Opus 1.2 Released

by jmvalin • 9 years ago

226 81 9 years ago

mbebenita• 9 years ago

I can't hear the difference between Opus 1.2 @ 32 kb/s and Uncompressed audio. I'm now excited about Opus 1.2 AND worried about my hearing.

shmerl12• 9 years ago

That's interesting. Does it mean that Opus 1.2 has now lower transparency level?

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...

jmvalin4• 9 years ago

The threshold for "transparency" varies a great deal across users. Some people I know cannot ABX 64 kb/s Opus from the uncompressed original, yet once in a while we hear of someone being able to ABX one particular sample all the way up 192 kb/s. There's also the issue of whether you have the reference to compare. Personally, I stop being able to ABX Opus somewhere around 128 kb/s, but I won't be able to tell that a song has been compressed with Opus at 96 kb/s unless I have the original to compare it to.

jzelinskie• 9 years ago

If you listen to older versions of Opus @ 32kbps, you'll hear the distortion more pronounced and then when you slowly upgrade versions you can hear it go away and then when comparing to uncompressed, you'll notice just because you know what you're looking for.

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.

shmerl12• 9 years ago

but with the recent Apple announcements it's looking like a chance to usurp h.265 is basically gone.

What announcement?

eutectic2• 9 years ago

Daala is dead, AV1 is the current contender.

Scaevolus• 9 years ago

Many pieces of Daala are being folded into AV1, which is an industry effort supported by most large software and hardware companies to produce an HEVC replacement. This post summarizes the results of the different experiments: https://people.xiph.org/~jm/daala/revisiting/

Unfortunately some of the most innovative techniques around frequency-domain prediction ended up not panning out. :(

lern_too_spel• 9 years ago

The two big Internet streaming companies have chosen VP9 over h.265 and are both developing AV1 to use instead of h.265's successor. Apple's announcement is unlikely to change anything as far as what gets used on the Internet.

makmanalp• 9 years ago

It's really amazingly impressive that it also holds well across the different musical pieces and different frequencies / timbres. Is this yet another order of magnitude improvement in audio file size?

I wonder why the MP3 at low bitrate sounds a bit like a lowpass filter.

jmvalin4• 9 years ago

At low bit-rate, lame applies a low-pass and resamples to a lower sampling rate. If it didn't to that, MP3 would end up completely starved of bits (trying to code all frequencies) and have really atrocious artefacts. Based on personal experience and the results from a few listening tests I saw, I think you can assume that Opus can now give you about the same quality as MP3 for about 60% of the bits. For example, 76 kb/s Opus should be around the same quality as 128 kb/s MP3.

Avery3R• 9 years ago

Because it basically is a low-pass filter. http://i.imgur.com/OqEks7A.jpg

zanny2• 9 years ago

Listening through all of them, 32 and 48 do have noticeable artifacting if you are using a good sound setup. On my phone though, even 48 was "as good as it gets" for its speaker.

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.

theandrewbailey• 9 years ago

"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.

looki• 9 years ago

I wasn't able to hear a difference on that website, but I tried some songs on my computer and there was audible hissing in some parts (it mostly sounded great to me, though). All that was gone at 48kbps, though. It's kind of crazy to see a full-length album sounding amazing at 20MB. I think if I were to convert everything I'd go a little higher (64?) to be safe, but wow.

77pt773• 9 years ago

It's really hard to exaggerate the quality of the opus codec.

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.

microcolonel3• 9 years ago

I don't know what you're looking for with the wavpack comparison, but 510kbps approaches the noise floor for most audio that isn't white noise or black metal. 96kbps is widely considered transparent on speakers (you have to try quite hard to notice 48kbps), 112-128kbps on headphones (and 96kbps at most for people older than 15, lol).

derefr2• 9 years ago

High-quality lossy files are fine for listening, but lossless is required if you want to sample the audio to create a remix or DJ set from it, because you're inevitably going to have to encode the output artifact of that—and you don't want to be chaining lossy encoding steps, as the loss-function of most psychoacoustic encodings tends to be exponential when applied repeatedly.

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.

awaaz• 9 years ago

Opus is something really, really cool!

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.

pimeys3• 9 years ago

I'm having all my music stored as Flac and automatically converted as Opus to my phone. I couldn't be happier to the quality and encoding speed. The only thing I think I should've done different is to use a lower bitrate than 192 kbps to store more music to the memory card.

I reasoned the additional lossy encoding of Bluetooth would be too much with lower bitrates, but now I'm not so sure...

shmerl12• 9 years ago

Yep, I do the same thing. I try to buy music only in FLAC, and then encode to Opus for playback.

pimeys3• 9 years ago

Although I'm not that happy with the replay gain support in Opus, so at work and at home I listen to the Flac files.

StavrosK• 9 years ago

Does Android support Opus natively? One would hope so, given how open Opus is.

cyphar2• 9 years ago

You can play them in VLC, but a few years ago I remember that Opus wasn't recognised by Android's "media service" (meaning the native players couldn't even detect the existence of Opus files). It's probably changed since then though.

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.

derf_7• 9 years ago

It's required by the Android Compatibility Definition Document (in both MKV and Ogg containers), and it's been there since v5.0: https://source.android.com/compatibility/android-cdd.pdf

ac29• 9 years ago

Yes, since 5.0: https://developer.android.com/guide/topics/media/media-forma...

That claims they need to be in a MKV container, but I just use the output of opusenc.

Veratyr• 9 years ago

Android supports the codec but there are issues with the MediaStore and how it deals with containers and file extensions.

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.

pimeys3• 9 years ago

I've been using Rocket Player with my Android 7 phone and it plays Opus just fine. Money well spent to the pro version.

https://play.google.com/store/apps/details?id=com.jrtstudio....

walterbell• 9 years ago

If you are sensitive to the quality of encrypted audio calls, a co-inventor of Opus (Koen Vos of Skype/SILK) now works at http://wire.com, which is taking an open approach to messaging.

indolering5• 9 years ago

Oh, when did he get hired? The audio quality sucks and my calls drop all the time.

kernelsanderz2• 9 years ago

Given that Opus is built into the browser, is the format backwards compatible? Or will browsers need to update their Opus Libraries to get these changes?

jmvalin4• 9 years ago

All Opus releases since 1.0 are fully compatible with the specification (RFC 6716) and all future releases will also be. That's why we have standards. If we ever decided to make something that's not compatible, it would be called a different name.

kernelsanderz2• 9 years ago

That's so awesome. I guess the webrtc audio encoding libraries would need to be updated in the browsers to take advantage of these improvements though?

JoshTriplett• 9 years ago

Opus defaults to variable bitrate (VBR), but for a variety of reasons some people prefer to use constant bitrate (CBR), which it has always supported.

For instance, if you want to encrypt speech, and don't want to leak information about its contents.

AstralStorm2• 9 years ago

Good Lord, they rediscovered integrated rounding! :)

(Re: quantization change in encoder. Also known as statistical or statistician rounding.)

77pt773• 9 years ago

Do you have any resources for a basic explanation on what that is?

tveita• 9 years ago

"round to whichever number sounds the best"?

Anyway I assume they're taking their well deserved credit for the implementation, not necessarily the discovery.

someSven• 9 years ago

I really hope every Linux distro and all these other OSs will support it from now on, right from the start. Including recognicing .opus files. It's the perfect format for podcasts, because it's great with voices even if the bitrate is low.

ktzar• 9 years ago

I've compressed 30 hours of one of my favourite podcasts in less than 100MB... And voice parts are almost indistinguishable from the original.

djmips• 9 years ago

My ears still feel that uncompressed is king for several of the test passages but Opus 1.2 was quite good. The problems with the compressed versions is hard to describe because I don't have the vocabulary but it was something that was only discernable on headphones and I would say had to do with phasing between left and right, a stereo 'presence' that was missing in all the compressed variations.

Opus 1.2 Released

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