How to compile ffmpeg to get only mp3 and mp4 support

Question

I'm building Electron app and I use ffmpeg to convert m4a or webm files to mp3, and also to merge video only mp4 with m4a audio file to mp4.

I am able to achieve this using [media-autobuild-suite] (https://github.com/jb-alvarado/media-autobuild_suite), using light build option, but the size of static files is arround 20mb and I'would like to shrink it a little bit more. I've compiled ffmpeg and ffprobe with this configuration.

--disable-libaom
--disable-version3
# Full
--disable-chromaprint
--disable-cuda-sdk
--disable-decklink
--disable-frei0r
--disable-libbs2b
--disable-libcaca
--disable-libcdio
--disable-libfdk-aac
--disable-libflite
--disable-libfribidi
--disable-libgme
--disable-libgsm
--disable-libilbc
--disable-libkvazaar
--disable-libmodplug
--disable-libnpp
--disable-libopenh264
--disable-libopenmpt
--disable-librtmp
--disable-librubberband
--disable-libssh
--disable-libtesseract
--disable-libxavs
--disable-libzmq
--disable-libzvbi
--disable-opencl
--disable-opengl
--disable-libvmaf
--disable-libcodec2
--disable-libsrt
--disable-ladspa
--disable-ffplay
#--enable-vapoursynth
#--enable-liblensfun
--disable-libndi_newtek

--enable-demuxer=mp3
--enable-demuxer=mov
--enable-demuxer=opus

--enable-parser=ac3
--enable-parser=mpegaudio
--enable-parser=h264
--enable-parser=opus

--enable-protocol=file
--enable-protocol=pipe

--enable-decoder=mp3
--enable-decoder=mp4
--enable-decoder=opus

--enable-encoder=mp3
--enable-encoder=mp4
--enable-encoder=opus

With this configuration I'm getting ffmpeg static file arround 2mb and ffprobe static file arround 2mb but with this error.

C:\Users\Admin\Desktop\ffmpeg compilations\2mb\local64>ffmpeg -i simple.m4a simple.mp3 
ffmpeg version N-93147-g9326117bf6 Copyright (c) 2000-2019 the FFmpeg developers built with gcc 8.2.1 (Rev1, Built by MSYS2 project) 20181214
configuration:  .... //here comes configuration as described above
libavutil      56. 26.100 / 56. 26.100
libavcodec     58. 47.102 / 58. 47.102
libavformat    58. 26.101 / 58. 26.101
libavdevice    58.  6.101 / 58.  6.101
libavfilter     7. 48.100 /  7. 48.100
libswscale      5.  4.100 /  5.  4.100
libswresample   3.  4.100 /  3.  4.100
libpostproc    55.  4.100 / 55.  4.100
Guessed Channel Layout for Input Stream #0.0 : stereo
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'simple.m4a':
Metadata:
  major_brand     : dash
  minor_version   : 0
  compatible_brands: iso6mp41
  creation_time   : 2018-10-31T19:47:32.000000Z
Duration: 00:02:38.92, start: 0.000000, bitrate: 127 kb/s
Stream #0:0(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, 7 kb/s (default)
Metadata:
  creation_time   : 2018-10-31T19:47:32.000000Z
  handler_name    : SoundHandler
[NULL @ 0000000000486200] Unable to find a suitable output format for 'simple.mp3' 
simple.mp3: Invalid argument

Any ideas what else should I include into this static file?

Answer 1

No need to disable things piecemeal: just use --disable-everything then enable what you need.

Here's an example you can start out with:

./configure
--disable-everything
--disable-network
--disable-autodetect
--enable-small
--enable-decoder=aac*,ac3*,opus,vorbis
--enable-demuxer=mov,m4v,matroska
--enable-muxer=mp3,mp4
--enable-protocol=file
--enable-libshine
--enable-encoder=libshine
--enable-filter=aresample

• Final binary size will be around 2-3 MB.
• No need to enable any parsers: the selected decoders will automatically select whichever are required.
• FFmpeg does not have a native MP3 encoder, so you'll need to use an external library such as libmp3lame or libshine. Since you mentioned Android I assumed you'll want libshine instead of libmp3lame to encode MP3.
• Test thoroughly. I probably forgot something.
• If you really want to go nuts then use --disable-all instead of --disable-everything and you'll additionally have to manually include the FFmpeg libraries that you want, but that's more work and more headache for not much return.

This will allow you to encode MP3 audio from most M4A and Webm inputs:

ffmpeg -i input.webm output.mp3

And will also let you re-mux MP4/M4V + M4A into MP4:

ffmpeg -i video.m4v -i audio.m4a -map 0:v -map 0:a -c copy output.mp4