Forgot your password?
typodupeerror
Open Source Software Linux

Opus 1.1 Released 62

Posted by Soulskill
from the onward-and-upward dept.
New submitter rvalles writes "Xiph.org just released a major update to their Opus audio codec. Opus 1.1 offers major improvements over last year's 1.0.2 release. Opus is a general-purpose, very flexible, open and royalty-free audio codec that offers low-latency and high quality/bitrate, incorporating technology from Skype's SILK codec and Xiph.Org's CELT codec. Its first release beat everything else last year at 64kbit/s in a listening test held at HydrogenAudio."
This discussion has been archived. No new comments can be posted.

Opus 1.1 Released

Comments Filter:
  • A quick question: Is this supported in hardware (to prolong battery life) in mobile devices that can play audio?

    I expect more generalised hardware (i.e., programmable DSPs) can be made to support it on the DSP that is present in the audio/video decode functional blocks of the SoC.

    • by Skuto (171945) on Friday December 06, 2013 @01:36PM (#45620039) Homepage

      Depends on what mobile device? The reference code has extensive ARM optimizations, that's in fact one of the main improvements in 1.1 And yes, it can be accelerated with a programmable DSP if present, IIRC there's some support for C55x in the same reference code.

      Audio decoding is fast enough on modern ARM SoC that dedicated hardware isn't strictly needed to get good battery life.

    • by savuporo (658486) on Friday December 06, 2013 @03:08PM (#45620871)

      The thing about audio encode/decode is that its relatively low MIPS - with todays mobile CPUs its almost not worth the complexity to offload it to DSP. During a call your CPU has to stay awake anyway and drain battery, there is very little wattage saving moving it to DSP. It would only make sense if you are dealing with multiple, and i mean more than 2 simultaneous encoded streams ( decode is cheap ). The story was different a few years ago when the dominant CPU was ARM9 running in a 150-200 mhz range, where audio codec easily chewed up 50% or more available MIPS.

      Video encoding is a whole different matter of course.

  • by Anne_Nonymous (313852) on Friday December 06, 2013 @01:32PM (#45619995) Homepage Journal

    So is this backwards compatible with my existing Monster Cables or do I have to buy new ones?

    • by jmv (93421) on Friday December 06, 2013 @01:50PM (#45620193) Homepage

      So is this backwards compatible with my existing Monster Cables or do I have to buy new ones?

      You will just need to update the firmware on your cables if you want to maintain optimal RDF (reality distortion field).

    • The psychoacoustic model of your old cables is completely wrong. To really get a musical experience, there will be rolled out a product just for your needs soon. Starting at the low, low price of $999.
  • by DigitAl56K (805623) on Friday December 06, 2013 @01:48PM (#45620167)

    As someone who has previously written outwardly facing articles on complex technology, I have to give props to "Monty" and Jean-Marc Valin for TFA. It takes a lot of skill to communicate good information about some very complex topics in a short amount of space, and they pull it off pretty well. I think it really helps sell the product and keep your enthusiasts more engaged when you can see how much work and thoughtfulness has gone into the guts of it - work that is often unseen, hidden within a dev team, or buried throughout a mailing list somewhere.

    • by Trepidity (597) <delirium-slashdot AT hackish DOT org> on Friday December 06, 2013 @02:47PM (#45620701)

      Yeah, Monty's writing on these topics is exceptionally clear. His series on the Daala video codec [xiph.org] introduces modern video encoding in a way that's amazingly accessible. Maybe he should write a textbook.

    • by ljw1004 (764174)

      I love this section from the Opus 1.1 release notes:

      1.1 also adds temporal VBR, an accidental discovery from a bug in an earlier pre-release. Temporal VBR is new heuristic that adds bits to loud frames and steals them from quiet frames. This runs counter to classic psychoacoustics; critical band energies matter, not the broadband frame energy. In addition, TVBR does not appear to be exploiting temporal postecho effects.

      Nevertheless, listening tests show a substantial advantage on a number of samples. I'll be the first to admit we haven't completely determined why, but my best theory is that strong, early reverberant reflections are better coded by the temporary allocation boost, stabilizing the stereo image after transients especially at low bitrates.

  • " Its first release beat everything else last year at 64kbit/s in a listening test held at HydrogenAudio."

    No offence, but this test was solely based on "user preference".
    - Wheres the Spectrum analysis of each codec?
    - Which codec is more true to the original .wav, using the above data as comparison?
    - Which codec cuts below 50hz?
    - Which codec emphasizes certain frequencies (8-10khz, typical LAME mp3)?
    - I'll automatically assume, your Opus codec (which is based on a voice codec) prioritizes bitrate quality bet

    • by Anonymous Coward

      Looking at the waveform of a compressed piece of audio is really not a "scientific test".
      As long as the ear can't hear the difference between the original file and the compressed one it doesn't matter a bit if they look very different.

        - Peder

    • >No offence, but this test was solely based on "user preference".
      Offense taken.
      That's how testing works in the audio industry. Mainly because it's the only thing that makes sense.

      >- Wheres the Spectrum analysis of each codec?
      A spectrum tells you almost nothing about how a codec sounds. Thus listening tests.

      >- Which codec is more true to the original .wav, using the above data as comparison?
      That's what a listening test answers. I know very few people who listen to music by unplugging their speakers,

      • Offense taken.
        That's how testing works in the audio industry. Mainly because it's the only thing that makes sense.

        Fair comment and i see your reasoning, however, if you want to appeal to more "knowledgeable" users in your tests, you should supply the following info:
        - What hardware playback device were you using for the tests?
        - What speakers/headphone devices were tested (DT 990 pro's / Ipod standard)
        - Were you tests consistent across the board of devices used?

        A spectrum tells you almost nothing about how a codec sounds. Thus listening tests.

        A spectrum analysis tells you everything regarding a codecs compression/quality ratio.
        If your aiming for your codec to simply "sound good" but actually "be comple

        • >- What hardware playback device were you using for the tests?
          >- What speakers/headphone devices were tested (DT 990 pro's / Ipod standard)
          In this style of test, that's mostly irrelevant. One wants testing on a wide range of equipment, and no, the list of equipment is not documented. I can say though it encompasses the range from earbuds to electrostats.

          >- Were you tests consistent across the board of devices used?
          Oh right. You didn't read anything about it. You're just commenting.

          >A spectru

          • Interesting, the comment system removed several lines of text right smack in the middle of the comment.

            • The text that got mangled:

              >You could increase that to 20hz for improved quality/compression ratio.
              >20hz is generally regarded as the cut off point for all audio production,
              No, 50Hz is usually the default cutoff (to control power draw and excursion) unless it's an audiophile or 'classy' production, then it's less than 1Hz often as low as .1Hz, at least in the codec. The goal is only to remove DC.

              >Pretty pictures might work on most people, but a page full of "hear say" does nothing to help Opus.
              Hi,

              • by atamido (1020905)

                >Pretty pictures might work on most people, but a page full of "hear say" does nothing to help Opus.
                Hi, I'm one of the authors of the codec. I wrote detailed pages explaining how aspects of the codec work, which you could not be bothered to read before lecturing us on what's supposedly wrong with Opus. Which one of us is indulging in 'hearsay' again?

                Oh, snap! That was awesome.

Chemist who falls in acid is absorbed in work.

Working...