[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 Kamedo2):

 Recommended cutoff frequency for FFmpeg AAC.
 [[Image(http://i41.tinypic.com/28al1fn.png)]]
 psymodel.h line 32:
 {{{
 #define AAC_CUTOFF(s) (s->bit_rate ?
 FFMIN3(FFMIN3(s->bit_rate/s->channels/2, 3000 + s->bit_rate/s->channels/4,
 12000 + s->bit_rate/s->channels/16), 20000, s->sample_rate / 2):
 (s->sample_rate / 2))
 }}}
 The LPF is not applied in VBR now, resulting in noticeably poor quality.

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Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2686#comment:57>
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