[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       |  klaussfreire
             Priority:  normal       |                   Status:  open
              Version:  git-master   |                Component:  avcodec
             Keywords:  aac          |               Resolution:
  regression                         |               Blocked By:
             Blocking:               |  Reproduced by developer:  1
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------

Comment (by Kamedo2):

 {{{-aac_coder faac}}} induces infinite loop whenever the bitrate is
 clamped to max. It never induces infinite loop when the bitrate is below
 the max.
 This bug is reproducible on any samples on any channel/sampling freq.
 settings.

 {{{
 ffmpeg74294 -y -i Whitenoise.flac -c:a aac -strict experimental -b:a 530k
 -ac 2 -ar 44100 -aac_coder faac whitenoise.mp4
 ffmpeg version N-74294-g45d9d16 Copyright (c) 2000-2015 the FFmpeg
 developers
   built with gcc 5.2.0 (GCC)
   configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-
 libmp3
 lame --enable-libvo-aacenc --enable-libvorbis --enable-libfdk-aac
 --enable-w32th
 reads --extra-ldflags=-static --extra-cflags='-mtune=nocona'
 --optflags=-O2
   libavutil      54. 30.100 / 54. 30.100
   libavcodec     56. 57.100 / 56. 57.100
   libavformat    56. 40.101 / 56. 40.101
   libavdevice    56.  4.100 / 56.  4.100
   libavfilter     5. 32.100 /  5. 32.100
   libswscale      3.  1.101 /  3.  1.101
   libswresample   1.  2.101 /  1.  2.101
   libpostproc    53.  3.100 / 53.  3.100
 Input #0, flac, from 'Whitenoise.flac':
   Duration: 00:00:05.00, start: 0.000000, bitrate: 1550 kb/s
     Stream #0:0: Audio: flac, 48000 Hz, stereo, s16
 [aac @ 01e37760] Too many bits per frame requested, clamping to max
 Output #0, mp4, to 'whitenoise.mp4':
   Metadata:
     encoder         : Lavf56.40.101
     Stream #0:0: Audio: aac ([64][0][0][0] / 0x0040), 44100 Hz, stereo,
 fltp (16
  bit), 529 kb/s
     Metadata:
       encoder         : Lavc56.57.100 aac
 Stream mapping:
   Stream #0:0 -> #0:0 (flac (native) -> aac (native))
 Press [q] to stop, [?] for help
 size=      86kB time=00:00:01.48 bitrate= 475.6kbits/s
 }}}
 {{{[aac @ 01e37760] Too many bits per frame requested, clamping to max}}}
 is the sign it fails.
 {{{
 ffmpeg74294 -y -i Whitenoise.flac -c:a aac -strict experimental -b:a 133k
 -ac 1 -ar 22050 -aac_coder faac whitenoise.m
 p4
 ffmpeg version N-74294-g45d9d16 Copyright (c) 2000-2015 the FFmpeg
 developers
   built with gcc 5.2.0 (GCC)
   configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-
 libmp3
 lame --enable-libvo-aacenc --enable-libvorbis --enable-libfdk-aac
 --enable-w32th
 reads --extra-ldflags=-static --extra-cflags='-mtune=nocona'
 --optflags=-O2
   libavutil      54. 30.100 / 54. 30.100
   libavcodec     56. 57.100 / 56. 57.100
   libavformat    56. 40.101 / 56. 40.101
   libavdevice    56.  4.100 / 56.  4.100
   libavfilter     5. 32.100 /  5. 32.100
   libswscale      3.  1.101 /  3.  1.101
   libswresample   1.  2.101 /  1.  2.101
   libpostproc    53.  3.100 / 53.  3.100
 Input #0, flac, from 'Whitenoise.flac':
   Duration: 00:00:05.00, start: 0.000000, bitrate: 1550 kb/s
     Stream #0:0: Audio: flac, 48000 Hz, stereo, s16
 [aac @ 01997760] Too many bits per frame requested, clamping to max
 Output #0, mp4, to 'whitenoise.mp4':
   Metadata:
     encoder         : Lavf56.40.101
     Stream #0:0: Audio: aac ([64][0][0][0] / 0x0040), 22050 Hz, mono, fltp
 (16 b
 it), 132 kb/s
     Metadata:
       encoder         : Lavc56.57.100 aac
 Stream mapping:
   Stream #0:0 -> #0:0 (flac (native) -> aac (native))
 Press [q] to stop, [?] for help
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/2686#comment:401>
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