[FFmpeg-trac] #2686(avcodec:open): Native AAC encoder collapses at high bitrates on some samples

[FFmpeg]

#2686: Native AAC encoder collapses at high bitrates on some samples
-------------------------------------+-------------------------------------
             Reporter:  Kamedo2      |                    Owner:
                 Type:  defect       |                   Status:  open
             Priority:  normal       |                Component:  avcodec
              Version:  git-master   |               Resolution:
             Keywords:  aac          |               Blocked By:
  regression                         |  Reproduced by developer:  1
             Blocking:               |
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------

Comment (by klaussfreire):

 No, it's not the loudest bin. It's a group of bins. Because the sine isn't
 represented on the mdct by a single bin, but rather a ripple pattern that
 has to be accurately encoded, or the resulting sine fluctuates in
 amplitude (hence the clipping).

 But I got a solution. I'm doing the listening tests now, but it sounds
 good. Basically, a two-front approach: lower the volume of near-clipping
 windows (and only those, to make it idempotent), and tweak tonal band
 priorization (because the sine wave was getting too few bits after all).

--
Ticket URL: <https://trac.ffmpeg.org/ticket/2686#comment:243>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker