[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
-------------------------------------+-------------------------------------
             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 Kamedo2):

 I listened to about 8 hours of songs, movies, sine and white noise, and
 5.1ch surround source. I'd say that abr is mature.

 klaussfreire, could you add a "redirect" feature that when set bitrate is
 too high, redirect to the maximum bitrate possible, rather than to print
 the error message and stop. This simplify many batch encodes, including
 when encoding from hundreds of videos that have various audio frequencies
 and number of channels. Currently it gets:
 {{{
 [aac @ 013efa60] Too many bits per frame requested
 }}}

 Also, I notice that this commandline
 {{{
 ffmpeg -i ffmpeg_aacvbr_pulse1.wav -c:a aac -strict experimental -q:a 0.1
 -ar 8000 -ac 1 ffmpeg_aacvbr_pulse1.mp4
 }}}
 gets the same Too many bits warning, and lowering the quality -q:a don't
 work. It only works when using -b:a, or setting higher frequency such as
 -ar 22050. It could be a problem when encoding from a video taken by some
 old digital cameras with 8kHz pcm audio attached.

 The error message:
 {{{
 ffmpeg56470.exe -y -i ffmpeg_aacvbr_pulse1.wav -c:a aac -strict
 experimental -q:a
  0.3 -ar 8000 ffmpeg_aacvbr_pulse1.mp4
 ffmpeg version N-56469-gf6622f9 Copyright (c) 2000-2013 the FFmpeg
 developers
   built on Sep 20 2013 15:29:55 with gcc 4.8.1 (GCC)
   configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-
 libfdk
 -aac --extra-ldflags=-static --extra-cflags='-march=native -mfpmath=sse'
 --optfl
 ags=-O2
   libavutil      52. 45.100 / 52. 45.100
   libavcodec     55. 33.100 / 55. 33.100
   libavformat    55. 18.100 / 55. 18.100
   libavdevice    55.  3.100 / 55.  3.100
   libavfilter     3. 86.102 /  3. 86.102
   libswscale      2.  5.100 /  2.  5.100
   libswresample   0. 17.103 /  0. 17.103
   libpostproc    52.  3.100 / 52.  3.100
 Guessed Channel Layout for  Input Stream #0.0 : stereo
 Input #0, wav, from 'ffmpeg_aacvbr_pulse1.wav':
   Metadata:
     encoder         : Coderium SoundEngine 4.59
   Duration: 00:00:12.12, bitrate: 1411 kb/s
     Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz,
 stereo, s16
 , 1411 kb/s
 [aac @ 030cbf00] Too many bits per frame requested
 Output #0, mp4, to 'ffmpeg_aacvbr_pulse1.mp4':
   Metadata:
     encoder         : Coderium SoundEngine 4.59
     Stream #0:0: Audio: aac, 8000 Hz, stereo, fltp, 128 kb/s
 Stream mapping:
   Stream #0:0 -> #0:0 (pcm_s16le -> aac)
 Error while opening encoder for output stream #0:0 - maybe incorrect
 parameters
 such as bit_rate, rate, width or height
 }}}

 I think this is about time we remove the -strict experimental flag.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2686#comment:161>
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