FFmpeg porting S3C2440

FFmpeg porting process:

FFmpeg is an open source, free, cross-platform video and audio streaming solution. It is free software and uses the LGPL or GPL license. Its porting also follows the LGPL or GPL porting method: configure, make, make install.

1. Download the ffmpeg open source library (ffmpeg-0.5.tar.bz2) and put it in the corresponding folder.

#tar jxvf ffmpeg-0.5.tar.bz2

#cd ffmpeg-0.5

2. Configure compilation options

#./configure --cross-prefix=/usr/local/arm/3.4.1/bin/arm-linux- --enable-cross-compile --target-os=linux --cc=arm-linux-gcc --arch=arm --prefix=/usr/local/ffmpeg --enable-shared --disable-static --enable-gpl --enable-nonfree --enable-ffmpeg --enable-ffplay --enable-ffserver --enable-swscale --disable-vhook --enable-pthreads --disable-network --disable-ipv6 --enable-libamr-nb --enable-libamr-wb --enable-libfaac --enable-libfaad --enable-libmp3lame --disable-armv5te --disable-armv6 --disable-armv6t2 --disable-yasm --disable-stripping --disable-optimizations --extra-cflags=-I/usr/local/ffextra/include --extra-ldflags=-L/usr/local/ffextra/lib

Cross compiler: arm-linux-gcc3.4.1

--cflags: ffmpeg third-party library header file declaration

--extra-ldflags: third-party library file path

3.

#make

4.

#make install

Copy the compiled library to the 2440 development board and configure the environment variables.

Compilation process error:

1：libavcodec/arm/dsputil_arm_s.S
libavcodec/arm/dsputil_arm_s.S: Assembler messages:
libavcodec/arm/dsputil_arm_s.S:25: Error: unknown pseudo-op: `.eabi_attribute'
libavcodec/arm/dsputil_arm_s.S:641: Error: bad instruction `push {r4-r10}'
libavcodec/arm/dsputil_arm_s.S:724: Error: bad instruction `pop {r4-r10}'
make: *** [libavcodec/arm/dsputil_arm_s.o] 错误 1

Solution: When making, some asm instructions cannot be found in
ffmpeg-0.5/libavcodec/arm/asm.S.
Line 24: .eabi_attribute 24, /val is changed to @.eabi_attribute 24, /val.
Line 28: .eabi_attribute 25, /val is changed to @.eabi_attribute 25, /val.

ffmpeg-0.5/libavcodec/arm/dsputil_arm_s.S
Line 641: push {r4-r10} is changed to stmfd sp!, {r4-r10} @ push {r4-r10}
Line 724: pop {r4-r10} is changed to ldmfd sp!, {r4-r10} @ pop {r4-r10}

2：/home/liao/ffmpeg-0.5/libavcodec/libavcodec.so: undefined reference to `dlerror'
/home/liao/ffmpeg-0.5/libavcodec/libavcodec.so: undefined reference to `dlclose'
/home/liao/ffmpeg-0.5/libavcodec/libavcodec.so: undefined reference to `dlopen'
/home/liao/ffmpeg-0.5/libavcodec/libavcodec.so: undefined reference to `dlsym'

Solution: The libdl library file is missing. Add the library file in the Makefile file.
Line 68: ffserver_g$(EXESUF): FF_LDFLAGS += $(FFSERVERLDFLAGS) followed by FF_LDFLAGS += -ldl

At this point, ffmpeg can be compiled successfully! !

Notice:

ffplay in ffmpeg requires SDL support. To compile ffplay, you need to follow the steps below:

Compile SDL and copy its include and lib files to the third-party library path (/usr/local/ffextra)

Modify line 2042 of the configure file before configuring:

SDL_CONFIG="${cross_prefix}sdl-config"改为SDL_CINFIG="/usr/local/sdl/bin/sdl-config"

ffmpeg decodes mp3 and wma audio formats into floating point types, which makes it difficult to run smoothly on arm.