[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
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             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            |
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Comment (by klaussfreire):

 They go up because twoloop will push all scalefactors down uniformly until
 it achieves the desired bitrate, but:

  * It won't work with VBR, VBR almost wholly depends on psy to dictate
 scalefactor band noise floors. Twoloop will push scalefactors down a bit
 more I think but not much at those high bitrates

  * It's still suboptimal, it's better to let psy decide, since psy
 understands perceptual entropy better

 Sadly, I didn't have time today to work on it. Lets hope I can do so
 tomorrow. With your analysis I'm confident I can patch psy without having
 to cap anything.

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Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2686#comment:45>
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