Xiph is amazing; I hope Daala actually becomes commonplace, but with the recent Apple announcements it's looking like a chance to usurp h.265 is basically gone.
Unfortunately some of the most innovative techniques around frequency-domain prediction ended up not panning out. :(
What announcement?
I usually encode music in Opus at around 140 Kb/s assuming it's transparent enough. At least using this: http://wiki.hydrogenaud.io/index.php?title=Opus#Music_encodi...
It is still pretty crazy that I find a sub 100 kbps sound sample to be indistinguishable from lossless. Definitely considering transcoding my flac library to 96 vbr opus for backup purposes.
I'm not sure what you mean. FLAC should be the backup.
I wonder why the MP3 at low bitrate sounds a bit like a lowpass filter.
I reasoned the additional lossy encoding of Bluetooth would be too much with lower bitrates, but now I'm not so sure...
That claims they need to be in a MKV container, but I just use the output of opusenc.
EDIT: It looks like TFA says that Android does use Opus:
> Opus is now widely deployed on a large range of platforms and devices (including Android, iOS, and all major browsers) and is exposed to untrusted data.
My tests (on a Pixel running 7.0 and the O beta) have determined that Opus is usually fine as long as the container and file extensions are both Ogg. I have had a few issues with certain files but I'm not sure why yet, I suspect it's album art or something.
I don't believe Android <= 6.0 supports Opus as audio on its own. The CDD initially only required support for Opus in a Matroska container and I attempted to put an Opus-only Matroska file on my phone and none of the players were able to play it. As of either 6.0 or 7.0 (can't remember which), Ogg support is required though.
https://play.google.com/store/apps/details?id=com.jrtstudio....
It's just amazing.
You can throw anything at it. No matter the sample rate and the bitrate and the output has good quality without any of that narrowband, wideband, ultra-wideband speex nonsense.
All that is missing is an "hybrid" mode just like wavpack that produces combined output of roughly the same size as flac.
re: wavpack, from wikipedia:
> WavPack also incorporates a "hybrid" mode which still provides the features of lossless compression, but it creates two files: a relatively small, high-quality, lossy file (.wv) that can be used by itself; and a "correction" file (.wvc) that, when combined with the lossy file, provides full lossless restoration. This allows the use of lossy and lossless codecs together.
This hybrid encoding format lets you keep files for both purposes (lossless for audio production and archiving, pre-encoded to HQ lossy for audio consumption) in less space than would be required to keep e.g. an ALAC file + a cached lossy M4A encoding of it, the way iTunes does when you specify "optimize tracks' space-usage for portable devices."
Such a hybrid design is ideal for e.g. the Internet Archive, where they want to keep lossless archival representations of files for historians to study, and to create encodings from; but also want to serve usable representations of those artifacts to users who care more about transfer-speed and bandwidth cost than perfect fidelity.
(Re: quantization change in encoder. Also known as statistical or statistician rounding.)
My last company (Zip Phone, YC S14) was a direct result of the fantastic work that the Opus team has done in the last few years. I remember researching audio codecs around the end of 2013 and stumbling across Opus, and being amazed at what it could do at extremely low bitrates, and everything was available completely for free! Spent my fair share of time on the Opus IRC channel on freenode (shout out to derf, gmaxwell, jmspeex, mark4o) bugging them with basic queries, and getting excellent support.
Opus rocks.
For instance, if you want to encrypt speech, and don't want to leak information about its contents.
