[FFmpeg-trac] #2686(avcodec:open): Native AAC encoder collapses at high bitrates on some samples

FFmpeg trac at avcodec.org
Sun May 4 17:02:57 CEST 2014


#2686: Native AAC encoder collapses at high bitrates on some samples
-------------------------------------+-------------------------------------
             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            |
-------------------------------------+-------------------------------------

Comment (by Timothy_Gu):

 Replying to [comment:281 Kamedo2]:



 > '''ABR with -aac_coder fast'''
 > Min / '''Average''' / Max bitrate: 128 / '''134''' / 141 kbps
 > Average Speed: '''28.0'''x
 > ffmpeg_r62950_v8f -i %i -c:a aac -strict experimental -b:a 128k
 -aac_coder fast %o
 > This is fast, but with very bad quality. I don't know if there's good
 use of this option.

 It is supposed to sound bad: [http://ffmpeg.org/ffmpeg-
 codecs.html#Options-2]:

 > This method sets a constant quantizer for all bands. This is the fastest
 of all the methods, yet produces the worst quality.

 Also, can you test -coder twoloop?

--
Ticket URL: <https://trac.ffmpeg.org/ticket/2686#comment:284>
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