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

FFmpeg trac at avcodec.org
Tue Sep 17 10:31:29 CEST 2013


#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            |
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Comment (by cehoyos):

 Replying to [comment:152 Kamedo2]:
 > Replying to [comment:151 cehoyos]:
 > > If you have time, it would be interesting to compare to the quality of
 other FFmpeg audio encoders, ie ac3, eac3 and mp2.
 > It may be wrong, but I guess the ac3 is the most used variant. The
 bitrate will be around 128kbps, so the extremely high bitrate of eac3 will
 not fit the frame,

 I am not sure I understand you.
 Afaik, nobody ever made a listening test using different internal FFmpeg
 encoders (not even a very cursory one). It would be interesting to know
 that "96kb eac3 ~ 128 kb ac3 ~ 128kb aac ~ 256kb mp2" (I assume this isn't
 the case, just as an example). Even if done with much less effort than
 your above tests (if you just mention your impression of each encoder
 after a few tests), I believe this would be interesting information.
 It was sometimes claimed that the wma encoders produce abysmal quality, so
 your comment on them (possibly with higher bitrates) would also be
 welcome.

 > I think. Are there some important use of eac3 and mp2, other than the BD
 and VCD encoding? (For BD the space is huge and quality at lower bitrate
 is insignificant.)

 I believe that ac3 is a very important codec (WMP plays it out-of-the-box
 in different containers), knowing if eac3 beats it would be interesting.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2686#comment:153>
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