Android NDK & FFMPEG build

2019-03-09 18:39发布

问题:

I'm trying to build FFMPEG library for my android application using the NDK. I have downloaded the source code from it's website and I think I build it (it's my first try working with NDK and ffmpeg). I have created a build.sh file which I'm using to execute it from command line on Mac OS X. But I have a few questions...

First things is as I know I need Android.mk file so I can use the builded library in my application,but I don't know how to do that for reasons which I told you above. After I run my build.sh I get android folder with a few folders and some libraries. So my first question is, how can I build the Android.mk file which I need...and maybe if someone can explain me why I need it.

My second question is I need some libraries from ffmpeg to be able to use them from my app, but after the build i can't see them in my source tree. I know that I have to enable them in my build.sh and I think I did,but I can't see them. So any kind of information about my build file will be helpful for me to understand how to configure it. Here is how it looks like :

    #!/bin/bash
######################################################
# Usage:
# put this script in top of FFmpeg source tree
# ./build_android
# It generates binary for following architectures:
# ARMv6 
# ARMv6+VFP 
# ARMv7+VFPv3-d16 (Tegra2) 
# ARMv7+Neon (Cortex-A8)
# Customizing:
# 1. Feel free to change ./configure parameters for more features
# 2. To adapt other ARM variants
# set $CPU and $OPTIMIZE_CFLAGS 
# call build_one
######################################################
NDK=~/Desktop/android-ndk-r5b
PLATFORM=$NDK/platforms/android-8/arch-arm/
PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.4.3/prebuilt/darwin-x86
function build_one
{
./configure \
    --target-os=darwin \
    --prefix=$PREFIX \
    --enable-cross-compile \
    --extra-libs="-lgcc" \
    --arch=arm \
    --cc=$PREBUILT/bin/arm-linux-androideabi-gcc \
    --cross-prefix=$PREBUILT/bin/arm-linux-androideabi- \
    --nm=$PREBUILT/bin/arm-linux-androideabi-nm \
    --sysroot=$PLATFORM \
    --extra-cflags=" -O3 -fpic -DANDROID -DHAVE_SYS_UIO_H=1 -Dipv6mr_interface=ipv6mr_ifindex -fasm -Wno-psabi -fno-short-enums -fno-strict-aliasing -finline-limit=300 $OPTIMIZE_CFLAGS " \
    --disable-doc \
    --disable-ffmpeg \
    --disable-ffplay \
    --disable-ffserver \
    --disable-ffprobe \
    --extra-ldflags="-Wl,-rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib -nostdlib -lc -lm -ldl -llog" \
    --enable-zlib \
    --enable-version3 \
    --enable-nonfree \
    --enable-libmp3lame \
    --enable-libspeex \
    --enable-libtheora \
    --enable-libfaac \
    --enable-libvorbis \
    --enable-libaacplus \
    --prefix=$DIST_DIR \
    $ADDITIONAL_CONFIGURE_FLAG

make clean
make  -j4 install
$PREBUILT/bin/arm-linux-androideabi-ar d libavcodec/libavcodec.a inverse.o
$PREBUILT/bin/arm-linux-androideabi-ld -rpath-link=$PLATFORM/usr/lib -L$PLATFORM/usr/lib  -soname libffmpeg.so -shared -nostdlib  -z,noexecstack -Bsymbolic --whole-archive --no-undefined -o $PREFIX/libffmpeg.so libavcodec/libavcodec.a libavformat/libavformat.a libavutil/libavutil.a libswscale/libswscale.a -lc -lm -lz -ldl -llog  --warn-once  --dynamic-linker=/system/bin/linker $PREBUILT/lib/gcc/arm-linux-androideabi/4.4.3/libgcc.a
}

#arm v6
#CPU=armv6
#OPTIMIZE_CFLAGS="-marm -march=$CPU"
#PREFIX=./android/$CPU 
#ADDITIONAL_CONFIGURE_FLAG=
#build_one

#arm v7vfpv3
CPU=armv7-a
OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=vfpv3-d16 -marm -march=$CPU "
PREFIX=./android/$CPU
ADDITIONAL_CONFIGURE_FLAG=
build_one

#arm v7vfp
#CPU=armv7-a
#OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=vfp -marm -march=$CPU "
#PREFIX=./android/$CPU-vfp
#ADDITIONAL_CONFIGURE_FLAG=
#build_one

#arm v7n
#CPU=armv7-a
#OPTIMIZE_CFLAGS="-mfloat-abi=softfp -mfpu=neon -marm -march=$CPU -mtune=cortex-a8"
#PREFIX=./android/$CPU 
#ADDITIONAL_CONFIGURE_FLAG=--enable-neon
#build_one

#arm v6+vfp
#CPU=armv6
#OPTIMIZE_CFLAGS="-DCMP_HAVE_VFP -mfloat-abi=softfp -mfpu=vfp -marm -march=$CPU"
#PREFIX=./android/${CPU}_vfp 
#ADDITIONAL_CONFIGURE_FLAG=
#build_one

Thanks for any kind of useful information/suggestions/examples and etc.

回答1:

I made a tutorial on how to build ffmpeg and x264 for android: zip with build of ffmpeg with x264

You can also download the zip file containing the files you need to make an application on android.



回答2:

If you want more detailed instruction of how to build ffmpeg and how to use it to build Android apps, please refer to the book Android NDK cookbook: http://www.packtpub.com/android-native-development-kit-cookbook/book

The Bonus Chapter 1 is dedicated to multimedia app development with Android NDK and ffmpeg, and it is available for free at http://www.packtpub.com/sites/default/files/downloads/Developing_Multimedia_Applications_with_NDK.pdf



回答3:

First of all, you should read the documentation for Android NDK and check out some sample apps. You'll find these details in android_NDK_home/docs and android_NDK_home/samples (where android_NDK_home is the folder name for your android NDK).

Also, check this link on stackoverflow: Using FFmpeg with Android-NDK

For a stept by step tutorial, this is a pretty good one: http://www.roman10.net/how-to-build-ffmpeg-for-android/

Also, you'll have to install/configure some elements on your Eclipse to enable support for developing applications that are built with the NDK: http://mhandroid.wordpress.com/2011/01/23/using-eclipse-for-android-cc-development/ http://wiki.eclipse.org/Sequoyah/ndk_checklist

And a pretty good project that uses the ffmpeg library: https://github.com/havlenapetr/FFMpeg