Opus Alternatives

opus reviews and mentions

• A maximally-dense encoding for n-choose-k
  2 projects | news.ycombinator.com | 20 May 2022

  At the heart of the opus audio codec is a maximally-encoding for combinations with replacement and sign[1], which is n-choose-k where n can be reused and there is a sign for each chosen dimension. Or stated another way, n dimensional integer vectors where the sum of absolute values add to k.

  This enumeration can be implemented with the same kind of recursion as in the link, with a little bit of elaboration. Though interestingly, it (and the formula in the link) can also be be implemented with recursive table lookups quite efficiently, and for small fixed N with closed form formula (also true for the simpler combination code in the link).

  These maximally dense algebraic codes can be designed for a great many possible applications.

  For example, for a generational rolling cuckoo filter Pieter Wuille and I came up with an algebraic code for coding 4 sorted generation numbers with the requirement that all 4 are within a window of half the total range[2]. In prior published work on cuckoo filters used a large table of all possible values of combinations with replacement (to efficiently pack small sorted numbers). We found the algebraic code to be faster than a big dumb table, presumably due to cache locality, even though our fastest encoder/decoder still use tables but only tiny ones (at least for the sizes we were considering).

  A challenge for implementing these sorts of functions is that their inverses often require operations like integer square or cube roots which are not particularly fast unless the ranges are small enough to implement them with tables.

  [1] https://github.com/xiph/opus/blob/master/celt/cwrs.c#L74

• TIL - you cannot loop MP3 files seamlessly.
  1 project | reddit.com/r/gamedev | 18 Feb 2022
• Comment : Google Duo: More reliable voice calls for more people on Android
  1 project | reddit.com/r/unexpected_relevance3 | 13 Feb 2022

  Currently, the royalty-free open-source codec Opus, is the most widely used codec for WebRTC-based VOIP applications.

• M1 Users - How are you Cross Compiling?
  12 projects | reddit.com/r/rust | 30 Nov 2021

  Got it, that makes sense -- thanks for the help! Another commenter pointed out some of those oddities in the flags; It looks like something opus is computing/setting in their makefile which the dependency is invoking.

• Music Software Development: What We Develop and How Much It Costs?
  1 project | dev.to | 22 Oct 2021

  Background noise removal distorts sound when playing music. We switch it off. ~40 kb/s is a standard bitrate for a voice call. Music needs 128 kb/s minimum. Opus supports up to 510 kb/s – so we increase it. We increase the number of audio channels from 1 to 2: from mono to stereo.

• [OC] ytmdl now supports getting metadata from Spotify as well. ytmdl v2021.08.01 Release
  4 projects | reddit.com/r/linux | 23 Aug 2021
• I won't be posting any more preimages against neuralhash for now
  2 projects | reddit.com/r/apple | 22 Aug 2021

  My name is Greg Maxwell. I am a retired. My main areas of interest are cryptography, digital signal processing, error correcting codes, and computer networking. Well known organizations I previously worked at include Juniper Networks and Mozilla. I am one of the authors of the Opus audio codec (among other codecs). I've contributed to many open source protocols and packages. I mostly entertain myself with recreational mathematics and reading. In the distant past I achieved some minor notoriety for my contributions to cracking the CSS protection scheme for DVDs and for publishing a huge cache of historical and public domain academic documents that JStor was keeping behind a paywall. I was one of the earliest developers of Bitcoin and developed numerous parts of the system including the cryptographic code and many of the privacy protocols used there. Some peer reviewed publications I've coauthored include 1, 2, 3, and 4. My partner is an attorney for creative commons and has previously served on the board of organizations such as Wikimedia and the Free Software foundation.

• Opus – an open source parallel corpus
  3 projects | news.ycombinator.com | 14 Aug 2021

  Opus is also the name of an incredibly well compressed audio codec: https://opus-codec.org

• Schiit: "Leave the unicorn formats in the cart" #saynotoMQA
  1 project | reddit.com/r/headphones | 18 Apr 2021

  Opus is a newer alternative to MP3 that's royalty free and you get smaller files as well for the same quality.

• Anon tries to play warzone
  1 project | reddit.com/r/greentext | 3 Apr 2021

  With 128 kbps stereo Opus codec? No way you're gonna tell the difference.

• When adding caption to HLS, I get errors. Unable to find mapping variant stream av_interleaved_write_frame(): Cannot allocate memory
  2 projects | reddit.com/r/ffmpeg | 29 Mar 2021

  Audio Count : 280 Count of stream of this kind : 1 Kind of stream : Audio Kind of stream : Audio Stream identifier : 0 StreamOrder : 1 ID : 2 ID : 2 Unique ID : 2 Format : Opus Format : Opus Format/Url : http://opus-codec.org/ Commercial name : Opus Internet media type : audio/opus Codec ID : A_OPUS Codec ID/Url : http://opus-codec.org Duration : 485541.000000 Duration : 8 min 5 s Duration : 8 min 5 s 541 ms Duration : 8 min 5 s Duration : 00:08:05.541 Duration : 00:08:05.541 Channel(s) : 2 Channel(s) : 2 channels Channel positions : Front: L R Channel positions : 2/0/0 Channel layout : L R Sampling rate : 48000 Sampling rate : 48.0 kHz Samples count : 23305968 Bit depth : 32 Bit depth : 32 bits Compression mode : Lossy Compression mode : Lossy Delay : 0 Delay : 00:00:00.000 Delay, origin : Container Delay, origin : Container Language : en Language : English Language : English Language : en Language : eng Language : en Default : Yes Default : Yes Forced : No Forced : No Details of subtitle: General Count : 331 Count of stream of this kind : 1 Kind of stream : General Kind of stream : General Stream identifier : 0 Complete name : sub.srt File name extension : sub.srt File name : sub File extension : srt File size : 11202 File size : 10.9 KiB File size : 11 KiB File size : 11 KiB File size : 10.9 KiB File size : 10.94 KiB Stream size : 11202 Stream size : 10.9 KiB (100%) Stream size : 11 KiB Stream size : 11 KiB Stream size : 10.9 KiB Stream size : 10.94 KiB Stream size : 10.9 KiB (100%) Proportion of this stream : 1.00000 File last modification date : UTC 2021-03-29 16:20:39 File last modification date (local) : 2021-03-29 20:50:39 ```

• Google Duo: More reliable voice calls for more people on Android
  1 project | reddit.com/r/Android | 2 Mar 2021

  Currently, the royalty-free open-source codec Opus, is the most widely used codec for WebRTC-based VOIP applications.

• Using Opus in Unity3d.
  2 projects | reddit.com/r/dissonance_voip | 31 Dec 2020

  If you don't own Dissonance it'll be a little more difficult. You'll need to compile opus into a dll (source code here) and then write a C# wrapper to call the opus methods from C# (using DllImport).