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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:sorry for being dense, but... by Anaerin · · Score: 4, Insightful

    As mentioned, it's needed for VoIP systems. With a full-duplex system, more than 150ms of lag is audible and noticeably uncomfortable, breaking the flow of conversation (As the apparent lag is doubled in a "conversation", with the delay at each end adding cumulatively). For simple half-duplex systems like gaming, more lag is not really noticeable.

  2. Re:That's all fine and dandy, but.... by nog_lorp · · Score: 4, Insightful

    Lol what? You're crazy. I suppose it is never worth inventing a new codec ever, since everyone uses old codecs! /fail argument

  3. Re:HE-AAC is worse than LE-AAC in terms of quality by woolpert · · Score: 5, Insightful

    HE-AAC uses SBR to reduce its data footprint. This results in worse reproduction of the source audio than LE-AAC at same bitrate (and often even lower bitrate). The whole deal with HE is that it can maintain good quality at very low bitrate, by giving up accuracy. So far, Apple's LE-AAC encoder in their Core Audio framework is the best choice for digitally non-lossless compression.

    While your rant appears informative if not insightful on its face, it is completely missing the point.

    This is a test of audio codecs at low bitrates.

    I don't know what this "LE-AAC" is you speak of (and rather suspect you don't either) but AAC-LC was actually in this test, as the low anchor.

    At these bitrates (~64kbps) HE-AAC (despite its "low-accuracy" as you put it) is perceptually better sounding than AAC-LC. Lossy audio codecs (even the LE-AAC [sic] encoder in Apple's Core Audio framework you love) can only be judged by how they sound, not how they look. "Accuracy" is not a metric very worthy of discussion.

  4. Re:Next level beats by Skuto · · Score: 4, Insightful

    Perhaps they could switch to "has not yet been challenged in court for any possible patent infringement". But who would use a codec like that? Besides Google, of course.

    Companies do this all the time. Anyone shipping H.264 has this risk, as the patent pool provides zero guarantee no outside patents will pop up.

    Actually, anyone shipping anything at all has this risk.

    Realistically, it's more like "does not infringe any known patents, or has licenses for them, and is not infringing any other patents that we could find in a patent search".