it would be nice to be able to switch from Vorbis to Opus at some
point, however we are constrained by operating systems support.

We use Ogg Vorbis files for both GNU/Linux and Android operating systems
(and *BSDs). According to the "Operating system support" table on
https://en.wikipedia.org/wiki/Opus_(audio_format) , it could be a
problem especially for Android, where Opus gained partial support only
since version 5, and with weird container/file extension limitations.

So from what I see we should stay with Ogg Vorbis for now.

Timothée