This tutorial will work you through steps of configuring an FFmpeg build tailored for RTMP streaming on macOS. At first I think of making it support general live streaming, with additional protocols like HLS, but to keep things simple let's stick with RTMP for now. (Anyway, I do include HLS in the protocol list as well as some related bitstream filters but it's untested.)
The built FFmpeg executable should
- Be able to pull/push RTMP streams, either by forwarding the stream from
rtmp://address or serving media files. - Be capable of extracting metadata from A/V packets, e.g., parsing the SPS/PPS of H.264 header, but
not the encoding/decoding part (will always use
-vcodec copy). Supported codecs: H.264 for video, AAC/MP3 for audio. - Be able to transmux common container formats (FLV, MP4, MPEG-2 TS).
- Optimized for binary size.
Strictly speaking it's not a really "minimal" build for RTMP, it's just small enough without losing core functionality.
cd $FFMPEG
./configure -h \
| rg '\[autodetect\]' \
| rg -o -e '--[^ ]+' \
| rg -e '--(enable|disable)' -r '--disable'which outputs:
--disable-pthreads
--disable-w32threads
--disable-os2threads
--disable-alsa
--disable-appkit
--disable-avfoundation
--disable-bzlib
--disable-coreimage
--disable-iconv
--disable-libxcb
--disable-libxcb-shm
--disable-libxcb-xfixes
--disable-libxcb-shape
--disable-lzma
--disable-sndio
--disable-sdl2
--disable-xlib
--disable-zlib
--disable-amf
--disable-audiotoolbox
--disable-cuda
--disable-cuvid
--disable-d3d11va
--disable-dxva2
--disable-nvdec
--disable-nvenc
--disable-v4l2-m2m
--disable-vaapi
--disable-vdpau
--disable-videotoolbox
Join these lines and we obtain DISABLE_AUTODETECT_LIST.
Here "everything" refers to all available small components (demuxers, decoders, parsers, ...) that we can turn on and off when building FFmpeg.
./configure -h | rg -e '--list-'The command above generates a meta list of --list-*s, each of which can be passed to configure
to query all available components in a specific subcategory. If we simply pass
--disable-everything, all the components from the big meta list will be disabled.
Based on our use case, we obtain the "everything" list as
EVERYTHING_LIST="
--disable-everything \
--enable-decoder=h264,aac,mp3 \
--enable-encoder=aac,libmp3lame \
--enable-parser=h264,aac,mp3 \
--enable-demuxer=flv,mov,mpegts,h264,aac,mp3,live_flv \
--enable-muxer=flv,mov,mpegts \
--enable-protocol=file,rtmp,pipe,hls \
--enable-bsf=aac_adtstoasc,h264_mp4toannexb"The bitstream filter "aac_adtstoasc" is necessary for transmuxing AAC audio in ADTS format (for MPEG-2 TS) into RTMP audio packet, so is ["h264_mp4toannexb"] (https://ffmpeg.org/ffmpeg-bitstream-filters.html#h264_005fmp4toannexb) for transmuxing H.264 video in AvcC (for RTMP/FLV, MP4, etc.) into Annex. B format (for MPEG-2 TS).
FFmpeg can either use its built-in RTMP implementation (see the libavformat/rtmp.*.(h|c) source
files) or depend on RTMPDump's librtmp via libavformat/librtmp.c. The latter has more complete
protocol support (e.g. RTMPE, RTMPS, etc). You can optionally pass --enable-librtmp to switch to
external RTMP dependency.
mkdir build
cd build
../configure \
${DISABLE_AUTODETECT_LIST} \
${EVERYTHING_LIST} \
--disable-avdevice --disable-swscale --disable-postproc --disable-doc \
--disable-runtime-cpudetect \
--enable-pthreads --enable-gpl --enable-version3 \
--enable-avcodec --enable-avformat --enable-swresample --enable-avfilter \
--disable-programs --enable-ffmpeg --enable-small
make -j4(FIXME: Do we need --enable-swresample?)
Sample output:
install prefix /usr/local
C compiler gcc
C library
ARCH x86 (generic)
big-endian no
runtime cpu detection no
standalone assembly yes
x86 assembler yasm
MMX enabled yes
MMXEXT enabled yes
3DNow! enabled yes
3DNow! extended enabled yes
SSE enabled yes
SSSE3 enabled yes
AESNI enabled yes
AVX enabled yes
AVX2 enabled yes
AVX-512 enabled yes
XOP enabled yes
FMA3 enabled yes
FMA4 enabled yes
i686 features enabled yes
CMOV is fast yes
EBX available yes
EBP available yes
debug symbols yes
strip symbols yes
optimize for size yes
optimizations yes
static yes
shared no
postprocessing support no
network support yes
threading support pthreads
safe bitstream reader yes
texi2html enabled no
perl enabled yes
pod2man enabled yes
makeinfo enabled yes
makeinfo supports HTML no
External libraries:
librtmp securetransport
External libraries providing hardware acceleration:
Libraries:
avcodec avfilter avformat avutil swresample
Programs:
ffmpeg
Enabled decoders:
aac h264 mp3
Enabled encoders:
aac
Enabled hwaccels:
Enabled parsers:
aac h264 mpegaudio
Enabled demuxers:
aac h264 mov mpegts
flv live_flv mp3
Enabled muxers:
adts flv latm mov mpegts
Enabled protocols:
file hls rtmp pipe
Enabled filters:
aformat anull atrim format null trim
Enabled bsfs:
aac_adtstoasc null h264_mp4toannexb
Enabled indevs:
Enabled outdevs:
The built ffmpeg executable is less than 2.5MB, with the following shared library usage:
$ otool -L ./ffmpeg
./ffmpeg:
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1252.0.0)
/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 150.0.0, current version 1445.12.0)
/System/Library/Frameworks/CoreVideo.framework/Versions/A/CoreVideo (compatibility version 1.2.0, current version 1.5.0)
/System/Library/Frameworks/CoreMedia.framework/Versions/A/CoreMedia (compatibility version 1.0.0, current version 1.0.0)
-
"nasm/yasm not found or too old."
Easy,
brew install yasm -
"ERROR: librtmp not found using pkg-config"
This happens only if
--enable-librtmpis passed. By checking./ffbuild/config.logyou will find it islibsslthat is missing. It is actually a macOS High Sierra issue, and can be fixed byexport PKG_CONFIG_PATH=/usr/local/opt/openssl/lib/pkgconfig.
On macOS, the
rgtool is not available by default. Use this command to obtain the "disable [autodetect]" list by only using tools that are available by default:The same for the "list everything" command: