FFMPEG使用错误整理

编译脚本

NDK编译工具链 r17c

脚本来源

#NDK目录 r17c是最后一个支持gcc的ndk
export NDK_HOME=/Users/loki/Desktop/tools/ndk/android-ndk-r17c
#生成交叉编译链工具
toolchain=${NDK_HOME}/build/tools/make-standalone-toolchain.sh
#生成交叉编译链保存在当前目录子文件夹android-toolchain
install_root=`pwd`/android-toolchain

#生成32位库最低支持到android4.3，64位库最低支持到android5.0 最新版的ffmpeg，x264需要最低 android-23 就是 android 6.0 因为cabs()等函数。
platforms=(
  "android-23"
  "android-23"
  "android-23"
  "android-23"
  "android-23"
)
#支持以下5种cpu框架
archs=(
  "arm"
  "arm"
  "arm64"
  "x86"
  "x86_64"
)
#cpu型号
abis=(
  "armeabi"
  "armeabi-v7a"
  "arm64-v8a"
  "x86"
  "x86_64"
)
echo $NDK_HOME
echo "安装在目录:$install_root"

num=${#abis[@]}

for ((i=0; i<num; i++))
do
   bash $toolchain --arch=${archs[i]} --platform=${platforms[i]} --abis=${abis[i]} --install-dir=$install_root/${abis[i]}
done

x264编译脚本

#!/bin/bash
NDK=/Users/loki/Desktop/tools/ndk/android-ndk-r17c
TOOL_ROOT=$NDK/android-toolchain

#五种类型cpu编译链
android_toolchains=(
   "armeabi"
   "armeabi-v7a"
   "arm64-v8a"
   "x86"
   "x86_64"
)

#优化编译项
extra_cflags=(
   "-march=armv5te -msoft-float -D__ANDROID__ -D__ARM_ARCH_5TE__ -D__ARM_ARCH_5TEJ__"
   "-march=armv7-a -mfloat-abi=softfp -mfpu=neon -mthumb -D__ANDROID__ -D__ARM_ARCH_7__ -D__ARM_ARCH_7A__ -D__ARM_ARCH_7R__ -D__ARM_ARCH_7M__ -D__ARM_ARCH_7S__"
   "-march=armv8-a -D__ANDROID__ -D__ARM_ARCH_8__ -D__ARM_ARCH_8A__"
   "-march=i686 -mtune=i686 -m32 -mmmx -msse2 -msse3 -mssse3 -D__ANDROID__ -D__i686__"
   "-march=core-avx-i -mtune=core-avx-i -m64 -mmmx -msse2 -msse3 -mssse3 -msse4.1 -msse4.2 -mpopcnt -D__ANDROID__ -D__x86_64__"
)

extra_ldflags="-nostdlib"
configure="--disable-cli \
           --enable-static \
           --enable-shared \
           --disable-opencl \
           --enable-strip \
           --disable-cli \
           --disable-win32thread \
           --disable-avs \
           --disable-swscale \
           --disable-lavf \
           --disable-ffms \
           --disable-gpac \
           --disable-lsmash"

#针对各版本不同的编译项
extra_configure=(
   "--disable-asm"
   ""
   ""
   "--disable-asm"
   "--disable-asm"
)

#交叉编译后的运行环境
hosts=(
  "arm-linux-androideabi"
  "arm-linux-androideabi"
  "aarch64-linux-android"
  "i686-linux-android"
  "x86_64-linux-android"
)

#交叉编译工具前缀
cross_prefix=(
  "arm-linux-androideabi-"
  "arm-linux-androideabi-"
  "aarch64-linux-android-"
  "i686-linux-android-"
  "x86_64-linux-android-"
)
PREFIX=$(pwd)/libs/

function build_x264
{
	index=$1
	export PATH=$TOOL_ROOT/${android_toolchains[index]}/bin:$PATH
	echo "开始配置${android_toolchains[index]}版本"
	#交叉编译最重要的是配置--host、--cross-prefix、sysroot、以及extra-cflags和extra-ldflags
	./configure ${configure} \
	           ${extra_configure[index]} \
	           --prefix=$PREFIX/${android_toolchains[index]} \
	           --host=${hosts[index]} \
	           --cross-prefix=${cross_prefix[index]} \
	           --sysroot=$TOOL_ROOT/${android_toolchains[index]}/sysroot \
	           --extra-cflags="${extra_cflags[index]}" \
	           --extra-ldflags="$extra_ldflags"
	make clean
	echo "开始编译并安装${android_toolchains[i]}版本"
	make -j4 & make install
}

for (( i = 0; i < 5; i++ )); do
	build_x264 i
done

ffmpeg编译脚本

#!/bin/bash
NDK=/Users/loki/Desktop/tools/ndk/android-ndk-r17c
TOOL_ROOT=$NDK/android-toolchain

#五种类型cpu编译链
android_toolchains=(
   "armeabi"
   "armeabi-v7a"
   "arm64-v8a"
   "x86"
   "x86_64"
)
#优化编译项
extra_cflags=(
   "-std=gnu11 -march=armv5te -msoft-float -D__ANDROID__ -D__ARM_ARCH_5TE__ -D__ARM_ARCH_5TEJ__"
   "-std=gnu11 -march=armv7-a -mfloat-abi=softfp -mfpu=neon -mthumb -D__ANDROID__ -D__ARM_ARCH_7__ -D__ARM_ARCH_7A__ -D__ARM_ARCH_7R__ -D__ARM_ARCH_7M__ -D__ARM_ARCH_7S__"
   "-std=gnu11 -march=armv8-a -D__ANDROID__ -D__ARM_ARCH_8__ -D__ARM_ARCH_8A__"
   "-std=gnu11 -march=i686 -mtune=i686 -m32 -mmmx -msse2 -msse3 -mssse3 -D__ANDROID__ -D__i686__"
   "-std=gnu11 -march=core-avx-i -mtune=core-avx-i -m64 -mmmx -msse2 -msse3 -mssse3 -msse4.1 -msse4.2 -mpopcnt -D__ANDROID__ -D__x86_64__"
)

#共同配置项,可以额外增加相关配置，详情可查看源文件目录下configure
#--disable-indev=v4l2  #解决libavdevice/v4l2.c:135:9: error: assigning to 'int (*)(int, unsigned long, ...)'
configure="--enable-gpl \
			--enable-version3 \
			--enable-nonfree \
			--enable-static \
			--disable-shared \
			--enable-small \
			--disable-programs \
			--disable-ffmpeg \
			--disable-doc \
			--disable-htmlpages \
			--disable-manpages \
			--disable-podpages \
			--disable-txtpages \
			--disable-hwaccels \
			--disable-filters \
			--disable-muxers \
			--disable-avdevice \
			--disable-indevs \
			--disable-outdevs \
			--disable-debug \
			--disable-postproc \
			--enable-avdevice \
			--disable-symver \
			--disable-stripping \
			--disable-encoders --enable-encoder=libx264 \
			--disable-decoders --enable-decoder=h264 \
			--disable-demuxers --enable-demuxer=h264 \
			--enable-libx264"
#针对各版本不同的编译项
extra_configure=(
   "--disable-asm"
   ""
   ""
   "--disable-asm"
   "--disable-asm"
)
#交叉编译工具前缀
cross_prefix=(
  "arm-linux-androideabi"
  "arm-linux-androideabi"
  "aarch64-linux-android"
  "i686-linux-android"
  "x86_64-linux-android"
)

#支持以下5种cpu框架
archs=(
  "arm"
  "arm"
  "arm64"
  "x86"
  "x86_64"
)

PREFIX=./libs/

function build_one
{
	i=$1
	export PATH=$TOOL_ROOT/${android_toolchains[i]}/bin:$PATH
	export PATH=$TOOL_ROOT/${android_toolchains[i]}/${cross_prefix[i]}/bin:$PATH
	echo "开始配置${android_toolchains[i]}版本"
	extra_include="./x264/libs/${android_toolchains[i]}/include"
   	extra_lib="./x264/libs/${android_toolchains[i]}/lib"
   	SYSROOT=$TOOL_ROOT/${android_toolchains[i]}/sysroot
   	GCC=$TOOL_ROOT/${android_toolchains[i]}/lib/gcc/${cross_prefix[i]}/4.9.x/libgcc.a

   	./configure ${configure} \
               ${extra_configure[i]} \
               --prefix=$PREFIX/${android_toolchains[i]} \
               --enable-cross-compile \
               --target-os=android \
               --arch=${archs[i]} \
               --cross-prefix=${cross_prefix[i]}- \
               --sysroot=$SYSROOT \
               --extra-cflags="${extra_cflags[i]} -I$extra_include" \
               --extra-ldflags="-L$extra_lib"
	make clean
	echo "开始编译并安装${android_toolchains[i]}版本"
	make -j4 
	make install
    
# 链接动态库： 将多个库打包为一个动态库
ld \
-rpath-link=$SYSROOT/usr/lib \
-L$SYSROOT/usr/lib \
-L$PREFIX/${android_toolchains[i]}/lib \
-L$extra_lib \
-soname libffmpeg.so -shared -nostdlib -Bsymbolic --whole-archive --no-undefined -o \
$PREFIX/${android_toolchains[i]}/libffmpeg.so \
libavcodec/libavcodec.a \
libavfilter/libavfilter.a \
libswresample/libswresample.a \
libavformat/libavformat.a \
libavutil/libavutil.a \
libswscale/libswscale.a \
$extra_lib/libx264.a \
-lc -lm -lz -ldl -llog --dynamic-linker=/system/bin/linker \
$GCC
}
build_one 1
build_one 2

遇到的问题

ffmpeg avformat_alloc_output_context2: flv -22 - Invalid argument

编译ffmpeg时未加入flv封装格式，--enable-muxer=flv

toolchains/llvm/prebuilt/darwin-x86_64/bin/armv7a-linux-androideabi19-clang is unable to create an executable file.

avformat_write_header -22 - Invalid argument

写入头之前需要使用avformat_new_stream创建好对应的Stream

avformat_alloc_output_context2 -22 - Invalid argument

avformat_alloc_output_context2方法参数需指定转码格式

如果是将RTMP stream转为flv文件,需将最后一个参数写为明确的.flv格式文件地址，

avformat_alloc_output_context2(&outFormatContext,
                                         NULL,
                                         NULL,
                                         "/sdcard/a3.flv"); //RTMP

如果是将RTMP串流逐帧处理，需将第三个参数写为flv

avformat_alloc_output_context2(&outFormatContext,
                                         NULL,
                                         "flv",
                                         NULL); //RTMP