[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       |  klaussfreire
             Priority:  normal       |                   Status:  open
              Version:  git-master   |                Component:  avcodec
             Keywords:  aac          |               Resolution:
  regression                         |               Blocked By:
             Blocking:               |  Reproduced by developer:  1
Analyzed by developer:  0            |
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Comment (by klaussfreire):

 Well, it is based on it, but it sounded very different to me, as it has
 important bugfixes. The encoded versions I mean, not the differences.

 Namely, in codebook_trellis_rate/encode_window_bands_info, it was using
 the wrong scalefactors and that's a major bug when encoding transients.

 And on the RD-reduction step, both v7 and v8g were assuming decreasing
 scalefactors had a predictable effect on distortion, and v9 just
 recomputes distortion, which proved to be a big improvement on VBR.

 That pretty much singlehandedly fixed the biggest issues in fatboy.

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Ticket URL: <https://trac.ffmpeg.org/ticket/2686#comment:331>
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