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

FFmpeg trac at avcodec.org
Sat Jul 20 21:17:04 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            |
-------------------------------------+-------------------------------------

Comment (by klaussfreire):

 LOL, sorry, the VBR condition is backwards. An old idiocy of mine, I
 always reverse if conditions. Kinda like coding dyslexia.

 It should be

 {{{
 #define _AAC_CUTOFF(bit_rate,channels,sample_rate) (bit_rate ?
 FFMIN3(FFMIN3( \
     bit_rate/channels, \
     3000 + bit_rate/channels/2, \
     12000 + bit_rate/channels/8), \
     20000, \
     sample_rate / 2): (sample_rate / 2))
 #define AAC_CUTOFF(s) ( \
     (s->flags & CODEC_FLAG_QSCALE) \
     ? _AAC_CUTOFF((int)(s->bit_rate * (s->global_quality ?
 s->global_quality : 120) / 120.0), 2, s->sample_rate) \
     : _AAC_CUTOFF(s->bit_rate, s->channels, s->sample_rate) \
 )
 }}}

 Though I'm getting some weird results with very low quality settings.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2686#comment:62>
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