[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):

 '''ABR with -aac_coder twoloop'''
 Min / '''Average''' / Max bitrate: 129 / '''130''' / 131 kbps
 Average Speed: '''13.6'''x
 ffmpeg_r62950_v8f -i %i -c:a aac -strict experimental -b:a 128k -aac_coder
 twoloop %o
 This sounds great.


 '''ABR with -aac_coder faac'''
 Min / '''Average''' / Max bitrate: 133 / '''157''' / 210 kbps
 Average Speed: '''12.0'''x
 ffmpeg_r62950_v8f -i %i -c:a aac -strict experimental -b:a 128k -aac_coder
 faac %o
 This has the worst quality. Long windows seems to have 2~3kHz LPF and
 short windows seems to have no LPF.


 '''VBR with -aac_coder twoloop'''
 Min / '''Average''' / Max bitrate: 111 / '''129''' / 146 kbps
 Average Speed: '''15.7'''x
 ffmpeg_r62950_v8f -i %i -c:a aac -strict experimental -q:a 0.7 -aac_coder
 twoloop %o
 This sounds great.


 '''VBR with -aac_coder faac'''
 Min / '''Average''' / Max bitrate: 213 / '''259''' / 311 kbps
 Average Speed: '''11.1'''x
 ffmpeg_r62950_v8f -i %i -c:a aac -strict experimental -q:a 0.7 -aac_coder
 faac %o
 Abysmal quality, comparable to ABR with -aac_coder faac, but with more
 bitrate.

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Ticket URL: <https://trac.ffmpeg.org/ticket/2686#comment:285>
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