Ubuntu环境编译FFmpeg3.2.2-for-android

前言

最近一直在弄FFmpeg如何在Android上集成开发使用。那么问题来了，作为一个Android应用程序员来说，想使用C算法库的某些算法就一脸懵逼了，因为我们只能调用别人编译好的xxx.so类库才能在应用层使用的如鱼得水。为此，本博客教大家如何编译FFmpeg，以实现得到在Android的调用所需的xx.so库文件（纯粹学习，大牛请慢走不送）。

准备环境

1、Ubuntu14.4的编译环境（可在windows下安装虚拟机VM）

2、android-ndk-r9d-linux-x86_64.tar.bz2

3、FFmpeg-3.2.2.tar.bz2

对于android-ndk-r9d-linux-x86_64.tar.bz2可在https://dl.google.com/android/ndk/android-ndk-r9d-linux-x86_64.tar.bz2自行下载

对于FFmpeg-3.2.2.tar.bz2可在http://ffmpeg.org/download.html#releases自行下载

步骤如下

1、首先把所需的安装包复制到ubuntu环境中并解压

ljw@ubuntu:~/ndk-lib/workspace/ffmpeg-demo$ ls
android-ndk-r9d-linux-x86_64.tar.bz2  ffmpeg-3.2.2.tar.bz2
ljw@ubuntu:~/ndk-lib/workspace/ffmpeg-demo$ pwd
/home/ljw/ndk-lib/workspace/ffmpeg-demo
ljw@ubuntu:~/ndk-lib/workspace/ffmpeg-demo$ tar jxvf android-ndk-r9d-linux-x86_64.tar.bz2
#......编译信息省略
ljw@ubuntu:~/ndk-lib/workspace/ffmpeg-demo$ tar jxvf ffmpeg-3.2.2.tar.bz2
#......省略
#结果如下
ljw@ubuntu:~/ndk-lib/workspace/ffmpeg-demo$ ls
android-ndk-r9d                       ffmpeg-3.2.2
android-ndk-r9d-linux-x86_64.tar.bz2  ffmpeg-3.2.2.tar.bz2
ljw@ubuntu:~/ndk-lib/workspace/ffmpeg-demo$

2、对文件重命名

将android-ndk-r9d重命名为ndk-r9d、ffmpeg-3.2.2重命名为ffmpeg（纯粹是为了方便编译！-_-||强迫症）

ljw@ubuntu:~/ndk-lib/workspace/ffmpeg-demo$ mv android-ndk-r9d ndk-r9d
ljw@ubuntu:~/ndk-lib/workspace/ffmpeg-demo$ mv ffmpeg-3.2.2 ffmpeg
ljw@ubuntu:~/ndk-lib/workspace/ffmpeg-demo$ ls
android-ndk-r9d-linux-x86_64.tar.bz2  ffmpeg  ffmpeg-3.2.2.tar.bz2  ndk-r9d

3、为了得到android所需xx.so类库，需要对ffmpeg目录下的configure进行一点改动

SLIBNAME_WITH_MAJOR='$(SLIBNAME).$(LIBMAJOR)'
LIB_INSTALL_EXTRA_CMD='$$(RANLIB) "$(LIBDIR)/$(LIBNAME)"'
SLIB_INSTALL_NAME='$(SLIBNAME_WITH_VERSION)'
SLIB_INSTALL_LINKS='$(SLIBNAME_WITH_MAJOR) $(SLIBNAME)'

将上述代码改为如下所示

SLIBNAME_WITH_MAJOR='$(SLIBPREF)$(FULLNAME)-$(LIBMAJOR)$(SLIBSUF)'
LIB_INSTALL_EXTRA_CMD='$$(RANLIB)"$(LIBDIR)/$(LIBNAME)"'
SLIB_INSTALL_NAME='$(SLIBNAME_WITH_MAJOR)'
SLIB_INSTALL_LINKS='$(SLIBNAME)'

4、在ffmpeg目录下执行./configure命令

如出现以下问题，则执行./configure –disable-yasm命令

yasm/nasm not found or too old. Use --disable-yasm for a crippled build.

If you think configure made a mistake, make sure you are using the latest
version from Git.  If the latest version fails, report the problem to the
ffmpeg-user@ffmpeg.org mailing list or IRC #ffmpeg on irc.freenode.net.
Include the log file "config.log" produced by configure as this will help
solve the problem.

5、在ffmpeg的同级目录建立simplefflib文件夹

6、在ffmpeg的统计目录建立build-ffmpeg-arm.sh脚步文件

#!/bin/bash

cd /home/ljw/ndk-lib/workspace/ffmpeg-demo/ffmpeg

make clean

export NDK=/home/ljw/ndk-lib/workspace/ffmpeg-demo/ndk-r9d
export PREBUILT=$NDK/toolchains/arm-linux-androideabi-4.8/prebuilt
export PLATFORM=$NDK/platforms/android-8/arch-arm
export PREFIX=/home/ljw/ndk-lib/workspace/ffmpeg-demo/simplefflib
build_one(){
./configure --target-os=linux --prefix=$PREFIX \
--enable-cross-compile \
--enable-runtime-cpudetect \
--disable-asm \
--arch=arm \
--cc=$PREBUILT/linux-x86_64/bin/arm-linux-androideabi-gcc \
--cross-prefix=$PREBUILT/linux-x86_64/bin/arm-linux-androideabi- \
--disable-stripping \
--nm=$PREBUILT/linux-x86_64/bin/arm-linux-androideabi-nm \
--sysroot=$PLATFORM \
--enable-gpl --enable-shared --disable-static --enable-small \
--disable-ffprobe --disable-ffplay --disable-ffmpeg --disable-ffserver --disable-debug \
--extra-cflags="-fPIC -DANDROID -D__thumb__ -mthumb -Wfatal-errors -Wno-deprecated -mfloat-abi=softfp -marm -march=armv7-a"
}

build_one

make
make install

cd ..

7、读者可修改相应的信息：NDK、PREBUILT、PLATFORM、PREFIX。这几处信息。

勿忘记为脚步文件添加权限：chmod 777 build-ffmpeg-arm.sh

8、执行脚步文件：./build-ffmpeg.arm.sh

9、编译成功之后，会在simplefflib中生成相应的include、lib文件（这就是我们想要的）。

10、在Android中集成

鉴于公司加密策略，以至于无法上传截图，只能手写，见谅

1、在Android工程中新建jni目录

2、在jni中新建FFmpeg-arm文件夹、Android.mk、Application.mk、xx.c（随便命名一个.c文件）

3、在FFmpeg-arm文件夹中放入上面的include文件夹

4、在FFmpeg-arm文件夹中一次放入libavcodec-57.so、libavdevice-57.so、libavfilter-6.so、libavformat-57.so、libavutil-55.so、libpostproc-54.so、libswresample-2.so、libswscale-4.so

5、在Android.mk中写入

# Copyright (C) 2009 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0 #
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
LOCAL_PATH := $(call my-dir)

# FFmpeg library
include $(CLEAR_VARS)
LOCAL_MODULE := avcodec
LOCAL_SRC_FILES := FFmpeg-arm/libavcodec-57.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE := avdevice
LOCAL_SRC_FILES := FFmpeg-arm/libavdevice-57.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE := avfilter
LOCAL_SRC_FILES := FFmpeg-arm/libavfilter-6.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE := avformat
LOCAL_SRC_FILES := FFmpeg-arm/libavformat-57.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE := avutil
LOCAL_SRC_FILES := FFmpeg-arm/libavutil-55.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE := postproc
LOCAL_SRC_FILES := FFmpeg-arm/libpostproc-54.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE := swresample
LOCAL_SRC_FILES := FFmpeg-arm/libswresample-2.so
include $(PREBUILT_SHARED_LIBRARY)

include $(CLEAR_VARS)
LOCAL_MODULE := swscale
LOCAL_SRC_FILES := FFmpeg-arm/libswscale-4.so
include $(PREBUILT_SHARED_LIBRARY)

# Program
include $(CLEAR_VARS)

LOCAL_MODULE    := xx
LOCAL_SRC_FILES := xx.c
LOCAL_LDLIBS += -llog
LOCAL_C_INCLUDES += $(LOCAL_PATH)/FFmpeg-arm/include
LOCAL_SHARED_LIBRARIES := avcodec avdevice avfilter avformat avutil postproc swresample swscale

include $(BUILD_SHARED_LIBRARY)

6、在Application.mk中写入

若要适配x86，则需要改写相应的脚步文件

APP_ABI := armeabi

结尾

到此为止，我们已经得到了可在Android调用的FFmpeg的库文件了，我在研究编译的时候花费了几天的时间，分析了很多博客的操作方法，为此总结了一下，希望能帮助到一群和我一样的菜鸟，本文的分析流程借鉴了雷大神的博客http://blog.csdn.net/leixiaohua1020/article/details/47008825/并将其中的小部分流程（主要是编译步骤）细化。学习之路，你我共勉！