[FFmpeg-user] vbr with libfdk_aac ?

[sean darcy]

ffmpeg --help full | grep -A 10 libfdk
ffmpeg version N-52058-g423089e Copyright (c) 2000-2013 the FFmpeg 
developers
............
libfdk_aac AVOptions:
   -afterburner       <int>        E...A. Afterburner (improved quality) 
(from 0 to 1)
   -eld_sbr           <int>        E...A. Enable SBR for ELD (for SBR in 
other configurations, use the -profile parameter) (from 0 to 1)
   -signaling         <int>        E...A. SBR/PS signaling style (from 
-1 to 2)
      default                      E...A. Choose signaling implicitly 
(explicit hierarchical by default, implicit if global header is disabled)
      implicit                     E...A. Implicit backwards compatible 
signaling
      explicit_sbr                 E...A. Explicit SBR, implicit PS 
signaling
      explicit_hierarchical              E...A. Explicit hierarchical 
signaling
   -latm              <int>        E...A. Output LATM/LOAS encapsulated 
data (from 0 to 1)
   -header_period     <int>        E...A. StreamMuxConfig and PCE 
repetition period (in frames) (from 0 to 65535)
   -vbr               <int>        E...A. VBR mode (1-5) (from 0 to 5)

But look at this. copying the wiki:

ffmpeg -i 17.wav -vn -c:a libfdk_aac -vbr 2 -afterburner 1 17.m4a
ffmpeg version N-52058-g423089e Copyright (c) 2000-2013 the FFmpeg 
developers
   built on Apr 13 2013 19:19:37 with gcc 4.7.2 (GCC) 20120921 (Red Hat 
4.7.2-2)
   configuration: --prefix=/usr --bindir=/usr/bin 
--datadir=/usr/share/ffmpeg --incdir=/usr/include/ffmpeg 
--libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --cpu=amdfam10 
--optflags='-Ofast -march=native -mtune=native -fopenmp 
-fomit-frame-pointer -pipe -fPIC' --enable-avresample 
--enable-libopencore-amrnb --enable-libopencore-amrwb 
--enable-libvo-amrwbenc --enable-version3 --enable-bzlib 
--disable-crystalhd --enable-frei0r --enable-libfdk-aac --enable-gnutls 
--enable-libass --enable-libcdio --enable-libcelt --enable-libdc1394 
--disable-indev=jack --enable-libfreetype --enable-libgsm 
--enable-libmp3lame --enable-openal --enable-libopencv 
--enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp 
--enable-libschroedinger --enable-libspeex --enable-libtheora 
--enable-libvorbis --enable-libv4l2 --enable-libvpx --enable-libx264 
--enable-libxvid --enable-x11grab --enable-avfilter --enable-postproc 
--enable-pthreads --disable-static --enable-shared --enable-gpl 
--enable-nonfree --enable-zlib   libavutil      52. 26.100 / 52. 26.100
   libavcodec     55.  2.100 / 55.  2.100
   libavformat    55.  2.100 / 55.  2.100
   libavdevice    55.  0.100 / 55.  0.100
   libavfilter     3. 53.101 /  3. 53.101
   libavresample   1.  1.  0 /  1.  1.  0
   libswscale      2.  2.100 /  2.  2.100
   libswresample   0. 17.102 /  0. 17.102
   libpostproc    52.  3.100 / 52.  3.100
[wav @ 0xe1ba00] max_analyze_duration 5000000 reached at 5015510 
microseconds
Guessed Channel Layout for  Input Stream #0.0 : stereo
Input #0, wav, from '17.wav':
   Duration: 00:30:31.07, bitrate: 1411 kb/s
     Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, 
stereo, s16, 1411 kb/s
[libfdk_aac @ 0xe43280] Note, the VBR setting is unsupported and only 
works with some parameter combinations
..........

BTW, also ran it with -afterburner.

sean