AAC: Nachrichten pro Woche

Here is this week portion of AAC-related news:

  • I was working on psychoacoustic model and fixes for it. Now encoder should always produce correct files (i.e. decodable without bitstream errors). Sound quality may be low though.
  • There was a bug in MDCT calculation which resulted in wrong spectrum.
  • My test device for AAC has broken 🙁 Where I can find a decent pair of headphones that won’t break that easily? Especially in this country.

And just in case my mentor’s reading this, here are my plans:

  • Improve and finish 3GPP TS26.403-based psychoacoustic model.
  • Implement block switching.
  • Add sine windows.
  • Sync my encoder with current AAC decoder code (maybe it will be committed by then?)

5 Responses to “AAC: Nachrichten pro Woche”

  1. Andreas says:

    Of course I’m reading it, 🙂

    Google reader owns!

  2. Robert Swain says:

    And there’s not much to be done on the AAC decoder as Michael is now making note of variable names and lack of doxygen comments and little else. 🙂

  3. Gabriel Bouvigne says:

    Hey, the white/pink noise is gone from the AAC encoder, that’s great!
    Of course, now there is still a lot of “usual” quantization noise 😉

  4. Benjamin Larsson says:

    Why are you planning to implement the sine windows ? AFAIK they are not part of mpeg4 aac.

  5. Kostya says:

    They are – and I’ve read that sine windows are better for harpsichord music.