[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):

 Replying to [comment:182 Kamedo2]:
 > My current impression, from non-blind test of non-samples: {{{v5 abr =
 v6 abr > v6 vbr >> v4 abr}}}

 That's weird ({{{v6 abr > v6 vbr}}}), because my tests showed the
 opposite, and you yourself said v6 vbr had decreased bit usage
 considerably (so it should imply higher efficiency, which is what I
 noticed).

 Do you have an example? Could you describe in that example what you feel
 is inferior compared to abr?

 Also, do you perhaps have something that results in abnormally large
 bitrates in your std calibration sample? That could be forcing you to pick
 a lower q to match the 128k average, and thus decrease overall quality. I
 did fix a few of those in v6, but maybe there's some left, or maybe it has
 to be further constrained.

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Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2686#comment:184>
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