This directory contains files used in goanna builds from FFmpeg
(http://ffmpeg.org). The current files are from FFmpeg as of
Release 3.4.2
All source files match their path from the library's source archive.

Currently, we only use the vp8 and vp9 portion of the library, and only on x86
based platforms. If this changes, configuration files will most likely
need to be updated.

AVX2 must be disabled on Linux 32 bits due to the use of yasm 1.1 on the build bots.
Once yasm is upgraded to 1.2 or later, AVX2 code could be re-enabled.
Add --disable-avx2 to configure on those platforms.

configuration files were generated as follow using the configure script:
./configure --disable-everything --disable-protocols --disable-demuxers --disable-muxers --disable-filters --disable-programs --disable-doc --disable-parsers --enable-parser=vp8 --enable-parser=vp9 --enable-decoder=vp8 --enable-decoder=vp9 --disable-static --enable-shared --disable-debug --disable-sdl2 --disable-libxcb --disable-securetransport --disable-iconv --disable-swresample --disable-swscale --disable-avdevice --disable-avfilter --disable-avformat --disable-d3d11va --disable-dxva2 --disable-vaapi --disable-vda --disable-vdpau --disable-videotoolbox --enable-decoder=flac --enable-asm --enable-x86asm

config*:
replace: /HAVE_(MALLOC_H|ARC4RANDOM|LOCALTIME_R|MEMALIGN|POSIX_MEMALIGN)/d

config_darwin32.h:
add to configure command: --disable-asm --disable-yasm --cc='clang -m32'

config_unix32.h:
add to configure command: --disable-asm --disable-x86asm --cc='clang -m32'
replace: s/HAVE_SYSCTL 1/HAVE_SYSCTL 0/ and s/HAVE_MEMALIGN 1/HAVE_MEMALIGN 0/ and s/HAVE_POSIX_MEMALIGN 1/HAVE_POSIX_MEMALIGN 0/


config_unix32.h/config_unix64.h/config_unix64.asm:
replace: s/HAVE_SYSCTL 1/HAVE_SYSCTL 0

config_win32/64.h/asm:
add to configure command: --toolchain=msvc

Regenerate defaults_disabled.{h,asm} with:
$ grep -E ".*_(INDEV|OUTDEV|DECODER|ENCODER|DEMUXER|MUXER|PARSER|FILTER|HWACCEL|PROTOCOL|ENCODERS|DECODERS|HWACCELS|INDEVS|OUTDEVS|FILTERS|DEMUXERS|MUXERS|PROTOCOLS) 0" config.h > ~/Work/Mozilla/mozilla-central/media/ffvpx/defaults_disabled.h
$ grep -E ".*_(INDEV|OUTDEV|DECODER|ENCODER|DEMUXER|MUXER|PARSER|FILTER|HWACCEL|PROTOCOL|ENCODERS|DECODERS|HWACCELS|INDEVS|OUTDEVS|FILTERS|DEMUXERS|MUXERS|PROTOCOLS) 0" config.asm > ~/Work/Mozilla/mozilla-central/media/ffvpx/defaults_disabled.asm

All new decoders/muxers/encoders/... should be added in the list of dummy functions found in libavcodec/dummy_funcs.c
otherwise linkage will fail on Windows. On other platforms they are optimised out and aren't necessary.

To update the source tree, the files listed in FILES should typically be able to be copied as-is from ffmpeg tree.
Compilation will reveal if any files are missing.