[FFmpeg-trac] #3816(undetermined:new): Native AAC encoder, problematic sample.

FFmpeg trac at avcodec.org
Wed Jul 30 08:36:35 CEST 2014


#3816: Native AAC encoder, problematic sample.
-------------------------------------+-------------------------------------
             Reporter:  YellowOnion  |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:  aac          |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:

 at mid-low (96-128) bitrates the native encoder produces highly distorted
 signal that isn't perceptively the same as the original, libvo-aac though
 generally worse, performs better on this specific sample.

 How to reproduce:

 {{{
 H:\Workings\Audio\Listening Tests\Test2.0>\video-working\ffmpeg -i
 trans.wav -vn -strict experimental -c:a aac -b:a 128k trans.ff128.m4a
 ffmpeg version N-64919-ga613257 Copyright (c) 2000-2014 the FFmpeg
 developers
   built on Jul 23 2014 00:35:22 with gcc 4.8.3 (GCC)
   configuration: --enable-gpl --enable-version3 --disable-w32threads
 --enable-avisynth --enable-bzlib --enable-fontcon
 fig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass
 --enable-libbluray --enable-libbs2b --enable-libcac
 a --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc
 --enable-libmodplug --enable-libmp3lame --enab
 le-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg
 --enable-libopus --enable-librtmp --enable-libsch
 roedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-
 libtwolame --enable-libvidstab --enable-libvo
 -aacenc --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx
 --enable-libwavpack --enable-libwebp --enable-libx2
 64 --enable-libx265 --enable-libxavs --enable-libxvid --enable-decklink
 --enable-zlib
   libavutil      52. 92.101 / 52. 92.101
   libavcodec     55. 69.100 / 55. 69.100
   libavformat    55. 48.101 / 55. 48.101
   libavdevice    55. 13.102 / 55. 13.102
   libavfilter     4. 11.102 /  4. 11.102
   libswscale      2.  6.100 /  2.  6.100
   libswresample   0. 19.100 /  0. 19.100
   libpostproc    52.  3.100 / 52.  3.100
 Guessed Channel Layout for  Input Stream #0.0 : stereo
 Input #0, wav, from 'trans.wav':
   Duration: 00:00:30.00, bitrate: 1411 kb/s
     Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, 2
 channels, s16, 1411 kb/s
 Output #0, ipod, to 'trans.ff128.m4a':
   Metadata:
     encoder         : Lavf55.48.101
     Stream #0:0: Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp,
 128 kb/s
     Metadata:
       encoder         : Lavc55.69.100 aac
 Stream mapping:
   Stream #0:0 -> #0:0 (pcm_s16le (native) -> aac (native))
 Press [q] to stop, [?] for help
 size=     476kB time=00:00:30.00 bitrate= 130.0kbits/s
 video:0kB audio:470kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 1.229722%
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/3816>
FFmpeg <https://ffmpeg.org>
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