一、编译

1.1 Reference

官网：https://ffmpeg.org/
Guide: https://trac.ffmpeg.org/wiki

1.2 FFmpeg Source Code Structure

• libavutil: 一些简化编程的函数的库，包括 随机数的生成、数据结构、数学公式，以及多媒体核心组件
• libavcodec: audio/video codecs 的编解码库
• libavformat: 各种多媒体容器格式的 demuxers & muxers 的库
• libavdevice: 媒体输入输出设备与各种常见媒体软件框架之间的交互的库
• libavfilter: 音频、视频、字幕的滤镜处理框架库
• libswscale: 执行高优化的图像缩放、色域或像素格式转换 等功能的库
• libswresample: 执行高优化的音频 重采样、重矩阵、和采样格式转换 等功能的库
• libavcodec provides implementation of a wider range of codecs.
• libavformat implements streaming protocols, container formats and basic I/O access.
• libavutil includes hashers, decompressors and miscellaneous utility functions.
• libavfilter provides a mean to alter decoded Audio and Video through chain of filters.
• libavdevice provides an abstraction to access capture and playback devices.
• libswresample implements audio mixing and resampling routines.
• libswscale implements color conversion and scaling routines.

1.3 Pre-install FFmpeg

• 创建一个用于学习 FFmpeg 的目录, say $HOME/learning

cd $HOME/learning
# ffmpeg_sources 放置所有下载的源码
mkdir ffmpeg_sources 
# ffmpeg_build 用于生成文件和libraries
mkdir ffmpeg_build 
# bin 放置所有生成的二进制文件，包括 ffmpeg, ffprobe, x264, x265
mkdir bin

• 安装基础依赖

sudo yum -y install autoconf automake bzip2 bzip2-devel cmake freetype-devel gcc gcc-c++ git libtool make mercurial pkgconfig zlib-devel

• NASM
  组装器，加速构建

cd ffmpeg_sources
curl -O -L https://www.nasm.us/pub/nasm/releasebuilds/2.15.05/nasm-2.15.05.tar.bz2
tar xjvf nasm-2.15.05.tar.bz2
cd nasm-2.15.05
sudo sh autogen.sh
./configure --prefix="$HOME/learning/ffmpeg_build" --bindir="$HOME/learning/bin"
make -j4
sudo make install

• YASM
  用于支持 FFmpeg 中的汇编优化

cd ffmpeg_sources
curl -O -L https://www.tortall.net/projects/yasm/releases/yasm-1.3.0.tar.gz
tar xzvf yasm-1.3.0.tar.gz
cd yasm-1.3.0
./configure --prefix="$HOME/learning/ffmpeg_build" --bindir="$HOME/learning/bin"
make -j4
sudo make install

• glib（坑多，建议跳过直接安装 pkgconfig）
  用于编译 pkgconfig，安装过程比较曲折，建议编译 pkgconfig 可以使用内置 glib ，就可以跳过这一步

cd ffmpeg_sources
curl -O -L http://ftp.gnome.org/pub/GNOME/sources/glib/2.54/glib-2.54.3.tar.xz
xz -d glib-2.54.3.tar.xz
tar -xvf glib-2.54.3.tar
cd glib-2.54.3
./configure --enable-libmount=no
sudo make -j4
sudo make install

注：./configure 过程中遇到的问题，参考 https://blog.csdn.net/windeal3203/article/details/76608248
若遇到 “No package 'libffi' found”

sudo yum -y install libffi-devel

若遇到 “No package 'libpcre' found”

curl -O -L https://sourceforge.net/projects/pcre/files/pcre/8.41/pcre-8.41.zip
unzip pcre-8.41.zip
cd pcre-8.41
./configure --enable-utf8 --enable-unicode-properties
sudo make -j4
sudo make install

若遇到“error: *** Could not find libmount”

sudo yum -y install libmount-devel.x86_64
# 如果安装成功了还是提示无法找到 libmount，configure glib 的时候增加 --enable-libmount=no 选项，影响未知

• pkgconfig
  用于检测可以编进 FFmpeg 的 libraries

cd ffmpeg_sources
curl -O -L https://pkg-config.freedesktop.org/releases/pkg-config-0.29.2.tar.gz
tar xzvf pkg-config-0.29.2.tar.gz
cd pkg-config-0.29.2
./configure --with-internal-glib
sudo make -j4
sudo make install

若遇到“error: Either a previously installed pkg-config or "glib-2.0 >= 2.16" could not be found”，./configure 增加 --with-internal-glib 选项，使用用内置 glib

• libx264
  视频 H264 编码器，要求 ffmpeg 编译的 configure 选项有 --enable-gpl --enable-libx264

cd ffmpeg_sources
git clone --depth 1 https://code.videolan.org/videolan/x264.git
cd x264
PKG_CONFIG_PATH="$HOME/learning/ffmpeg_build/lib/pkgconfig" ./configure --prefix="$HOME/learning/ffmpeg_build" --bindir="$HOME/learning/bin" --enable-static
make -j4
sudo make install

• libx265
  视频 H265 编码器，要求 ffmpeg 编译的 configure 选项有 --enable-gpl --enable-libx265

cd ffmpeg_sources
git clone https://bitbucket.org/multicoreware/x265_git --depth 1
cd ./x265_git/build/linux
sudo cmake -G "Unix Makefiles" -DCMAKE_INSTALL_PREFIX="$HOME/learning/ffmpeg_build" -DENABLE_SHARED:bool=off ../../source
make -j4
sudo make install

• libfdk_aac
  AAC 音频编码器，要求 ffmpeg 编译的 configure 选项有 --enable-libfdk_aac 和 --enable-nonfree

cd ffmpeg_sources
git clone --depth 1 https://github.com/mstorsjo/fdk-aac
cd fdk-aac
# git 拉代码特别慢的情况下，可以直接下载 sourceforge 的打包版本
# wget https://downloads.sourceforge.net/opencore-amr/fdk-aac-2.0.1.tar.gz
# tar xzvf fdk-aac-2.0.1.tar.gz
# cd fdk-aac-2.0.1
autoreconf -fiv
./configure --prefix="$HOME/learning/ffmpeg_build" --disable-shared
make -j4
sudo make install

• libopus
  OPUS 音频编码器，要求 ffmpeg 编译的 configure 选项有 --enable-libopus

cd ffmpeg_sources
curl -O -L https://archive.mozilla.org/pub/opus/opus-1.3.1.tar.gz
tar xzvf opus-1.3.1.tar.gz
cd opus-1.3.1
./configure --prefix="$HOME/learning/ffmpeg_build" --disable-shared
make -j4
sudo make install

1.4 Compile FFmpeg with x264, x265, aac and opus

cd ffmpeg_sources
curl -O -L https://ffmpeg.org/releases/ffmpeg-snapshot.tar.bz2
tar xjvf ffmpeg-snapshot.tar.bz2
cd ffmpeg
PATH="$HOME/learning/bin:$PATH" PKG_CONFIG_PATH="$HOME/learning/ffmpeg_build/lib/pkgconfig" ./configure \
  --prefix="$HOME/learning/ffmpeg_build" \
  --pkg-config-flags="--static" \
  --extra-cflags="-I$HOME/learning/ffmpeg_build/include" \
  --extra-ldflags="-L$HOME/learning/ffmpeg_build/lib" \
  --extra-libs=-lpthread \
  --extra-libs=-lm \
  --bindir="$HOME/learning/bin" \
  --enable-gpl \
  --enable-libfdk_aac \
  --enable-libopus \
  --enable-libx264 \
  --enable-libx265 \
  --enable-nonfree
make -j4
sudo make install
hash -d ffmpeg

若 ./configure 遇到：ERROR: x265 not found using pkg-config，查看 ffbuild/config.log 发现是"Perhaps you should add the directory containing `x265.pc'"问题时，在 $HOME/learning/bin/ffmpeg_build/lib/pkgconfig 路径下自己写一个 x265.pc，内容如下:

prefix=$HOME/learning/ffmpeg_build
exec_prefix=${prefix}
libdir=${exec_prefix}/lib
includedir=${prefix}/include

Name: x265
Description: H.265/HEVC encoder library
Version: 3.5
Libs: -L${libdir} -lx265
Libs.private: -lstdc++ -lm -ldl -lpthread
Cflags: -I${includedir}

再执行 ./configure 即可。
至此，支持视频 264&265 音频 opus&aac 编解码的 ffmpeg & ffprobe 就编译完成了，可以在 $HOME/learning/bin 里找到。