NDK r15编译FFmpeg 4.0

下载地址

https://ffmpeg.org/releases/ffmpeg-4.0.tar.bz2

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编译前准备

由于编译出来的动态库文件名的版本号在.so之后（例如libavcodec.so.5.100.1），而android平台不能识别这样文件名，所以需要修改这种文件名。

将configure文件的以下内容

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)'

替换成

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

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创建编译脚本

新建文件build_android.sh，内容如下：

#!/bin/sh
NDK=/Users/username/Library/Android/sdk/ndk-bundle
SYSROOT=$NDK/platforms/android-26/arch-arm
TOOLCHAIN=$NDK/toolchains/arm-linux-androideabi-4.9/prebuilt/darwin-x86_64

function buile_one()
{
    ./configure \
    --prefix=$PREFIX \
    --enable-shared \
    --disable-static \
    --disable-doc \
    --disable-ffmpeg \
    --disable-ffplay \
    --disable-ffprobe \
    --disable-avdevice \
    --disable-symver \
    --cross-prefix=$TOOLCHAIN/bin/arm-linux-androideabi- \
    --target-os=linux \
    --arch=arm \
    --enable-cross-compile \
    --sysroot=$SYSROOT \
    --extra-cflags="-Os -fpic $ADDI_CFLAGS" \
    --extra-ldflags="$ADDI_LDFLAGS" \
    $ADDITIONAL_CONFIGURE_FLAG
    make clean
    make
    make install
}
CPU=arm
PREFIX=$(pwd)/android/$CPU
ADDI_CFLAGS="-marm"
buile_one

根据您的实际环境，修改脚本前三行的路径。

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编译

执行编译脚本./build_android.sh编译，编译完成后在./android目录下。

如有不明，请仔细阅读文末给出的参考blog。

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编译中可能会遇到的一些错误

错误一

libavcodec/aaccoder.c: In function 'search_for_ms':
libavcodec/aaccoder.c:803:25: error: expected identifier or '(' before numeric constant
                     int B0 = 0, B1 = 0;
                         ^
libavcodec/aaccoder.c:865:28: error: lvalue required as left operand of assignment
                         B0 += b1+b2;
                            ^
libavcodec/aaccoder.c:866:25: error: 'B1' undeclared (first use in this function)
                         B1 += b3+b4;
                         ^
libavcodec/aaccoder.c:866:25: note: each undeclared identifier is reported only once for each function it appears in
make: *** [libavcodec/aaccoder.o] Error 1

解决：将libavcodec/aaccoder.c文件B0变量替换成b0

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错误二

libavcodec/hevc_mvs.c: In function 'derive_spatial_merge_candidates':
libavcodec/hevc_mvs.c:208:15: error: 'y0000000' undeclared (first use in this function)
             ((y ## v) >> s->ps.sps->log2_min_pu_size))
               ^
libavcodec/hevc_mvs.c:204:14: note: in definition of macro 'TAB_MVF'
     tab_mvf[(y) * min_pu_width + x]
              ^
libavcodec/hevc_mvs.c:274:16: note: in expansion of macro 'TAB_MVF_PU'
     (cand && !(TAB_MVF_PU(v).pred_flag == PF_INTRA))
                ^
libavcodec/hevc_mvs.c:368:23: note: in expansion of macro 'AVAILABLE'
     is_available_b0 = AVAILABLE(cand_up_right, B0) &&
                       ^
libavcodec/hevc_mvs.c:208:15: note: each undeclared identifier is reported only once for each function it appears in
             ((y ## v) >> s->ps.sps->log2_min_pu_size))
               ^
libavcodec/hevc_mvs.c:204:14: note: in definition of macro 'TAB_MVF'
     tab_mvf[(y) * min_pu_width + x]
              ^
libavcodec/hevc_mvs.c:274:16: note: in expansion of macro 'TAB_MVF_PU'
     (cand && !(TAB_MVF_PU(v).pred_flag == PF_INTRA))
                ^
libavcodec/hevc_mvs.c:368:23: note: in expansion of macro 'AVAILABLE'
     is_available_b0 = AVAILABLE(cand_up_right, B0) &&
                       ^
libavcodec/hevc_mvs.c:207:15: error: 'x0000000' undeclared (first use in this function)
     TAB_MVF(((x ## v) >> s->ps.sps->log2_min_pu_size),                     \
               ^
libavcodec/hevc_mvs.c:204:34: note: in definition of macro 'TAB_MVF'
     tab_mvf[(y) * min_pu_width + x]
                                  ^
libavcodec/hevc_mvs.c:274:16: note: in expansion of macro 'TAB_MVF_PU'
     (cand && !(TAB_MVF_PU(v).pred_flag == PF_INTRA))
                ^
libavcodec/hevc_mvs.c:368:23: note: in expansion of macro 'AVAILABLE'
     is_available_b0 = AVAILABLE(cand_up_right, B0) &&
                       ^
libavcodec/hevc_mvs.c: In function 'ff_hevc_luma_mv_mvp_mode':
libavcodec/hevc_mvs.c:208:15: error: 'y0000000' undeclared (first use in this function)
             ((y ## v) >> s->ps.sps->log2_min_pu_size))
               ^
libavcodec/hevc_mvs.c:204:14: note: in definition of macro 'TAB_MVF'
     tab_mvf[(y) * min_pu_width + x]
              ^
libavcodec/hevc_mvs.c:274:16: note: in expansion of macro 'TAB_MVF_PU'
     (cand && !(TAB_MVF_PU(v).pred_flag == PF_INTRA))
                ^
libavcodec/hevc_mvs.c:683:24: note: in expansion of macro 'AVAILABLE'
     is_available_b0 =  AVAILABLE(cand_up_right, B0) &&
                        ^
libavcodec/hevc_mvs.c:207:15: error: 'x0000000' undeclared (first use in this function)
     TAB_MVF(((x ## v) >> s->ps.sps->log2_min_pu_size),                     \
               ^
libavcodec/hevc_mvs.c:204:34: note: in definition of macro 'TAB_MVF'
     tab_mvf[(y) * min_pu_width + x]
                                  ^
libavcodec/hevc_mvs.c:274:16: note: in expansion of macro 'TAB_MVF_PU'
     (cand && !(TAB_MVF_PU(v).pred_flag == PF_INTRA))
                ^
libavcodec/hevc_mvs.c:683:24: note: in expansion of macro 'AVAILABLE'
     is_available_b0 =  AVAILABLE(cand_up_right, B0) &&
                        ^
make: *** [libavcodec/hevc_mvs.o] Error 1

解决：将libavcodec/hevc_mvs.c文件的变量B0改成b0，xB0改成xb0，yB0改成yb0

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问题三

libavcodec/opus_pvq.c: In function 'quant_band_template':
libavcodec/opus_pvq.c:498:9: error: expected identifier or '(' before numeric constant
     int B0 = blocks;
         ^
libavcodec/opus_pvq.c:559:12: error: lvalue required as left operand of assignment
         B0 = blocks;
            ^
make: *** [libavcodec/opus_pvq.o] Error 1

解决：将libavcodec/opus_pvq.c文件的变量B0改成b0

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参考

• https://blog.csdn.net/leixiaohua1020/article/details/47008825/
• https://blog.csdn.net/hejjunlin/article/details/52661331
• http://alientechlab.com/how-to-build-ffmpeg-for-android/