9 ms·

Opus 1.2 Released

226 points by jmvalin 9y ago

mbebenita 9y 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.
- shmerl 9y 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_encoding_quality http://wiki.hydrogenaud.io/index.php?title=Opus#Music_encodi...
  - jmvalin 9y 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 9y 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.
  - shmerl 9y ago
    > but with the recent Apple announcements it's looking like a chance to usurp h.265 is basically gone. What announcement?
    - reubenmorais 9y ago
      I assume they're talking about HEVC support in macOS High Sierra and iOS 11. https://www.apple.com/newsroom/2017/06/macos-high-sierra-delivers-advanced-technologies-for-storage-video-and-graphics/ https://www.apple.com/newsroom/2017/06/macos-high-sierra-del... https://developer.apple.com/videos/play/wwdc2017/503/ https://developer.apple.com/videos/play/wwdc2017/503/
      - shmerl 9y ago
        That was expected, since Apple are part of MPEGLA cartel and they strongly oppose free codecs. But it doesn't really mean anything, since everyone else would have to pay arm and leg to use it, so the pressure to adopt free codec is still here. I hope AV1 will come out soon enough. Daala itself isn't really ready as is.
        indolering 9y ago
        Apple held off on adoption of HEVC and they certainly don't make as much money as they pay. As much as I hate Apple's love for proprietary technology, had AV1 been released on schedule Apple might have adopted it.
        shmerl 9y ago
        I'm not convinced. Otherwise they would have joined Alliance for Open Media. Their absence speaks for itself and shows where their allegiance lies.
        derf_ 9y ago
        More to the point, VP9 is available today and is a perfectly good substitute for HEVC, with the benefit that you don't have to pay for a license from three different patent pools and an as-yet unknown (but certainly non-zero) number of third parties on undisclosed terms in order to use it.
  - eutectic 9y ago
    Daala is dead, AV1 is the current contender.
    - shmerl 9y ago
      Daala isn't dead, but it's not production ready. AV1 is using Daala in part for the reference.
      - eutectic 9y ago
        My understanding is that most of the development effort has been moved over.
        shmerl 9y ago
        I don't think it can move fully, since Daala is by design a different type of codec (using lapped transforms), while AV1 is more "classic" / block-DCT type of codec. I.e. it makes sense to develop Daala further. Not sure what's going on in practice though. I guess it's better to ask Xiph / Mozilla.
        derf_ 9y ago
        Our development is focused on AV1 for now. We may return to Daala in the long term: it has competitive performance with HEVC on perceptual metrics despite a vastly simpler design than AV1 or even VP9, and despite being less mature than the classic block-based approaches and missing many tools that we simply didn't have a chance to implement (e.g., Daala has only basic MPEG2-style B-frames with no bi-prediction, as just one example). Like the old adage says, if you have two baseball players who can run to first base in the same time, and one has perfect form while the other one looks lousy, which one do you pick? The guy with lousy form, because teach him the right form... However, a lot of Daala's design is predicated on having a very constrained legal budget and not being able to rely on anyone else's patents. With the Alliance for Open Media, both of those constraints are relaxed. So even in the best case the result is likely to look pretty different from the way Daala looks today. Ultimately we're interested in making a codec people will actually use, and that means working with our partners.
  - Scaevolus 9y 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/ https://people.xiph.org/~jm/daala/revisiting/ Unfortunately some of the most innovative techniques around frequency-domain prediction ended up not panning out. :(
    - kuschku 9y ago
      Sadly, Google is trying to patent AV1, and only giving a patent license to users of its implementation. If you want to build your own implementation, either to implement it in hardware, or to release it under a different license, then you’ll be fucked.
      - shmerl 9y ago
        That doesn't make sense really. Do you have a source for it?
        wolf550e 9y ago
        https://encode.ru/threads/2648-Published-rANS-patent-by-Storeleap/page3 https://encode.ru/threads/2648-Published-rANS-patent-by-Stor...
        shmerl 9y ago
        403 Forbidden Anyway, as TD-Linux said above, any implementation is allowed. > 1.1. Patent License. Subject to the terms and conditions of this License, each Licensor, on behalf of itself and successors in interest and assigns, grants Licensee a non-sublicensable, perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as expressly stated in this License) patent license to its Necessary Claims to make, use, sell, offer for sale, import or distribute any Implementation. > 2.6. Implementation. “Implementation” means any implementation, including the Reference Implementation, that is an Encoder and/or a Decoder. An Implementation also includes components of an Implementation only to the extent they are used as part of an Implementation. http://aomedia.org/license/patent/ http://aomedia.org/license/patent/ I really have no idea what "to the extent they are used as part of an Implementation" means though.
  - deleted 9y ago
    [deleted]
  - lern_too_spel 9y 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.
    - voltagex_ 9y ago
      I predict a lot of angry smart TV owners - I have a 4K TV that can't decode certain VP9 profiles in hardware, so YouTube on the TV itself is very limited. Not sure what's available in S90x chipsets, though. Does anything do VP9.2 + Opus in hardware?
      - AstralStorm 9y ago
        Yes, the chips exist, but why do you need hardware decoding in something as unreadable as a TV?
      - clouddrover 9y ago
        I think the solution there is to get a streaming stick or a streaming set top box that supports VP9 to plug into the TV. Or alternatively a small form factor PC like a Zotac mini pc, or palmtop if it's strong enough: https://www.zotac.com/product/mini_pcs/zbox_p_series https://www.zotac.com/product/mini_pcs/zbox_p_series Intel's Compute Card is aimed at giving you a way to upgrade the computing side of devices like TVs without having to buy a new TV: https://arstechnica.com/gadgets/2017/01/intels-compute-card-is-a-pc-that-can-fit-in-your-wallet/ https://arstechnica.com/gadgets/2017/01/intels-compute-card-...
      - shmerl 9y ago
        Such people can either use lower quality H.264 versions which are commonly provided, or as others said, get an external device to decode modern free codecs.
- makmanalp 9y 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.
  - jmvalin 9y 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 9y ago
    Because it basically is a low-pass filter. http://i.imgur.com/OqEks7A.jpg http://i.imgur.com/OqEks7A.jpg
- zanny 9y 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 9y 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.
    - zanny 9y ago
      I have a local backup of native files, but I also have some external 1TB drives I usually get access to once a year and store at relatives places in case my house burns down. They aren't big enough to store my entire media library so I usually end up downsampling to "good enough" copies in case of a disaster.
- looki 9y 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.
77pt77 9y 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.
- microcolonel 9y 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).
  - derefr 9y 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 9y 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.
pimeys 9y 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...
- shmerl 9y ago
  Yep, I do the same thing. I try to buy music only in FLAC, and then encode to Opus for playback.
  - pimeys 9y 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 9y ago
  Does Android support Opus natively? One would hope so, given how open Opus is.
  - cyphar 9y 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.
    - floatboth 9y ago
      Opus in Ogg is natively supported on Android. The extension needs to be .ogg not .opus.
walterbell 9y 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 http://wire.com, which is taking an open approach to messaging.
- indolering 9y ago
  Oh, when did he get hired? The audio quality sucks and my calls drop all the time.
kernelsanderz 9y 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?
- jmvalin 9y 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.
  - kernelsanderz 9y 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?
    - jmvalin 9y ago
      Even that should happen relatively quickly since so far we've also preserved API and ABI compatibility (since 1.0). Also, we're working closely with the Firefox and Chrome teams so they know what's going on with Opus.
      - derf_ 9y ago
        In fact, libopus 1.2 has already landed in Firefox (including for WebRTC) and will be available in the next Nightly: https://bugzilla.mozilla.org/show_bug.cgi?id=1374870 https://bugzilla.mozilla.org/show_bug.cgi?id=1374870
JoshTriplett 9y 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.
AstralStorm 9y ago
Good Lord, they rediscovered integrated rounding! :) (Re: quantization change in encoder. Also known as statistical or statistician rounding.)
- 77pt77 9y ago
  Do you have any resources for a basic explanation on what that is?
- tveita 9y 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 9y 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 9y 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 9y 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.

226 points by jmvalin 9y 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.

shmerl 9y 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_encoding_quality http://wiki.hydrogenaud.io/index.php?title=Opus#Music_encodi...
- jmvalin 9y 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 9y 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.
- shmerl 9y ago
  > but with the recent Apple announcements it's looking like a chance to usurp h.265 is basically gone. What announcement?
  - reubenmorais 9y ago
    I assume they're talking about HEVC support in macOS High Sierra and iOS 11. https://www.apple.com/newsroom/2017/06/macos-high-sierra-delivers-advanced-technologies-for-storage-video-and-graphics/ https://www.apple.com/newsroom/2017/06/macos-high-sierra-del... https://developer.apple.com/videos/play/wwdc2017/503/ https://developer.apple.com/videos/play/wwdc2017/503/
    - shmerl 9y ago
      That was expected, since Apple are part of MPEGLA cartel and they strongly oppose free codecs. But it doesn't really mean anything, since everyone else would have to pay arm and leg to use it, so the pressure to adopt free codec is still here. I hope AV1 will come out soon enough. Daala itself isn't really ready as is.
      - indolering 9y ago
        Apple held off on adoption of HEVC and they certainly don't make as much money as they pay. As much as I hate Apple's love for proprietary technology, had AV1 been released on schedule Apple might have adopted it.
        shmerl 9y ago
        I'm not convinced. Otherwise they would have joined Alliance for Open Media. Their absence speaks for itself and shows where their allegiance lies.
        derf_ 9y ago
        More to the point, VP9 is available today and is a perfectly good substitute for HEVC, with the benefit that you don't have to pay for a license from three different patent pools and an as-yet unknown (but certainly non-zero) number of third parties on undisclosed terms in order to use it.
- eutectic 9y ago
  Daala is dead, AV1 is the current contender.
  - shmerl 9y ago
    Daala isn't dead, but it's not production ready. AV1 is using Daala in part for the reference.
    - eutectic 9y ago
      My understanding is that most of the development effort has been moved over.
      - shmerl 9y ago
        I don't think it can move fully, since Daala is by design a different type of codec (using lapped transforms), while AV1 is more "classic" / block-DCT type of codec. I.e. it makes sense to develop Daala further. Not sure what's going on in practice though. I guess it's better to ask Xiph / Mozilla.
        derf_ 9y ago
        Our development is focused on AV1 for now. We may return to Daala in the long term: it has competitive performance with HEVC on perceptual metrics despite a vastly simpler design than AV1 or even VP9, and despite being less mature than the classic block-based approaches and missing many tools that we simply didn't have a chance to implement (e.g., Daala has only basic MPEG2-style B-frames with no bi-prediction, as just one example). Like the old adage says, if you have two baseball players who can run to first base in the same time, and one has perfect form while the other one looks lousy, which one do you pick? The guy with lousy form, because teach him the right form... However, a lot of Daala's design is predicated on having a very constrained legal budget and not being able to rely on anyone else's patents. With the Alliance for Open Media, both of those constraints are relaxed. So even in the best case the result is likely to look pretty different from the way Daala looks today. Ultimately we're interested in making a codec people will actually use, and that means working with our partners.
- Scaevolus 9y 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/ https://people.xiph.org/~jm/daala/revisiting/ Unfortunately some of the most innovative techniques around frequency-domain prediction ended up not panning out. :(
  - kuschku 9y ago
    Sadly, Google is trying to patent AV1, and only giving a patent license to users of its implementation. If you want to build your own implementation, either to implement it in hardware, or to release it under a different license, then you’ll be fucked.
    - shmerl 9y ago
      That doesn't make sense really. Do you have a source for it?
      - wolf550e 9y ago
        https://encode.ru/threads/2648-Published-rANS-patent-by-Storeleap/page3 https://encode.ru/threads/2648-Published-rANS-patent-by-Stor...
        shmerl 9y ago
        403 Forbidden Anyway, as TD-Linux said above, any implementation is allowed. > 1.1. Patent License. Subject to the terms and conditions of this License, each Licensor, on behalf of itself and successors in interest and assigns, grants Licensee a non-sublicensable, perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable (except as expressly stated in this License) patent license to its Necessary Claims to make, use, sell, offer for sale, import or distribute any Implementation. > 2.6. Implementation. “Implementation” means any implementation, including the Reference Implementation, that is an Encoder and/or a Decoder. An Implementation also includes components of an Implementation only to the extent they are used as part of an Implementation. http://aomedia.org/license/patent/ http://aomedia.org/license/patent/ I really have no idea what "to the extent they are used as part of an Implementation" means though.
- deleted 9y ago
  [deleted]
- lern_too_spel 9y 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.
  - voltagex_ 9y ago
    I predict a lot of angry smart TV owners - I have a 4K TV that can't decode certain VP9 profiles in hardware, so YouTube on the TV itself is very limited. Not sure what's available in S90x chipsets, though. Does anything do VP9.2 + Opus in hardware?
    - AstralStorm 9y ago
      Yes, the chips exist, but why do you need hardware decoding in something as unreadable as a TV?
    - clouddrover 9y ago
      I think the solution there is to get a streaming stick or a streaming set top box that supports VP9 to plug into the TV. Or alternatively a small form factor PC like a Zotac mini pc, or palmtop if it's strong enough: https://www.zotac.com/product/mini_pcs/zbox_p_series https://www.zotac.com/product/mini_pcs/zbox_p_series Intel's Compute Card is aimed at giving you a way to upgrade the computing side of devices like TVs without having to buy a new TV: https://arstechnica.com/gadgets/2017/01/intels-compute-card-is-a-pc-that-can-fit-in-your-wallet/ https://arstechnica.com/gadgets/2017/01/intels-compute-card-...
    - shmerl 9y ago
      Such people can either use lower quality H.264 versions which are commonly provided, or as others said, get an external device to decode modern free codecs.
makmanalp 9y 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.
- jmvalin 9y 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 9y ago
  Because it basically is a low-pass filter. http://i.imgur.com/OqEks7A.jpg http://i.imgur.com/OqEks7A.jpg
zanny 9y 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 9y 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.
  - zanny 9y ago
    I have a local backup of native files, but I also have some external 1TB drives I usually get access to once a year and store at relatives places in case my house burns down. They aren't big enough to store my entire media library so I usually end up downsampling to "good enough" copies in case of a disaster.
looki 9y 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.

77pt77 9y 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.

microcolonel 9y 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).
- derefr 9y 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 9y 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.

pimeys 9y 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...

shmerl 9y ago
Yep, I do the same thing. I try to buy music only in FLAC, and then encode to Opus for playback.
- pimeys 9y 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 9y ago
Does Android support Opus natively? One would hope so, given how open Opus is.
- cyphar 9y 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.
  - floatboth 9y ago
    Opus in Ogg is natively supported on Android. The extension needs to be .ogg not .opus.

walterbell 9y 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 http://wire.com, which is taking an open approach to messaging.

indolering 9y ago
Oh, when did he get hired? The audio quality sucks and my calls drop all the time.

kernelsanderz 9y 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?

jmvalin 9y 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.
- kernelsanderz 9y 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?
  - jmvalin 9y ago
    Even that should happen relatively quickly since so far we've also preserved API and ABI compatibility (since 1.0). Also, we're working closely with the Firefox and Chrome teams so they know what's going on with Opus.
    - derf_ 9y ago
      In fact, libopus 1.2 has already landed in Firefox (including for WebRTC) and will be available in the next Nightly: https://bugzilla.mozilla.org/show_bug.cgi?id=1374870 https://bugzilla.mozilla.org/show_bug.cgi?id=1374870

JoshTriplett 9y 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.

AstralStorm 9y ago

Good Lord, they rediscovered integrated rounding! :) (Re: quantization change in encoder. Also known as statistical or statistician rounding.)

77pt77 9y ago
Do you have any resources for a basic explanation on what that is?
tveita 9y 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 9y 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 9y 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 9y 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.