FFmpeg Cross-compilation Configuraton

Initial configuration for cross-compiling FFmpeg targeting MIPS architecture:

./configure \
--prefix=$(pwd)/output \
--enable-cross-compile --arch=mips --target-os=linux \
--cross-prefix=mips-linux-gnu- --cc=mips-linux-gnu-gcc-7.2.0 \
--disable-everything \
--disable-autodetect \
--enable-avdevice \
--enable-avfilter \
--disable-msa \
--disable-debug \
--disable-protocols --enable-protocol=file \
--disable-demuxers --enable-demuxer=mov \
--disable-muxers --enable-muxer=mp4 --enable-muxer=mov \
--disable-decoders --enable-decoder=pcm_alaw --enable-decoder=h264 --enable-decoder=mpeg4 \
--disable-encoders --enable-encoder=pcm_s16le \
--disable-bsfs --enable-bsf=h264_mp4toannexb \
--enable-static --enable-shared \
--disable-programs --enable-ffmpeg \
--extra-cflags=-muclibc --extra-cxxflags=-muclibc \
--enable-small

Resolving Compilation Issues

After encountering linking errors, the configuration was adjusted:

./configure \
--prefix=$(pwd)/output \
--enable-cross-compile --arch=mips --target-os=linux \
--cross-prefix=mips-linux-gnu- --cc=mips-linux-gnu-gcc \
--disable-mipsdsp --disable-mipsdspr2 --disable-mips32r2 --disable-mipsfpu --disable-mips64r2 --disable-mips32r6 \
--disable-everything \
--disable-autodetect \
--enable-avdevice \
--enable-avfilter \
--disable-msa \
--disable-debug \
--disable-protocols --enable-protocol=file \
--disable-demuxers --enable-demuxer=mov \
--disable-muxers --enable-muxer=mp4 --enable-muxer=mov \
--disable-decoders --enable-decoder=pcm_s16le --enable-decoder=pcm_alaw --enable-decoder=h264 --enable-decoder=mpeg4 \
--disable-encoders --enable-encoder=pcm_s16le \
--disable-bsfs --enable-bsf=h264_mp4toannexb \
--enable-static --disable-shared \
--disable-programs --enable-ffmpeg \
--extra-cflags=-muclibc --extra-cxxflags=-muclibc \
--enable-small

Minimal Build Configuraton

Further optimization led to a streamlined configuration excluding unnecessary components:

./configure \
--prefix=$(pwd)/output \
--enable-cross-compile --arch=mips --target-os=linux \
--cross-prefix=mips-linux-gnu- --cc=mips-linux-gnu-gcc \
--disable-mipsdsp --disable-mipsdspr2 --disable-mips32r2 --disable-mipsfpu --disable-mips64r2 --disable-mips32r6 \
--enable-avdevice \
--enable-avfilter \
--disable-msa \
--disable-debug \
--disable-protocols --enable-protocol=file \
--disable-decoders --enable-decoder=pcm_s16le \
--disable-encoders --enable-encoder=pcm_s16le \
--enable-static --disable-shared \
--disable-programs --enable-ffmpeg \
--disable-doc \
--extra-cflags=-muclibc --extra-cxxflags=-muclibc \
--enable-small

Missing Function Definitions

To resolve undefined function references, add the following macros to common.h:

#define fmin(x, y) ((x) > (y) ? (y) : ((x) == (x) ? (x) : (y)))
#define fmax(x, y) ((x) < (y) ? (y) : ((x) == (x) ? (x) : (y)))
#define fminf(x, y) fmin(x, y)
#define fmaxf(x, y) fmax(x, y)