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Next-Gen Low-Latency Open Codec Beats HE-AAC

Posted by timothy on from the ogg-still-rocks-anyhow dept.

Aldenissin writes "From the Xiph.org developers, Opus is a non-patent encumbered codec designed for interactive usages, such as VoIP, telepresence, and remote jamming, that require very low latency. When they started working on Opus (then known as CELT), they used the slogan 'Why can't your telephone sound as good as your stereo?', and they weren't kidding. Now, test results demonstrate that Opus's performance against HE-AAC, one of the strongest (but highest-latency) codecs at this bitrate, bests the quality of two of the most popular and respected encoders for the format, on the majority of individual audio samples receiving a higher average score overall. Hydrogenaudio conducted a 64kbit/sec multiformat listening test including Opus, aoTuV Vorbis, two HE-AAC encoders, and a 48kbit/sec AAC-LC low anchor. Comparing 30 diverse samples using the highly sensitive ABC/HR methodology, Opus is running with 22.5ms of total latency but the codec can go as low as 5ms."

4 of 166 comments (clear)

  1. Re:HE-AAC is worse than LE-AAC in terms of quality by parlancex · · Score: 3, Interesting

    That's the whole idea behind any lossy codec. You're trading mathematical accuracy for psycho-acoustical accuracy; personally, I don't care if the root mean square error is higher, I just need it to sound like the original.

    Anyway, if this really IS an improvement over HE-AAC, which uses some very techniques, I'll be extremely impressed, and quite pleased that it's patent free.

  2. Re:HE-AAC is worse than LE-AAC in terms of quality by woolpert · · Score: 3, Interesting

    The sad thing is it shouldn't be better than HE-AAC. Being low latency does tend to mean one is better at the kind of time-domain issues many find so objectionable, but outside that OPUS is really packing a MUCH smaller toolkit than HE-AAC.

    This is really egg on AAC's face, IMHO, and quite the upset. OPUS is so immature the bitstream isn't even stable yet.

  3. Re:HE-AAC is worse than LE-AAC in terms of quality by jmv · · Score: 4, Interesting

    If we were talking about a 96 kb/s test, I'd agree with you. But at 64 kb/s, HE-AAC sounds much better than AAC-LC. The guys who organized this test picked the best AAC implementation they could find at the rate the test was run at.

    --
    Opus: the Swiss army knife of audio codec
  4. Re:ok but how is dtmf detection? by parlancex · · Score: 3, Interesting

    You do realize that most modern VoIP hardware / software supports out of band DTMF? In fact, the most modern software demands it.